Reliability of Commercially Available and State-of-the-Art SiC MOSFETs Under Gate Stress and Body Diode Stress

An ideal transistor from a circuit designers standpoint consists of an ultra-low on-resistance, majority carrier switching, low gate current drive, and normally-off design. These features are inherent in the silicon carbide (SiC) power MOSFET, with the small footnote that the device, although having surpassed many hurdles along the way, is still plagued by a few key issues that limit commercial adoption into todays systems threshold voltage instability and body diode forward voltage degradation. These issues result in a limited application space for SiC MOSFETs due to the bias-dependent threshold voltage and oversizing (cost increasing) of the anti-parallel SiC Schottky diodes to ensure the body diodes do not conduct current, respectively. These reliability issues need to be studied across device vendors, SiC MOSFET structures, SiC MOSFET device generations, active areas, gate-bias electric fields, and temperature to allow for an accurate assessment of the technology. The work proposed herein addresses all of these variables and will help industry better understand the instabilities of the devices over a range of conditions, as well as the implications to the end user, due to APEI, Inc.s unique in-house system design team. Commercial Applications and Other Benefits: Proposed long term testing includes high temperature positive and negative gate bias, body diode bias, and switching tests across a number of commercial and state-of-the-art SiC MOSFET manufacturers such as Cree, Rohm Semiconductor, GE, Microsemi, and STMicroelectronics. Individual device performance data will be collected at strategic time intervals throughout testing with the end goal being an accurate assessment of any device performance shift as a result of the applied bias. As a leader in wide bandgap electronics, APEI, Inc. has a vested interest in developing qualification and reliability test programs in order to further advance the adoption of SiC devices into commercial, industrial, military, aerospace, and energy exploration applications. By remaining device neutral, APEI, Inc. is able to provide independent, unbiased, accurate results as a 3rd-party testing facility.