Reliability Assessment of Avalanche Mode Operating Power MOSFETs through Coffin Manson Law based Mathematical Models

A possible alternative to traditional, time crunching, endurance tests in accomplishing the reliability assessment of power devices are reliability models. Two possible approaches are compared in this paper to estimate the level of reliability of power MOSFETs working in avalanche mode. Although both the considered approaches exploit mathematical models carried out from the Coffin-Manson law, they differ in correlating the progressive degradation of the metal Source to different physical variables, the temperature variation and the total strain respectively. The consistence of the proposed techniques is evaluated by comparing estimations with endurance tests results. The described approaches can be usefully applied to assess the reliability of MOSFETs working in avalanche mode in a large set of applications in the automotive field.