Online Threshold Voltage Monitoring for Silicon Carbide Planar and Trench MOSFETs under γ-Ray Exposure

Traditional threshold-voltage ( V th ) measurements are usually performed either offline or during in situ state monitoring, are typically conducted offline or in situ state monitoring, limiting their ability to assess V th accurately during the aging process. This paper proposes an online method to monitor the V th of silicon carbide (SiC) metal oxide semiconductor field effect transistors (MOSFETs) within the space environment characterized by high-energy ionizing radiation. After observing the V th degradation during the experimental procedure, we simulated the total ionizing dose (TID)-induced degradation to validate the sampled V th of our experiment. The study also predicts V th degradation trends by analyzing the mechanisms of TID-induced degradation. A comprehensive 5-h TID experiment was performed using monitoring methods on a γ-ray plane at a dose rate of 50 rad(Si)/s, provided by a Co-60 source. V th measurements for planar MOSFETs and trench MOSFETs were collected every 15 min with a sampling accuracy of 0.1 V. The monitoring results aligned closely with the predicted trends. To further verify the efficacy of the monitoring technology, technology computer-aided design (TCAD) simulations were conducted to assess the V th sensitivity to TID. The proposed monitoring technology offers adjustable sampling accuracy and frequency, high precision, and a broad sampling range, making it suitable for most reliability test online monitoring applications. This method provides valuable insights for predicting the end-of-life and ensuring the space reliability of SiC MOSFETs.