Enhanced Performance of HgCdTe Midwavelength Infrared Electron Avalanche Photodetectors With Guard Ring Designs

In this article, the performance of midwavelength infrared (MWIR) HgCdTe electron avalanche photodiodes (e-APDs) with variable annealing processes and guard ring design is investigated. Carrier distribution in the device is performed by simulation methods to better understand the mercury interstitial dynamic transport mechanism. It is found that the device with suitable annealing time can effectively reduce the dark current while maintaining the bandwidth at a high level. Surface leakage current and the effect of guard ring design in ion implanted-type HgCdTe e-APDs are clarified by the electric-field distribution. The simulated results show that the dark current, excess noise factor, and mean square noise can be decreased with a guard ring design. In addition, the temperature-dependent performance of HgCdTe e-APD with guard ring is simulated, indicating optimization operating window. This article demonstrates the significance of guard ring designs for HgCdTe APDs, and the simulation method will provide an effective way to determine the source of the current generation mechanism.