Patent ID: 7544545

Claim:
A method of manufacturing a semiconductor device comprising: forming a N−(P−) type epitaxial region on N+(P+) type substrate; forming a polysilicon diode trench in said epitaxial region; forming an insulating layer in said polysilicon diode trench; filling said polysilicon diode trench with polysilicon; implanting a P+(N+) type dopant, forming a P+(N+) type region of said polysilicon in said polysilicon diode trench; implanting a N+(P+) type dopant, forming a N+(P+) type region of said polysilicon in said polysilicon diode trench to form a polysilicon diode in said polysilicon diode trench, wherein a portion of said polysilicon diode is lower than said top surface of said polysilicon diode trench; and forming a metal-oxide-semiconductor field effect transistor (MOSFET) transistor trench in said epitaxial region, wherein, forming said diode is performed prior to forming said MOSFET transistor trench.