| abstract |
A silicon wafer having a controlled defect distribution is provided, and a denude zone having a sufficient depth inward from the surface of the wafer is combined with a high gathering effect in the bulk area of the wafer. In silicon wafers, oxygen precipitates, which serve as intrinsic gathering sites, show a vertical distribution. The oxygen precipitate concentration profile from the top surface to the bottom surface of the wafer is defined by first and second peaks at predetermined first and second depths from the top and bottom surfaces of the wafer, and the top and bottom surfaces of the wafer and the first and second peaks. Denude zones therebetween, and a concave region between the first and second peaks corresponding to the bulk region of the wafer. For this oxygen precipitate concentration profile, the wafer is subjected to a rapid thermal annealing process at a temperature below about 1200 ° C. in a gas mixture atmosphere containing ammonia and argon. By using this rapid thermal annealing process, slip dislocations can be reduced in the device region of the wafer, and sublimation of silicon dioxide in the rapid thermal annealing chamber can also be reduced. |