Voltage Switching Limits of Lateral GaN Power Devices

Abstract

The dv/dt switching limitations of power semiconductor devices are evaluated in a boost (PFC) power converter using circuit simulations. State-of-the-art commercial silicon CoolMOS devices, commercial Silicon Carbide (SiC) Junction Barrier Schottky (JBS) diodes, and emerging Gallium Nitride (GaN) lateral power transistors are considered. It is shown that although SiC and GaN power devices have low stored charge and small capacitances, they experience high switching dv/dt stresses which may pose serious switching limitations especially in high-frequency power converters. This problem is likely to be further exacerbated by the presence of a high density of crystal defects in SiC and GaN materials which will manifest in the form of poor field-reliability. Specific guidelines for device selection are recommended in order to optimize both performance and field-reliability.