| 摘要 |
PURPOSE:To obtain such a large capacity ion source that makes plasma uniformly generable, by constituting a magnet of a back plate to be mutually independent with that of a side wall. CONSTITUTION:A lot of permanent magnets 3 are set up in a side wall 2a of a plasma generating chamber and the back of a back plate 2b, and polarity N and S of each magnet 3 are set up so as to be alternately changed with adjacent N and S themselves, and these magnets 3 are constituted to be mutually independent on the plasma generating chamber side wall 2a and the back plate 2b. argon gas and nitrogen gas taken in from a gas intake port 13 are d.c. discharged and ionized by an anode and a cathode 1 by the plasma generating chamber side wall 2a and the back plate 2b, generating plasma there. This generated plasma is surrounded by a cusp field of these magnets 3 installed in the side wall 2a and the back plate 2b, passing through a lot of apertures of a plasma electrode 11 and an accelerating electrode 12, and an ion is emitted as an ion beam. With this constitution, generation of the plasma is equalized.
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