Production of uniform large-diameter radio-frequency discharge plasma

A new radio-frequency (rf) discharge plasma source at frequency of 13.56 MHz is presented. The rf plasma is produced by a modified magnetron-typed rf discharge using a cylindrical electrode with permanent magnet rings. The electron density of 2.5×1010 cm−3 with an electron temperature of 3.7 eV, uniform within a few percent over 50 cm in diameter, is obtained on both sides at 5–6 cm from the axial center of the rf electrode when the rf power is 600 W under argon pressure of 3.6×10−4 Torr.