To provide a technology to manufacture products having substantially the same electric characteristics regardless of the number of carbon atoms included in a silicon wafer, in a method of manufacturing a semiconductor device, which includes irradiation of ions of light elements or electron beams.

The method of manufacturing the semiconductor device includes an irradiation step of irradiating at least part of a region to be irradiated of a silicon crystal with ions of light elements or electron beams. At the irradiation step, an irradiation condition for ions of light elements or electron beams is so set that the content of a silicon cluster may exceed 0.06 times the content of carbon-oxygen composite defects in the region to be irradiated with ions of light elements or electron beams.