Microwave energized ion source for ion implantation

Abstract

A microwave energized ion source apparatus is supported by a support tube extending into a cavity defined by a housing assembly and includes a dielectric plasma chamber, a pair of vaporizers, a microwave tuning and transmission assembly and a magnetic field generating assembly. The chamber defines an interior region into which source material and ionizable gas are routed. The chamber is overlied by a cap having an arc slit through which generated ions exit the chamber. The microwave tuning and transmission assembly, which feeds microwave energy to the chamber in the TEM mode, includes a coaxial microwave energy transmission line center conductor. One end of the conductor fits into a recessed portion of the chamber and transmits microwave energy to the chamber. The center conductor extends through an evacuated portion of a coaxial tube surrounding the conductor. A vacuum seal is disposed in or adjacent the coaxial tube and from the boundary between the evacuated coaxial tube and a non-evacuated region. The arc slit cap is secured to a chamber housing surrounding the chamber and is adapted to interfit with a clamping assembly secured to an end of the support tube such that the arc slit is aligned with a predetermined ion beam line. The energy transmission center conductor is coupled to a tuning center conductor which is slideably overlied by a pair of slug tuners. Moving the slug tuners along their paths of travel changes an impedance of the microwave energy input to the chamber.