Shield gate trench MOSFET and manufacturing method thereof

Abstract

The invention discloses a shield gate trench MOSFET and a manufacturing method thereof, and belongs to the field of integrated circuits. The shield gate trench MOSFET mainly comprises: a substrate sheet; an epitaxial layer grown on the substrate sheet; the hard mask is formed by depositing silicon oxide on the epitaxial layer and is removed after the deep groove is formed; the deep trench is obtained by etching the epitaxial layer on the hard mask by using a trench mask; the field dielectric layer grows on the surface of the deep groove and is flush with the surface of the source polycrystalline silicon; the source polysilicon is filled on the field dielectric layer in the deep trench; the gate trench is obtained by etching the field dielectric layer on the surface of the field dielectric layer by using an active region mask; the grid silicon oxide is formed by oxidizing the surface of the grid groove; and the grid polycrystalline silicon is deposited on the grid silicon oxide of the grid groove. According to the invention, the thick field dielectric layer is reserved between the gate and source electrodes for isolation, so that the gate-source electric leakage condition can be reduced, the parasitic capacitance of the device is reduced, and the parameter performance of the device is further improved.

Description

technical field [0001] The present application relates to the technical field of integrated circuits, and in particular, to a shielded gate trench MOSFET and a manufacturing method thereof. Background technique [0002] The prior art MOSFET manufacturing process is to first deposit a layer of silicon oxide on the epitaxial layer as a hard mask, and then make deep trenches through photolithography and etching processes, grow a thick oxide film in the deep trenches, fill the Polysilicon, remove surface polysilicon to form source, wet etching thick oxide film to form small trenches, grow gate oxide film, fill polysilicon and etch to form gate, and then perform body implantation and push well, source implantation and annealing , interlayer dielectric deposition and other subsequent processes, and finally form a complete MOSFET. [0003] In the prior art process, the isolation oxide film between the source and the gate polysilicon is simultaneously formed, that is, the source po...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the problems of excessive device gate-source leakage, poor device reliability and poor performance in the prior art, the present application mainly provides a shielded gate trench MOSFET and a manufacturing method thereof

Images