Professor Russell Gwilliam

Professor

Email:
Phone: Work: 01483 68 9845
Room no: 16 NC 00

Further information

Publications

Highlights

  • Smith AJ, Gwilliam RM, Stolojan V, Knights AP, Coleman PG, Kallis A, Yeong SH. (2009) 'Enhancement of phosphorus activation in vacancy engineered thin silicon-on-insulator substrates'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 106 (10) Article number ARTN 103514
  • Slotte J, Rummukainen M, Tuomisto F, Markevich VP, Peaker AR, Jeynes C, Gwilliam RM. (2008) 'Evolution of vacancy-related defects upon annealing of ion-implanted germanium'. AMER PHYSICAL SOC PHYSICAL REVIEW B, 78 (8) Article number ARTN 085202
  • Lourenco MA, Gwilliam RM, Homewood KP. (2007) 'Extraordinary optical gain from silicon implanted with erbium'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 91 (14) Article number ARTN 141122

Journal articles

  • Marqués LA, Aboy M, Dudeck KJ, Botton GA, Knights AP, Gwilliam RM. (2014) 'Modeling and experimental characterization of stepped and v-shaped {311} defects in silicon'. Journal of Applied Physics, 115 (14)

    Abstract

    We propose an atomistic model to describe extended {311} defects in silicon. It is based on the combination of interstitial and bond defect chains. The model is able to accurately reproduce not only planar {311} defects but also defect structures that show steps, bends, or both. We use molecular dynamics techniques to show that these interstitial and bond defect chains spontaneously transform into extended {311} defects. Simulations are validated by comparing with precise experimental measurements on actual {311} defects. The excellent agreement between the simulated and experimentally derived structures, regarding individual atomic positions and shape of the distinct structural {311} defect units, provides strong evidence for the robustness of the proposed model. © 2014 AIP Publishing LLC.

  • Ishii M, Crowe IF, Halsall MP, Hamilton B, Knights AP, Gwilliam RM. (2014) 'Electrical observation of non-radiative recombination in Er doped Si nano-crystals during thermal quenching of intra-4f luminescence'. Japanese Journal of Applied Physics, 53 (3)

    Abstract

    Thermal quenching of luminescence of Er dopants in Si nano-crystals (Si-nc's) was investigated employing an impedance model for the analysis of photo-injected charges. Relaxation response indicated that Er doping forms not only optical centers but also trapping centers near the Si-nc's. The response time constant of trapped charges was dependent on temperature, with the dependence correlating to thermal quenching. These findings indicate that quenching occurs by trapping followed by consumption of charges. The complex analyses revealed that the response represents nonradiative recombination at the centers rather than release of confined charges from the Si-nc through the centers. We propose a possible energy diagram for the non-radiative recombination. © 2014 The Japan Society of Applied Physics.

  • Razali MA, Gwilliam RM, Secchi M, Bersani M. (2014) 'Point defect engineering study of phosphorus ion implanted germanium'. Physica Status Solidi (C) Current Topics in Solid State Physics, 11 (1), pp. 9-11.

    Abstract

    We present experimental results on shallow junction formation in germanium by phosphorus ion implantation and standard rapid thermal processing. An attempt is made to improve phosphorus electrical activation using point defect engineering method by introducing an excess of point defects in germanium prior to the phosphorus implantation. The focus is on studying the phosphorus activation and diffusion as a function of germanium co-implant energy. Hall Effect and Secondary Ion Mass Spectrometry (SIMS) measurements are employed for characterisation of phosphorus activation and diffusion, respectively. Phosphorus activation was improved at higher annealing temperature for the implants with germanium co-implant. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • Finch P, O'Driscoll I, Blood P, Smowton PM, Sobiesierski A, Gwilliam RM. (2014) 'Femtosecond pulse generation from a two-section mode-locked quantum-dot laser using random population'. Proceedings of SPIE - The International Society for Optical Engineering, 9002

    Abstract

    290 fs optical pulses have been demonstrated using a two-section, passively mode-locked InAs quantum dot laser with a proton bombarded absorber, at a repetition rate of 20 GHz, centred around 1220 nm. Optical pulsewidth measurements between 300 K and 20 K, reveal that the pulsewidth decreases by a factor of 29, from 8.4 ps at 250 K to 290 fs at 20 K with a corresponding change in optical bandwidth. Rate equation analysis shows that this is due to the decreased emission rate compared to the recombination rate at 20 K in the random population regime. Random population ensures the dots act as independent oscillators across the entire inhomogeneous distribution thereby allowing access to the full gain spectrum. Proton bombardment of the absorber section shortens the recovery time of the absorber while the dots remain randomly populated..

  • Fedorenko YG, Hughes MA, Colaux JL, Jeynes C, Gwilliam RM, Homewood KP, Curry RJ, Yao J, Hewak DW, Lee T-H, Elliott SR, Gholipour B. (2014) 'Electrical properties of amorphous chalcogenide/silicon heterojunctions modified by ion implantation'. Proceedings of SPIE - The International Society for Optical Engineering, 8982

    Abstract

    Doping of amorphous chalcogenide films of rather dissimilar bonding type and resistivity, namely, Ga-La-S, GeTe, and Ge-Sb-Te by means of ion implantation of bismuth is considered. To characterize defects induced by ionbeam implantation space-charge-limited conduction and capacitance-voltage characteristics of amorphous chalcogenide/silicon heterojunctions are investigated. It is shown that ion implantation introduces substantial defect densities in the films and their interfaces with silicon. This comes along with a gradual decrease in the resistivity and the thermopower coefficient. It is shown that conductivity in GeTe and Ge-Sb-Te films is consistent with the two-type carrier conduction model. It is anticipated that ion implantation renders electrons to become less localized than holes leading to electron conductivity in certain cases as, for example, in GeTe.

  • Hughes MA, Federenko Y, Gwilliam RM, Homewood KP, Curry RJ, Yao J, Gholipour B, Hewak DW, Lee TH, Elliott SR. (2014) 'Optical and electronic properties of bismuth-implanted glasses'. Proceedings of SPIE - The International Society for Optical Engineering, 8982

    Abstract

    Photoluminescence (PL) and excitation spectra of Bi melt-doped oxide and chalcogenide glasses are very similar, indicating the same Bi center is present. When implanted with Bi, chalcogenide, phosphate and silica glasses, and BaF crystals, all display characteristically different PL spectra to when Bi is incorporated by melt-doping. This indicates that ion implantation is able to generate Bi centers which are not present in samples whose dopants are introduced during melting. Bi-related PL bands have been observed in glasses with very similar compositions to those in which carrier-type reversal has been observed, indicating that these phenomena are related to the same Bi centers, which we suggest are interstitial Bi and Bi clusters.

  • Dudeck KJ, Botton GA, Huante-Ceron E, Knights AP, Gwilliam RM. (2013) 'Direct observation of indium precipitates in silicon following high dose ion implantation'. Semiconductor Science and Technology, 28 (12)

    Abstract

    We present electron microscopy, electrical measurement and secondary ion mass spectroscopy (SIMS) characterization of silicon doped with indium to concentrations well above the assumed solid solubility. Samples have been prepared using ion implantation at an energy of 40 keV to achieve as-implanted indium concentrations up to 1 × 10 cm, with post-implantation annealing performed at temperatures between 600 and 1050 °C. We provide direct evidence for nano-scale indium precipitates in the silicon matrix and on the sample surface after annealing. Precipitates having a tetragonal crystal structure and a rectangular shape were observed in all of the samples implanted at the highest dose of 1 × 10 cm , and some of the samples implanted with a lower dose. Comparing SIMS and electron microscopy data allows us to conclude a solid solubility of ≈10 cm, consistent with previously published work (Solmi et al 2002 J. Appl. Phys. 92 1361-6). This paper determines the limitations of indium utility as a dopant in silicon with regard to solid solubility and dose loss. The latter is in excess of 75% for samples annealed at temperatures at and above 750 °C. © 2013 IOP Publishing Ltd.

  • Finch P, O'Driscoll I, Blood P, Smowton PM, Sobiesierski A, Gwilliam RM. (2013) 'Femtosecond pulse generation in passively mode locked InAs quantum dot lasers'. Applied Physics Letters, 103 (13)

    Abstract

    Optical pulse durations of an InAs two-section passively mode-locked quantum dot laser with a proton bombarded absorber section reduce from 8.4 ps at 250 K to 290 fs at 20 K, a factor of 29, with a corresponding increase in optical bandwidth. Rate equation analysis of gain and emission spectra using rate equations suggests this is due to the very low emission rate of carriers to the wetting layer in the low temperature, random population regime which enables dots across the whole inhomogeneous distribution to act as independent oscillators. © 2013 AIP Publishing LLC.

  • Lourenço MA, Mustafa Z, Ludurczak W, Wong L, Gwilliam RM, Homewood KP. (2013) 'High temperature luminescence of Dy in crystalline silicon in the optical communication and eye-safe spectral regions'. Optics Letters, 38 (18), pp. 3669-3672.

    Abstract

    We report on photoluminescence in the 1.3 and 1.7 μm spectral ranges in silicon doped with dysprosium. This is attributed to the Dy internal transitions between the second Dy excited state and the ground state, and between the third Dy excited state and the ground state. Luminescence is achieved by Dy implantation into Si substrates codoped with boron, to form dislocation loops, and show a strong dependence on fabrication process. The spectra consist of several sharp lines with the strongest emission at 1736 nm, observed up to 200 K. No Dy luminescence is observed in samples without B codoping, showing the paramount importance of dislocation loops to enable the Dy emission. © 2013 Optical Society of America.

  • Dudeck KJ, Botton GA, Marqués LA, Knights AP, Gwilliam RM. (2013) 'Sub-ångstrom experimental validation of molecular dynamics for predictive modeling of extended defect structures in Si'. Physical Review Letters, 110 (16)

    Abstract

    In this Letter we present the detailed, quantitative comparison between experimentally and theoretically derived structures of the extended {311} defect in silicon. Agreement between experimental and theoretical column positions of better than ±0.05 nm has been achieved for all 100 atomic columns in the defect structure. This represents a calculated density of 5.5×1014 silicon interstitials per cm2 on {311} planes, in agreement with previous work [S. Takeda, Jpn. J. Appl. Phys., Part 2, 30, L639 (1991)JAPLD80021-4922]. We show that although the {311} defect is made up of five-, six-, seven-, and eight-member rings, the shape of these rings varies as a function of position along the defect, and these variations can be determined experimentally with high precision and accuracy. The excellent agreement between the calculated and experimentally derived structure, including the position of atomic columns and the shape of the distinct structural units of the defect, provides strong evidence for the quality and robustness of the molecular dynamics simulation approach for structural studies of defects. The experimental approach is straightforward, without the need for complicated image processing methods, and is therefore widely applicable. © 2013 American Physical Society.

