我們的目標是使用單一光刻製程製造約瑟夫森參數放大器，而成功的約瑟夫森結作為首要條件。在製程步驟中，有三個關鍵步驟得參數需要確認：蒸鍍、曝光方法和氧化控制。對於蒸鍍，我們利用電子束系統並分析由該系統鋁薄膜沉積的穩定性。對於曝光方式為光刻，而結果顯示線寬最小極限為2 μm至3 μm。另外我們採用十字型蒸發驗證光刻膠厚度(3.3 μm)。透過電子穿隧顯微鏡發現約瑟夫森結重疊完整。在氧化條件方面，我們採用動態或靜態氧化來創建約瑟夫森結的絕緣層。結果表明，在氧壓為20mtorr時，結電阻隨面積變化不明顯，Ro的結果並不一致。目前新的測試正在進行中，一旦氧化條件確定，結合鍍膜的穩定性，我們有信心製造出可控的約瑟夫森
結。而氧化測試片中也生產數片的約瑟夫森參數放大器並安排量測，正在進行中。另外，為了未來先進的約瑟夫森參數放大器製程做好準備，我們探索和測試了離子銑削技術的基礎原理，並提出了其在該製程中的應用，這將有助於約瑟夫森參數放大器的進一步研究和開發。
本研究由國家科學及技術委員會的量子系統前瞻技術開發計畫(Taiwan Quantum Program)所資助。

We aim to fabricate Josephson Parametric Amplifier (JPA) using a single lithography process, with a focus on achieving successful Josephson junctions(JJ) as the primary objective. We propose three key steps to confirm the parameters: evaporation, exposure method, and oxidation control. For evaporation, we utilize an electron beam system and analyze the stability of aluminum thin films deposited by this system. The exposure method is photolithography the line width limit is 2 μm to 3 μm. we use cross-type evaporation to verify the photoresist thickness(3.3 μm), and the experimental results show that the JJ has complete overlap. In terms of oxidation conditions, we employ either dynamic or static oxidation to create the insulating layer of JJ. The results showed that at an oxygen pressure of 20mtorr, the junction resistance not obviously varied depending on the area, and the results of Ro are not consistent. As the new test is currently in progress, once the oxidation conditions are determined, in conjunction with the stability of the evaporation film, we can proceed with confidence in producing controllable JJ. The multiple JPAs have been fabricated on the oxidation test wafer, and measurements are currently underway. In addition, to prepare for future advanced JPA fabrication processes, we have explored and tested the fundamental principles of ion milling technology and proposed its potential application in the process. This will contribute to further research and development of advanced JPA.

This research is funded by the Taiwan Quantum Program, a forward-looking technology development project of the National Science and Technology Commission.

[1] Tsuyoshi Yamamoto, K Inomata, M Watanabe, K Matsuba, T Miyazaki, William D
Oliver, Yasunobu Nakamura, and JS Tsai. Flux-driven josephson parametric amplifier.
Applied Physics Letters, 93(4):042510, 2008.
[2] Vernon Newhouse. Applied superconductivity. Elsevier, 2012.
[3] Theodore Van Duzer and Charles William Turner. Principles of superconductive
devices and circuits. 1981.
[4] Vinay Ambegaokar and Alexis Baratoff. Tunneling between superconductors. Physical
Review Letters, 10(11):486, 1963.
[5] Carl Nordling and Jonny ¨ Osterman. Physics handbook: Elementary constants and
units, tables, formulae and diagrams and mathematical formulae. (No Title), 1985.
[6] Charles P Poole, Horacio A Farach, and Richard J Creswick. Superconductivity.
Academic press, 2013.
[7] Florent Lecocq, Ioan M Pop, Zhihui Peng, Iulian Matei, Thierry Crozes, Thierry
Fournier, C´ecile Naud, Wiebke Guichard, and Olivier Buisson. Junction fabrication
by shadow evaporation without a suspended bridge. Nanotechnology, 22(31):315302,
2011.
[8] Ke Zhang, Meng-Meng Li, Qiang Liu, Hai-Feng Yu, and Yang Yu. Bridge-free fabrication
process for al/alox/al josephson junctions. Chinese Physics B, 26(7):078501,
2017.
[9] Teemu Elo, TS Abhilash, MR Perelshtein, I Lilja, EV Korostylev, and PJ Hakonen.
Broadband lumped-element josephson parametric amplifier with single-step lithography.
Applied Physics Letters, 114(15):152601, 2019.
[10] Daniel Arweiler. Multi-squid josephson parametric amplifiers. pages 1–122, 2018.
[11] JT Monroe, D Kowsari, K Zheng, C Gaikwad, J Brewster, DS Wisbey, and
KW Murch. Optical direct write of dolan–niemeyer-bridge junctions for transmon
qubits. Applied Physics Letters, 119(6):062601, 2021.
[12] A Serway Raymond and WJ John. Principles of physics. London: Saunders College
Pub, page 602, 1998.
[13] Amr Osman. Reliability and reproducibility of josephson junction fabrication-steps
towards an optimized process. 2019.
[14] Alicia M Langton. Factors contributing to the conservation of Phacelia submutica
(Boraginaceae), a threatened species in western Colorado: Reproductive biology and
seed ecology. Utah State University, 2015.
[15] Wu Yulin, Deng Hui, Yu Haifeng, Xue Guangming, Tian Ye, Li Jie, Chen Yingfei,
Zhao Shiping, and Zheng Dongning. Fabrication of al/alo x/al josephson junctions
and superconducting quantum circuits by shadow evaporation and a dynamic oxidation
process. B: , (6):206–210, 2013.
[16] Edwar Xie. Optimized fabrication process for nanoscale Josephson junctions used in
superconducting quantum circuits. PhD thesis, Master’s thesis, Technische Universit
¨at M¨unchen, 2013.
[17] Joseph E Boggio. The pressure dependence of the oxidation of aluminum at 298° k.
Surface Science, 14(1):1–6, 1969.