Open Access Nano Express

Comparison of nickel silicide and aluminium ohmic contact metallizations for low-temperature quantum transport measurements

Craig M Polley*, Warrick R Clarke and Michelle Y Simmons

Author affiliations

CQC2T, School of Physics, University of New South Wales, Sydney, NSW 2052, Australia

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Citation and License

Nanoscale Research Letters 2011, 6:538  doi:10.1186/1556-276X-6-538

Published: 3 October 2011

Abstract

We examine nickel silicide as a viable ohmic contact metallization for low-temperature, low-magnetic-field transport measurements of atomic-scale devices in silicon. In particular, we compare a nickel silicide metallization with aluminium, a common ohmic contact for silicon devices. Nickel silicide can be formed at the low temperatures (<400°C) required for maintaining atomic precision placement in donor-based devices, and it avoids the complications found with aluminium contacts which become superconducting at cryogenic measurement temperatures. Importantly, we show that the use of nickel silicide as an ohmic contact at low temperatures does not affect the thermal equilibration of carriers nor contribute to hysteresis in a magnetic field.