METHOD FOR PRODUCING EPITAXIAL SILICON WAFER AND EPITAXIAL SILICON WAFER

摘要

PROBLEM TO BE SOLVED: To improve the gettering capability of an epitaxial silicon wafer and to provide an epitaxial silicon wafer in which shortening of the carrier diffusion length is suppressed. SOLUTION: A method for producing the epitaxial silicon wafer comprises the steps of: growing a nitrogen-doped silicon single crystal rod by a Czochralski method; slicing the silicon single crystal rod into silicon single crystal wafers; subjecting the silicon single crystal wafers to heat treatment so as to diminish the crystal defects in the vicinity of the surface of each silicon single crystal wafer; further forming a silicon epitaxial layer on the surface of each silicon single crystal wafer; and subjecting each resultant silicon single crystal wafer to heat treatment comprising rapid heating and rapid cooling. The objective epitaxial silicon wafer is characterized in that the silicon epitaxial layer is formed on the nitrogen-doped silicon single crystal wafer, dislocation loops are contained in the bulk, the BMD density in the bulk is >=5×108 pieces/cm3, and the carrier diffusion length is 300 to 600μm.