InGaAs/InP single photon avalanche diodes with low tunneling current

Abstract

Avalanche photodiodes(APDs) have attracted more and more attention due to their single photon detection ability. However, low dark current is a prerequisite for APDs which are used as single photon avalanche photodiodes (SPADs).In this work,Planar-type Separate Absorption Grading Charge Multiplication(SAGCM) InP/InGaAs APD are fabricated and simulated with ISE-TCAD. We present a detailed analysis of dark current and gain experimentally and theoretically. The effect of the generation-recombination process,the tunneling process,the surface leakage process and the multiplication process on the total dark current are discussed.The dark current gain ratio (Id/M) is used to demonstrate the tunneling current. Simulation results indicate that the thickness of multiplication and trap-assisted tunneling effect have a great influence on the tunneling current:thin multiplication layer and traps will lead to a substantial increase in the tunneling current component, therefore appropriate multiplication layer thickness and low traps are necessary to obtain good APDs with low dark current. Compared with the simulation results,it shows that our APDs have low tunneling current even at breakdown point.In addition, the distinctions between different process of dark current provide a good guidance for the optimization of the APD.