Hitachi-high-technologies Corporation

Shigeru Kokubo

Hideo Todokoro

Takashi Ohshima

Souichi Katagiri

Keigo Kasuya

Hisaya Murakoshi

Boklae Cho

Hisao Nitta

A charged particle beam apparatus includes a field emission electron source, electrodes for applying an electric field to the field emission electron source, and a vacuum exhaust unit for keeping the pressure around the field emission electron source at 1&#xd7;10Pa or less. The apparatus uses electron beams emitted to have an electron-beam-center radiation angle of 1&#xd7;10sr or less, and uses the electric current thereof, the second order differentiation of which is negative or zero with respect to time, and which reduces at a rate of 10% or less per hour. A heating unit is provided for the field emission electron source, and a detection unit is provided for the electric current of the electron beam. The field emission electron source is repeatedly heated to keep the electric current of the electron beam to be emitted, at a predetermined value or higher.

Charged particle beam apparatus, and method of controlling the same

The disclosed charged particle beam apparatus includes a field-emission electron source including &#x3c;310&#x3e; single crystal of tungsten; a vacuum chamber having the electron source therein; an exhausting system for exhausting the vacuum chamber; a filament connected to the electron source to let flow a current through the electron source and thereby heat the electron source; a power supply for letting a current flow through the filament; an ammeter for measuring a total current emitted from the electron source; and a controlling unit for exercising control to cause the power supply to let a current flow through the filament when the total current measured periodically has become a predetermined ratio or less as compared with a total current from the electron source found immediately after first electron beam emission, or a total current from the electron beam found immediately after a current is let flow through the filament.

Field-emission electron gun and method for controlling same

Provided is a charged particle beam apparatus, which can emit a stable electron beam, having high brightness and a narrow energy width. The charged particle beam apparatus comprises a field emission electron source, electrodes for applying an electric field to the field emission electron source, and a vacuum exhaust unit for keeping the pressure around the field emission electron source at 1 10&#x2212;8 Pa or less. The apparatus is so constituted as to use such one of the electron beams emitted as has an electron-beam-center radiation angle of 1&#xd7;10sr or less, and to use the electric current thereof, the second order differentiation of which is negative or zero with respect to the time, and which reduces at a rate of 10% or less per hour. The charged particle beam apparatus further comprises a heating unit for the field emission electron source, and a detection unit for the electric current of the electron beam. The field emission electron source is repeatedly heated to keep the electric current of the electron beam to be emitted, at a predetermined value or higher.

Growing community of inventors

Mito, Japan

Shigeru Kokubo