| abstract |
(57) [Summary] [Problem] In addition to the absence of point defect aggregates, Oxygen concentration is 1.2 × 10 18 atoms / cm 3 (former AS The IG effect can be obtained even with TM) or more. SOLUTION: The minimum interstitial lattice which belongs to a perfect region [P] adjacent to a region [I] in which interstitial silicon type point defects are predominantly present and in which no point defect aggregates are present, and which can form interstitial dislocations. A region having a concentration lower than the silicon concentration is referred to as [P I ]. When the region is [P V ], an ingot consisting of at least either the region [P V ] or the region [P I ] and having an oxygen concentration of at least 1.2 × 10 18 atoms / cm 3 (former ASTM) is used. The wafer cut from the ingot is pulled from room temperature to 900 to 1200 ° C in a hydrogen or argon gas atmosphere at 5 to 50 ° C / Heat at a rate of minutes and hold for 5 to 120 minutes. |