Shielded gate mosfet and fabricating method thereof

Abstract

A fabricating method of a shielded gate MOSFET is provided, includes the steps of forming a semiconductor substrate having a trench, forming a sacrifice oxide layer in the trench, the sacrifice oxide layer covering a side wall of the trench, forming a source polycrystalline silicon region in the trench, forming an insulation oxide layer above the source polycrystalline silicon region to have the source polycrystalline silicon region fully enclosed by the sacrifice oxide layer and the insulation oxide layer, depositing polycrystalline silicon into the trench and carrying out a back etching to control a thickness of the insulation oxide layer above the source polycrystalline silicon region, forming a gate oxide layer in the trench, the gate oxide layer covering the side wall of the trench, forming a gate polycrystalline silicon region in the trench, and forming a body layer and a heavily doped region around the trench in an ion implantation manner.