Carbon nanotubes interconnects
Copper interconnects, when miniaturised, suffer from poor conductivity and electromigration, where the interconnect can thin at high current loads. This is why extracting heat from computer microprocessors is crucial, and new materials and solutions are required to cope with the increased miniaturisation and demand for power. High-quality carbon nanotubes have high current carrying capabilities, high thermal conductivity and high tensile strength and are ideal replacements, provided they can be produced and manipulated at conditions compatible with semiconductor processes.
Vertically-aligned carbon nanotubes (VACNTs) grown with conventional chemical vapour deposition methods at low temperatures (below 600oC), result in highly defective, low density VACNTs with low growth rates, which is unsuitable for both industrial feasibility and interconnect applications. The Graphene Centre at the ATI can grow patterned, high-aspect ratio, high-quality CNT whilst maintaining the substrate temperature below 450°C (Figure 1).
These interconnects have very good mechanical properties, with excellent compliance and electrical contact reproducibility, however a well-designed metal capping contact is required to ensure an ohmic-type contact.
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