[17p-A307-1~10] Latest trend of device technologies for quantum computing

△ [17p-A307-8] Microwave Characterization of Superconducting Ta Films Using Nb Buffer Layer

〇Yoshiro Urade¹, Kay Yakushiji¹, Manabu Tsujimoto¹, Takahiro Yamada¹, Kazumasa Makise¹, Wataru Mizubayashi¹, Kunihiro Inomata¹ (1.AIST)

Keywords:superconducting qubit, tantalum, niobium

Ta is one of promising materials for low-loss electrodes of superconducting qubits. To obtain low-loss α-phase Ta films, we need to heat substrates up to several hundred degrees Celsius. At room temperature, β-phase Ta with larger loss grows. In this study, we use a Nb buffer layer to grow α-phase Ta films at room temperature and characterize their physical properties. Moreover, we fabricate planar microwave resonators made of the films and characterize them by microwave in a 10 mK environment.