Dresden 2026 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 43: Superconducting Electronics: Qubits
TT 43.8: Talk
Wednesday, March 11, 2026, 11:30–11:45, CHE/0089
Improving performance of planar tantalum resonators and transmon qubits on silicon using advanced deposition techniques — Maciej W. Olszewski1, Lingda Kong2, •Simon Reinhardt2, Daniel Tong2, Shilling Du3, Gabriele Di Gianluca4, Haoran Lu2, Saswata Roy1, Aleksandra Biedron5, David A. Muller2, and Valla Fatemi2 — 1Department of Physics, Cornell University, USA — 2School of Applied and Engineering Physics, Cornell University, USA — 3Cornell NanoScale Facility, USA — 4Department of Physics, University of Florida, USA — 5NY Creates, USA
The cubic phase of tantalum is a very promising material for superconducting transmon qubits, due to its self-limiting surface oxide, low bulk losses, and low kinetic inductance.
We present a novel method of growing high-crystallinity tantalum films on silicon with magnetron sputtering, using a significantly lower substrate temperature than found in literature. Using coplanar waveguide resonators, we measure the losses and microwave performance of our films, achieving single photon quality factors above four million for resonators with gap size of 3-µm. We present first results on transmon qubits based on these low loss tantalum films.
Funding: This prototype was primarily supported by the Microelectronics Commons Program, a DoW initiative, under award number N00164-23-9-G061. Funding for shared facilities used in this prototype was provided by the Microelectronics Commons Program, a DoW initiative, under award number N00164-23-9-G061.
Keywords: tantalum; superconducting resonators; sputtering; dielectric loss; transmon qubits