Detection and Analysis of Stress Wave in MOSFET Under Gate-Source Overvoltage Failure

As a real-time, online, and non-invasive monitoring method, acoustic emission (AE) monitoring technology has a promising future in the condition monitoring and fault diagnosis of power devices such as power MOSFETs. Stress waves are generated when power MOSFETs are turned on and off. Currently, most scholars have only researched the influence of circuit parameters on stress waves in normal devices or the relationship between stress waves and the aging state of devices or modules. However, the correlation between the characteristics of the stress wave and the specific failures inside the device has not been determined. As a result, the experiment for gate-source overvoltage failure was carried out in this work. The differential acoustic emission sensor was used to acquire stress waves of power MOSFETs under different gate-source voltages, including stress waves during chip overvoltage failure. The characteristics of stress waves are analyzed from the perspectives of time-domain and frequency-domain, and it can be concluded that the time-domain peak-to-peak value, signal energy, and wavelet peak value of the stress wave during the failure process are significantly different from those under normal conditions. The experimental results laid the groundwork for making a connection between device failures and the characteristics of the stress wave, which indicates that it will be possible to apply the acoustic emission monitoring technology to the fault diagnosis of power devices in the future.