Optimization of surface passivation for InGaAs/InP pin photodetectors using ammonium sulfide

Abstract

In this work, the effect of the process parameters during chemical and electrochemical passivation of InGaAs/InP PIN photodetectors using (NH4)2Sx (x >1) has been studied in detail. It has been observed that the time of passivation, temperature of the sulfide solution and illumination during electrochemical treatment play significant roles in the efficacy of the passivation process. These parameters therefore have to be carefully optimized in order to reduce the dark current of the detectors to a minimum value. The yield of the process is also found to improve with sulfur passivation.