Degradation behavior and mechanism of SiC power MOSFETs by total ionizing dose irradiation under different gate voltages

Abstract

In this work, the degradation behavior of the SiC power MOSFETs under total ionizing dose (TID) irradiation at different gate voltages was investigated. To simulate the radiation environment, 60CO was used as the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\gamma$</tex> -ray source, the dose rate was 50rad/s, and the cumulative absorbed dose was 1M Rad. The experimental results show that when a gate voltage is impressed to the test device, the threshold voltage is obviously negative shift, the output characteristic and capacitance curve also have negative shift phenomenon. Meanwhile, the device with positive gate voltage has more obvious shift than negative bias voltage. Furthermore, the blocking characteristics of the device had a noticeable change after irradiation, it means that the TID effect has an effect on the body diode. Changes in gate capacitance were also analyzed. The reason for this degradation could be that the high-energy particle radiation exciting plenty of electron-hole pairs in the oxide layer of MOSFET, the electrons flow out of the metal electrode after radiation, and the holes are captured by the oxide layer to form a new interface trap charge. This paper may have some reference value for the application of SiC power MOSFET in aerospace.