Failure analysis of power transistors

This article illustrates a number of types of degradation and material damage found in the microstructures of the component parts of power transistors. The various types of damage are clarified with reference to the results of metallographical investigations which clearly trace the microstructural changes and damage sustained back to causes such as current or voltage overload, or temperature cycling in service,The thermomechanical fatigue processes presented show that semiconductor components are subject to damage by long term material degradation.