Method for increasing breakdown voltage of power MOS field effect transistor

Abstract

The invention provides a method for increasing breakdown voltage of a power MOS field effect transistor, comprising the following steps: etching out a first shallow groove in the substrate of the power MOS field effect transistor; depositing a first oxide layer in the first shallow groove; etching out a plurality of second shallow grooves in the first oxide layer; forming two polysilicon gates onthe substrate and the first oxide layer; carrying out ion implantation on the surface of the substrate on the outer sides of the two polysilicon gates, thereby forming a first active region and a second active region; depositing a second oxide layer on the polysilicon gate; and fabricating a field plate on the second oxide layer. The method not only eliminates the included angle formed during thegrowth process of the polysilicon in the power MOS field effect transistor, but also disperses the electric field strength on the surface of the power MOS field effect transistor, thereby reducing the electric field strength on the surface of the power MOS field effect transistor to the utmost extent and increasing the breakdown voltage of power MOS field effect transistor.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for increasing the breakdown voltage of a power MOS field effect transistor. Background technique [0002] Power MOS field effect transistors have been used for many years, and their design and manufacturing methods have been continuously improved. The full name of MOS in English is Metal-Oxide-Semiconductor, that is, metal-oxide-semiconductor. To be precise, this name describes the structure of power MOS field effect transistors in integrated circuits, that is, on semiconductor devices with a certain structure, plus silicon and metal. Structurally speaking, MOS tubes can be divided into enhancement type (E type) and depletion type (D type). Power MOS field effect tubes generally have three electrodes: source (source), drain (drain) and The gate (gate) and the circuit formed by the power MOS field effect transistor are generally called MOS circuits, but there...

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Problems solved by technology

[0005] In order to solve the problem in the prior art that the MOS field effect is easily broken down due to the included angle of polysilicon in the MOS field effect, the present invention provides a method for increasing the breakdown voltage of the MOS field effect

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