Wu X, Long J L, Ku H S, Lake R E, Bal M, Pappas D P
National Institute of Standards and Technology, Boulder, Colorado 80305, USA.
Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
Appl Phys Lett. 2017 Jul;111(3). doi: 10.1063/1.4993937.
Fabrication of sub-micron Josephson junctions is demonstrated using standard processing techniques for high-coherence, superconducting qubits. These junctions are made in two separate lithography steps with normal-angle evaporation. Most significantly, this work demonstrates that it is possible to achieve high coherence with junctions formed on aluminum surfaces cleaned in situ with Ar milling before the junction oxidation. This method eliminates the angle-dependent shadow masks typically used for small junctions. Therefore, this is conducive to the implementation of typical methods for improving margins and yield using conventional CMOS processing. The current method uses electron-beam lithography and an additive process to define the top and bottom electrodes. Extension of this work to optical lithography and subtractive processes is discussed.
利用用于高相干超导量子比特的标准加工技术展示了亚微米约瑟夫森结的制造。这些结是通过两次单独的光刻步骤和法向角蒸发制成的。最重要的是，这项工作表明，对于在结氧化之前用氩离子铣原位清洁的铝表面上形成的结，可以实现高相干性。该方法消除了通常用于小结的与角度相关的荫罩。因此，这有利于使用传统CMOS工艺实施提高裕度和产量的典型方法。当前方法使用电子束光刻和加法工艺来定义顶部和底部电极。讨论了将这项工作扩展到光刻和减法工艺的情况。
