An RF magnetron-type plasma source

A trial experiment to generate a uniform and high-density plasma RF glow discharge with application of an axial magnetic field has been developed. Experiments have been carried out using a cylindrical electrode earthed (Al) of inner diameter 130 mm and length 185 mm. Two types of inner electrode have been employed. One is a linearly tapered conical rod of 70 mm diameter at the top and 10 mm at the lower end. The other is a four-segmented rod electrode (Al). The top, second, third and fourth segments are of 70 mm, 50 mm, 30 mm and 10 mm, respectively. A DC axial magnetic field is applied by a pair of Helmholtz coils, the variable range of which is 0 to 300 G. The uniform plasma density profile is obtained with the electrode shape modified. With axial magnetic field, the plasma density is enhanced about 11 times, but the uniformity becomes worse.