High coherence fluxonium manufactured with a wafer-scale uniformity process
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.
Keywords
Cite
@article{arxiv.2405.05481,
title = {High coherence fluxonium manufactured with a wafer-scale uniformity process},
author = {Fei Wang and Kannan Lu and Huijuan Zhan and Lu Ma and Feng Wu and Hantao Sun and Hao Deng and Yang Bai and Feng Bao and Xu Chang and Ran Gao and Xun Gao and Guicheng Gong and Lijuan Hu and Ruizi Hu and Honghong Ji and Xizheng Ma and Liyong Mao and Zhijun Song and Chengchun Tang and Hongcheng Wang and Tenghui Wang and Ziang Wang and Tian Xia and Hongxin Xu and Ze Zhan and Gengyan Zhang and Tao Zhou and Mengyu Zhu and Qingbin Zhu and Shasha Zhu and Xing Zhu and Yaoyun Shi and Hui-Hai Zhao and Chunqing Deng},
journal= {arXiv preprint arXiv:2405.05481},
year = {2025}
}