Reliability of SiC Power MOSFETs under High Repetitive Pulse Current Conditions

摘要

Due to technology advancements in material sciences, power MOSFETs manufactured with wide band gap materials such as silicon carbide (SiC), gallium nitride (GaN) have been proposed as an alternative to silicon (Si) based MOSFETs and IGBTs. Reliability of these power switches is important when considering their vital role in power converters for aerospace, railways, hybrid electric vehicles, and power system applications. In this paper, 1200V 4H-SiC MOSFET 2D device model is designed and simulated using technology computer-aided design (TCAD). Later mixed mode simulations are carried out under repetitive pulse current conditions. During the testing, device characteristics such as threshold voltage (V_(th)), on state resistance (R_(ds-on)), and junction temperature (T_j) are recorded. Instability in the threshold voltage of the device is identified due to trapping of interface charges at the gate oxide as a result of the pulse current stress on the device. Fur therm o re it is identified that junction temperature and on state resistance increases with the increase in the number of pulse current cycles which can eventually lead to device failure.