Patent ID: 7182809

Claim:
A single crystal silicon ingot having a central axis, a seed end, an opposite end, and a constant diameter portion between the seed end and the opposite end having a lateral surface and a radius, R, extending from the central axis to the lateral surface, the single crystal silicon ingot being grown from a silicon melt and then cooled from the solidification in accordance with the Czochralski method, the single crystal silicon ingot being characterized in that: a. the constant diameter portion comprises an axially symmetric region in which vacancies are the predominant intrinsic point defect, the axially symmetric region being generally cylindrical in shape and having a radius, r as , extending from the central axis wherein r as is at least about 0.95 R, the axially symmetric region having a length as measured along the central axis of at least about 20% of the length of the constant diameter portion of the ingot; b. the axially symmetric region comprises nitrogen at a concentration of about 1×10 13 atoms/cm 3 to about 1×10 15 atoms/cm 3 ; and c. the axially symmetric region comprises oxygen at a concentration between about 7 ppma and about 10.5 ppma at about 5–6 mm inward of the lateral surface; and d. the axially symmetric region being substantially free of nuclei which form oxidation induced stacking faults.