Investigation and improvement of DMOS switches under fast electro-thermal cycle stress

In this article, the failure behavior of DMOS switches under repetitive clamping stress is shown to be dominated by thermomechanical deformation of the metallization. Electromigration stress is not a significant factor in the failure. This was verified with special stress tests, and the thermomechanical characteristics were furthermore highlighted by FEM simulation. Based on these findings, a novel metallization system that significantly improves the fast temperature cycle reliability is described.