IGBT power device conductivity modulation trench igbt short circuit electric field FinFET 도체 반도체 부도체 acceptor P형 도핑 N형 도핑 반도체 도핑 반도체의 정의 반도체 소자 공학 Selfheating high k high k dielectric field plate Drain Extension GP SJ IGBT FP SJ IGBT dual gate Superjunction hole extraction hole barrier Superjunction IGBT superjunction structure 에너지 밴드 planar igbt breakdown voltage floating p layer carrier storage layer ret igbt igbt electric field igbt breakdown SiC bandgap SiC igbt latch up CS igbt igbt 동작 fs igbt npt igbt pt igbt SiGe tail current 반도체란 donor 밴드갭 SIC