Influence of Junction Temperature on Reliability of an Insulated Gate Bipolar Transistor

Abstract

The operating performance and reliability of semiconductor devices, like insulated gate bipolar transistors (IGBTs) are closely related to their operating temperature. Thermal modelling of semiconductor devices helps in understanding the heat transfer characteristics and plays a significant role in extending the life and reliability of IGBT modules. Present work describes the development of an analytical method to calculate the transient thermal impedance and junction temperatures of the IGBT. A computational technique is also developed based on the analytical method. The input parameters for this technique essentially consist of thermal resistances of all the layers of IGBT, capacitance values, ambient temperature, voltage and current across IGBT. Output parameters are transient thermal impedance and junction temperatures. Results obtained show that there is a substantial decrement of junction temperature of 53% due to change of duty cycle to 0.5 to 0.3 and it further reduces in case of duty cycle 0.1. Results obtained also show that the mathematical model developed is effective and accurate to predict temperatures during transient conditions and is applicable for other devices, such as diodes and thyristors.