Improvement of surface leakage current of 2.6 µm InGaAs photodetectors by using inductive coupled plasma chemical vapor deposition technology

Low surface leakage current is one of the prerequistites to reach the low leakage and high efficiencies of mesa type photodiodes. In this paper, we have studied the surface leakage of 2.6 mu m mesa InGaAs p-i-n photodetectors by using two different passivation technologies: inductive coupled plasma chemical vapor deposition (ICPCVD) and plasma enhanced chemical vapor deposition (PECVD). It is found that the total leakage current of the detector with ICPCVD technology is significantly reduced compared to that with PECVD technology due to the decrease of the device's surface leakage current. A TCAD-based dark current model further reveals that the reduction of the surface leakage current at the low reverse voltage is about two orders of magnitude. As a result, ICPCVD is the promising deposition technology for SiNx passivation layer on mesa InGaAs photodetectors. (C) 2015 The Japan Society of Applied Physics