METHOD FOR FORMING SILICON CARBIDE DEVICE HAVING SHIELD GATE

摘要

PROBLEM TO BE SOLVED: To provide a method for forming a silicon carbide device having a shield gate.SOLUTION: A silicon carbide semiconductor substrate is formed, the silicon carbide semiconductor substrate having a plurality of first doped regions which are apart from each other in a lateral direction under a main surface and a second doped region extending from the main surface to a third doped region existing on the first doped region. A fourth doped region extending from the main surface to the first doped region is formed. A gate trench is formed, the gate trench having a lower part disposed on a part of one region in the first doped regions. The substrate is subjected to a high temperature process so that silicon carbide atoms are re-arranged along a side wall of the trench and a round corner is formed in the trench. A surface layer is removed from the substrate, the surface layer being formed along the side wall of the gate trench during the high temperature process.SELECTED DRAWING: Figure 1