Patent ID: 6777882
Filing Date: 2004-08-17
Classification: H01J

Abstract:
An ion beam generator for an ion implantation system, the ion beam generator comprising:an ion source for generating ions to be implanted; and an extraction electrode assembly comprising a plurality of electrodes for extracting and accelerating ions from the ion source; the extraction assembly including a source electrode at a potential of the ion source, an extraction electrode adjacent to the source electrode to extract ions from the ion source along a first ion extraction axis, and a ground electrode downstream of the extraction electrode along said first ion extraction axis; wherein the source electrode and the extraction electrode each have a curved portion adjacent an electrode aperture, a curvature of each curved portion being in a first plane defined between the first ion extraction axis and a second axis orthogonal thereto, a distance radially from a surface of the curved portion of the source electrode to a surface of the curved portion of the extraction electrode being constant over at least a part of the each said curved portion.