Preparation method used for silicon carbide MOSFET device and capable of realizing p+ region self-alignment process

Abstract

The invention discloses a preparation method used for a silicon carbide MOSFET device and capable of realizing a p+ region self-alignment process. According to the preparation method of the invention,the first ion implantation mask layer of p-wells is subjected to photoetching; and ion implantation is performed on the p-wells, so that p-well regions can be formed; after the ion implantation of the p-wells, a second ion implantation mask layer for source contact n+ regions is deposited; the second ion implantation mask layer is not subjected to photoetching, but directly subjected to etching,so that n+ ion implantation regions can be formed; ion implantation is performed, so that source contact n+ regions are formed; after the source contact n+ regions are formed, a third ion implantationmask layer for source contact p+ regions is deposited; the third ion implantation mask layer is not subjected to photoetching, but directly subjected to etching, so that p+ ion implantation regions are formed; ion implantation is performed, so that the source contact p+ regions are formed; and therefore, the self-alignment process of channel regions is achieved, at the same time, the self-alignment process of the p+ regions is achieved; primary photoetching is reduced; a process is simplified; manufacturing cost is decreased; and the uniformity and long-term reliability of the on resistance of the silicon carbide MOSFET device are improved.

Description

technical field [0001] The invention belongs to the technical field of semiconductors, and in particular relates to a method for preparing a silicon carbide MOSFET device with a p+ region self-alignment process. Background technique [0002] Silicon carbide material has excellent physical and electrical properties. With its unique advantages such as wide band gap, high thermal conductivity, large saturation drift velocity and high critical breakdown electric field, it has become a high-power, high-frequency, high-voltage It is an ideal semiconductor material for high temperature resistant and radiation resistant devices, and has broad application prospects in military and civil affairs. Silicon carbide MOSFET devices have the advantages of fast switching speed and small on-resistance, and can achieve a high breakdown voltage level at a small drift layer thickness, reduce the volume of the power switch module, and reduce energy consumption. , Converters and other application...

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Problems solved by technology

[0004] However, during the thermal oxidation process of polysilicon, the side moves to achieve self-aligned implantation in the source region and form a self-aligned channel. This method has strict requirements on the thermal oxidation process of polysilicon, and the size of the formed channel cannot be precisely controlled. Misalignment issues to the p+ region

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