Reverse breakdown studies of GaN MOSCAPs and their implications in vertical GaN power devices

Abstract

P-n diodes and metal-oxide-semiconductor-capacitors (MOSCAPs) are integral parts of vertical GaN power MOSFETs. The voltage in the off-state in trench MOSFETs is held by the p-n junction (source-drain) and the MOSCAP (gate-drain). Although the understanding of the reverse bias behavior of the p-n diode and the MOSCAP component is critical, the literature is sparse pertaining to the reverse bias studies of GaN MOSCAPs. In this work, we present a detailed investigation on the reverse bias behavior of in situ grown GaN MOSCAPs. A photo-assisted I-V technique is also presented to estimate the reverse breakdown field of the gate-dielectric.