Analysis Of Power MOSFETs Failure Mechanisms Based On TCAD Model

Power MOSFETs are widely used in power electronics systems due to their excellent high-frequency characteristics, but they are prone to degradation failure during long-term use, which has become a major issue affecting system safety. Current research on the degradation failure of power MOSFETs mainly focuses on the analysis of the regularities between their degradation-sensitive features and external stress. The microscopic mechanism of degradation is not yet complete. In view of this problem, this paper proposes a failure mechanism analysis of power MOSFETs based on TCAD model. Firstly, a two-dimensional structural model of power MOSFET is established using relevant process parameters. Then, by changing the external electrical stress of the device, the distribution of internal stress is studied, and the position of power MOSFETs most susceptible to degradation failure is determined. Then, the predetermined susceptible position is injected with a rated charge to simulate the degradation failure of the device, and the output of its SS curve is obtained. Finally, the SS test of the power MOSFET during the accelerated degradation test is performed, and the test results are compared with the simulation results to verify the correctness of the simulation.