Performance and Reliability of SiC Power MOSFETs

Due to the wide bandgap and other key materials properties of 4H-SiC, SiC MOSFETs offer performance advantages over competing Si-based power devices. For example, SiC can more easily be used to fabricate MOSFETs with very high voltage ratings, and with lower switching losses. Silicon carbide power MOSFET development has progressed rapidly since the market release of Cree’s 1200V 4H-SiC power MOSFET in 2011. This is due to continued advancements in SiC substrate quality, epitaxial growth capabilities, and device processing. For example, high-quality epitaxial growth of thick, low-doped SiC has enabled the fabrication of SiC MOSFETs capable of blocking extremely high voltages (up to 15kV); while dopant control for thin highly-doped epitaxial layers has helped enable low on-resistance 900V SiC MOSFET production. Device design and processing improvements have resulted in lower MOSFET specific on-resistance for each successive device generation. SiC MOSFETs have been shown to have a long device lifetime, based on the results of accelerated lifetime testing, such as high-temperature reverse-bias (HTRB) stress and time-dependent dielectric breakdown (TDDB).