Ion source, ion beam processing/observation apparatus, charged particle beam apparatus, and method for observing cross section of sample

An ion beam machining and observation method, where a gas ion beam emitted from a gas field ion source having a vacuum chamber and a gas supply mechanism to introduce gas into the vacuum chamber and generating gas ions in the vacuum chamber is irradiated onto a sample, and where the gas supply mechanism includes at least two gas introduction systems, each system having a gas cylinder, a gas volume control valve, and a stop valve, and a gas switching control unit, comprising:

• switching, by the gas switching control unit, a kind of gas introduced into the vacuum chamber by the stop valve of each system and setting gas pressure conditions for the vacuum chamber by the gas volume control valve of each system;
• and
• forming a pyramid structure of atoms at an apex of an emitter tip of the gas field ion source when the gas switching control unit switches a kind of gas being introduced into the vacuum chamber by the stop valve of each system.

An ion beam machining and observation method, where a gas ion beam emitted from a gas field ion source having a vacuum chamber and a gas supply mechanism to introduce gas into the vacuum chamber and generate gas ions in the vacuum chamber is irradiated onto a sample, and where the gas supply mechanism includes at least two gas introduction systems, each system having a gas cylinder, a gas volume control valve, and a stop valve, and a gas switching control unit, comprising:

• forming a pyramid structure of atoms at an apex of an emitter tip of the gas field ion source;
• and
• evaporating the pyramid structure at the apex of the emitter tip of the gas field ion source when the gas switching control unit switches the kind of gas being introduced into the vacuum chamber by the stop valve of each system.