A single photon avalanche diode and a light detection device

By forming a mutation junction in the SPAD and using the second p-type epitaxial layer as the depletion region extension region, the problem of small depletion region width in traditional SPADs is solved, thereby improving photon detection efficiency and sensitivity.

CN122138482APending Publication Date: 2026-06-02SHANGHAI SILICON PRINTING TECH CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
SHANGHAI SILICON PRINTING TECH CO LTD
Filing Date
2026-04-21
Publication Date
2026-06-02

AI Technical Summary

Technical Problem

Traditional single-photon avalanche diodes (SPADs) have low photon detection efficiency due to the small depletion region width caused by the gradually changing junction, especially at a wavelength of 940nm where the efficiency is less than 1.4%, which weakens the photodetection capability.

Method used

By forming abrupt junction in SPAD and setting a second p-type epitaxial layer on the side of the p-type buried layer away from the n-type buried layer, this layer is used as an extension region of the depletion region, increasing the width of the depletion region, reducing the breakdown voltage, and increasing the escalation of the applied voltage.

Benefits of technology

It significantly improves optical detection capability and increases the width of the depletion region, thereby improving photon detection efficiency and sensitivity.

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Abstract

This invention discloses a single-photon avalanche diode and a photodetector. The single-photon avalanche diode includes a substrate, a first p-type epitaxial layer, an n-type buried layer, a p-type buried layer, a second p-type epitaxial layer, an anode contact region, and a cathode contact region. The first p-type epitaxial layer is located on one side of the substrate; the n-type buried layer and the p-type buried layer are located on the side of the first p-type epitaxial layer away from the substrate, and the n-type buried layer and the p-type buried layer form an abrupt junction; the second p-type epitaxial layer is located on the side of the p-type buried layer away from the n-type buried layer; the anode contact region is located on the side of the second p-type epitaxial layer away from the p-type buried layer and is coupled to the p-type buried layer; the cathode contact region is located on the side of the n-type buried layer away from the substrate and is coupled to the n-type buried layer. The technical solution of this invention can improve the photodetector capability of the device.
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