Patent ID: 6743289
Filing Date: 2004-06-01
Classification: C30B,H01L,Y10T

Abstract:
A process for preparing a single crystal silicon wafer, the process comprising thermally annealing a single crystal silicon wafer at a temperature in excess of about 1000Â° C. in an atmosphere of hydrogen, argon, oxygen nitrogen, or a mixture thereof, said wafer having a central axis, a front side and a back side which are generally perpendicular to the central axis, a central plane between the front and back sides, a circumferential edge, a radius extending from the central axis to the circumferential edge, a first axially symmetric region extending radially inward from the circumferential edge in which silicon self-interstitials are the predominant intrinsic point defect and which is substantially free of agglomerated interstitial defects, a second axially symmetric region, located radially inward of the first axially symmetric region, in which vacancies are the predominant intrinsic point defect and which is substantially free of agglomerated vacancy defects, and a third axially symmetric region, located radially inward of the second axially symmetric region, which comprises agglomerated vacancy defects, the thermal anneal acting to dissolve agglomerated vacancy defects present in the third axially symmetric region within a layer extending from the front side toward the central plane.