Investigating the Failure Mechanism of Short-Circuit Tests in 1.2-kV SiC JBS-Integrated MOSFETs

In this article, the failure mechanism of a 1.2-kV monolithic junction barrier-controlled Schottky diode integrated silicon carbide metal-oxide-semiconductor field-effect transistor (JMOS) under short-circuit (SC) tests has been investigated by an experimental validation and simulation analysis. As a new type of device, JMOS has superior performance and chip area efficiency. However, the SC ruggedness of the JMOS needs further investigation. When comparing vertical double-diffused metal-oxide-semiconductor field-effect transistor (VDMOS) and JMOS devices in the SC test study, the leakage current of the JMOS is much higher than that of a common VDMOS. During the SC test, the JMOS drain current cannot be successfully suppressed after gate turn-off, and the thermionic emission current due to heat generation in the Schottky barrier diode (SBD) region continues flowing into the n-drift region. The SBD thermionic emission current is rapidly increased by the increasing lattice temperature, which can reach over 1600 K. Eventually, the JMOS undergoes thermal runaway due to positive electrothermal feedback. A mechanistic study was set up to analyze the relationship between the SC limit and the leakage current in the SBD region of the heated materials. Finally, the key to improve the SC ruggedness of the JMOS is decreasing the leakage current in the SBD region.