Self-aligned trench type power device and manufacturing method thereof

Abstract

The invention provides a manufacturing method of a self-aligned trench type power device, which comprises the steps of implanting ions into the surface of a silicon wafer, carrying out high temperature annealing, forming a P-type implantation region and an N-type implantation region, and sequentially preparing a first silicon oxide layer, a magnesium oxide layer and a second silicon oxide layer; growing a mask material on the second silicon oxide layer so as to form a mask pattern; carrying out etching so as to form a trench; removing the mask material by adopting an acid solution; preparing a polycrystalline silicon layer on the surface of the crystal silicon wafer at the moment, and enabling the trench to be filled with polycrystalline silicon; removing the polycrystalline silicon on the surface of the crystal silicon wafer by using dry etching; carrying out thermal oxidation and dry etching; carrying out implantation on the crystal silicon wafer after thermal oxidation and dry etching so as to form a source electrode contact region; and preparing a metal layer on the crystal silicon wafer surface where the source electrode contact region is formed, and carrying out annealing. Correspondingly, the invention further provides a self-aligned trench type power device. Through the technical scheme provided by the invention, the device area is reduced, the on-resistance and the manufacturing cost of the device are reduced, and the device performance is improved.

Description

technical field [0001] The present invention relates to the technical field of semiconductors, in particular to a method for manufacturing a self-aligned trench power device and a self-aligned trench power device. Background technique [0002] Trench power devices are widely used. The drain and source poles are located on both sides of the device, allowing the current to flow vertically inside the device, increasing the current density, improving the rated current, and the on-resistance per unit area is also small. [0003] At present, the photolithography process is commonly used to form the source metal contact of the active region of the trench power device. The photolithography process has high etching accuracy and low defect density. However, in order to integrate more chips in the same area, the size of adjacent trenches must be reduced. At this time, the more resistors connected in parallel, the smaller the total on-resistance. Therefore, the reduction of the size of ...

AI Technical Summary

Problems solved by technology

However, due to the reduction in size, the requirements for lithography accuracy are higher. The cost of lithography machines is very expensive, and the depreciation speed is fast when used. The higher the requirements for lithography accuracy, the cost of purchasing lithography machines The higher it is, the longer it will take to make the device, which is not conducive to industrial production

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