论文标题
氮等离子体钝化的niobium谐振器，用于超导量子电路
Nitrogen Plasma Passivated Niobium Resonators for Superconducting Quantum Circuits
论文作者
论文摘要
用于超导量子电路的氮化物金属结构中的微波损失受到暴露于环境环境的时间尺度的天然表面氧化物层的限制。在这项工作中，我们表明，氮血浆处理在金属空气界面形成氮化物层，以防止这种氧化。 X射线光电子光谱证实了氮的掺杂超过5 nm，并抑制了氧气的存在。在环境环境中衰老15天后，这种钝化保持稳定。低温微波表征显示了$（2.9 \ pm0.5）的平均填充因子调整后的两级损失切线$ \ rm {fδ_{fδ_{tls}} $（2.9 \ pm0.5）\ cdot10^{ - 7} $，用于谐振器，用于3 $ \rmμ$ m m $ m m $ $ m m $ $ $ $ $ $ $ $ $ \ pm0.3） $ \rmμ$ m中心地带，超过了未经广泛的样本的性能四倍。
Microwave loss in niobium metallic structures used for superconducting quantum circuits is limited by a native surface oxide layer formed over a timescale of minutes when exposed to an ambient environment. In this work, we show that nitrogen plasma treatment forms a niobium nitride layer at the metal-air interface which prevents such oxidation. X-ray photoelectron spectroscopy confirms the doping of nitrogen more than 5 nm into the surface and a suppressed oxygen presence. This passivation remains stable after aging for 15 days in an ambient environment. Cryogenic microwave characterization shows an average filling factor adjusted two-level-system loss tangent $\rm{Fδ_{TLS}}$ of $(2.9\pm0.5)\cdot10^{-7}$ for resonators with 3 $\rmμ$m center strip and $(1.0\pm0.3)\cdot10^{-7}$ for 20 $\rmμ$m center strip, exceeding the performance of unpassivated samples by a factor of four.
