PRODUCTION OF RF SLAB PLASMA USING RECTANGULAR MAGNETIC LINE CUSP FIELD

A cylindrical dense ion beam has not been suitable to high current and high energy ion implantation due to the many difficulties in removing heat rapidly from the center part of irradiated area, in keeping uniformity of the beam itself and in irradiating the sample over a large area. For the above mentioned reasons, the development of rf slab plasma by using rectangular magnetic line cusp field was started. This plasma source consists of a rectangular ionization chamber, rectangular coils and rectangular rf electrodes. In this plasma source, a slab plasma is produced by capacitively coupling a 13.56 MHz radio frequency field to pair of rf periphery electrodes placed in the region of a circular magnetic line cusp field around the ionization chamber. Two electrodes are positioned in such a way that the accelerated electrons undergo magnetron motion along inner circumference of ionization chamber, efficiently producing a plasma in this place. This plasma diffuses in the center region of the weaken cusp field. The above process makes it possible to produce a large volume of uniform slab plasma. This plasma source can be used with any kind of reactive gases such as oxygen.