Gas field ionization ion source and ion beam device
View Patent ↗Provided is a gas field ionization ion source capable of emitting heavy ions with high brightness which are suitable for processing a sample. The gas field ionization ion source according to the present invention includes a temperature controller individually controlling the temperature of the tip end of an emitter electrode ( 1 ) and the temperature of a gas injection port part ( 3 ) of a gas supply unit.
1. An ion beam device, comprising:
a sample stage holding a sample;
a gas field ionization ion source emitting an ion beam generated by a gas mixture mainly containing gases of plural elements;
a lens system converging the ion beam and projecting the ion beam onto the sample;
a deflection system deflecting the ion beam to change an irradiation position of the ion beam on the sample;
a secondary electron detector detecting secondary electrons emitted from the sample;
an image processing unit forming an observation image of the sample using a result of detection by the secondary electron detector; and
a controller controlling the lens system and the deflection system to adjust the irradiation position of the ion beam,
wherein the image processing unit forms a first observation image corresponding to a first species of ion beams emitted from the gas field ionization ion source and a second observation image corresponding to a second species of ion beams emitted from the gas field ionization ion source, the second species being different from the first species, and
wherein the image processing unit compares the first observation image with the second observation image to form a new image.
2. The ion beam device according to claim 1 ,
the gas field ionization ion source further comprising:
an electrode unit including an emitter electrode and an extraction electrode;
a gas supply unit supplying the gas mixture to near a tip end of the emitter electrode;
a voltage application unit applying a voltage between the emitter electrode and the extraction electrode to form an electrical field for ionizing the gas; and
an extraction limiting diaphragm having an aperture allowing passage of an ion beam emitted from the emitter electrode.
3. The ion beam device according to claim 2 , further comprising:
a first storage storing data indicating a correspondence between a type of ions emitted from the emitter electrode and a voltage value applied by the voltage application unit during the emission.
4. The ion beam device according to claim 3 , further comprising a second storage storing data indicating a correspondence between a type of ions emitted from the emitter electrode and setting values of the lens system and the deflection system, wherein
the controller reads data corresponding to the data stored in the first storage from the second storage, and controls the lens system and the deflection system based on the setting values indicated by the read data.
5. The ion beam device according to claim 2 , further comprising:
a temperature controller individually controlling a temperature of the tip end of the emitter electrode and a temperature of a gas injection port part of the gas supply unit,
wherein the temperature controller keeps the temperature of the gas injection port part of the gas supply unit higher than that of the tip end of the emitter electrode during ion emission, and variably controls the temperature of the gas injection port part depending on a boiling temperature of the gas.
6. The ion beam device according to claim 1 ,
wherein the image processing unit compares the first observation image with the second observation image to form an image specific to surface roughness or an image specific to surface element species.