Cold cathode ion beam source

Abstract

The present device comprises, in a preferred embodiment, a permanent magnet assembly which is formed to closely resemble a doughnut with the inside surface defining an aperture having first and second ends. Said inside surface is formed concave to substantially resemble the letter 'C', or a mirror image letter 'C'. The permanent magnet provides magnetic flux from one end of the 'C' to the other and hence the magnetic flux lines, or the magnetic flux field, form, in conjunction with the concave letter 'C' configuration of the permanent magnet, an enclosure. Within the enclosure there is located an anode, and the anode is shielded from electrons by the magnetic flux field. In one embodiment, in close proximity to the second end of said aperture of the permanent magnet piece there is located a cathode, while at said first end of the aperture there is located a screen. In another embodiment, which is used for sputtering, there is no screen employed. A source of electrical voltage (which has a first terminal with a first voltage and a second terminal with a second voltage, which second voltage is negative to said first voltage) has it first and second terminals respectively connected to said anode and said cathode to cause an electrostatic field therebetween. Said cathode is not coupled to said permanent magnet in a permanent way and in some uses in movable. The arrangement has a means for injecting an ionizable fluid, such as oxygen, nitrogen, argon or the like, into the region defined by the position of the magnetic flux, the position of the cathode and the position of the screen. Accordingly when electrical energy is applied to the anode and the cathode, a dense plasma results and ultimately ions pass through the screen to provide a source of ions, and/or ultimately dislodged material passes from the cathode to a substrate.