Electrical Parameters Characterization of Aged IGBTs by Thermo-Electrical Overstress

During their lifetime, power semiconductor devices such as Insulated Gate Bipolar Transistors (IGBTs) can suffer from different failure mechanisms. This paper reports the monitored changes in the electrical parameters of tested IGBTs when subjected to accelerated ageing through thermo-electrical overstress. The changes are indicative that the device is at the onset of failure and hence can be utilized within prognostic techniques so as to determine the health state of the device. The study describes how the accelerated ageing strategy was implemented providing details of the implemented hardware and software. Tested IGBTs were characterized before, during and after accelerated ageing. Details of the IGBT characterization setup are provided. Furthermore, the corresponding monitored changes in the die-attach X-Ray imagery, gate threshold voltage, collector leakage current, transfer characteristics, transconductance, output characteristics and internal free-wheeling diode forward characteristics are presented and discussed