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 article analyzes the generation principle of the mechanical stress wave in cascode gallium nitride (GaN) HEMT first 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 waves in the 60–90 and 150–180 kHz frequency bands are generated when the device is turned on or off. It is positively correlated with the drain–source voltage and has a good peak parameter fitting curve on the package surface, while the stress wave has no relationship with the gate–source voltage.