We report on the electrical characterisation of a series of thin chromium oxide films, grown by dc sputtering, to evaluate their suitability for use as on-chip resistors in nanoelectronics. By increasing the level of oxygen doping, the room-temperature sheet resistance of the chromium oxide films was varied from 28Ω/□ to 32.6kΩ/□. The variation in resistance with cooling to 4.2K in liquid helium was investigated; the sheet resistance at 4.2K varied with composition from 65Ω/□ to above 20GΩ/□. All of the films measured displayed ohmic behaviour at all measured temperatures. For on-chip devices for quantum phase-slip measurements using niobium-silicon nanowires, interfaces between niobium-silicon and chromium oxide are required. By characterising the interface contact resistance, we found that a gold intermediate layer is favourable: the specfic contact resistivity of chromium-oxide-to-gold interfaces was 0.15 mΩcm2, much lower than the value for direct chromium-oxide to niobium-silicon interfaces, 65mΩcm2. We conclude that these chromium oxide films are suitable for use in nanoscale circuits as high-value resistors, with resistivity tunable by oxygen content.
@article{arxiv.1407.8467,
title = {Compact chromium oxide thin film resistors for use in nanoscale quantum circuits},
author = {C. R. Nash and J. C. Fenton and N. G. N. Constantino and P. A. Warburton},
journal= {arXiv preprint arXiv:1407.8467},
year = {2015}
}