| abstract |
A magnetron especially advantageous for low-pressure plasma sputtering or sustained self-sputtering having reduced area but full target coverage. The magnetron includes an outer pole face surrounding an inner pole face with a gap therebetween. The outer pole of the magnetron of the invention is smaller than that of a circular magnetron similarly extending from the center to the periphery of the target. A preferred triangular shape having a small apex angle of 20 to 30° may be formed from outer bar magnets of one magnetic polarity enclosing an inner magnet of the other magnetic polarity. The magnetron allows the generation of plasma waves in the neighborhood of 22 MHz which interact with the 1 to 20 eV electrons of the plasma to thereby increase the plasma density. |