Minimizing Thermal Imbalance of RC-IGBT by Bonding Technology

Abstract

This paper describes a bonding technology for suppressing the thermal imbalance of a reverse conducting insulated gate bipolar transistor (RC-IGBT). The thermal imbalance is a difference of the heat distribution between the IGBT and free-wheeling diode (FWD) regions operating of the RC-IGBT. The heat distribution is determined by design of each active area. The different heat distribution unexpectedly increases the maximal thermal resistance and temperature at the bonded area. In this study, the temperature-uniform effects by the bonding are calculated by simulation to reduce the difference of the heat distribution. It was found that covering the FWD region with the bonding effectively decreased the thermal imbalance. The proposed structure improved the difference of the thermal resistance by more than 74% compared to the conventional structure. Additionally, the difference in temperature at the bonded area of the proposed structure was almost zero. Finally, the highest temperature of the bonded area in the proposed structure reduced by more than 13^°C compared to the conventional structure, which is 25% higher power cycle capability.