Analysis of thermal cycling effects in power devices under non-constant cumulative stress

This work experimentally investigates the reliability of TO-247 packaged power devices, with the goal of analyzing the impact of non-constant cumulative power cycling tests. Power devices are first stressed with a constant junction temperature cycling. Cumulative distribution function is experimentally evalu-ated and fitted with a Weibull statistics. According to the Miner's rule, the lifetime of components is calculated under a given non-constant cumulative stress at different levels of probabilities of failure. Experimental power cycling tests are then carried out to verify the accuracy of the predicted lifetime values.