Sheagren, Calder, Barry, Peter, Shirokoff, Erik and Tang, Qing Yang 2020. Atomic layer deposition niobium nitride films for high-Q resonators. Journal of Low Temperature Physics 199 (3-4) , pp. 875-882. 10.1007/s10909-020-02336-2 |
Abstract
Niobium nitride (NbN) is a useful material for fabricating detectors because of its high critical temperature and relatively high kinetic inductance. In particular, NbN can be used to fabricate nanowire detectors and mm-wave transmission lines. When deposited, NbN is usually sputtered, leaving room for concern about uniformity at small thicknesses. We present atomic layer deposition niobium nitride (ALD NbN) as an alternative technique that allows for precision control of deposition parameters such as film thickness, stage temperature, and nitrogen composition. Atomic-scale control over film thickness admits a high degree of uniformity for films 4–30 nm thick; control over deposition temperature gives rise to growth rate changes, which can be used to optimize film thickness and critical temperature. In order to characterize ALD NbN in the radio-frequency regime, we construct single-layer microwave resonators and test their performance as a function of stage temperature and input power. ALD processes can admit high resonator quality factors, with ≥43% of resonators above Qi=106, which in turn increase detector multiplexing capabilities. Furthermore, we find critical temperatures in the range of 7.5–10.9 K that vary as a function of cycle count and deposition temperature.
Item Type: | Article |
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Date Type: | Published Online |
Status: | Published |
Schools: | Physics and Astronomy |
Publisher: | Springer |
ISSN: | 0022-2291 |
Date of Acceptance: | 13 January 2020 |
Last Modified: | 01 Feb 2023 13:45 |
URI: | https://orca.cardiff.ac.uk/id/eprint/155702 |
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