Method of manufacturing epitaxial wafer and method of producing single crystal as material therefor

摘要

Epitaxial wafers showing marked IG effects can be manufactured from silicon single crystals doped or not doped with nitrogen without requiring any additional heat treatment process step while reducing the density of epitaxial layer defects. According to the first manufacturing method, an epitaxial layer is allowed to grow on the surface of a wafer sliced from a single crystal produced by employing a cooling rate of not less than 7.3° C./min in the temperature range of 1200-1050° C. in the step of pulling up thereof. According to the second manufacturing method, an epitaxial layer is allowed to grow on the surface of a silicon wafer sliced from a silicon single crystal doped with 1x1012 atoms/cm3 to 1x1014 atoms/cm3 as produced by employing a cooling rate of not less than 2.7° C./min in the temperature range of 1150-1020° C. and then a cooling rate of not more than 1.2° C./min in the temperature range of 1000-850° C. in the step of pulling up thereof.