Patent ID: 6955718

Claim:
A process for the preparation of a single crystal silicon wafer having a controlled oxygen precipitation behavior, the process comprising the steps of: selecting a wafer sliced from a single crystal silicon ingot grown by the Czochralski method comprising a front surface, a back surface, a central plane between the front and back surfaces, a front surface layer which comprises the region of the wafer between the front surface and a distance D measured from the front surface and toward the central plane, and a bulk layer which comprises the region of the wafer between the central plane and the front surface layer; heating the wafer to an annealing temperature T A to form crystal lattice vacancies in the front surface and bulk layers; cooling the heated wafer from T A to an upper nucleation temperature T U at a rate R to form a vacancy concentration profile in the wafer wherein the peak density of vacancies is in the bulk layer with the concentration generally decreasing from the location of the peak density in the direction of the front surface of the wafer; and controlling cooling of the vacancy concentration profiled wafer from an upper nucleation temperature T U to a lower nucleation temperature T L for a nucleation duration t n to form oxygen precipitate nucleation centers in the bulk layer that are incapable of being dissolved at temperatures below about 1150° C. and a region free of oxygen precipitate nucleation centers in the surface layer.