Preparation method of semiconductor device and shield gate trench device

Abstract

The invention relates to a preparation method of a semiconductor device and a shield gate trench device, and the method comprises the steps: obtaining a substrate provided with a trench, forming a first dielectric layer on the inner wall of the trench, forming a polycrystalline silicon structure in a space where the first dielectric layer is not formed in the trench, and enabling the top of the polycrystalline silicon structure to be lower than the surface of the substrate; removing the part, higher than the polycrystalline silicon structure, of the first dielectric layer through wet etching; bombarding the top of the polycrystalline silicon structure by plasma to partially remove the top of the polycrystalline silicon structure; thermally growing a first oxide layer on the inner wall of the groove and the surface of the polycrystalline silicon structure; and filling the groove with a second dielectric layer, wherein the groove is filled with the second dielectric layer. The edge of the polycrystalline silicon structure is bombarded by the plasma, so that the width of the top of the polycrystalline silicon structure is reduced, the purpose of preventing small holes from being formed in the two sides of the top of the polycrystalline silicon structure is achieved, and then the purpose of eliminating gate source short circuit caused by abnormal filling is achieved.

Description

technical field [0001] The present application relates to the technical field of semiconductors, and in particular, to a preparation method of a semiconductor device and a shielded gate trench device. Background technique [0002] Shield Gate Trench (SGT, Shield Gate Trench) products are easy to form small holes on both sides of the top of the shield gate polysilicon. When the polysilicon gate is subsequently formed in the deep trench, the polysilicon gate is likely to enter the small hole, resulting in a gate-source short circuit. Moreover, since the protruding structure on the top of the shielding gate is easy to form a sharp charge concentration, it may cause the breakdown and leakage of the shielding gate and the gate during operation. SUMMARY OF THE INVENTION [0003] Based on this, it is necessary to provide a fabrication method of a semiconductor device and a shielded gate trench device. [0004] In order to achieve the above object, on the one hand, the present i...

AI Technical Summary

Problems solved by technology

When the polysilicon gate is subsequently formed in the deep trench, the polysilicon gate is easy to enter the small hole, causing a gate-source short circuit

And because the protruding structure on the top of the shielding grid is easy to form a sharp charge concentration, it may cause breakdown and leakage of the shielding grid and the gate during operation.

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