  • Hughes MA, Gwilliam RM, Homewood K, Curry RJ, Gholipour B, Hewak DW, Lee T-H, Elliott SR, Suzuki T, Ohishi Y, Kohoutek T. (2013) 'On the analogy between photoluminescence and carrier-type reversal in Bi-and Pb-doped glasses'. Optics Express, 21 (7), pp. 8101-8115.

    Abstract

    Reaction order in Bi-doped oxide glasses depends on the optical basicity of the glass host. Red and NIR photoluminescence (PL) bands result from Bi2+ and Bin clusters, respectively. Very similar centers are present in Bi-and Pb-doped oxide and chalcogenide glasses. Bi-implanted and Bi melt-doped chalcogenide glasses display new PL bands, indicating that new Bi centers are formed. Bi-related PL bands have been observed in glasses with very similar compositions to those in which carrier-type reversal has been observed, indicating that these phenomena are related to the same Bi centers, which we suggest are interstitial Bi2+ and Bi clusters. © 2013 Optical Society of America.

  • Crowe IF, Papachristodoulou N, Halsall MP, Hylton NP, Hulko O, Knights AP, Yang P, Gwilliam RM, Shah M, Kenyon AJ. (2013) 'Donor ionization in size controlled silicon nanocrystals: The transition from defect passivation to free electron generation'. Journal of Applied Physics, 113 (2)

    Abstract

    We studied the photoluminescence spectra of silicon and phosphorus co-implanted silica thin films on (100) silicon substrates as a function of isothermal annealing time. The rapid phase segregation, formation, and growth dynamics of intrinsic silicon nanocrystals are observed, in the first 600 s of rapid thermal processing, using dark field mode X-TEM. For short annealing times, when the nanocrystal size distribution exhibits a relatively small mean diameter, formation in the presence of phosphorus yields an increase in the luminescence intensity and a blue shift in the emission peak compared with intrinsic nanocrystals. As the mean size increases with annealing time, this enhancement rapidly diminishes and the peak energy shifts further to the red than the intrinsic nanocrystals. These results indicate the existence of competing pathways for the donor electron, which depends strongly on the nanocrystal size. In samples containing a large density of relatively small nanocrystals, the tendency of phosphorus to accumulate at the nanocrystal-oxide interface means that ionization results in a passivation of dangling bond (P-centre) type defects, through a charge compensation mechanism. As the size distribution evolves with isothermal annealing, the density of large nanocrystals increases at the expense of smaller nanocrystals, through an Ostwald ripening mechanism, and the majority of phosphorus atoms occupy substitutional lattice sites within the nanocrystals. As a consequence of the smaller band-gap, ionization of phosphorus donors at these sites increases the free carrier concentration and opens up an efficient, non-radiative de-excitation route for photo-generated electrons via Auger recombination. This effect is exacerbated by an enhanced diffusion in phosphorus doped glasses, which accelerates silicon nanocrystal growth. © 2013 American Institute of Physics.

  • Yang P, Gwilliam RM, Crowe IF, Papachristodoulou N, Halsall MP, Hylton NP, Hulko O, Knights AP, Shah M, Kenyon AJ. (2013) 'Size limit on the phosphorous doped silicon nanocrystals for dopant activation'. Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms,

    Abstract

    We studied the photoluminescence spectra of silicon nanocrystals doped with and without phosphorus as a function of isothermal annealing time. Silicon nanocrystals were prepared by the implantation of 80 keV Si into a 500 nm SiO film to an areal density of 8 × 10 at/cm. Half of the samples were co-implanted with P at 80 keV to 5 × 10 at/cm. The photoluminescence of the annealed samples were photo-excited at wavelength of 405 nm. For short anneal times, when the nanocrystal size distribution has a relatively small mean diameter, formation in the presence of phosphorus yields an increase in the luminescence intensity and a blue shift in the emission peak compared with intrinsic nanocrystals. As the mean size increases with annealing time, this enhancement rapidly diminishes and the peak energy shifts to the red. Our results indicate the donor electron generation depends strongly on the nanocrystal size. We also found a critical limit above which it allows dopant activation. © 2013 Elsevier B.V. All rights reserved.

  • Razali MA, Gwilliam RM, Secchi M, Bersani M. (2013) 'Point defect engineering study of phosphorus ion implanted germanium'. Physica Status Solidi (C) Current Topics in Solid State Physics, 2 (12)

    Abstract

    We present experimental results on shallow junction formation in germanium by phosphorus ion implantation and standard rapid thermal processing. An attempt is made to improve phosphorus electrical activation using point defect engineering method by introducing an excess of point defects in germanium prior to the phosphorus implantation. The focus is on studying the phosphorus activation and diffusion as a function of germanium co-implant energy. Hall Effect and Secondary Ion Mass Spectrometry (SIMS) measurements are employed for characterisation of phosphorus activation and diffusion, respectively. Phosphorus activation was improved at higher annealing temperature for the implants with germanium co-implant. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • Finch P, O'Driscoll I, Blood P, Smowton PM, Sobiesierski A, Gwilliam R. (2013) 'Femtosecond pulse generation in proton bombarded passively mode locked InAs quantum dot lasers'. 2013 Conference on Lasers and Electro-Optics, CLEO 2013,

    Abstract

    Sub-picosecond optical pulses are demonstrated in a two-section passively mode locked InAs quantum dot laser structure using a randomly populated distribution and a proton bombarded absorber. © 2013 The Optical Society.

  • Yang P, Gwilliam RM, Crowe IF, Papachristodoulou N, Halsall MP, Hylton NP, Hulko O, Knights AP, Shah M, Kenyon AJ. (2013) 'Size limit on the phosphorous doped silicon nanocrystals for dopant activation'. Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms, 307, pp. 456-458.

    Abstract

    We studied the photoluminescence spectra of silicon nanocrystals doped with and without phosphorus as a function of isothermal annealing time. Silicon nanocrystals were prepared by the implantation of 80 keV Si into a 500 nm SiO film to an areal density of 8 × 10 at/cm. Half of the samples were coimplanted with P at 80 keV to 5 × 10 at/cm. The photoluminescence of the annealed samples were photo-excited at wavelength of 405 nm. For short anneal times, when the nanocrystal size distribution has a relatively small mean diameter, formation in the presence of phosphorus yields an increase in the luminescence intensity and a blue shift in the emission peak compared with intrinsic nanocrystals. As the mean size increases with annealing time, this enhancement rapidly diminishes and the peak energy shifts to the red. Our results indicate the donor electron generation depends strongly on the nanocrystal size. We also found a critical limit above which it allows dopant activation. © 2013 Elsevier B.V. All rights reserved.

  • Finch P, O'Driscoll I, Blood P, Smowton PM, Sobiesierski A, Gwilliam R. (2013) 'Femtosecond pulse generation in proton bombarded passively mode locked InAs quantum dot lasers'. CLEO: Science and Innovations, CLEO_SI 2013,

    Abstract

    Sub-picosecond optical pulses are demonstrated in a two-section passively mode locked InAs quantum dot laser structure using a randomly populated distribution and a proton bombarded absorber. © OSA 2013.

  • Ishii M, Crowe IF, Halsall MP, Hamilton B, Knights AP, Gwilliam RM. (2012) 'Investigation of the thermal charge "trapping-detrapping" in silicon nanocrystals: Correlation of the optical properties with complex impedance spectra'. Applied Physics Letters, 101 (24)

    Abstract

    The charge confinement in silicon nanocrystals over the temperature range 35-300K was investigated by complex impedance spectroscopy (CIS). A charge response found in the "dark" (i.e., no laser pumping) CIS spectrum indicated a frequency shift with temperature, which was well correlated with the temperature dependent photoluminescence (PL) intensity. From equivalent circuit analyses of this frequency shift, we were able to determine the charge "trapping-detrapping" mechanism giving rise to the luminescence. We find that the luminescence decay transient, expressed as a stretched exponential function, can be mathematically converted to a CIS spectrum. © 2012 American Institute of Physics.

  • Graham C, Seeds A, Gwilliam R. (2012) 'Nitrogen ion implanted InP based photo-switch'. Optics Express, 20 (24), pp. 26696-26703.

    Abstract

    An Indium Phosphide-based device, switched by telecommunication wavelength laser pulses capable of operating at microwave frequencies up to 15 GHz has been designed and fabricated. Initial results confirm that using high energy nitrogen ion implantation to create EL-2 type trapping levels produces a photocarrier recombination time of a few picoseconds. The ion size and mass selected produces uniform bulk point defects in an InGa As light absorbing region leading to high photocurrent mobility not exhibited in heavy ion irradiated samples resulting in a reduced peak pulse power requirement to switch the device. © 2012 Optical Society of America.

  • Berhanuddin DD, Lourenço MA, Jeynes C, Milosavljević M, Gwilliam RM, Homewood KP. (2012) 'Structural analysis of silicon co-implanted with carbon and high energy proton for the formation of the lasing G-centre'. Journal of Applied Physics, 112 (10)

    Abstract

    We investigate a new approach for efficient generation of the lasing G-centre (carbon substitutional-silicon self-interstitial complex) which crucially is fully compatible with standard silicon ultra-large-scale integration technology. Silicon wafers were implanted with carbon and irradiated with high energy protons to produce self-interstitials that are crucial in the formation of the G-centre. Rutherford backscattering spectrometry (RBS) and transmission electron microscopy were used to study the structure of the post-implanted silicon samples and to investigate the behaviour of the self-interstitials and damage introduced by the carbon and proton implantation. The effect of substrate pre-amorphisation on the G-centre luminescence intensity and formation properties was also investigated by implanting Ge prior to the carbon and proton irradiation. Photoluminescence measurements and RBS results show a significantly higher G-centre peak intensity and silicon yield, respectively, in samples without pre-amorphisation. © 2012 American Institute of Physics.

