SiC and GaN – Beyond simple SiC-MOSFETs and GaN-HEMTs Nando Kaminski

Abstract:
Wide band-gap (WBG) devices have matured to a level that the SiC-MOSFET and the GaN-HEMT have become part of the power electronics mainstream and replace silicon devices in more and more applications already. However, the development of the devices carries on as gradual improvement generation by generation, but also as progress in the device technology, such that more sophisticated device structures have become viable. This work reviews the advances in device structures reported in recent years. For SiC, these are e.g. the super-junction MOSFET, the Ultra-Narrow-Body MOSFET, and monolithic integration, but also aspects of gate stability and power cycling capability. GaN power electronic device technology splits into lateral devices for < 1000 V and vertical devices for 1200 V. Monolithic integration is the key to fully exploit the high-speed potential of GaN HEMTs. New multi-channel HEMTs are explored to deliver even higher current densities and to use super-junction approaches also inside GaN. Vertical 1200 V GaN transistors based on inversion MISFETs and FinFETs already demonstrated switching with low losses. But only junction FinFET devices could combine these benefits with a competitive switching ruggedness with respect to long short-circuit times and an avalanching capability.