Physics of failure based reliability model of high-power InGaAs-AlGaAs strained QW lasers

High-power laser manufacturers often perform accelerated multi-cell life-tests by applying significant amounts of stresses to lasers to generate failures in relatively short test durations and then use an empirical model to estimate lifetimes of the lasers. A drawback of this approach is overestimation of lifetimes at usage conditions due to the lack of failures generated under intermediate and low stress conditions. Many groups have studied reliability and degradation processes in GaAs-based lasers, but none of these studies have yielded a reliability model based on physics of failure. The lack of such model is a concern for space applications where complete understanding of degradation mechanisms is necessary. Furthermore, our group reported a new failure mode in multi-mode and single-mode InGaAs-AlGaAs strained QW lasers in 2009 and 2016, respectively. Our group also reported in 2017 that bulk failure due to catastrophic optical bulk damage (COBD) is the dominant failure mode of both SM and MM lasers. For the present study, we performed physics of failure (PoF) investigation to develop a PoF-based reliability model. Our physics of failure investigation consisted of (i) a series of long-term and short-term life-tests that exclusively generated COBD failures and (ii) destructive and non-destructive failure analyses using electron beam induced current, time-resolved electroluminescence, time-resolved photoluminescence, focused ion beam, highresolution TEM, and deep level transient spectroscopy.