Patent ID: 6958092
Filing Date: 2005-10-25
Classification: C30B,H01L,Y10S,Y10T

Abstract:
1. A single crystal silicon wafer comprising: (a) two major generally parallel surfaces, one of which is a front surface of the wafer and the other of which is a back surface of the wafer; (b) a central plane between and parallel to the front and back surfaces; (c) a front surface layer which comprises the region of the wafer extending a distance, D 1 , of at least about 10 μm from the front surface toward the central plane; and (d) a bulk layer which comprises the region of the wafer extending from the central plane to the front surface layer, the wafer being characterized in that: the wafer has a non-uniform distribution of crystal lattice vacancies wherein (a) the bulk layer has a crystal lattice vacancy concentration which is greater than in the front surface layer, (b) the crystal lattice vacancies have a concentration profile having a peak density of crystal lattice vacancies at or near the central plane, and (c) the concentration of crystal lattice vacancies generally decreases from the position of peak density toward the front surface of the wafer; and the front surface of the wafer has an epitaxial layer deposited thereon, the epitaxial layer having a thickness of at least about 0.1 μm.