Applied Materials, Inc.
Shaped repeller for an indirectly heated cathode ion source

Abstract:

A system for extending the life of a repeller in an IHC ion source is disclosed. The system includes an IHC ion source wherein the back surface of the repeller has been shaped to reduce the possibility of electrical shorts. The separation distance between the back surface of the repeller and the chamber wall behind the repeller is increased along its outer edge, as compared to the separation distance near the center of the repeller. This separation distance reduces the possibility that deposited material will flake and short the repeller to the chamber wall. Further, in certain embodiments, the separation distance between the back surface of the repeller and the chamber wall near the center of the repeller is unchanged, so as to minimize the flow of gas that exits from the chamber. The back surface of the repeller may be tapered, stepped or arced to achieve these criteria.