Patent ID: 7807545

Claim:
A method for manufacturing a SIMOX wafer comprising the following sequential steps: forming a first ion-implanted layer at a first depth in a silicon wafer by heating the wafer at a temperature in the range from 200 to 600° C. and implanting oxygen ions from a surface of the wafer at the rate of 5×10 16 to 3×10 17 atoms/cm 2 ; cooling the wafer to a temperature in the range from room temperature to 200° C. and implanting oxygen ions from the surface of the wafer at the rate of 1×10 14 to 1×10 16 atoms/cm 2 to form a second ion-implanted layer that is in an amorphous state at a second depth in the wafer such that the second ion-implanted layer becomes continuous with the first ion-implanted layer on a front surface side of the wafer; and following the formation of the first ion-implanted layer and the second ion-implanted layer, performing a heat-treatment at an elevated temperature, wherein the elevated temperature during the heat-treatment is not lower than 1300° C. but less than the melting point of silicon while maintaining the wafer in an atmosphere containing oxygen and hydrochloric gas that is between 0.2 to 0.5 volume % mixed therewith during elevation of the temperature and maintaining the temperature for 6 to 36 hours to change the first and the second ion-implanted layers into a BOX layer.