Novel failure mechanism of nanoscale mesa-type avalanche photodiodes under harsh environmental stresses

Avalanche photodiode (APD) is an indispensable receiver component because of its high bandwidth and low noise performance. Recently, APD reliability, under harsh environmental stresses such as high heat and humidity, has drawn great interest in the applications of passive optical network, wireless, military, and free space optics. The authors study the APD degradation under the harsh environment of high humidity and high bias. The failure morphology through cross-sectional scanning electron microscopy is shown, and a new moisture degradation model based on electrochemical oxidation to account for the failure mechanism is developed.