Epitaxial method of overweight red phosphorus-doped substrate

Abstract

The invention relates to an epitaxial method of an overweight red phosphorus-doped substrate, and the method comprises the following steps: growing an intrinsic silicon layer with the thickness exceeding the required thickness on the overweight red phosphorus-doped substrate to absorb impurities in a gas phase, etching the intrinsic silicon layer to the required thickness, and carrying out epitaxyon the intrinsic silicon layer. The method is completely different from the isolation thought in the prior art; impurities in a gas phase are absorbed by generating an over-thick intrinsic silicon layer; compared with the prior art, the method has the advantages that the doping in the gas phase is effectively removed, the problem that the gas phase doping greatly influences the resistivity in theepitaxial process of the overweight red phosphorus-doped substrate is solved, the edge of the epitaxial wafer prepared by the epitaxial method is highly consistent with the SRP in the center, and theyield of products is improved.

Description

technical field [0001] The invention relates to a production method of an epitaxial wafer, in particular to an epitaxial method of a super-heavily doped red phosphorus substrate. Background technique [0002] In the production process of epitaxial wafers in the prior art, self-doping phenomena generally exist. Self-doping is due to thermal evaporation or the diffusion of the by-products of chemical reactions to the substrate. The silicon and impurities in the substrate enter the gas phase, changing the doping composition and concentration in the gas phase, resulting in the actual impurity in the epitaxial layer. A phenomenon in which a distribution deviates from an ideal situation. The self-doping phenomenon is serious in epitaxy of super-heavily doped red phosphorus substrates (substrate resistivity ≤ 1.0mohm-cm). resistance profile, the shape of the extended resistance curve) is significantly different. [0003] Chinese patent application document CN106505093A discloses...

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Problems solved by technology

However, this isolation method can only solve the self-doping between the substrate and the epitaxial layer, and cannot solve the influence of the gas phase doping composition and concentration on the resistivity, especially for the epitaxial process of the super heavily doped red phosphorus substrate. , the doping composition has a great influence on the resistivity, and the doping composition in the gas phase will cause a significant difference in the SRP between the edge and the center of the epitaxial wafer, resulting in a decrease in yield

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