4H-SiC Trench Metal Oxide Semiconductor Field Effect Transistors with Low On-Resistance

Abstract

The fabrication and characteristics of high-performance 4H-SiC trench metal oxide semiconductor field effect transistors (MOSFETs) are presented. Vertical trench etching of SiC without sub trenches was performed by inductive coupled plasma-reactive ion etching (ICP-RIE) with SF6, O2, and HBr. It was found that the drain–source current (Ids) of a single channel plane was strongly dependent on the crystallographic planes, but that of unit cells was almost independent of the crystallographic planes. Specific on-resistance (Ron,sp) at gate–source voltage (Vgs)=20 V, drain–source voltage (Vds)=1 V is estimated to be 2.9 mΩ cm2, and the blocking voltage is 900 V. Moreover, Ids at Vds=5 V is over 100 A. The chip is 3.0×3.0 mm2. The lowest on-resistance in the fabricated trench MOSFETs is 1.7 mΩ cm2 and the blocking voltage is 790 V. The chip is 0.5×0.5 mm2.