2017/06/16 by Lukas Grünhaupt, Uwe von Lüpke, Daria Gusenkova +8 · 22 citations
Computer Science · Physics and Astronomy · #Argon #Fabrication #Focused ion beam #Ion beam #Ion beam-assisted deposition #Ion milling machine #Josephson effect #Physics of Superconductivity and Magnetism #Quantum Information and Cryptography #Quantum and electron transport phenomena #Resonator #Superconductivity #Thin film #cond-mat.supr-con #quant-ph
paper · pdf · doi:10.1063/1.4990491
published in Applied Physics Letters 111(7) (American Institute of Physics) · 4 pages, 4 figures, supplementary material
arxiv created 2017/06/16 · openalex created_date 2017/06/30 · openalex publication_date 2017/08/14 · arxiv updated 2017/08/25 · openalex updated_date 2026/08/05
We present an argon ion beam milling process to remove the native oxide layer forming on aluminum thin films due to their exposure to atmosphere in between lithographic steps. Our cleaning process is readily integrable with conventional fabrication of Josephson junction quantum circuits. From measurements of the internal quality factors of superconducting microwave resonators with and without contacts, we place an upper bound on the residual resistance of an ion beam milled contact of 50 mΩ μm2 at a frequency of 4.5 GHz. Resonators for which only 6% of the total foot-print was exposed to the ion beam milling, in areas of low electric and high magnetic fields, showed quality factors above 106 in the single photon regime, and no degradation compared to single layer samples. We believe these results will enable the development of increasingly complex superconducting circuits for quantum information processing.