Improvements of microwave ion source for 300 mm-diameter SIMOX wafer production

To meet the needs for volume production of 300 mm-diameter SIMOX wafers, improvements were made for the conventional microwave ion source to obtain an implant current above 100 mA. The plasma chamber diameter was increased from 80 mm to 90 mm to produce a uniform plasma in the ion source. Convex extraction electrodes were used to transport the extracted O⁺ beams to the implant chamber with high transmission efficiency. A maximum extraction current of about 240 mA was obtained at the extraction voltage of 50-65 kV. A beam trajectory simulation showed that an implant current of 100-150 mA would be easily achieved using the improved microwave ion source in the Hitachi SIMOX ion implanter, the UI-5000