Analysis of the Stress Wave Characteristic Parameter of Cascode GaN HEMT

Mechanical stress wave characteristic parameters are important for analyzing the health of power devices, and are the basis of power cycling experiments to establish the connection between the device's health status and its mechanical stress wave. Based on acoustic emission detection technology, this paper analyzes the generation principle of the mechanical stress wave in Cascode GaN HEMT firstly, and then designs repeatability tests to analyze the stress wave characteristics at different locations of the device and the variation law of stress wave characteristic parameters. We found that the stress wave acoustic emission source is at the bottom-middle of the device. Stress wave in the 60k-90kHz and 150k-180kHz frequency bands are generated when the device is turned on or off. It is positively correlated with the drain-source voltage and have a good peak parameter fitting curve on the package surface, while the stress wave has no relationship with the gate-source voltage.