A method of preparing a silicon epitaxial wafer from a heavily doped silicon single crystal substrate and an epitaxial wafer formed thereby

Abstract

The application discloses a method for preparing a silicon epitaxial wafer from a heavily doped silicon single crystal substrate and an epitaxial wafer formed by the method. The method is as follows: a carbon-oxygen co-doped heavily boron or phosphorus straight-drawn single crystal silicon wafer is used as a substrate, the substrate is pre-treated by epitaxial high-temperature hydrogen, then the temperature is increased to an epitaxial temperature to further grow an epitaxial layer, and finally a high-quality silicon epitaxial wafer is prepared. The high-temperature hydrogen pre-treatment step is as follows: the temperature is increased to 1200-1250 DEG C at a rate of 40-60 DEG C / s, kept for 150-300 s, then the temperature is decreased to 600-800 DEG C at a rate of 20-50 DEG C / s, and kept for 30-120 s. The silicon epitaxial wafer prepared by the method can form a high-density carbon-promoted carbon-oxygen co-precipitation induced stacking fault layer with a certain width under a clean area of a substrate surface layer after a device heat processing process, the silicon epitaxial wafer has the characteristics of absorbing self-interstitials and inhibiting boron or phosphorus outward diffusion, and a device with stable voltage resistance and strong impurity gettering capability can be obtained.

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