US Patent 7453074 Ion implanter with ionization chamber electrode design

An ion implanter includes an ion source for generating an ion beam moving along a beam line and a vacuum or implantation chamber wherein a workpiece, such as a silicon wafer is positioned to intersect the ion beam for ion implantation of a surface of the workpiece by the ion beam. An ion source includes a ionization chamber and an ionization chamber electrode defining an ionization chamber aperture, wherein the ionization chamber electrode includes a raised portion for generating substantially uniform electric fields in the region adjacent the ionization chamber electrode.