  • Berhanuddin DD, Lourenco MA, Gwilliam RM, Homewood KP. (2012) 'Co-Implantation of Carbon and Protons: An Integrated Silicon Device Technology Compatible Method to Generate the Lasing G-Center'. WILEY-V C H VERLAG GMBH ADVANCED FUNCTIONAL MATERIALS, 22 (13), pp. 2709-2712.
  • O'Driscoll I, Blood P, Smowton PM, Sobiesierski A, Gwilliam R. (2012) 'Effect of proton bombardment on InAs dots and wetting layer in laser structures'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 100 (26) Article number ARTN 261105
  • Sandall I, Tan CH, Smith A, Gwilliam R. (2012) 'Planar InAs photodiodes fabricated using He ion implantation'. Optics Express, 20 (8), pp. 8575-8583.

    Abstract

    We have performed Helium (He) ion implantation on InAs and performed post implant annealing to investigate the effect on the sheet resistance. Using the transmission line model (TLM) we have shown that the sheet resistance of a p InAs layer, with a nominal doping concentration of 1 × 10 cm , can increase by over 5 orders of magnitude upon implantation. We achieved a sheet resistance of 1 × 10 ω/Square in an 'asimplanted' sample and with subsequent annealing this can be further increased to 1 × 10 ω/Square. By also performing implantation on p-i-n structures we have shown that it is possible to produce planar photodiodes with comparable dark currents and quantum efficiencies to chemically etched reference mesa InAs photodiodes. © 2012 Optical Society of America.

  • Antwis L, Gwilliam R, Smith A, Jeynes C, Homewood K. (2012) 'Characterization of a-FeSi /c-Si heterojunctions for photovoltaic applications'. Semiconductor Science and Technology, 27 (3)

    Abstract

    Amorphous iron disilicide (a-FeSi ) shows potential as a photovoltaic material due to its bandgap of ∼0.9 eV and high absorption coefficient. We present a detailed characterization of a-FeSi , with particular emphasis on the electrical properties of a-FeSi /c-Si heterostructures, under both dark and illuminated conditions. The samples were prepared on quartz and silicon substrates using RF co-sputtering of an iron/silicon target. Optical transmission spectroscopy was used to confirm the bandgap of the samples. Van der Pauw measurements and currentvoltage analysis techniques were used to determine the carrier type and conduction mechanisms of the samples. The results show that a-FeSi forms a rectifying pn heterojunction on p-type crystalline silicon. The silicide is characterized by very high carrier concentrations, resulting in the depletion region being almost entirely formed within the silicon substrate. Initial JV results suggest carrier recombination within the silicide to be the dominant contribution to the conduction across the junction, with photovoltaic effects having been observed under AM1.5 conditions. © 2012 IOP Publishing Ltd.

  • Antwis L, Gwilliam R, Smith A, Jeynes C, Homewood K. (2012) 'Characterization of a-FeSi /c-Si heterojunctions for photovoltaic applications'. Semiconductor Science and Technology, 27 (3)

    Abstract

    Amorphous iron disilicide (a-FeSi ) shows potential as a photovoltaic material due to its bandgap of ∼0.9 eV and high absorption coefficient. We present a detailed characterization of a-FeSi , with particular emphasis on the electrical properties of a-FeSi /c-Si heterostructures, under both dark and illuminated conditions. The samples were prepared on quartz and silicon substrates using RF co-sputtering of an iron/silicon target. Optical transmission spectroscopy was used to confirm the bandgap of the samples. Van der Pauw measurements and currentvoltage analysis techniques were used to determine the carrier type and conduction mechanisms of the samples. The results show that a-FeSi forms a rectifying pn heterojunction on p-type crystalline silicon. The silicide is characterized by very high carrier concentrations, resulting in the depletion region being almost entirely formed within the silicon substrate. Initial JV results suggest carrier recombination within the silicide to be the dominant contribution to the conduction across the junction, with photovoltaic effects having been observed under AM1.5 conditions. © 2012 IOP Publishing Ltd.

  • England J, Phaneuf MW, Laquerre A, Smith A, Gwilliam R. (2012) 'Ion beam assisted crystallization of amorphous silicon layers using high current density Gallium beams'. Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms, 272, pp. 409-413.

    Abstract

    We have investigated ion beam assisted crystallization as a possible method for the creation of crystalline Si layers on amorphous substrates. Ion beam assisted crystallization has previously been characterised with pulsed and modest continuous beam current densities, but not at the high densities that would be required for high throughput processes. In this study, amorphous Si layers were implanted with Ga using a focused ion beam (FIB) tool and with Ga, Ar, Ge and As using beamline implanters. Crystallization was only observed for Ga, implying Ga alone was acting to reduce the activation energy. The observed rates of crystallization also implied that the relaxation state of the a-Si, influenced by the beam conditions, was an important driver for the phase transformation. © 2011 Elsevier B.V. All rights reserved.

  • Coleman PG, Edwardson CJ, Knights AP, Gwilliam RM. (2012) 'Vacancy-type defects created by single-shot and chain ion implantation of silicon'. New Journal of Physics, 14

    Abstract

    Vacancy-type defects created by single-energy implantation of Czochralski-grown single-crystal silicon by 4MeV silicon ions at doses of 10 and 10 cm have been compared with those created by an energy chain of implants of 0.4, 0.9, 1.5, 2.2 and 4MeV ions, each at one-fifth of the singleenergy dose. Measurements were taken for as-implanted samples and after annealing to temperatures up to 600 °C. In contrast to the expectation that a more uniform depth distribution of interstitials and vacancies would lead to a more efficient recombination and consequently fewer surviving vacancies, vacancyrelated damage survived in the chain-implanted samples to higher temperatures, before almost complete annealing at 600 °C. It is therefore concluded that it is the absolute initial monovacancy concentration, rather than any initial separation of vacancy-and interstitial-rich regions, that determines the probability of survival as divacancies, and that there exists a threshold divacancy concentration of 1-2 × 10 cm for clustering at 400-500 °C. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

  • Giubertoni D, Demenev E, Jestin Y, Meirer F, Gennaro S, Iacob E, Pepponi G, Pucker G, Bersani M, Gupta S, Saraswat KC, Gwilliam RM, Jeynes C, Colaux JL. (2012) 'Solid phase epitaxial re-growth of Sn ion implanted germanium thin films'. AIP Conference Proceedings, 1496, pp. 103-106.

    Abstract

    Doping of Ge with Sn atoms by ion implantation and annealing by solid phase epitaxial re-growth process was investigated as a possible way to create GeSn layers. Ion implantation was carried out at liquid nitrogen to avoid nano-void formation and three implant doses were tested: 5×10, 1×10 and 5×10 at/cm, respectively. Implant energy was set to 45 keV and implants were carried out through an 11 nm SiNO film to prevent Sn out-diffusion upon annealing. This was only partially effective. Samples were then annealed in inert atmosphere either at 350°C varying anneal time or for 100 s varying temperature from 300 to 500°C. SPER was effective to anneal damage without Sn diffusion at 350° for samples implanted at medium and low fluences whereas the 5×10 at/cm samples remained with a ∼15 nm amorphous layer even when applying the highest thermal budget. © 2012 American Institute of Physics.

  • O'Driscoll I, Blood P, Sobiesierski A, Smowton PM, Gwilliam R. (2012) 'Evaluating InAs QD lasers for space borne applications'. Conference Digest - IEEE International Semiconductor Laser Conference, , pp. 94-95.

    Abstract

    Decrease of photoluminescence with increasing dose is due to bombardment induced wetting layer non-radiative recombination. To exploit the relative radiation immunity of QD lasers one should maximise the QD density and capture probability per dot. © 2012 IEEE.

  • Scapellato GG, Bruno E, Mirabella S, Priolo F, Napolitani E, De Salvador D, Mastromatteo M, Carnera A, Smith AJ, Gwilliam R. (2012) 'Role of self-interstitials on B diffusion in Ge'. Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms, 282, pp. 8-11.

    Abstract

    B diffusion in crystalline Ge is investigated under equilibrium and non-equilibrium conditions in a large temperature range (200-800°C), in order to discriminate the role of self-interstitials (Is) and the energy barriers involved in the microscopic mechanism of B migration. To this aim, we copiously furnished Is by 200 or 300 keV H irradiation, and performed a direct comparison with B diffusion in thermal conditions at the same temperature (T). The diffused profiles of B were simulated assuming the kick-out model, and the extracted parameters (migration length, λ, and formation rate of mobile B, g) indicated that the B diffusion is always mediated by Is showing different features at low and high T regimes. For T lower than 600°C the thermal generation of Is is negligible and the only barrier to g (measured to be ∼0.1 eV) is due to the Is migration and B mobile formation. At T higher than 600°C, the thermal generation of Is starts to overcome the Is supply from the irradiation, and the activation energy of g increases to 3.0-3.5 eV. The migration length in the low-T regime has the largest value (∼20 nm), while it decreases down to 1-2 nm by increasing T, showing a negative activation energy of ∼-0.64 eV, compatible with a dissociation process which stops the diffusion event. In this regard, we observed that the mobile B migration length depends only on T, regardless of the point defects concentration. These results and the energy barriers measurements contribute to a further comprehension of the B diffusion and point defects in crystalline Ge. © 2011 Elsevier B.V. All rights reserved.

  • Halsall MP, Crowe IF, Southern R, Yang P, Gwilliam RM. (2012) 'Broadband near-infrared emission from bismuth doped silicon oxide films prepared by ion-implantation'. Conference on Optoelectronic and Microelectronic Materials and Devices, Proceedings, COMMAD, , pp. 23-24.

    Abstract

    A series of Bismuth (Bi) doped silicon oxide layers were prepared by ion-implantation. All the samples exhibit strong room temperature near-infrared photoluminescence in the range 1.0μm-1.3μm which we assign to Bi related centres in the oxide matrix, similar to that reported previously for Bi doped oxides fabricated by alternative methods. The activation and sensitization of these luminescent centres was studied as a function of anneal temperature and co-doping with silicon (Si) and aluminium (Al). Comparision with Erbium doped films prepared in a similar way reveals comparable emission intensity from the Bi doped films. The even wider Bi-related luminescence makes this system very promising for use in on-chip, broadband lasers and amplifiers, particularly for use in telecommunications. © 2012 IEEE.

