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arXiv · 1303.4071

Improved superconducting qubit coherence using titanium nitride

J. Chang·M. R. Vissers·A. D. Corcoles·M. Sandberg·J. Gao·David W. Abraham·Jerry M. Chow·Jay M. Gambetta·M. B. Rothwell·G. A. Keefe·Matthias Steffen·D. P. Pappas
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Abstract

We demonstrate enhanced relaxation and dephasing times of transmon qubits, up to ~ 60 \mu s by fabricating the interdigitated shunting capacitors using titanium nitride (TiN). Compared to lift-off aluminum deposited simultaneously with the Josephson junction, this represents as much as a six-fold improvement and provides evidence that previous planar transmon coherence times are limited by surface losses from two-level system (TLS) defects residing at or near interfaces. Concurrently, we observe an anomalous temperature dependent frequency shift of TiN resonators which is inconsistent with the predicted TLS model.

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J. Chang, M. R. Vissers, A. D. Corcoles, M. Sandberg, J. Gao, David W. Abraham, Jerry M. Chow, Jay M. Gambetta, M. B. Rothwell, G. A. Keefe, Matthias Steffen, D. P. Pappas. 2013-03-17. Improved superconducting qubit coherence using titanium nitride. https://doi.org/10.1063/1.4813269

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