Patent ID: 9299529
Filing Date: 2016-03-29
CPC Classification: H01J

Claim Text:
1. An ion source comprising: a plasma generating chamber configured to serve as a container for generating therein a plasma and as an anode, while allowing a source gas to be introduced therein; a cathode provided in the plasma generating chamber and configured to emit electrons for ionizing the source gas to generate the plasma; and a repeller structure disposed in opposed relation to the cathode within the plasma generating chamber to reflect the electrons toward the cathode, wherein the repeller structure comprises: a target member configured to be sputtered by the plasma to emit given ions, and provided with a through-hole penetrating between a sputterable surface and a reverse surface thereof; and a repeller body which supports the target member while being inserted in the through-hole of the target member, and has a repeller surface exposed on the side of the sputterable surface through the through-hole, the target member directly contacting the repeller body and being electrically conductive with respect to each other, and wherein a center of an electron emitting portion of the cathode and a center of the repeller surface are located approximately coaxially with each other, and wherein the target member is made of a material selected from the group consisting of gallium oxide, gallium nitride, gallium phosphide, gallium arsenide and gallium fluoride, and a magnet is provided outside the plasma generating chamber to generate a magnetic field along a line that, connects the cathode to the repeller structure positioned in the plasma generating chamber, the magnetic field being parallel to a plasma generating chamber axis, so as to cause electrons to move back and forth between the cathode and the repeller while circling the magnetic field, with the direction of the magnetic field as its rotating axis, and further wherein the plasma generating chamber is provided with an ion extraction port arranged on the plasma generating chamber parallel to the plasma generating chamber axis.