Research on the Mechanism of Electrical Erosion Accelerating Failure in High-Current Pulse Thyristor-Based Switches

High-current pulse thyristor-based switches operate under high-current pulse conditions and are subjected to coupled electromagnetic-thermomechanical stresses, resulting in the progressive development of thermal fatigue-induced failure mechanisms. The study revealed that localized overheating triggers electrical erosion of the aluminum layer, which further accelerates the thermal fatigue failure of high-current switches. To investigate this phenomenon, a microscopic model of the silicon-aluminum interface incorporating surface roughness effects was developed to quantify the transient temperature rise and electrical erosion threshold under varying pulsed current conditions, with experimental validation demonstrating strong agreement. Furthermore, using a thermal network model, we established a correlation between the electrical erosion threshold and the average junction temperature for different high-current pulses and clamping stresses, thereby defining the operational range for electrical erosion in high-current pulse thyristor-based switches. This provides theoretical guidance for the reliable operation of these switches.