  • Mazzucato S, Royall B, Ketlhwaafetse R, Balkan N, Salmi J, Puustinen J, Guina M, Smith A, Gwilliam R. (2012) 'Dilute nitride and GaAs n-i-p-i solar cells'. Nanoscale Research Letters, 7

    Abstract

    We demonstrate for the first time the operation of GaInNAs and GaAs n-i-p-i doping solar cells with ion-implanted selective contacts. Multiple layers of alternate doping are grown by molecular beam epitaxy to form the n-i-p-i structure. After growth, vertical selective contacts are fabricated by Mg and Si ion implantation, followed by rapid thermal annealing treatment and fabrication into circular mesa cells. As means of characterisation, spectral response and illuminated current-voltage (I-V) were measured on the samples. The spectral response suggests that all horizontal layers are able to contribute to the photocurrent. Performance of the devices is discussed with interest in the n-i-p-i structure as a possible design for the GaInP/GaAs/GaInNAs tandem solar cell. © 2012 Mazzucato et al.

  • Milosavljevic M, Lourenco MA, Gwilliam RM, Homewood KP. (2011) 'Role of heavy ion co-implantation and thermal spikes on the development of dislocation loops in nanoengineered silicon light emitting diodes'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 110 (3) Article number ARTN 033508
  • Scapellato GG, Boninelli S, Napolitani E, Bruno E, Smith AJ, Mirabella S, Mastromatteo M, De Salvador D, Gwilliam R, Spinella C, Carnera A, Priolo F. (2011) 'Self-interstitials injection in crystalline Ge induced by GeO2 nanoclusters'. AMER PHYSICAL SOC PHYSICAL REVIEW B, 84 (2) Article number ARTN 024104
  • Coleman PG, Nash D, Edwardson CJ, Knights AP, Gwilliam RM. (2011) 'The evolution of vacancy-type defects in silicon-on-insulator structures studied by positron annihilation spectroscopy'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 110 (1) Article number ARTN 016104
  • Loiacono R, Reed GT, Mashanovich GZ, Gwilliam R, Henley SJ, Hu YF, Feldesh R, Jones R. (2011) 'Laser erasable implanted gratings for integrated silicon photonics'. Optical Society of America Optics Express, 19 (11), pp. 10728-10734.

    Abstract

    In this work we experimentally demonstrate laser erasable germanium implanted Bragg gratings in SOI. Bragg gratings are formed in a silicon waveguide by ion implantation induced amorphization, and are subsequently erased by a contained laser thermal treatment process. An extinction ratio up to 24dB has been demonstrated in transmission for the fabricated implanted Bragg gratings with lengths up to 1000 mu m. Results are also presented, demonstrating that the gratings can be selectively removed by UV pulsed laser annealing, enabling a new concept of laser erasable devices for integrated photonics.

  • Crowe IF, Halsall MP, Hulko O, Knights AP, Gwilliam RM, Wojdak M, Kenyon AJ. (2011) 'Probing the phonon confinement in ultrasmall silicon nanocrystals reveals a size-dependent surface energy'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 109 (8) Article number ARTN 083534
  • Lourenço M, Gwilliam R, Homewood K. (2011) 'Eye-safe 2 μm luminescence from thulium-doped silicon.'. Optical Society of America Opt Lett, United States: 36 (2), pp. 169-171.

    Abstract

    We report on photoluminescence in the 1.7-2.1 μm range of silicon doped with thulium. This is achieved by the implantation of Tm into silicon that has been codoped with boron to reduce the thermal quenching. At least six strong lines can be distinguished at 80 K; at 300 K, the spectrum is dominated by the main emission at 2 μm. These emissions are attributed to the trivalent Tm(3+) internal transitions between the first excited state and the ground state.

  • Knights AP, Bradley JDB, Hulko O, Stevanovic DV, Edwards CJ, Kallis A, Coleman PG, Crowe IF, Halsall MP, Gwilliam RM. (2011) 'Probing the formation of silicon nano-crystals (Si-ncs) using variable energy positron annihilation spectroscopy'. Journal of Physics: Conference Series, 262 (1)
  • Scapellato GG, Bruno E, Smith AJ, Napolitani E, De Salvador D, Mirabella S, Mastromatteo M, Carnera A, Gwilliam R, Priolo F. (2011) 'Role of self-interstitials on B diffusion in Ge'. Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms,
  • England J, Phaneuf MW, Laquerre A, Smith A, Gwilliam R. (2011) 'Ion beam assisted crystallization of amorphous silicon layers using high current density Gallium beams'. Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms,
  • Crowe IF, Kashtiban RJ, Sherliker B, Bangert U, Halsall MP, Knights AP, Gwilliam RM. (2010) 'Spatially correlated erbium and Si nanocrystals in coimplanted SiO2 after a single high temperature anneal'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 107 (4) Article number ARTN 044316
  • Doylend JK, Knights AP, Luff BJ, Shafiiha R, Asghari M, Gwilliam RM. (2010) 'Modifying functionality of variable optical attenuator to signal monitoring through defect engineering'. INST ENGINEERING TECHNOLOGY-IET ELECTRONICS LETTERS, 46 (3), pp. 234-235.
  • Kashtiban RJ, Bangert U, Crowe I, Halsall P, Sherliker B, Harvey J, Eccles J, Knights AP, Gwilliam R, Gass M. (2010) 'Structural and compositional study of Erbium-doped silicon nanocrystals by HAADF, EELS and HRTEM techniques in an aberration corrected STEM'. Journal of Physics: Conference Series, 209
  • Collart EJH, Teel R, Free C, Wan Z, Kopalidis P, Razali MA, Gwilliam R, Smith A, Tsidilkovski E, Karpowicz T. (2010) 'Process characterization of low temperature ion implantation using ribbon beam and spot beam on the AIBT iPulsar high current'. AIP Conference Proceedings, 1321, pp. 49-52.
  • Halsall MP, Crowe IF, Hylton NP, Hulko O, Knights AP, Ruffell S, Gwilliam RM, Wojdak M, Kenyon AJ. (2010) 'Novel processing for Si-nanocrystal based photonic materials'. ECS Transactions, 28 (3), pp. 3-13.
  • Loiacono R, Reed GT, Gwilliam R, Mashanovich GZ, O'Faolain L, Krauss T, Lulli G, Jeynes C, Jones R, Kubby JA, Reed GT. (2010) 'Germanium implanted Bragg gratings in Silicon on Insulator waveguides'. SPIE-INT SOC OPTICAL ENGINEERING SILICON PHOTONICS V, San Francisco, CA: 7606 Article number ARTN 76060G
  • Wright NM, Smith AJ, Litvinenko K, Gwilliam R, Mashanovich G, Reed GT, Kubby JA, Reed GT. (2010) 'Effects of annealing silicon ion irradiated rib waveguides with respect to free carrier lifetime'. SPIE-INT SOC OPTICAL ENGINEERING SILICON PHOTONICS V, San Francisco, CA: 7606 Article number ARTN 76060H
  • Lourenco MA, Opoku C, Gwilliam RM, Homewood KP. (2010) 'Photoluminescence study of thulium-doped silicon substrates for light emitting diodes'. ELSEVIER SCIENCE BV OPTICAL MATERIALS, Herceg Novi, MONTENEGRO: 32 (12), pp. 1597-1600.
  • Homewood KP, Lourenco MA, Gwilliam RM. (2010) 'Nano-engineered silicon light emitting diodes and optically active waveguides'. ELSEVIER SCIENCE BV OPTICAL MATERIALS, Herceg Novi, MONTENEGRO: 32 (12), pp. 1601-1605.
  • Smith AJ, Gwilliam RM, Stolojan V, Knights AP, Coleman PG, Kallis A, Yeong SH. (2009) 'Enhancement of phosphorus activation in vacancy engineered thin silicon-on-insulator substrates'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 106 (10) Article number ARTN 103514
  • Rudawski NG, Jones KS, Gwilliam R. (2009) 'Stressed solid-phase epitaxial growth of (011) Si'. MATERIALS RESEARCH SOC JOURNAL OF MATERIALS RESEARCH, 24 (2), pp. 305-309.
  • Logan DF, Jessop PE, Knights AP, Gwilliam RM. (2009) 'The use of deep-level dopants in silicon-on-insulator optical waveguide modulators'. Optics InfoBase Conference Papers,

    Abstract

    The dependence of silicon's absorption coefficient at λ = 1.55 μm on the charge state of deep levels is modeled and measured experimentally. Improved designs for p-i-n rib waveguide modulators based on this effect are presented. © 2009 Optical Society of America.

  • Ali-Boucetta H, Bensalem R, Alleg S, Smith A, Gwilliam R, Sealy B. (2009) 'Simulation of electrical properties in ion implanted GaAs'. Physics Procedia, 2 (3), pp. 797-801.
  • Wright NM, Thomson DJ, Litvinenko KL, Headley WR, Smith AJ, Knights AP, Deane JHB, Gardes FY, Mashanovich GZ, Gwilliam R, Reed GT, Kubby JA, Reed GT. (2009) 'Free carrier lifetime modification in silicon'. SPIE-INT SOC OPTICAL ENGINEERING SILICON PHOTONICS IV, San Jose, CA: 7220 Article number ARTN 722006
  • Roschuk T, Wilson PRJ, Li J, Dunn KA, Wojcik J, Crowe IF, Gwilliam RM, Halsall MP, Knights AP, Mascher P. (2009) 'Structure and luminescence of rare earth-doped silicon oxides studied through XANES and XEOL'. ECS Transactions, 25 (9), pp. 213-222.
  • Bennett NS, Cowern NEB, Smith AJ, Kah M, Gwilliam RM, Sealy BJ, Noakes TCQ, Bailey P, Giubertoni D, Bersani M. (2008) 'Differential Hall characterisation of ultrashallow doping in advanced Si-based materials'. ELSEVIER SCIENCE BV MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS, Strasbourg, FRANCE: 154, pp. 229-233.

