Electron emitters and methods of fabricating the electron emitters are disclosed. According to certain embodiments, an electron emitter includes a tip with a planar region having a diameter in a range of approximately (0.05-10) micrometers. The electron emitter tip is configured to release field emission electrons. The electron emitter further includes a work-function-lowering material coated on the tip.

An optical characterization system utilizing a micro-lens array (MLA) is provided. The system may include an electron source and a MLA including a micro-deflection array (MDA). The MDA may include an insulator substrate and a plurality of hexapole electrostatic deflectors disposed on the insulator substrate. The MDA may further include a plurality of voltage connecting lines configured to electrically couple the plurality of hexapole electrostatic deflectors to one or more voltage sources. The MDA may be configured to split a primary electron beam from the electron source into a plurality of primary electron beamlets. The system may be configured to focus the plurality of primary electron beamlets at a wafer plane.

An electron microscope equipped with automatic beam alignment is provided. The electron microscope can include a vacuum chamber having a receiving space to allow a measurement target specimen to be positioned inside the vacuum chamber. The electron microscope can also include an electron gun coupled to a top of the vacuum chamber with an insulating panel between the electron gun and the vacuum chamber and including a filament module configured to receive power from a power supply and emit an electron beam toward the measurement target specimen. The filament module can be connected to the power supply via a flexible wire inserted into a through hole of the insulating panel such that an assembly error is prevented from occurring when the filament module is coupled to the through hole and the electron beam emitted from the filament module is automatically aligned with a reference optical axis.

This invention provides a charged particle source, which comprises an emitter and means for 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 optical characterization system utilizing a micro-lens array (MLA) is provided. The system may include an electron source and a MLA including a micro-deflection array (MDA). The MDA may include an insulator substrate and a plurality of hexapole electrostatic deflectors disposed on the insulator substrate. The MDA may further include a plurality of voltage connecting lines configured to electrically couple the plurality of hexapole electrostatic deflectors to one or more voltage sources. The MDA may be configured to split a primary electron beam from the electron source into a plurality of primary electron beamlets. The system may be configured to focus the plurality of primary electron beamlets at a wafer plane.

The present invention is to provide an electron microscope capable of being activated to an appropriate temperature by disposing an NEG at an extraction electrode around an electron source. The present invention is an electron microscope provided with an electron gun, in which the electron gun includes an electron source, an extraction electrode, and an accelerating tube, the accelerating tube is connected to the extraction electrode at a connection portion, the extraction electrode includes a first heater and a first NEG, and the first heater and the first NEG are spaced apart in an axial direction of an electron beam emitted from the electron source.

A method for manufacturing an electron source includes steps of sandwiching a welding object in which a tip of an electron emission material and a tungsten filament overlap in direct contact between a pair of welding electrodes, and welding the tip and the tungsten filament by causing a current to flow while pressing forces are applied to the welding object by the pair of welding electrodes. A thickness of the welding object is within a range of 50 to 500 m.

Thermionic cathodes and an electron emission apparatus are provided. The thermionic cathodes comprise perovskite material in crystal or sintered form. The thermionic cathodes provide strong electron emission at low operating temperatures.

The disclosed embodiments relate to a charged particle source module for generating and emitting a charged particle beam, such as an electron beam, comprising: a frame including a first frame part, a second frame part, and one or more rigid support members which are arranged between said first frame part and said second frame part; a charged particle source arrangement for generating a charged particle beam, such as an electron beam, wherein said charged particle source arrangement, such as an electron source, is arranged at said second frame part; and a power connecting assembly arranged at said first frame part, wherein said charged particle source arrangement is electrically connected to said connecting assembly via electrical wiring.

A thermionic cathode, an electron emission apparatus, and a method of fabricating the thermionic cathode are provided. The thermionic cathode includes an emitter. The emitter includes a lanthanum hexaboride (LaB.sub.6) crystal having a crystallographic orientation of (310). The operating temperature of the thermionic cathode is greater than 1800 K.