Endcap for indirectly heated cathode of ion source

摘要

An ion source for use in an ion implanter. The ion source comprises a gas confinement chamber having conductive chamber walls that bound a gas ionization zone. The gas confinement chamber includes an exit opening to allow ions to exit the chamber. A base positions the gas confinement chamber relative to structure for forming an ion beam from ions exiting the gas confinement chamber. A portion of a cathode extends into an opening in the gas confinement chamber. The cathode includes a cathode body defining an interior region in which a filament is disposed. The cathode body comprises an inner tubular member a coaxial outer tubular member and an endcap having a reduced cross section body portion with a radially extending rim. The endcap is pressed into the inner tubular member. The filament is energized to heat the endcap which, in turn, emits electrons into the gas ionization zone. The filament is protected from energized plasma in the gas ionization zone by the cathode body.