    Abstract

    Strained Si channels are commonly used by manufacturers to enhance CMOS performance and research into novel channel materials (SiGe and Ge) is well underway. How these materials affect the electrical properties of the impurities used to dope them is largely unclear and the ability to accurately characterise dopant activation is key to finding this out. In the case of Si, since much is known about the relationship between carrier concentration and mobility, dopant activation can be assessed by competing techniques, however for the newer materials this information is not available. This paper demonstrates the differential Hall technique as a method capable of satisfying these gaps in our knowledge of dopant activation and mobility. Previously we have shown the technique, which combines Hall effect measurements with successive native oxide removal, can measure independent carrier and mobility profiles with resolution better than 1 nm for B-implanted Si and SOI. Presently we show the technique is extendable to characterise n-type dopants (Sb and As) and importantly, can be applied to novel substrates (focussing here on strained Si). In addition, the inherent assumption of the technique - uniform layer removal - is investigated and shown reasonable. Complementary ion beam analysis is used to show how we investigate and correct for Hall scattering effects and designated software is used to apply necessary corrections, transforming raw data into reproducible and highly resolved, carrier and mobility profiles. (C) 2008 Elsevier B.V. All rights reserved.

  • Wright NM, Thomson DJ, Litvinenko KL, Headley WR, Smith AJ, Knights AP, Deane JHB, Gardes FY, Mashanovich GZ, Gwilliam R, Reed GT. (2008) 'Free carrier lifetime modification for silicon waveguide based devices'. OPTICAL SOC AMER OPT EXPRESS, 16 (24), pp. 19779-19784.

    Abstract

    We investigate the effect of silicon ion irradiation on free carrier lifetime in silicon waveguides, and thus its ability to reduce the density of two-photon-absorption (TPA) generated free carriers. Our experimental results show that free carrier lifetime can be reduced significantly by silicon ion implantation. Associated excess optical absorption from the implanted ions can be reduced to an acceptable level if irradiation energy and dose are correctly chosen. Simulations of Raman scattering suggest that net gain can be achieved in certain cases without the need for an integrated diode in reverse bias to remove the photo-generated free carriers. (c) 2008 Optical Society of America

  • Bennett NS, Radamson HH, Beer CS, Smith AJ, Gwilliam RM, Cowern NEB, Sealy BJ. (2008) 'Enhanced n-type dopant solubility in tensile-strained Si'. ELSEVIER SCIENCE SA THIN SOLID FILMS, 517 (1), pp. 331-333.
  • Slotte J, Rummukainen M, Tuomisto F, Markevich VP, Peaker AR, Jeynes C, Gwilliam RM. (2008) 'Evolution of vacancy-related defects upon annealing of ion-implanted germanium'. AMER PHYSICAL SOC PHYSICAL REVIEW B, 78 (8) Article number ARTN 085202
  • Rudawski NG, Jones KS, Gwilliam R. (2008) 'Dopant-stress synergy in Si solid-phase epitaxy'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 92 (23) Article number ARTN 232110
  • O'Reilly L, Horan K, McNally PJ, Bennett NS, Cowern NEB, Lankinen A, Sealy BJ, Gwilliam RM, Noakes TCQ, Bailey P. (2008) 'Constraints on micro-Raman strain metrology for highly doped strained Si materials'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 92 (23) Article number ARTN 233506
  • Rudawski NG, Jones KS, Gwilliam R. (2008) 'Stressed solid-phase epitaxial growth of ion-implanted amorphous silicon'. ELSEVIER SCIENCE SA MATERIALS SCIENCE & ENGINEERING R-REPORTS, 61 (1-6), pp. 40-58.
  • Rudawski NG, Jones KS, Gwilliam R. (2008) 'Kinetics and morphological instabilities of stressed solid-solid phase transformations'. AMER PHYSICAL SOC PHYSICAL REVIEW LETTERS, 100 (16) Article number ARTN 165501
  • Lourenco MA, Gwilliam RM, Homewood KP. (2008) 'Silicon light emitting diodes emitting over the 1.2-1.4 mu m wavelength region in the extended optical communication band'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 92 (16) Article number ARTN 161108
  • Knights AP, Bulk MP, Jessop PE, Waugh P, Loiacono R, Mashanovich GZ, Reed GT, Gwilliam RM. (2008) 'Optical filters utilizing ion implanted Bragg gratings in SOI waveguides'. Hindawi Publishing Corporation Advances in Optical Technologies, 2008 Article number 276165

    Abstract

    The refractive index modulation associated with the implantation of oxygen or silicon into waveguides formed in silicon-on- insulator (SOI) has been investigated to determine the feasibility of producing planar, implantation induced Bragg grating optical filters. A two-dimensional coupled mode theory-based simulation suggests that relatively short grating lengths, on the order of a thousand microns, can exhibit sufficient wavelength suppression, of > 10 dB, using the implantation technique. Fabricated planar implanted slab-guided SOI waveguides demonstrated an extinction of −10 dB for TE modes and −6 dB for TM modes for the case of oxygen implantation. Extinctions of −5 dB and −2 dB have been demonstrated with silicon implantation.

  • Cowern NEB, Smith AJ, Bennett N, Sealy BJ, Gwilliam R, Webb RP, Colombeau B, Paul S, Lerch W, Pakfar A. (2008) 'Vacancy engineering - An ultra-low thermal budget method for high-concentration 'diffusionless' implantation doping'. Materials Science Forum, 573-574, pp. 295-304.
  • Kah M, Smith AJ, Hamilton JJ, Sharp J, Yeong SH, Colombeau B, Gwilliam R, Webb RP, Kirkby KJ. (2008) 'Interaction of the end of range defect band with the upper buried oxide interface for B and BF2 implants in Si and silicon on insulator with and without preamorphizing implant'. A V S AMER INST PHYSICS JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, Napa, CA: 26 (1), pp. 347-350.
  • Bennett NS, Cowern NEB, Smith AJ, Kah M, Gwilliam RM, Sealy BJ, Noakes TCQ, Bailey P, Giubertoni D, Bersani M. (2008) 'Differential Hall characterisation of ultrashallow doping in advanced Si-based materials'. ELSEVIER SCIENCE BV MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS, Strasbourg, FRANCE: 154, pp. 229-233.
  • Bennett NS, Smith AJ, Gwilliam RM, Webb RP, Sealy BJ, Cowern NEB, O'Reilly L, McNally PJ. (2008) 'Antimony for n-type metal oxide semiconductor ultrashallow junctions in strained Si: A superior dopant to arsenic?'. A V S AMER INST PHYSICS JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, Napa, CA: 26 (1), pp. 391-395.
  • Renaud CC, Pantouvaki M, Gregoire S, Lealman I, Cannard P, Cole S, Moore R, Gwilliam R, Seeds AJ. (2007) 'A monolithic MQW InP-InGaAsP-Based optical comb generator'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE JOURNAL OF QUANTUM ELECTRONICS, 43 (11-12), pp. 998-1005.
  • Rudawski NG, Jones KS, Gwilliam R. (2007) 'Solid phase epitaxy in uniaxially stressed (001) Si'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 91 (17) Article number ARTN 172103
  • Milgram JN, Knights AP, Homewood KP, Gwilliam RM. (2007) 'Considerations for interpretation of luminescence from silicon-on-insulator light emitting structures'. IOP PUBLISHING LTD SEMICONDUCTOR SCIENCE AND TECHNOLOGY, 22 (10), pp. 1104-1110.
  • Lourenco MA, Gwilliam RM, Homewood KP. (2007) 'Extraordinary optical gain from silicon implanted with erbium'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 91 (14) Article number ARTN 141122
  • Pantouvaki M, Renaud CC, Cannard P, Robertson MJ, Gwilliam R, Seeds AJ. (2007) 'Fast tuneable InGaAsP DBR laser using quantum-confined stark-effect-induced refractive index change'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, 13 (5), pp. 1112-1121.
  • Reed GT, Yang PY, Headley WR, Waugh PM, Mashanovich GZ, Thomson D, Gwilliam RM, Teo EJ, Blackwood DJ, Breese MBH, Bettiol AA, Kubby JA, Reed GT. (2007) 'Novel fabrication techniques for silicon photonics'. SPIE-INT SOC OPTICAL ENGINEERING SILICON PHOTONICS II, San Jose, CA: 6477 Article number ARTN 64770E
  • Gwilliam R, Sealy B, Smith AJ, Cowern NEB, Colombeau B. (2007) 'Vacancy engineering for ultra-shallow junction formation'. Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms, 261 (1-2 SPEC. ISS.), pp. 600-603.

    Abstract

    Vacancy engineering has been proven to be a viable alternative to pre-amorphisation and solid phase epitaxy for creating ultra-shallow junctions. This paper investigates the effect of implantation order - i.e. whether the dopant implant is preceded or followed by the vacancy generating co-implant - in terms of Rs and diffusion. It is found that for optimal efficiency the co-implant should be performed first. Ultra-shallow boron layers created using this sequence can result in highly stable, ultra-shallow boron layers which do not deactivate significantly during annealing at 700 °C for times ∼15 min. © 2007 Elsevier B.V. All rights reserved.

  • Seeds AJ, Renaud CC, Pantouvaki M, Robertson M, Lealman I, Rogers D, Firth R, Cannard PJ, Moore R, Gwilliam R. (2007) 'Photonic synthesis of THz signals'. Proceedings of the 36th European Microwave Conference, EuMC 2006, , pp. 1107-1110.

    Abstract

    In this paper we present a review of our work on photonic synthesis of high spectral purity THz signals. This work includes novel developments on optical frequency comb generation (integrated, 2THz span, 25 GHz spacing), frequency locking of semiconductor lasers (1kHz channel stability, 10 ns switching time) and high speed photodetectors integrated with antennas (3dB bandwidth >108 GHz, 0.2 A/W responsivity, 148 μW output power at 457 GHz). © 2006 EuMA.

