Patent ID: 7135351
Filing Date: 2006-11-14
Classification: H01L

Abstract:
1. A process for preparing a silicon wafer, the wafer being sliced from a single crystal silicon ingot grown in accordance with the Czochralski method and having a front surface, a back surface, an imaginary central plane approximately equidistant between the front and back surfaces, a front surface layer which has a resistivity of greater than about 50 ohm cm and which comprises a region of the wafer between the front surface and a distance, D 1 , which as measured from the front surface and toward the central plane is greater than about 5 microns but less than about 30 microns, and a bulk layer which comprises the imaginary central plane but not the front surface layer, the process comprising: heat-treating the single crystal silicon wafer in a rapid thermal annealer to form crystal lattice vacancies in the front surface layer and in the bulk layer; and rapidly cooling the heat-treated wafer to form a template for oxygen precipitation.