4H-SiC MOSFETs with a Stable Protective Coating for Harsh Environment Applications

In this work we present 4H-SiC metal-oxide-semiconductor field-effect transistors (MOSFETs) with a stable protective coating for harsh environment applications. Both inversion channel (IC) and buried channel (BC) MOSFETs were realized on n-4H-SiC substrates with a p-epilayer. Stacked ONO gate dielectric and Ti/TiN/Pt/Ti interconnect were used. Ni and Ti ohmic contacts in combination with a-SiOx/a-SiNy and a-SiOx/a-SiC protective coatings were compared. The MOSFETs showed excellent transistor characteristics up to 600 degrees C and exceptional stability during long-term aging at 600 degrees C in air and during accelerated aging at 700 degrees C including temperature cycling and air/moisture environment.