SPAD with high detection efficiency and low dark count based on standard CMOS process

Abstract

The invention discloses an SPAD with high detection efficiency and low dark count based on a standard CMOS process. The SPAD is prepared on a P substrate that is provided based on the CMOS process; anN-buried layer is arranged on the P substrate to play an isolation role, the buried N-type injection has the characteristic of inverted doping distribution, the doping concentration increases with the increase of depth, and a virtual protection ring is formed; an N-well region, a P-well region and a heavily doped P+ region are respectively arranged in a diffusion doping region of the N-buried layer, and the N-well region is taken as a component part of a photosensitive PN junction; the P-well region serves as a protection ring; the heavily doped P+ region, a shallow P-well region and the N-type region jointly form a P+P- / N-well photosensitive PN junction, and the combination of two P-type injections with different concentrations form a gradient junction to reduce the dark count of devices; the depletion region of the PN junction is the main occurrence region of avalanche multiplication, and meanwhile, the heavily doped P+ region is also taken as an anode contact region of a photodetector; an N-well contact region is arranged in the N-well region at the edge, and the N-well contact region is a heavily doped N+ region and serves as a cathode contact region of the photodetector.

Description

Technical field [0001] The invention relates to the field of photoelectric detection and photoelectric sensors, in particular to a SPAD with high detection efficiency and low dark count based on a standard CMOS process. Background technique [0002] As a detection technology for extremely weak light signals, single-photon detection has broad application prospects in the fields of quantum communication, astronomical photometry, medical imaging and radar detection. In view of its huge scientific research value and strategic position, single-photon detection has become the current One of the hot spots in the field of photoelectric detection. As the core component of the detection system, the single-photon detector determines the performance parameters of the entire single-photon detection system. Therefore, designing a miniature single-photon detector with high detection efficiency and low dark count is one of the key issues that need to be solved urgently. [0003] The traditional s...

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Problems solved by technology

E. Kamrani and others designed a high-gain SPAD structure, although the breakdown voltage is low (12V), but the detection efficiency is only 15%

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