Method for improving on-chip resistivity uniformity of epitaxial wafer

Abstract

The invention discloses a method for improving on-chip resistivity uniformity of an epitaxial wafer, and relates to the technical field of a fabrication method for a silicon substrate epitaxial layer. The method comprises the following steps of corroding an epitaxial furnace base under a high temperature by a high-purity hydrogen chloride gas; loading a silicon substrate sheet into a pit of the epitaxial furnace base, and blowing an epitaxial furnace cavity by high-purity hydrogen during the temperature rising process of an epitaxial furnace until a set temperature is reached; performing heat preservation for over 5 minutes; performing large-flow and variable-flow blowing when the temperature of the epitaxial furnace is risen to the set temperature, wherein the gas flow is set 100-(-400)L/min, and the time is more than 4 minutes; and reducing the temperature of the epitaxial furnace to an epitaxial growth temperature, and performing epitaxial growth of the silicon substrate sheet. By the method, the on-chip resistivity of the epitaxial wafer can be more uniform, the finished rate is greatly improved, and the profile consistency of SRP curve is greatly improved.

Description

technical field [0001] The invention relates to the technical field of a method for manufacturing an epitaxial layer of a silicon substrate, in particular to a method for improving the uniformity of resistivity in an epitaxial wafer. Background technique [0002] In the case of high-temperature epitaxy on heavily arsenic-doped substrates, As high-temperature volatilization leads to poor uniformity of epitaxial resistivity in the wafer; at the same time, substrates with different As concentrations have inconsistent high-temperature volatilization of As, resulting in different self-doping between furnaces, which in turn leads to poor uniformity of epitaxial resistivity. The resistivity of the epitaxial layer fluctuates greatly. The high-temperature volatilization and self-doping of As heavily doped substrate gradually decreases with the epitaxial growth time, resulting in the longitudinal curve profile of the epitaxial layer being a curve, and different self-doping conditions,...

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Problems solved by technology

[0002] In the case of high-temperature epitaxy on heavily arsenic-doped substrates, As high-temperature volatilization leads to poor uniformity of epitaxial resistivity in the wafer; at the same time, substrates with different As concentrations have inconsistent high-temperature volatilization of As, resulting in different self-doping between furnaces, which in turn leads to poor uniformity of epitaxial resistivity. Epitaxial layer resistivity fluctuates greatly

The high-temperature volatilization and self-doping of As heavily doped subst

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