Dr Luke Antwis
Academic and research departments
Publications
We have investigated the use of conventional ion implantation to fabricate enriched 28 Si layers for use in quantum computers. The final compositions of samples enriched using ultra-low energy (800 eV and 2 keV) and low energy (20 keV) 28 Si implants of varying fluences (1x10 16-3.8x10 17 cm-2) using two different implanters were measured using channelled Rutherford Backscattering Spectroscopy. The dynamic, binary collision approximation program TRIDYN was used to model the implantation profiles to guide the analysis of the RBS spectra. It was found that ultra-low energy implants achieved high 28 Si enrichment levels but were heavily contaminated with oxygen due to poor vacuum in the implanter wafer end station. It was shown that oxidation could be reduced by using an accelerator with an end station with better vacuum and increasing the implant energy to 20 keV. However, TRIDYN simulations predict that the best 28 Si enrichment levels that could be achieved under these conditions would saturate at ~99.2 % due to self-sputtering. We modelled a range of conditions with TRIDYN and so recommend low energies (99.9 %) with the lowest possible fluences (~5-10x10 17 cm-2).
Additional publications
Heines, M., Antwis, L., Bara, S., Caerts, B., Cocolios, T.E., Eisenwinder, S., Fletcher, J., Kieck, T., Knecht, A., Niikura, M. and Ritjoho, N., 2023. Muonic x-ray spectroscopy on implanted targets. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 541, pp.173-175.
Antwis, L., Browton, M. and Palitsin, V., 2014. Development of a fast acting vacuum isolation valve for use with ambient ion beam analysis techniques. Vacuum, 99, pp.26-27.
Antwis, L., Gwilliam, R., Smith, A., Homewood, K. and Jeynes, C., 2012. Characterization of a-FeSi2/c-Si heterojunctions for photovoltaic applications. Semiconductor Science and Technology, 27(3), p.035016.
Antwis, L., Wong, L., Smith, A., Homewood, K., Jeynes, C. and Gwilliam, R., 2011, January. Optimization and characterisation of amorphous iron disilicide formed by ion beam mixing of Fe/Si multilayer structures for photovoltaic applications. In AIP Conference Proceedings (Vol. 1321, No. 1, pp. 278-281). American Institute of Physics.
Smith, A.J., Antwis, L.D., Yeong, S.H., Knights, A.P., Colombeau, B., Sealy, B.J. and Gwilliam, R.M., 2008, November. Junction Leakage Analysis of Vacancy Engineered Ultra‐Shallow p‐type Layers. In AIP Conference Proceedings (Vol. 1066, No. 1, pp. 22-25). American Institute of Physics.