High coherence fluxonium manufactured with a wafer-scale uniformity process

• URL: http://arxiv.org/abs/2405.05481v2
• Date: Wed, 30 Apr 2025 09:21:38 GMT
• Title: High coherence fluxonium manufactured with a wafer-scale uniformity process
• Authors: Fei Wang, Kannan Lu, Huijuan Zhan, Lu Ma, Feng Wu, Hantao Sun, Hao Deng, Yang Bai, Feng Bao, Xu Chang, Ran Gao, Xun Gao, Guicheng Gong, Lijuan Hu, Ruizi Hu, Honghong Ji, Xizheng Ma, Liyong Mao, Zhijun Song, Chengchun Tang, Hongcheng Wang, Tenghui Wang, Ziang Wang, Tian Xia, Hongxin Xu, Ze Zhan, Gengyan Zhang, Tao Zhou, Mengyu Zhu, Qingbin Zhu, Shasha Zhu, Xing Zhu, Yaoyun Shi, Hui-Hai Zhao, Chunqing Deng,
• Abstract summary: We introduce an overlap process for Josephson junction fabrication that achieves nearly 100% yield and maintains uniformity across a 2-inch wafer.<n>This work paves the way for scalable high coherence fluxonium processors using CMOS-compatible processes.
• Score: 29.75774681877928
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Fluxonium qubits are recognized for their high coherence times and high operation fidelities, attributed to their unique design incorporating a superinductor, which is typically implemented using an array of over 100 Josephson junctions. However, this complexity poses significant fabrication challenges, particularly in achieving high yield and junction uniformity with traditional methods. Here, we introduce an overlap process for Josephson junction fabrication that achieves nearly 100% yield and maintains uniformity across a 2-inch wafer with less than 5% variation for the phase slip junction and less than 2% for the entire junction array. We use a compact junction array design that achieves state-of-the-art dielectric loss tangents and flux noise levels, as confirmed by multiple devices. This enables fluxonium qubits to reach energy relaxation times exceeding 1 millisecond at the flux frustration point. This work paves the way for scalable high coherence fluxonium processors using CMOS-compatible processes, marking a significant step towards practical quantum computing.

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