  • Zavada JM, Nepal N, Lin JY, Jiang HX, Brown E, Hommerich U, Hite J, Thaler GT, Abernathy CR, Pearton SJ, Gwilliam R. (2006) 'Ultraviolet photoluminescence from Gd-implanted AlN epilayers'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 89 (15) Article number ARTN 152107
  • Jeynes C, Peng N, Barradas NP, Gwilliam RM. (2006) 'Quality assurance in an implantation laboratory by high accuracy RBS'. ELSEVIER SCIENCE BV NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, Seville, SPAIN: 249, pp. 482-485.
  • Webb M, Jeynes C, Gwilliam R, Royle A, Sealy B. (2006) 'Characterising ion-cut in GaAs by Rutherford backscattering spectroscopy'. ELSEVIER SCIENCE BV NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, Seville, SPAIN: 249, pp. 429-431.
  • Milosavljevic M, Lourenco MA, Shao G, Gwilliam RM, Homewood KP. (2006) 'Optimising dislocation-engineered silicon light-emitting diodes'. SPRINGER APPLIED PHYSICS B-LASERS AND OPTICS, 83 (2), pp. 289-294.
  • Burr E, Pantouvaki M, Fice M, Gwilliam R, Krysa A, Roberts J, Seeds A. (2006) 'Signal stability in periodically amplified fiber transmission systems using multiple quantum well saturable absorbers for regeneration'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC JOURNAL OF LIGHTWAVE TECHNOLOGY, 24 (2), pp. 747-754.
  • Han SY, Hite J, Thaler GT, Frazier RM, Abernathy CR, Pearton SJ, Choi HK, Lee WO, Park YD, Zavada JM, Gwilliam R. (2006) 'Effect of Gd implantation on the structural and magnetic properties of GaN and AlN'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 88 (4) Article number ARTN 042102
  • Sealy BJ, Smith AJ, Bennett N, Li L, Jeynes C, Emerson NG, Gwilliam RM, Cowern NEB, Alzanki T, Colombeau B, Collart EJH. (2006) 'Shallow junctions in silicon via low thermal budget processing'. Extended Abstracts of the Sixth International Workshop on Junction Technology, IWJT '06, , pp. 10-15.

    Abstract

    The paper summarises recent findings concerning the fabrication of ultra-shallow junctions in silicon for future generations of CMOS devices. In particular we concentrate on vacancy engineering to achieve carrier concentrations of 5-6 × 10 cm for boron in silicon without diffusion and report for the first time preliminary data for antimony implants into strained silicon in which even higher carrier concentrations were obtained. All of this can be produced at temperatures below 800°C for annealing times of 10 seconds, without the need for spike annealing, fast ramp rates or laser processing. © 2006 IEEE.

  • Smith AJ, Cowern NEB, Gwilliam R, Sealy BJ, Colombeau B, Collart EJH, Gennaro S, Giubertoni D, Bersani M, Barozzi M. (2006) 'Vacancy-engineering implants for high boron activation in silicon on insulator'. Applied Physics Letters, 88 (8)

    Abstract

    The formation of boron interstitial clusters is a key limiting factor for the fabrication of highly conductive ultrashallow doped regions in future silicon-based device technology. Optimized vacancy engineering strongly reduces boron clustering, enabling low-temperature electrical activation to levels rivalling what can be achieved with conventional preamorphization and solid-phase epitaxial regrowth. An optimized 160 keV silicon implant in a 55145 nm silicon-on-insulator structure enables stable activation of a 500 eV boron implant to a concentration ∼5× 1020 cm-3. © 2006 American Institute of Physics.

  • Renaud CC, Pantouvaki M, Gregoire S, Seeds AJ, Lealman I, Cannard P, Gwilliam R. (2006) 'A monolithic MQW InP/InGaAsP-based comb generator'. 2006 International Topical Meeting on Microwave Photonics, MWP,

    Abstract

    We report a monolithic optical frequency comb generator using quaternary/quaternary multiple quantum well InP/InGaAsP material as phase modulator and gain medium in a Frequency Modulated (FM) laser design. The modulation was generated by quantum confined Stark effect to achieve a comb-line spacing of 24.4 GHz. The laser was fabricated using a single epitaxial growth step and quantum well intermixing to realize low loss phase and modulation sections. The resulting comb generator produces lines with a spacing exactly given by the modulation frequency, differential phase noise between adjacent lines of -82 dBc/Hz at 1 kHz offset and a comb spectrum width of up to 2 THz.

  • Gwilliam RM, Cowern NEB, Colombeau B, Sealy B, Smith AJ, Hadzievski L, Marinkovic BP, Simonovic NS. (2006) 'Ultra-shallow junction formation in SOI using vacancy engineering'. AMER INST PHYSICS Physics of Ionized Gases, Natl Park Kopaonik, SERBIA: 876, pp. 181-190.
  • Smith AJ, Cowern NEB, Gwilliam R, Sealy BJ, Colombeau B, Collart EJH, Gennaro S, Giubertoni D, Bersani M, Barozzi M. (2006) 'Junction stability of B doped layers in SOI formed with optimized vacancy engineering implants'. AIP Conference Proceedings, 866, pp. 84-87.

    Abstract

    Forming highly stable, low resistive, ultra shallow p-type junctions is well known to be a challenge for future transistor devices. This paper investigates the junction stability of boron layers formed with an optimized 160keV silicon vacancy engineering implant in SOI. It is demonstrated that when the electrical activation is well above the solid solubility a combination of diffusion and possible boron precipitation, during prolonged annealing at 850°C, drives the boron to return to an equilibrium level of electrical activation, which is compensated by the carrier mobility to maintain a constant Rs. Reducing the anneal temperature to 700°C shows it is possible to create highly stable p-type junctions in terms of diffusion and sheet resistance. © 2006 American Institute of Physics.

  • Pantouvaki M, Kong SF, Fice MJ, Seeds AJ, Gwilliam RM, Cannard P. (2006) '10 Gb/s noise suppression using an ion implanted waveguide saturable absorber'. Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference, CLEO/QELS 2006,

    Abstract

    Noise suppression of 3dB per pass is demonstrated using a top-implanted passive InGaAsP/InGaAsP multiple quantum well ridge waveguide saturable absorber. The contrast ratio and recovery time are 3dB and ∼16ps respectively. © 2006 Optical Society of America.

  • Bennett NS, O'Reilly L, Smith AJ, Gwilliam RM, McNally PJ, Cowern NEB, Sealy BJ, Kirkby KJ, Chivers D, Gwilliam R, Smith A. (2006) 'Strain-enhanced activation of Sb ultrashallow junctions'. AMER INST PHYSICS Ion Implantation Technology, Marseille, FRANCE: 866, pp. 54-57.
  • Bennett NS, Cowern NEB, Smith AJ, Gwilliam RM, Sealy BJ, O'Reilly L, McNally PJ, Cooke G, Kheyrandish H. (2006) 'Highly conductive Sb-doped layers in strained Si'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 89 (18) Article number ARTN 182122
  • Bennett NS, Smith AJ, Gwilliam R, Cowern NEB, Sealy BJ, Beer CS, O'Reilly L, McNally PJ, Colombeau B, Dilliway GD, Harper R. (2006) 'Enhanced antimony activation for ultra-shallow junctions in strained silicon'. Materials Research Society Symposium Proceedings, 912, pp. 59-64.

    Abstract

    Sheet resistance (Rs) reductions are presented for antimony and arsenic doped layers produced in strained Si. Results re-emphasise the Rs reduction for As comes purely as a result of mobility improvement [1,2] whereas for Sb, a superior lowering is observed from improvements in both mobility and activation. For the first time, strain is shown to enhance the activation of dopant atoms whilst Sb is seen to create stable ultra-shallow junctions. Our results propose Sb as a viable alternative to As for the creation of highly activated, low resistance ultra-shallow junctions for use with strain-engineered CMOS devices. © 2006 Materials Research Society.

  • Gennaro S, Giubertoni D, Bersani M, Anderle M, Foggiato J, Yoo WS, Gwilliam R. (2006) 'The effect of flash annealing on the electrical properties of indium/carbon Co-implants in silicon'. AIP Conference Proceedings, 866, pp. 113-116.

    Abstract

    Shallow Indium implants and Indium-Carbon co-implants have been subjected to flash anneals and a combination of furnace treatments in order to evaluate the electrical properties of the implant and differentiate the behavior between low temperature and high temperature ultra fast thermal treatments, It is found that by using "flash" anneals, higher levels of electrical activation are achievable for the given experimental conditions, This behavior is related to the indium dose and to the dopant diffusion within the layer and its interaction with the carbon. © 2006 American Institute of Physics.

  • Peaker AR, Markevich VP, Capan I, Dobaczewski L, Slotte J, Rummukainen M, Pivac B, Gwilliam R, Jeynes C. (2006) 'Understanding ion implantation defects in germanium'. ECS Transactions, 3 (2), pp. 67-76.

    Abstract

    The recent interest in germanium as an alternative channel material for PMOS has revealed major differences from silicon in relation to ion implantation. In this paper we describe some initial results of a fundamental study into defect creation and removal in ion implanted germanium. In this stage of the work we have used silicon and germanium implants into germanium and into germanium rich silicon-germanium. The defect evolution in these samples is compared with electron and neutron irradiated material using annealing studies in conjunction with deep level transient spectroscopy, positron annihilation and Rutherford back scattering. It is proposed that both vacancy and interstitial clustering are important mechanisms in implanted germanium and the likely significance of this is discussed. copyright The Electrochemical Society.

  • Pantouvaki M, Liu CP, Renaud CC, Seeds AJ, Cole S, Robertson M, Gwilliam R. (2006) 'Monolithically integrated QCSE-tuned InGaAsP MQW ridge waveguide DBR laser'. Conference Proceedings - International Conference on Indium Phosphide and Related Materials, 2006, pp. 72-74.

    Abstract

    The first QCSE-tuned ridge waveguide InGaAsP MQW DBR laser monolithically integrated with QW-intermixed tuning sections is demonstrated. QCSE is used for tuning with minimal thermal effects over ∼7nm for <2.5V applied voltage change. © 2006 IEEE.

  • White N, Chen J, Mulcahy C, Biswas S, Gwilliam R. (2006) 'Chicane deceleration - An innovative energy contamination control technique in low energy ion implantation'. AIP Conference Proceedings, 866, pp. 335-339.

    Abstract

    High current beams suitable for USJ implantation were generated by 'Chicane Deceleration' involving an s-bend to block contaminants. Implanted wafers were analyzed with 200eV O beams at 45° to resolve the sources of dopant profile variation in fine detail. Energy contamination is essentially eliminated, but for B channeling remains important. Unannealed X values from 5 to 7 nm are reported for different implant species. © 2006 American Institute of Physics.

