Design of Single-Photon Avalanche Diode with High Gain Based on Planar Structure

Abstract

Single-photon avalanche diodes (SPADs) can detect exceptionally faint light signals and it can be widely used in radar detection, autonomous driving, fluorescence detection and other fields. Based on a 180nm standard Bipolar-CMOS-DMOS(BCD) process, this paper designs a SPAD device with high photon detection probability(PDP). The device has a good spectral response in the range of 440∼740nm. It uses a planar N+/ P-well with a radius of 10 µm to form the PN junction, which is the photosensitive region, the N-well is a protective ring that can effectively prevent edge breakdown. The Technology-Computer-Aided-Design(TCAD) simulation software is applied to qualitatively analyze the basic working principle of the SPAD device. And the device’s actual electrical parameters is obtained through an established test platform. Under the over-bias voltage of 1V, experimental results show that more than 30% PDP can be achieved in the range of wavelengths 480 nm-660 nm. The peak PDP is 42.7% at 560 nm and the dark count rate is 11.5 Hz/μm 2 . The test results show that the SPAD has high photon detection probability and low dark count rate.

Keywords: Single-photon avalanche diode, Photon detection probability, Dark count rate, Spectral response