Unclamped Inductive Switching (UIS) Characteristics of GaN Power Devices: Mechanism, Testing, and Design Optimization

This paper systematically discusses the working principles, UIS testing methods, and structural optimization design of gallium nitride (GaN) power devices. First, the basic structure and operating mechanism of GaN devices are examined. The formation mechanism of the two-dimensional electron gas conductive channel in p-GaN HEMTs and the avalanche characteristics of vertical-structure devices are analyzed. Next, the UIS testing method is described, and the differences in test standards between traditional silicon devices and GaN devices are compared. Based on a study of failure mechanisms, a new p-GaN HEMT structure incorporating a p-type buried layer is tested. This structure significantly improves the UIS tolerance of the device by optimizing the electric field distribution, providing an effective solution to the reliability challenges of GaN power devices.