Nitrogen ions from a gas field ion source held at a pressure of 1.0 x 10^(-6) pa to 1.0 x 10^(-2) pa

摘要

A focused ion beam apparatus has an ion source chamber in which is disposed an emitter for emitting ions. A gas supply unit supplies nitrogen gas to the ion source chamber so that the nitrogen gas adsorbs on the surface of the emitter, and the gas supply unit maintains the pressure in the ion source chamber in the range 1.0×10⁻⁶ Pa to 1.0×10⁻² Pa. An extracting electrode is spaced from the emitter, and a voltage is applied to the extracting electrode to ionize the adsorbed nitrogen gas and extract nitrogen ions in the form of an ion beam. A temperature control unit controls the temperature of the emitter.