PURPOSE: To draw out only an ion from a drawer electrode by forming a filamentary electrode in the shape of a rod, and impressing high-frequency power upon the filamentary electrode to generate electric-discharge plasma.
CONSTITUTION: A rodlike filamentary electrode 2 is arranged in a casing 1 for a plasma chamber as to be subsequently connected to a high-frequency power source 5 via a terminal 4 which passes through the casing 1 via an insulator 3 so that the casing 1 may be grounded. When high-frequency power is impressed upon the filamentary electrode 2, the level of an electric field near the filamentary electrode is intensified so as to simply generate electric discharge. The skin effect of a high frequency causes an electric current to flow through only the surface of the filamentary electrode 2 so that the filamentary electrode may be heated. The filamentary electrode can thus be heated without any problem even if it is large in its cross-sectional area, so that the service life of a filament may be lengthened while a high frequency type ion source may be stably driven over a long period of time.
ROKKAKU TADASHI
TSURUSAKI KAZUYA
KAJINISHI KUNIYUKI
KATO MITSUO
