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 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, the curve profile is inconsistent, resulting in additional variation in the epitaxial wafer between furnaces , affecting the BVDSS discreteness of subsequent devices

Therefore, there is an urgent need for new methods to suppress the poor uniformity of resistivity in the furnace and the large fluctuation between furnaces caused by high-temperature As volatilization.

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