Design and Implementation of Single-Photon Detector Based on Complementary Metal Oxide Semiconductor Imaging Technology

With the continuous advancement of science and technology, single-photon avalanche diodes (SPADs) play an indispensable role in extremely weak light detection. However, in application scenarios requiring simultaneous detection of visible and infrared light, single-wave-peak SPADs often prove inadequate, while using multiple single-wave-peak devices reduces the overall system integration. To address this issue, a dual-wavepeak SPAD capable of responding to both visible and infrared light regions was designed. To ensure the device achieves its intended functionality, the rationality of the design was first verified using semiconductor process simulation software (TCAD), followed by the construction of an external quenching circuit to test the performance parameters of the SPAD. The test results showed that the avalanche breakdown voltage of the device is 12.75 V. Under room temperature conditions (22 °C) with an excess bias voltage of 0.5 V, the photon detection probability (PDP) of the SPAD reached 32% at 520 nm and 12% at 840 nm. Additionally, when the excess bias voltage was 1 V, the dark count rate (DCR) was 1 kHz. Therefore, this SPAD can achieve dual-wave-peak detection of both visible and near-infrared light while maintaining the DCR within a low range.