Patent ID: 7803228

Claim:
A process for producing high-resistance silicon wafers wherein it comprises subjecting silicon wafers obtained by the Czochralski method and having a resistivity of 100 Ωcm or above, an initial interstitial oxygen concentration of 8×10 17 atoms/cm 3 or above (ASTM F 121-1979) and, further, a carbon concentration of 5×10 15 to 5×10 17 atoms/cm 3 (ASTM F 123-1981) to first heat treatment consisting in 0.5 to 5 hours of heat treatment at 850-1000° C. employing a rate of heat-up of 0.5 to 10° C./minute at least in the temperature range of 700-850° C. and, further, to second heat treatment consisting in 1 to 2 hours of heat treatment at 1150° C. or above followed by subsequent lowering of the temperature and heat treating at 1000-1150° C. for 2 to 10 hours.