Observation of the surface degradation mode of InP/InGaAs APD's during bias-temperature test

We report the surface degradation mode observed during a bias-temperature (BT) test for InP/InGaAs APD's. Failure analyses using the light-beam-induced current (LIBIC) method clarify that the degradation is caused by local avalanche multiplication in the guard-ring periphery. Based on the analyses, we propose a failure mechanism.