Method of minimizing field stop insulated gate bipolar transistor (IGBT) buffer and emitter charge variation

摘要

This invention discloses an insulated gate bipolar transistor (IGBT) formed in a semiconductor substrate. The IGBT comprises a buffer layer of a first conductivity type formed below an epitaxial layer of the first conductivity having body and source regions therein. The IGBT further includes a lowly doped substrate layer below the buffer layer and a dopant layer of a second conductivity type disposed below the lowly doped substrate layer and above a drain electrode of said IGBT attached to a bottom surface of said semiconductor substrate wherein the dopant layer of the second conductivity type has a higher dopant concentration than the lowly doped substrate layer.