New temperature-independent aging indicator for power semiconductor devices – Application to IGBTs

The accurate online estimation of power electronic module health is critical for predictive maintenance, particularly in predicting the remaining useful life of systems under field operating conditions. Conventional aging indicators often require complex, costly procedures involving junction temperature estimation, which limits their suitability for on-line monitoring. This study introduces a novel electrical aging indicator tailored for bond-wire contact degradation, offering ease of online implementation and temperature independence. The indicator is based on experimental and theoretical insights into the behavior of the zero-temperature coefficient (ZTC) in the I-V characteristics of IGBTs affected by top-metal interconnect degradation. The results show that the degradation of the bond-wire contacts has an effect on the ZCT point with a strong impact on the current and very little on the voltage. Leveraging this result enables the development of an online monitoring approach, the methodology of which is demonstrated through power cycling tests. Both traditional and new aging indicators show strong correlations with aging. In addition, the proposed new indicator has a better sensitivity to the degradation. • A new aging indicator for top-side degradations of bipolar power devices is defined. • This parameter is based on the zero-temperature coefficient (ZCT) point. • The new aging indicator is more sensitive than the traditional one. • It is temperature independent and easily implementable for on-line monitoring • A full demonstration of implementation under near-operational conditions is given.