Electron source and electron beam device using the same

Patent metadata

Field	Value
Publication number	US-10707046-B2
Application number	US-201716480405-A
Country	US
Kind code	B2
Filing date	Dec 8, 2017
Priority date	Feb 28, 2017
Publication date	Jul 7, 2020
Grant date	Jul 7, 2020

Abstract

An electron source that can be used stably for a long time even when hexaboride is used, and an electron beam device using the electron source are provided. The invention is directed to an electron source which includes a filament made of a metal, a metal tube that is fixed to the filament and has a plurality of recesses disposed at least in two axial directions so as to surround a central axis at an outer periphery, and a columnar hexaboride tip that emits an electron, is disposed so as to protrude from the inside of the metal tube to a side opposite to the filament, and is in contact with a bottom of each of the plurality of recesses of the metal tube.

First claim

The invention claimed is:

1. An electron source comprising:
a filament made of a metal;
a metal tube that is fixed to the filament and has a plurality of recesses disposed at least in two axial directions so as to surround a central axis at an outer periphery; and
a columnar hexaboride tip that emits an electron, is disposed so as to protrude from the inside of the metal tube to a side opposite to the filament, and is in contact with a bottom of each of the plurality of recesses of the metal tube.

2. The electron source according to claim 1 , wherein
the metal tube is joined to the filament by spot welding.

3. The electron source according to claim 1 , wherein
the metal tube has a plurality of other recesses at other positions of the metal tube in the axial direction, in addition to the plurality of recesses.

4. The electron source according to claim 1 , wherein
the hexaboride tip has a square pole shape, and
the plurality of recesses are formed in two axes and four directions with respect to the hexaboride tip having the square pole shape.

5. The electron source according to claim 1 , wherein
the hexaboride tip has a circular cylindrical shape, and
the plurality of recesses are formed in three axes and three directions with respect to the hexaboride tip having the circular cylindrical shape.

6. The electron source according to claim 1 , wherein
the metal tube is made of tantalum or niobium.

7. The electron source according to claim 1 , wherein
an inner diameter of the metal tube is in a range of 1.1 to 1.5 times the largest diameter of the hexaboride tip.

8. The electron source according to claim 1 , wherein
a thickness of the metal tube is in a range of 100 to 200 μm.

9. An electron beam device comprising:
an electron source;
a sample stand on which a sample is placed; and
an electron optical system for irradiating a sample on the sample stand with an electron emitted from the electron source, wherein
the electron source is the electron source according to claim 1 .

10. An electron source comprising:
a filament made of a metal;
a metal tube that is fixed to the filament and has a plurality of recesses disposed at least in two axial directions so as to surround a central axis at an outer periphery;
a graphite sheet or rhenium foil disposed inside the metal tube; and
a columnar hexaboride tip that emits an electron, is disposed so as to protrude from the inside of the metal tube to a side opposite to the filament, and is in contact with the graphite sheet or rhenium foil disposed at the bottom of each of the plurality of recesses of the metal tube.

11. An electron beam device comprising:
an electron source;
a sample stand on which a sample is placed; and
an electron optical system for irradiating a sample on the sample stand with an electron emitted from the electron source, wherein
the electron source is the electron source according to claim 10 .

12. An electron source comprising:
a filament made of a metal;
a metal tube that is fixed to the filament and has a plurality of recesses disposed at least in two axial directions so as to surround a central axis at an outer periphery; and
a columnar hexaboride tip that emits an electron, is disposed so as to protrude from the inside of the metal tube to a side opposite to the filament, and is coated with glassy carbon or a mixture of glassy carbon and boride carbon and is in contact with the plurality of recesses of the metal tube.

13. An electron beam device comprising:
an electron source;
a sample stand on which a sample is placed; and
an electron optical system for irradiating a sample on the sample stand with an electron emitted from the electron source, wherein
the electron source is the electron source according to claim 12 .

Assignees

• Hitachi High Tech Corp

Inventors

• Kusunoki Toshiaki
• Kasuya Keigo
• Ohshima Takashi
• Hashizume Tomihiro
• Arai Noriaki
• Ose Yoichi

Classifications

• H01J2209/02

  Manufacture of cathodes · CPC title

• H01J37/073 Primary

  Electron guns using field emission, photo emission, or secondary emission electron sources · CPC title

• H01J37/065 Primary

  Construction of guns or parts thereof (H01J37/067 - H01J37/077 take precedence) · CPC title

• H01J1/148

  with compounds having metallic conductive properties, e.g. lanthanum boride, as an emissive material · CPC title

• H01J1/18

  Supports; Vibration-damping arrangements · CPC title