Preparation method of trench gate field effect transistor

Abstract

The invention provides a preparation method of a trench gate field effect transistor. By etching the vertex angle of the gate trench to form the smooth transition section, the etching rate at the vertex angle position of the trench in the etching process is reduced, so that the oxide layer on the vertex angle of the trench cannot be quickly consumed and can be retained, and the problem of ion diffusion between the gate electrode and the well region is effectively avoided.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for preparing a trench gate field effect transistor. Background technique [0002] In a trench gate field effect transistor, a gate structure is disposed within a gate trench of a substrate, and a well region and a source region are formed in the substrate on the sides of the gate trench. At present, a method for fabricating a trench gate field effect transistor generally includes: first, forming a gate electrode in a gate trench of a substrate, and then forming a well region in the substrate on the side of the gate trench. However, the trench gate field effect transistor formed according to the current fabrication process is prone to the problem of interdiffusion of ions between the gate electrode and the well region, thereby causing the electrical properties of the device to drift. SUMMARY OF THE INVENTION [0003] The purpose of the present invention is to p...

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Problems solved by technology

[0003] The purpose of the present invention is to provide a method for preparing a trench gate field effect transistor, so as to solve the problem that ion interdiffusion easily occurs between the gate electrode and the well region in the existing trench gate field effect transistor

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