An emitter with a protective cap layer on an exterior surface of the emitter is disclosed. The emitter can have a diameter of 100 nm or less. The protective cap layer includes ruthenium. Ruthenium is resistant to oxidation and carbon growth. The protective cap layer also can have relatively low sputter yields to withstand erosion by ions. The emitter may be part of a system with an electron beam source. An electric field can be applied to the emitter and an electron beam can be generated from the emitter. The protective cap layer may be applied to the emitter by sputter deposition, atomic layer deposition (ALD), or ion sputtering.

In an example, a method to form a low work function insert includes preparing a mixture that includes a first powder that contains barium, a second powder that contains calcium, a third powder that contains at least one of aluminum, samarium, or magnesium, and a fourth powder that contains a refractory metal. The method may also include heating the mixture, contained in a crucible, in a furnace. Oxygen concentration in the furnace may be maintained at a low partial pressure during heating of the mixture in the furnace. The low work function of the insert allows electrons to be readily extracted from its surface.

The purpose of the present invention, relating to lanthanide boride, which is known as a low work function material, is to provide a novel low work function material with low chemical reactivity, in particular a low work function material of which the material surface, after being exposed to atmospheric gases, can be cleaned at a heating temperature lower than in the prior art. The present invention is a laminate containing a lanthanide boride film formed on a substrate, the surface of said film being covered by a thin film, wherein the thin film is a monatomic layer of a hexagonal boron nitride thin film.

An ion source capable of extracting a ribbon ion beam with improved uniformity is disclosed. One of the walls of the ion source has a protrusion on its interior surface facing the chamber. The protrusion creates a loss area that serves as a sink for free electrons and ions. This causes a reduction in plasma density near the protrusion, and may improve the uniformity of the ribbon ion beam that is extracted from the ion source by modifying the beam current near the protrusion. The shape of the protrusion may be modified to achieve the desired uniformity. The protrusion may also be utilized with a cylindrical ion source. In certain embodiments, the protrusion is created by a plurality of mechanically adjustable protrusion elements.

A permanently sealed vacuum tube is used to provide the electrons for an electron microscope. This advantageously allows use of low vacuum at the sample, which greatly simplifies the overall design of the system. There are two main variations. In the first variation, imaging is provided by mechanically scanning the sample. In the second variation, imaging is provided by point projection. In both cases, the electron beam is fixed and does not need to be scanned during operation of the microscope. This also greatly simplifies the overall system.

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 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 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.

An inverse photoemission spectroscopy apparatus is configured to detect a light generated by the relaxation of electrons to an unoccupied state of a sample. The apparatus includes an electron source for generating electrons with which a sample is irradiated, a wavelength selector for extracting a light having a certain wavelength from the light generated in the sample, a photodetector for detecting the light extracted by the wavelength selector; and a focusing optics disposed between the sample and the photodetector. The electron source contains yttrium oxide as a thermionic emission material.

An electron beam device for inspecting a sample with an electron beam is described. The electron beam device includes an electron beam source including a thermal field emitter, which includes an emitter tip having an emission facet configured for electron emission, wherein the emission facet has an emission facet width; and a first side facet and a second side facet, wherein an edge facet is formed between the first side facet and the second side facet, which has an edge facet width. The edge facet width is between 20% and 40% of the emission facet width. The electron beam source further includes an extractor device; and a heating device for heating the thermal field emitter. The electron beam device further includes electron beam optics and a detector device for detecting secondary charged particles generated at an impingement or hitting of the primary electron beam on the sample.