Development of the epitaxial superconducting qubits using nitride dielectric material and the substrate

2015 Fiscal Year Final Research Report

• Project/Area Number: 25420352
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Electron device/Electronic equipment
• Research Institution: National Institute of Information and Communications Technology
• Principal Investigator: QIU WEI 国立研究開発法人情報通信研究機構, 未来ICT研究所ナノICT研究室, 研究員 (90535189)
• Co-Investigator(Renkei-kenkyūsha): KAWAKAMI AKIRA 国立研究開発法人情報通信研究機構, 未来ICT研究所ナノICT研究室, 主任研究員 (90359092)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 超伝導 / TiN / NbN / 超伝導共振器 / 誘電損失 / エピタキシャル / ジョセフソン接合 / 超伝導量子回路

Outline of Final Research Achievements

This funded research project studies the intrinsic two level systems (TLSs) due to the dielectric loss of superconducting quantum circuit. Full epitaxially grown superconducting NbN resonator fabricates on a hydrogen terminated single crystal Si(100) substrate with a thin TiN film served as a buffer layer. The dielectric loss of this TiN/NbN resonator device is 2.25x10e-6, comparable to the same level of epitaxiall grown TiN resonator, and a significant improvement from the loss of 1x10e-4 level in epitaxial NbN resonator in single crystal MgO substrate. The TiN/NbN structure results in a more smooth surface roughness (< 0.5 nm), improved from a relatively high surface roughness (> 0.5 nm) in epitaxial TiN thin film, which is more suitable for novel Josephson device in superconducting quantum bit circuit.

Free Research Field

工学