Kazuo Mera

High-current microwave ion source for wide-energy-range O+ ion implantation

A high-current microwave ion source which is used for O+ ion implantation in separation by implanted oxygen (SIMOX) wafer fabrication is presented. The source consists of a new transform waveguide which efficiently propagates a 2.45 GHz microwave power into the ion source, a cylindrical plasma chamber of 90 mm in diameter, and a multiaperture extraction electrode system. The extracted beams are mass separated and then postaccelerated up to 200 keV. Ion source operates stably for a long time and the microwave absorption efficiency is as high as 80%. A total extraction current of 240 mA is obtained at the extraction voltage of 50–60 kV and the mass-separated O+ current reaches about 100 mA at the same extraction voltage. The data show that the ion source has a good potential to provide 100 mA-class O+ ion beams stably in the wide energy range demanded for SIMOX ion implantation.