  • Milosavljevic M, Shao G, Lourenco MA, Gwilliam RM, Homewood KP, Edwards SP, Valizadeh R, Colligon JS. (2005) 'Transition from amorphous to crystalline beta phase in co-sputtered FeSi2 films as a function of temperature'. AMER INST PHYSICS JOURNAL OF APPLIED PHYSICS, 98 (12) Article number ARTN 123506
  • Homewood KP, Lourenco MA, Milosavljevic M, Shao G, Gwilliam RM. (2005) 'Dislocation engineered silicon for light emission'. IEEE 2005 IEEE LEOS Annual Meeting Conference Proceedings (LEOS), Sydney, AUSTRALIA: , pp. 608-609.

Conference papers

  • Peng N, Jeynes C, Gwilliam RM, Webb RP, Pan F, Chen X. (2012) 'On fabrication of high concentration Mn doped Si by ion implantation: problem and challenge'. ELSEVIER SCIENCE BV 18TH INTERNATIONAL VACUUM CONGRESS (IVC-18), Beijing, PEOPLES R CHINA: 18th International Vacuum Congress (IVC)/International Conference on Nanoscience and Technology (ICNT)/14th International Conference on Surfaces Science (ICSS)/Vacuum and Surface Sciences Conference of Asia and Australia (VASSCAA) 32, pp. 408-411.
  • Razali MA, Smith AJ, Jeynes C, Gwilliam RM, Pelaz L, Santos I, Duffy R, Torregrosa F, Bourdelle K. (2012) 'Temperature-Dependant Study Of Phosphorus Ion Implantation In Germanium'. AMER INST PHYSICS ION IMPLANTATION TECHNOLOGY 2012, Valladolid, SPAIN: 19th International Conference on Ion Implantation Technology (IIT) 1496, pp. 193-196.
  • Sandall I, Tan CH, Smith A, Gwilliam R. (2012) 'Planar InAs photodiodes fabricated using He ion implantation'. 2012 IEEE Photonics Conference, IPC 2012, , pp. 165-166.

    Abstract

    This work has shown that it is possible to use He implantation with InAs to produce highly resistive areas and that when combined with post implantation annealing, a sufficiently high resistive region can be formed to allow the fabrication of a planar photodiode. © 2012 IEEE.

  • Loiacono R, Topley R, Nakyobe A, Mashanovich G, Gwilliam R, Lulli G, Feldesh R, Jones R, Reed G. (2011) 'Very low energy implanted Bragg gratings in SOI for wafer scale testing applications'. IEEE Proceedings of 8th IEEE International Conference on Group IV Photonics, London, UK: 8th IEEE GFP, pp. 51-53.

    Abstract

    We present Bragg gratings with an effective index change introduced by implanting germanium at only 15KeV. An extinction ratio of 35dB at 1350nm is demonstrated for device lengths of 600μm, furthermore laser annealing is demonstrated.

  • Loiacono R, Reed GT, Mashanovich GZ, Gwilliam RM, Lulli G, Feldesh R, Jones R. (2011) 'Low energy silicon on insulator ion implanted gratings for optical wafer scale testing'. SPIE Proceedings of SPIE - The International Society for Optical Engineering, San Francisco, USA: Silicon Photonics VI 7943

    Abstract

    Silicon photonics shows tremendous potential for the development of the next generation of ultra fast telecommunication, tera-scale computing, and integrated sensing applications. One of the challenges that must be addressed when integrating a "photonic layer" onto a silicon microelectronic circuit is the development of a wafer scale optical testing technique, similar to that employed today in integrated electronics industrial manufacturing. This represents a critical step for the advancement of silicon photonics to large scale production technology with reduced costs. In this work we propose the fabrication and testing of ion implanted gratings in sub micrometer SOI waveguides, which could be applied to the implementation of optical wafer scale testing strategies. An extinction ratio of over 25dB has been demonstrated for ion implanted Bragg gratings fabricated by low energy implants in submicron SOI rib waveguides with lengths up to 1mm. Furthermore, the possibility of employing the proposed implanted gratings for an optical wafer scale testing scheme is discussed in this work.

  • Homewood KP, Lourenço MA, Gwilliam RM. (2010) '1.1 to 1.6 μm silicon light emitting diodes and optical gain'. Proceedings of IEEE 7th International Conference on Group IV Photonics GFP, Beijing, China: 7th IEEE GFP, pp. 302-304.

    Abstract

    We report silicon LEDs showing light emission from 1.1 to 1.6 μm and demonstrate optical gain by incorporating optically active impurities. Nano-engineering enables room temperature operation. As one exemplar, we show that erbium, with local strain engineering provides useful optical emission and gain at 1.5 μm.

  • Lourenço MA, Wong L, Gwilliam RM, Homewood KP. (2010) 'Luminescence of Tm3+in dislocation engineered silicon substrates'. Proceedings of 7th IEEE International Conference on Group IV Photonics, Beijing, China: 7th IEEE GFP, pp. 159-161.

    Abstract

    Photoluminescence at 1.2 to1.4 μm is demonstrated in dislocation engineered silicon substrates doped with Tm3+ leading to the development of forward biased light emitting devices operating at a turn-on voltage of only 1 V.

  • Antwis L, Wong L, Smith A, Homewood K, Jeynes C, Gwilliam R. (2010) 'Optimization and characterisation of amorphous iron disilicide formed by ion beam mixing of Fe/Si multilayer structures for photovoltaic applications'. AIP Conference Proceedings, Kyoto, Japan: Ion Implantation Technology 2101: 18th International Conference on Ion Implantation Technology IIT 2010 1321, pp. 278-281.

    Abstract

    This study presents an optimization and characterization of amorphous Iron Disilicide (a‐FeSi2) synthesized using Ion Beam Mixing (IBM) of Fe∕Si multilayer structures. The layers were deposited using RF magnetron sputtering, and subsequently irradiated with Ar+ and Fe+ beams of 150 and 200 keV. Rutherford Back Scattering (RBS) analysis was used to determine the structure and level of silicidation of the samples. The nature of the band‐gap and the optical absorption coefficients were determined by optical transmission analysis. The results demonstrate that the synthesis of a‐FeSi2 can be achieved using this technique, with the total level of silicidation being highly dependant upon the initial structure configuration and beam parameters. Direct band‐gap energies of ∼0.90 eV have been observed for those samples with the highest levels of silicidation, with optical absorption coefficients of ∼ 104 cm−1. Therefore this method of fabrication has been shown to produce a‐FeSi2 layers without the need for post‐synthesis treatment, using established technologies without compromising the optical properties that make this material such a promising semiconductor for the photovoltaics market.

  • Bailey MJ, Jeynes C, Sealy BJ, Webb RP, Gwilliam RM. (2010) 'On artefacts in the secondary ion mass spectrometry profiling of high fluence H+ implants in GaAs'. ELSEVIER SCIENCE BV NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, Univ Cambridge, Cambridge, ENGLAND: 19th International Conference on Ion Beam Analysis 268 (11-12), pp. 2051-2055.
  • Hylton NP, Crowe IF, Knights AP, Halsall MP, Ruffell S, Gwilliam RM. (2010) 'Optical spectroscopy of Er doped Si-nanocrystals on sapphire substrates fabricated by ion implantation into SiO2'. Proceedings of SPIE - The International Society for Optical Engineering, San Francisco, USA: Silicon Photonics V 7606

    Abstract

    We present the results of an optical investigation of a series of Er doped silicon nanocrystal (Si-NC) samples which were fabricated via ion implantation into SiO2 on sapphire substrates, followed by a range of rapid thermal processing. The photoluminescence spectra of the Si-NC emission revealed an increase in luminescence intensity and a red-shift of the peak wavelength as a function of annealing conditions. We attribute the former effect to the reduction of implantation induced defects with increasing annealing temperature/duration. Measurements of the rate of decay of photoluminescence intensity at room temperature show a corresponding increase in the carrier lifetimes which is also an indication of a reduced contribution from non-radiative centers. The red-shift of the peak Si-NC intensity is ascribed to an increasing mean Si-NC size as a function of the annealing conditions. Also presented is an estimation of the relative Er sensitization which reveals that the smallest Si-NC size distribution leads to the greatest sensitization ratio. Further investigation in the form of excitation spectroscopy was used to show that Er ions are sensitized not only by energy transfer from the Si-NCs, but also, crucially, from defect states in the SiO2.

  • Crowe IF, Hulko O, Knights AP, Hylton NP, Halsall MP, Ruffell S, Gwilliam RM. (2010) 'Formation of Si-nanocrystals in SiO2 via ion implantation and rapid thermal processing'. Proceedings of SPIE - The International Society for Optical Engineering, San Francisco, USA: Silicon Photonics V 7606

    Abstract

    We present a combined analysis using cross-sectional transmission electron microscopy (X-TEM) and Raman spectroscopy to study the early formation dynamics of Si-nanocrystals, formed in SiO2 thin films after Si+ implantation and rapid thermal processing (RTP). We obtained values for the diffusion coefficient of Si in thermally grown SiO2 and the activation energy to precipitate formation in the first 100 seconds of high temperature annealing. These values indicate that the formation of Si-nanocrystals in implanted oxides proceeds much more efficiently than purely via a self diffusion process. We propose that the nanocrystal formation is assisted by the presence of both oxygen vacancies and SiO molecular species, presumably generated by the ion irradiation. Microscopy images reveal the ensemble nanocrystal population to be most accurately represented by a lognormal distribution function with characteristic values for the mean particle diameter, d and variance, σ. The evolution of the silicon nanocrystals with annealing was also investigated by measuring the Raman scattering signal associated with the TO phonon mode arising from Si-Si bonds in Si-rich oxides grown on transparent (Al2O3) substrates. This greatly simplifies the experimental observation of the Raman spectra from Si-nanocrystals as compared to previous studies of nanocrystals in oxide films on silicon substrates.

  • Knights AP, Milgrarn JN, Wojcik J, Mascher P, Crowe I, Sherliker B, Halsall MP, Gwilliam RM. (2009) 'Observation of non-radiative de-excitation processes in silicon nanocrystals'. WILEY-BLACKWELL PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE, Edmonton, CANADA: 3rd International Conference on Optical, Optoelectronic and Photonic Materials and Applications 206 (5), pp. 969-972.
  • Vassilevski K, Nikitina I, Horsfall A, Wright N, O'Neill AG, Gwilliam R, Johnson CM, PerezTomas A, Godignon P, Vellvehi M, Brosselard P. (2009) 'Silicon Carbide Static Induction Transistor with Implanted Buried Gate'. TRANS TECH PUBLICATIONS LTD SILICON CARBIDE AND RELATED MATERIALS 2008, Barcelona, SPAIN: 7th European Conference on Silicon Carbide and Related Materials 615-617, pp. 735-738.
  • Reed GT, Mashanovich G, Gardes FY, Gwilliam RM, Wright NM, Thomson DJ, Timotijevic BD, Litvinenko KL, Headley WR, Smith AJ, Knights AP, Jessop PE, Tarr NG, Deane JHB. (2009) 'Silicon photonics at the University of Surrey'. Proceedings of SPIE - The International Society for Optical Engineering, Dresden, Germany: Photonic Materials, Devices, and Applications III 7366, pp. 736602.1-736602.12.

