Single axis combined ion and vapor source

Abstract

Combining an evaporation source and an ion beam source to provide a crucible anode surface, and heating that crucible anode surface to a high enough temperature to cause evaporation of anode material, provides for emission of atoms and ions selectively and independently controllable and directed along the identical path. A high melting point material auxiliary anode, connected to the crucible anode by a variable resistance, provides independent control of the vapor flux by selectively shifting the discharge current from auxiliary anode to crucible anode. The crucible anode contains the material which is to be evaporated. A gas plasma discharge is supplied between a heated cathode filament and the heated crucible anode. Electrons carrying a discharge current bombard the crucible anode material surface, causing a temperature rise which causes an increase in discharge current. At a high enough discharge current level, the anode material in the crucible anode melts and vaporizes, forming a stream which passes through an extraction grid to deposit vaporized anode material on a substrate. The gas discharge generates ions, which are accelerated by voltages on the anodes, forming an ion beam which also strikes the substrate. The flux of the ion beam is controlled by the discharge current. The ion energy is controlled by the anode power supply. Shifting a portion of the discharge current from the auxiliary anode to the crucible anode increases the amount of vapor flux for a given ion flux.