Patent ID: 8545622

Claim:
A method for manufacturing an annealed wafer, the method comprising the steps of: providing a silicon single crystal substrate having a volume density of voids with a size of 50 nm or less being less than 1×10 4 /cm 3 , and wherein providing the silicon single crystal substrate includes growing a silicon single crystal ingot by the Czochralski method using a nitrogen dopant concentration, a relative V/G value, and a cooling rate defined over a temperature range, from 1100° C. to 1000° C., wherein the nitrogen dopant concentration is from 1×10 14 atoms/cm 3 to 5×10 14 atoms/cm 3 , the relative V/G value is from 1.3 to 1.5, and the cooling rate is 4° C./min or more; and annealing the substrate.