This invention provides a charged particle source, which comprises an emitter and means of generating a magnetic field distribution. The magnetic field distribution is minimum, about zero, or preferred zero at the tip of the emitter, and along the optical axis is maximum away from the tip immediately. In a preferred embodiment, the magnetic field distribution is provided by dual magnetic lens which provides an anti-symmetric magnetic field at the tip, such that magnetic field at the tip is zero.

This invention provides a charged particle source, which comprises an emitter and means fo generating a magnetic field distribution. The magnetic field distribution is minimum, about zero, or preferred zero at the tip of the emitter, and along the optical axis is maximum away from the tip immediately. In a preferred embodiment, the magnetic field distribution is provided by dual magnetic lens which provides an anti-symmetric magnetic field at the tip, such that magnetic field at the tip is zero.

This invention provides a charged particle source, which comprises an emitter and means of generating a magnetic field distribution. The magnetic field distribution is minimum, about zero, or preferred zero at the tip of the emitter, and along the optical axis is maximum away from the tip immediately. In a preferred embodiment, the magnetic field distribution is provided by dual magnetic lens which provides an anti-symmetric magnetic field at the tip, such that magnetic field at the tip is zero.

The present disclosure relates to a gas field ion source comprising a housing, an electrically conductive tip arranged within the housing, a gas supply for supplying one or more gases to the housing, wherein the one or more gases comprise neon or a noble gas with atoms having a mass larger than neon, and an extractor electrode having a hole to permit ions generated in the neighborhood of the tip to pass through the hole. A surface of the extractor electrode facing the tip can be made of a material having a negative secondary ion sputter rate of less than 10.sup.5 per incident neon ion.

The disclosure relates to a method of operating a gas field ion beam system in which the gas field ion beam system comprises an external housing, an internal housing, arranged within the external housing, an electrically conductive tip arranged within the internal housing, a gas supply for supplying one or more gases to the internal housing, the gas supply having a tube terminating within the internal housing, and an extractor electrode having a hole to permit ions generated in the neighborhood of the tip to pass through the hole into the external housing. The method comprises the step of regularly heating the external housing, the internal housing, the electrically conductive tip, the tube and the extractor electrode to a temperature of above 100 C.

The present disclosure relates to a gas field ion source having a gun housing, an electrically conductive gun can base attached to the gun housing, an inner tube mounted to the gun can base, the inner tube being made of an electrically isolating ceramic, an electrically conductive tip attached to the inner tube, an outer tube mounted to the gun can base, the outer tube being made of an electrically isolating ceramic, and an extractor electrode attached to the outer tube. The extractor electrode can have an opening for the passage of ions generated in proximity to the electrically conductive tip.

An electron gun 901 capable of suppressing an uneven temperature distribution at an extraction electrode and a length-measuring SEM 900 are provided. The electron gun 901 is equipped with: a charged particle source 1; an extraction electrode 3 for extracting charged particles from the charged particle source 1 and allowing some of the charged particles to pass while blocking some other charged particles; and an auxiliary structure 5 disposed in contact with the extraction electrode 3. The length-measuring SEM 900 is equipped with the electron gun 901 and a computer system 920 for controlling the electron gun 901.

A repeller may be mounted inside an arc chamber of an ion implantation apparatus for doping impurities into a surface film of a semiconductor wafer. The repeller may include a body including an outer circumferential surface and a surface area enlargement portion on the body. The surface area enlargement portion may include striped grooves continuously formed on the outer circumferential surface of the body at intervals in a longitudinal direction of the body.

This invention provides a charged particle source, which comprises an emitter and means fo generating a magnetic field distribution. The magnetic field distribution is minimum, about zero, or preferred zero at the tip of the emitter, and along the optical axis is maximum away from the tip immediately. In a preferred embodiment, the magnetic field distribution is provided by dual magnetic lens which provides an anti-symmetric magnetic field at the tip, such that magnetic field at the tip is zero.