Method for Improving the Uniformity of Resistivity of Epitaxial Layer

Abstract

The invention provides a method for improving the uniformity of the electrical resistivity of an epitaxial layer. According to the method for improving the uniformity of the electrical resistivity of the epitaxial layer, pre-covering is conducted inside a cavity with a selected dopant according to the distribution condition of the electrical resistivity of the epitaxial layer grown on a test sample, namely, a film containing the dopant is grown inside the cavity, and then epitaxy processing is conducted on a substrate. In the epitaxy process, the dopant on the internal side wall of the pre-covered cavity and a base can be diffused out under the influence of high temperature, and thus the concentration of the dopant gas on the edge of the substrate can be changed; the dopant gas enters the epitaxial layer, the distribution of the electrical resistivity of the epitaxial layer is changed, the influence of doping on the uniformity of the electrical resistivity of the epitaxial layer is reduced, and the qualified rate of products is increased.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for improving the resistivity uniformity of an epitaxial layer. Background technique [0002] The epitaxial process refers to the growth of a single crystal layer on a single crystal substrate, and the newly grown layer is called an epitaxial layer. The combined structure of substrate and epitaxial layer is called epitaxial wafer, and epitaxial wafer is divided into homogeneous epitaxial wafer and heterogeneous epitaxial wafer. In the homoepitaxial wafers widely used at present, the dopants of the substrate and the epitaxial layer mainly include N-type elements and P-type elements. In existing epitaxial wafers, the element types and concentrations of the dopant are different between the substrate and the epitaxial layer. For example, a commonly used epitaxial wafer has an N-type substrate, that is, the substrate is doped with one or more of N-type e...

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Problems solved by technology

[0005] The object of the present invention is to provide a method for improving the uniformity of the resistivity of the epitaxial layer to solve the problem of poor uniformity of the resistivity of the epitaxial layer on the substrate caused by the self-doping phenomenon

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