High-frequency switching limitations in Gallium Nitride (GaN) and Silicon Carbide (SiC) power devices for boost converter applications

The dv/dt switching limitations of power semiconductor devices in a boost DC-DC power converter are evaluated using circuit simulations and accurate circuit simulation models. State-of-the-art commercial silicon CoolMOS devices, commercial Silicon Carbide (SiC) power Schottky Barrier Diodes (SBD's), and emerging Gallium Nitride (GaN) power transistors are considered. It is shown that although SiC and GaN power devices have low stored charge and small capacitances, these devices will 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 developed in order to optimize both performance and field-reliability.