    Abstract

    Silicon Photonics is a field that has seen rapid growth and dramatic changes in the past 5 years. According to the MIT Communications Technology Roadmap [1], which aims to establish a common architecture platform across market sectors with a potential $20B in annual revenue, silicon photonics is among the top ten emerging technologies. This has in part been a consequence of the recent involvement of large semiconductor companies around the world, particularly in the USA. Significant investment in the technology has also followed in Japan, Korea, and in the European Union. Low cost is a key driver, so it is imperative to pursue technologies that are mass-producible. Therefore, Silicon Photonics continues to progress at a rapid rate. This paper will describe some of the work of the Silicon Photonics Group at the University of Surrey in the UK. The work is concerned with the sequential development of a series of components for silicon photonic optical circuits, and some of the components are discussed here. In particular the paper will present work on optical waveguides, optical filters, modulators, and lifetime modification of carriers generated by two photon absorption, to improve the performance of Raman amplifiers in silicon.

  • Bennett NS, Cowern NEB, Kheyrandish H, Paul S, Lerch W, Smith AJ, Gwilliam R, Sealy BJ. (2008) 'Vacancy engineering for highly activated 'diffusionless' boron doping in bulk silicon'. Proceedings of the 38th European Solid-State Device Research Conference, Edinburgh, UK: ESSDERC 2008, pp. 290-293.

    Abstract

    Simulation and physical experiments have shown that vacancy engineering implants have the potential to provide outstanding pMOS source/drain performance for several future CMOS device generations. Using vacancy-generating implants prior to boron implantation, hole concentrations approaching 1021cm-3 can be achieved using low thermal budget annealing. In this new study we propose that the vacancy engineering technique is not reliant on the implementation of SOI-based CMOS but is also directly applicable to bulk silicon technologies.

  • Logan DF, Jessop PE, Knights AP, Gwilliam RM, Halsall MP. (2008) 'The effect of doping type and concentration on optical absorption via implantation induced defects in silicon-on-insulator waveguides'. Proceedings of Conference on Optoelectronic and Microelectronic Materials and Devices, Proceedings, COMMAD, Sydney, Australia: COMMAD 2008, pp. 152-155.

    Abstract

    The influence of the charge state of ion implantation induced defects in SOI waveguides on the absorption of sub-bandgap wavelengths is described. It is found that waveguides pre-doped with boron absorb with significantly greater efficiency than those pre-doped with phosphorus. Following annealing at 300degC this difference is approximately 8 dBcm-1, while the intrinsic loss of the waveguides is limited to 2 dBcm-1. These results have significant ramifications for a number of integrated optical devices fabricated in silicon

  • Seeds AJ, Pozzi F, Renaud CC, Fice MJ, Ponnampalam L, Rogers DC, Lealman IF, Gwilliam R. (2008) 'Microwave photonics: Opportunities for photonic integration'. Proceedings of the 14th European Conference on Integrated Optics and Technical Exhibition, Eindhoven, The Netherlands: ECIO'08, pp. 123-132.
  • Milosavljevic M, Lourenco MA, Shao G, Gwilliam RM, Homewood KP. (2008) 'Formation of dislocation loops in silicon by ion irradiation for silicon light emitting diodes'. ELSEVIER SCIENCE BV NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, Florence, ITALY: 9th European Conference on Accelerators in Applied Research and Technology 266 (10), pp. 2470-2474.
  • Wright NM, Thomson DJ, Litvinenko KL, Headley WR, Smith AJ, Knights AP, Gardes FY, Mashanovich GZ, Gwilliam R, Reed GT. (2008) 'Free carrier lifetime modification for silicon waveguide based devices'. IEEE Proceedings of 5th IEEE International Conference on Group IV Photonics, Cardiff, UK: 5th IEEE GFP, pp. 122-124.

    Abstract

    We investigate the effects of implanting silicon directly into a silicon waveguide to modify carrier lifetime. Experimental results show over 85% reduction in the carrier lifetime for only a small net increase in optical absorption.

  • Smith AJ, Antwis LD, Yeong SH, Knights AP, Colombeau B, Sealy BJ, Gwilliam RM, Seebauer EG, Kondratenko YV, Felch SB, Jain A. (2008) 'Junction Leakage Analysis of Vacancy Engineered Ultra-Shallow p-type Layers'. AMER INST PHYSICS ION IMPLANTATION TECHNOLOGY 2008, Monterey, CA: 17th International Conference on Ion Implantation Technology 1066, pp. 22-25.
  • Smith AJ, Yeong SH, Colombeau B, Sealy BJ, Gwilliam RM, Seebauer EG, Kondratenko YV, Felch SB, Jain A. (2008) 'The Formation of Ultra-Shallow Phosphorous Doped Layers Using Vacancy Engineering'. AMER INST PHYSICS ION IMPLANTATION TECHNOLOGY 2008, Monterey, CA: 17th International Conference on Ion Implantation Technology 1066, pp. 38-41.
  • Kah M, Smith AJ, Hamilton JJ, Yeong SH, Columbeau B, Gwilliam R, Webb RP, Kirkby KJ, Seebauer EG, Kondratenko YV, Felch SB, Jain A. (2008) 'A Comparative Study of Interaction of End of Range (EOR) Defect Band with Upper Buried Oxide (BOX) Interface for B and BF(2) Implants in SOI and Bulk Silicon with Pre-Amorphizing Implant'. AMER INST PHYSICS ION IMPLANTATION TECHNOLOGY 2008, Monterey, CA: 17th International Conference on Ion Implantation Technology 1066, pp. 51-54.
  • Peng N, Jeynes C, Gwilliam RM, Kirkby KJ, Webb RP. (2007) 'Depth profile analysis for MgB2 thin films, formed by B implantation in Mg ribbons using energetic ion backscatterings'. ELSEVIER SCIENCE BV PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS, Dresden, GERMANY: 8th International Conference on Materials and Mechanisms of Superconductivity and High Temperature Superconductors 460, pp. 600-601.
  • Lourenco MA, Milosavljevic M, Shao G, Gwilliam RM, Homewood KP. (2007) 'Dislocation engineered silicon light emitting devices'. ELSEVIER SCIENCE SA THIN SOLID FILMS, Kyoto, JAPAN: Asia-Pacific Conference on Semiconducting Silicides 515 (22), pp. 8113-8117.
  • Mistry P, Gomez-Morilla I, Smith RC, Thomson D, Grime GW, Webb RP, Gwilliam R, Jeynes C, Cansell A, Merchant M, Kirkby KJ. (2007) 'Maskless proton beam writing in gallium arsenide'. ELSEVIER SCIENCE BV NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, Singapore, SINGAPORE: 10th International Conference on Nuclear Microprobe Technology and Applications held in Conjunction with the 2nd International Workshop on Proton Beam Writing 260 (1), pp. 437-441.
  • Ishibashi Y, Kobayashi T, Prins AD, Nakahara J, Lourenco MA, Gwilliam RM, Homewood KP. (2007) 'Excitation and pressure effects on photoluminescence from dislocation engineered silicon material'. WILEY-V C H VERLAG GMBH PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, Barcelona, SPAIN: 12th International Conference on High Pressure Semiconductor Physics (HPSP-12) 244 (1), pp. 402-406.
  • Lourenco MA, Milosavljevic M, Shao G, Gwilliam RM, Homewood KP. (2006) 'Boron engineered dislocation loops for efficient room temperature silicon light emitting diodes'. ELSEVIER SCIENCE SA THIN SOLID FILMS, Singapore, SINGAPORE: 3rd International Conference on Materials for Advanced Technologies/9th International Conference on Advanced Materials 504 (1-2), pp. 36-40.
  • Auret FD, Peaker AR, Markevich VP, Dobaczewski L, Gwilliam RM. (2006) 'High-resolution DLTS of vacancy-donor pairs in P-, As- and Sb-doped silicon'. ELSEVIER SCIENCE BV PHYSICA B-CONDENSED MATTER, Awaji Isl, JAPAN: 23rd International Conference on Defects in Semiconductors 376, pp. 73-76.
  • Gennaro S, Giubertoni D, Bersani M, Foggiato J, Yoo WS, Gwilliam R. (2006) 'Nonconventional flash annealing on shallow indium implants in silicon'. A V S AMER INST PHYSICS JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, Daytona Beach, FL: 8th International Workshop on Fabrication, Characterization, and Modeling of Ultra-Shallow Doping Profiles in Semiconductors 24 (1), pp. 473-477.
  • Alzanki T, Gwilliam R, Emerson N, Smith A, Webb R, Sealy BJ. (2006) 'Electrical profiles of 20 nm junctions in Sb implanted silicon'. ELSEVIER SCIENCE BV NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, Pacific Grove, CA: 14th International Conference on Ion Beam Modification of Materials (IBMM 2004) 242 (1-2), pp. 693-695.
  • Mistry P, Gomez-Morilla I, Grime GW, Webb R, Jeynes C, Gwilliarn R, Cansell A, Merchant M, Kirkby KJ. (2006) 'Proton beam lithography at the University of Surrey's Ion Beam Centre'. ELSEVIER SCIENCE BV NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, Pacific Grove, CA: 14th International Conference on Ion Beam Modification of Materials (IBMM 2004) 242 (1-2), pp. 387-389.
  • Cowern NEB, Smith AJ, Colombeau B, Gwilliam R, Sealy BJ, Collart EJH. (2005) 'Understanding, modeling and optimizing vacancy engineering for stable highly boron-doped ultrashallow junctions'. IEEE IEEE INTERNATIONAL ELECTRON DEVICES MEETING 2005, TECHNICAL DIGEST, Washington, DC: IEEE International Electron Devices Meeting, pp. 989-992.

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