Patent ID: 7199057

Claim:
A method for eliminating boron contamination in an annealed wafer, the method comprising, annealing a silicon wafer having a surface on which a native oxide film has formed containing boron of environmental origin or from chemical treatment prior to the annealing, wherein in the annealing, the silicon wafer is subjected to temperature heat-up in a mixed gas atmosphere having a ratio of hydrogen gas to an inert gas of 5% to 100% so as to remove the boron-containing native oxide film, and subsequent annealing in an inert gas atmosphere, and a boron concentration in the wafer surface and a boron concentration in the bulk silicon are made to be substantially same by the annealing, wherein a ratio of the boron concentration in the wafer surface to the boron concentration in the bulk silicon is controlled to be 0.78 to 1.10.