Abstract
A plasma filament ion source has been developed as a long-lived ion source for use in ion implantation. This ion source uses a primary discharge to serve as an electron source for a second discharge, which is formed into a plasma filament replacing a thermionic metallic filament used in the Freeman type ion source. The operation is relatively facile and good beam stability can be obtained. With any combination of a plasma filament of either argon or neon and a feed gas of either fluoride (AsF5, PF5, PF3, or BF3) or hydride (AsH3), the lifetime was found to be more than 90 hours with an extraction voltage of 40kV and the corresponding ion current density over 20mA/cm2. Mass spectrometry results show that this ion source has an ability of generating a considerable amount of As+ and P+ ions from AsF5 and PF5, and hence will be useful for realizing a fully cryopumped ion implanter system. This ion source is also eminently suitable for use in oxygen ion production.
