Epitaxial silicon wafer

Abstract

An epitaxial silicon wafer is provided with a boron-doped silicon substrate and an epitaxial layer formed on a surface of the silicon substrate, wherein the boron concentration in the silicon substrate is 2.7×10 17 atoms/cm 3 or more and 1.3×10 19 atoms/cm 3 or less, and an initial oxygen concentration in the silicon substrate is 11×10 17 atoms/cm 3 or less. When an oxygen precipitate evaluation heat treatment, such as a heat treatment at 700° C. for 3 hours and a heat treatment at 1,000° C. for 16 hours is executed on the epitaxial silicon wafer, the density of oxygen precipitate in the silicon substrate is 1×10 10 /cm 3 or less.

What is claimed is: 
     
         1 . An epitaxial silicon wafer in which an epitaxial layer is formed on a surface of a boron-doped silicon substrate, wherein
 the boron concentration in the silicon substrate is 2.7×10 17  atoms/cm 3  or more and 1.3×10 19  atoms/cm 3  or less,   an initial oxygen concentration in the silicon substrate is 11×10 17  atoms/cm 3  or less, and   when an oxygen precipitate evaluation heat treatment is executed on the epitaxial silicon wafer, the density of oxygen precipitate in the silicon substrate is 1×10 10 /cm 3  or less.   
     
     
         2 . The epitaxial silicon wafer as claimed in  claim 1 , wherein
 the boron concentration Y (atoms/cm 3 ) and the initial oxygen concentration X (×10 17  atoms/cm 3 ) satisfy a relational expression of X≤−4.3×10 −19 Y+16.3.