Effects of guard-ring’s depth and space on the performance of silicon avalanche photodetector arrays with TCAD simulation

In this paper, we simulated and analyzed the effects of guard-ring's depth and space on the performance of silicon avalanche photodetector (APD) based on the traditional n⁺-p-π-p⁺ structure. Two shallow trenches (ST) outside of the active region was used as the guard rings and the effects of depth and the spacing between the two ST on the performance of silicon APD arrays was simulated and analyzed. In order to optimize the parameters of the shallow trenches, we calculated the different characteristics of APD under different conditions, including the characteristics of APD such as breakdown voltage, multiplication factor, dark current, photocurrent and so on. The result shows the breakdown voltage and multiplication of APD become higher because of the shallow trench guard-rings and they are related to the PN junction depth.