Reliability Improvement and Optimization of Trench Orientation of 4H-SiC Trench-Gate Oxide

Reliability of gate oxide for trench-gate MOSFET was improved by deposited oxide film with uniform thickness and high-temperature annealing after trench etching. Optimum wafer orientation and trench direction for the trench gate was investigated, and the gate oxide on (11-20) plane of carbon face exhibited the longest lifetime. Influences by the roughness of sidewall and the radius of trench corner are discussed.