Patent ID: 7582357

Claim:
An epitaxial wafer which includes an epitaxial layer on a surface of a silicon semiconductor substrate, wherein the silicon semiconductor substrate is grown by the Czochralski method on a condition that a ring-shaped region of oxygen induced stacking fault emerges in a crystal surface over a whole length of a straight body portion of a pulled silicon single crystal, and wherein the silicon semiconductor substrate is sliced from the silicon single crystal, which has dopants consisting of carbon and boron, with boron ranging from 1×10 17 to 1×10 19 atoms/cm 3 and carbon ranging from 1×10 15 to 2×10 16 atoms/cm 3 (ASTM F123-1981), and wherein the number of defect to be observed on the surface of the epitaxial wafer is not more than 10 count/wf.