Failure analysis of a thin film thermoelectric generator

This paper describes a reliability study performed on a batch of thin film thermoelectric generators. The study took the form of an accelerated life testing program which was required to reduce the time needed to obtain significant data regarding the reliability of the devices. By extrapolation of the results of this test the mean time to failure of the devices at the upper limit of normal operating temperatures, i.e., 200 °C, was found to be 5×104 hours. The results also provided evidence of three degradation mechanisms. These were contact migration, corrosion and intermetallic formation. The high value of the activation energy for the failure process made it possible to conclude that the dominant failure mechanism was the latter.