Step-Change in HV-H³TRB Performance of Latest Silicon IGBTs and Advanced Humidity Testing Methods

Abstract:
To assess the progress in humidity performance of recent silicon IGBTs, three different IGBT modules were HV-H³TRB (High Voltage-High Humidity High Temperature Reverse Bias) tested. The reliability of these modules has reached a point at which they exceed the standard test duration of 1000 h by a factor of three or more without exhibiting detectable signs of degradation. This leap in reliability performance should eliminate humidity driven field failures completely. However, there is a risk that the HV-H³TRB does not cover all humidity effects or that the field operating conditions (mission profile) are so different from the test conditions, in particular more extreme, that additional mechanisms are triggered. Consequently, advanced and combined tests have been proposed to detect potential risks. The results of such tests show that a preconditioning with a Power Cycling Test (PCT) can indeed reduce the lifetime in a subsequent HV-H³TRB test, while there is no indication that passive condensation cycles in between the high humidity and high temperature phases accelerate the degradation.