Abstract

Avalanche photodiodes (APDs) are important building blocks for high-sensivity, low-noise receivers deployed in the datacenter, wireless and cloud computing networks. Maintaining stable dark current is a crucial task for overall robust sysem reliability. To achieve design-in low dark current stability, good knowledge of reliability physics is indispensable. In this work, we study the physical mechanisms of 10G/25G mesa-type APD degradation. We institute a predictive reliability model to account for the degradation processes. A comprehensive comparison of APD and IC transistor is also illustrated in terms of dielectric breakdown, mobile ion migration and hot carrier injection. The model suggests that surface leakage current is the dominant factor for the mesa-type APD degradation. Based on the model, it is predicted that highly reliable 10G/25G APD can be achieved with the suppression of weak links at the surface/interface states.

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