Method for manufacturing 6-inch POWERMOS transistor epitaxial layer

Abstract

The invention relates to a method for manufacturing a 6-inch power metal oxide semiconductor (POWERMOS) transistor epitaxial layer. The method is characterized by comprising the following steps of: 1) selecting a suitable POWERMOS transistor substrate slice and performing a certain preprocessing; 2) performing HCl gas-phase corrosion on the substrate slice at a certain temperature; 3) performing primary H2 speed-variable sweeping; 4) depositing an undoped intrinsic layer with the thickness of 1 to 2 mu m on the substrate slice; 5) performing secondary H2 speed-variable sweeping; and 6) forming a second epitaxial layer on the intrinsic layer. By the method, an autodoping phenomenon is inhibited to the maximum at a high temperature and substrate impurities are effectively prevented from diffusing and doping to the epitaxial layer, so that the resistivity uniformity and the width of a transition area are ensured; therefore, the requirements on both the breakdown voltage (BVDSS) and the on-resistance (RDSON) of the device are met.

Description

technical field [0001] The invention relates to a method for manufacturing the epitaxial layer of a 6-inch POWERMOS tube. Background technique [0002] With the development of electronic devices, devices that can control large currents and high voltages are being widely put into practical use. POWERMOS is a kind of device resulting from this. It is very popular because of its precise control. However, compared with general epitaxy, 6-inch POWERMOS epitaxy has a thicker epitaxial layer, high resistivity, and a relatively large surface area, which is 4 inches. 2.25 times and 1.44 times of 5 inches, so there are special requirements and standards for epitaxial wafers. [0003] The structure of the POWERMOS epitaxial wafer is to grow a layer of high resistivity epitaxial layer (N+ / N) on the N+ substrate, which cannot be realized by the ordinary epitaxial process. If the "silicon transfer (mass-transfer)" process is adopted, the base The silicon on the seat will be transferred ...

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Problems solved by technology

Due to the self-doping phenomenon, the transition region is widened, thereby reducing the effective thickness of the epitaxial layer

At the same time, the resistivity in the middle is larger than that at the edge, and the transition zone in the middle is narrower than the transition zone at the edge. As a result, the breakdown voltage BVDSS and the on-resistance RDSON distribution of the entire device are poorly distributed, resulting in Device Yield Decline

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