Patent ID: 7105050
Filing Date: 2006-09-12
Classification: A61K,C30B

Abstract:
1. A process for the preparation of a silicon single crystal in which molten silicon is solidified into a crystal in accordance with the Czochralski method to form an ingot having a central axis, a seed-cone, an end-cone, a constant diameter portion between the seed-cone and the end-cone having a lateral surface, and a radius, R, extending from the central axis to the lateral surface of at least about 75 mm, the constant diameter portion having an axial length, L, the process comprising; controlling a ratio, v/G cooling said regions from the temperature of solidification at a rate which allows silicon self-interstitial atoms to diffuse radially to the lateral surface and to diffuse axially to vacancy dominated regions to reduce the concentration of silicon self-interstitial atoms in the region(s) in which silicon self-interstitial atoms were initially the predominant intrinsic point defect and to reduce the concentration of crystal lattice vacancies in the region(s) in which crystal lattice vacancies were initially the predominant intrinsic point defect.