中国物理B ›› 2026, Vol. 35 ›› Issue (4): 48501-048501.doi: 10.1088/1674-1056/ae0164

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Effect of a deep virtual guard ring on performance of a miniaturized high-photosensitivity silicon single-photon avalanche diode

Enle Zhou(周恩乐)1, Dajing Bian(卞大井)1, and Yue Xu(徐跃)1,2,†   

  1. 1 College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China;
    2 National and Local Joint Engineering Laboratory of RF Integration & Micro-Assembly Technology, Nanjing 210023, China
  • 收稿日期:2025-07-22 修回日期:2025-08-27 接受日期:2025-09-02 出版日期:2026-03-24 发布日期:2026-03-24
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 62171233) and the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20241891).

Effect of a deep virtual guard ring on performance of a miniaturized high-photosensitivity silicon single-photon avalanche diode

Enle Zhou(周恩乐)1, Dajing Bian(卞大井)1, and Yue Xu(徐跃)1,2,†   

  1. 1 College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China;
    2 National and Local Joint Engineering Laboratory of RF Integration & Micro-Assembly Technology, Nanjing 210023, China
  • Received:2025-07-22 Revised:2025-08-27 Accepted:2025-09-02 Online:2026-03-24 Published:2026-03-24
  • Contact: Yue Xu E-mail:yuex@njupt.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 62171233) and the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20241891).

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摘要： We developed a miniaturized high-sensitivity single-photon avalanche diode (SPAD) device based on 180 nm bipolar complementary metal-oxide-semiconductor double-diffused metal-oxide-semiconductor technology and investigated the effect of a deep virtual guard ring (VGR) on device performance. To mitigate the degradation in photon detection efficiency (PDE) and dark count rate (DCR) induced by device scaling, we innovatively implemented a P-type implant/high-voltage n-well SPAD structure. This configuration deepens and widens the multiplication region to broaden the spectral response, while the specialized adoption of the P-type epitaxial VGR technology suppresses premature edge breakdown and reduces dark noise. Furthermore, a unique layout was devised to maximize the photosensitive area and increase the fill factor of the device. Through technology computer-aided design simulations, the effect of the guard ring width on the electric field distribution inside the device was systematically studied. Experimental results demonstrate that the fill factor of the device reaches 31.5% when the pitch is scaled down to 8.5 μm. The novel device achieves a high peak PDE of 24% at 555 nm and an ultralow DCR of 0.41 cps$\cdotμ $m$^{-2}$ at 5 V excess bias voltage.

关键词: single-photon avalanche diode (SPAD), virtual guard ring (VGR), photon detection efficiency (PDE), dark count rate (DCR), premature edge breakdown (PEB)

Abstract: We developed a miniaturized high-sensitivity single-photon avalanche diode (SPAD) device based on 180 nm bipolar complementary metal-oxide-semiconductor double-diffused metal-oxide-semiconductor technology and investigated the effect of a deep virtual guard ring (VGR) on device performance. To mitigate the degradation in photon detection efficiency (PDE) and dark count rate (DCR) induced by device scaling, we innovatively implemented a P-type implant/high-voltage n-well SPAD structure. This configuration deepens and widens the multiplication region to broaden the spectral response, while the specialized adoption of the P-type epitaxial VGR technology suppresses premature edge breakdown and reduces dark noise. Furthermore, a unique layout was devised to maximize the photosensitive area and increase the fill factor of the device. Through technology computer-aided design simulations, the effect of the guard ring width on the electric field distribution inside the device was systematically studied. Experimental results demonstrate that the fill factor of the device reaches 31.5% when the pitch is scaled down to 8.5 μm. The novel device achieves a high peak PDE of 24% at 555 nm and an ultralow DCR of 0.41 cps$\cdotμ $m$^{-2}$ at 5 V excess bias voltage.

Key words: single-photon avalanche diode (SPAD), virtual guard ring (VGR), photon detection efficiency (PDE), dark count rate (DCR), premature edge breakdown (PEB)

中图分类号:  (Semiconductor-device characterization, design, and modeling)

  • 85.30.De
85.60.Dw (Photodiodes; phototransistors; photoresistors) 85.60.Gz (Photodetectors (including infrared and CCD detectors)) 42.79.Pw (Imaging detectors and sensors)