HIGH BRIGHTNESS SOLID STATE ION BEAM GENERATOR, ITS USE, AND METHOD FOR MAKING SUCH A GENERATOR

摘要

Ion sources or generators for focused ion beam emission (FIB) applications emitting ion beams into vacuum or a gas are used in industry and research for the characterization and processing of surfaces. With appropriate focusing, such ion beams can be confined to diameters of a few nanometers. The tip of technical FIB generators for producing such focused beams consists of a liquid metal, gallium in general, which tends to fluctuate during operation. This has a negative influence on the stability of the emission current and the focus definition. It is also possible to generate an FIB with solid tips, consisting of a solid metal, but such tips detoriorate rapidly during operation due to erosion of material from the tip apex. The present invention concerns a novel FIB source generating free space ion beams from a solid source but does not exhibit the above-mentioned erosion effect at the apex. The novel FIB generator consists of a combination of two essentially unitary bodies, a solid electrolyte body with a sharp tip and a solid ion reservoir body, both bodies having close contact with each other. The reservoir is made of or contains the same material, in general a metal as the mobile ions. Loss of ions from the electrolyte body due to emission is compensated by an inflow of ions from the reservoir body during operation. This practically preserves electro-neutrality which is a precondition for continuous mode operation. Erosion of the tip of the electrolyte body does not occur since the counter ions form a solid matrix and the emitted ions are replenished during operation.