公开(公告)号：US20240120168A1

公开(公告)日：2024-04-11

申请号：US17768244

申请日：2019-10-31

Applicant: Hitachi High-Tech Corporation

Inventor： Takashi Ohshima ,  Hideo Morishita ,  Tatsuro Ide ,  Naohiro Kohmu ,  Momoyo Enyama ,  Yoichi Ose ,  Toshihide Agemura ,  Junichi Katane

IPC: H01J37/073 ,  H01J1/34 ,  H01J37/147 ,  H01J37/22 ,  H01J37/26 ,  H01J37/285

CPC classification number: H01J37/073 ,  H01J1/34 ,  H01J37/1474 ,  H01J37/22 ,  H01J37/265 ,  H01J37/285 ,  H01J2237/06333

Abstract: An electron beam emitted from a photoexcited electron gun is increased in luminance. An electron gun 15 includes: a photocathode 1 including a substrate 11 and a photoelectric film 10; a light source 7 that emits pulsed excitation light; a condenser lens 2 that focuses the pulsed excitation light toward the photocathode; and an extractor electrode 3 that faces the photocathode and that accelerates an electron beam generated from the photoelectric film by focusing the pulsed excitation light by the condenser lens, transmitting the pulsed excitation light through the substrate of the photocathode, and causing the pulsed excitation light to be incident on the photocathode. The pulsed excitation light is condensed at different timings at different positions on the photoelectric film of the photocathode.

公开(公告)号：US12165828B2

公开(公告)日：2024-12-10

申请号：US17768244

申请日：2019-10-31

Applicant: Hitachi High-Tech Corporation

Inventor： Takashi Ohshima ,  Hideo Morishita ,  Tatsuro Ide ,  Naohiro Kohmu ,  Momoyo Enyama ,  Yoichi Ose ,  Toshihide Agemura ,  Junichi Katane

IPC: H01J37/073 ,  H01J1/34 ,  H01J37/147 ,  H01J37/22 ,  H01J37/26 ,  H01J37/285

Abstract: An electron beam emitted from a photoexcited electron gun is increased in luminance. An electron gun 15 includes: a photocathode 1 including a substrate 11 and a photoelectric film 10; a light source 7 that emits pulsed excitation light; a condenser lens 2 that focuses the pulsed excitation light toward the photocathode; and an extractor electrode 3 that faces the photocathode and that accelerates an electron beam generated from the photoelectric film by focusing the pulsed excitation light by the condenser lens, transmitting the pulsed excitation light through the substrate of the photocathode, and causing the pulsed excitation light to be incident on the photocathode. The pulsed excitation light is condensed at different timings at different positions on the photoelectric film of the photocathode.

公开(公告)号：US12217928B2

公开(公告)日：2025-02-04

申请号：US17798092

申请日：2020-03-25

Applicant: Hitachi High-Tech Corporation

Inventor： Hideo Morishita ,  Takashi Ohshima ,  Tatsuro Ide ,  Naohiro Kohmu ,  Toshihide Agemura ,  Yoichi Ose ,  Junichi Katane

IPC: H01J37/073 ,  H01J1/34

Abstract: The electron gun is provided with a first anode electrode and a second anode electrode to generate an acceleration and deceleration electric field. A lens electric field makes it possible to irradiate a sample with an electron beam emitted from a part outside an optical axis of the photoelectric film without being blocked by a differential exhaust diaphragm. A wide range of electron beams off-optical axis can be used even in a high-brightness photocathode that requires high vacuum. As a result, the photoelectric film and the electron gun can be extended in life, can be stabilized, and can be increased in brightness. Further, it is possible to facilitate a control of emitting electron beams from a plurality of positions on the photoelectric film, a timing control of emitting electron beams from a plurality of positions, a condition control of an electron beam in an electron microscope using electron beams.

公开(公告)号：US11784022B2

公开(公告)日：2023-10-10

申请号：US17425872

申请日：2019-01-28

Applicant: Hitachi High-Tech Corporation

Inventor： Takashi Ohshima ,  Tatsuro Ide ,  Hideo Morishita ,  Yoichi Ose ,  Tsunenori Nomaguchi ,  Toshihide Agemura

IPC: H01J37/073 ,  G02B3/04 ,  H01J37/147 ,  H01J37/22 ,  H01J37/28

CPC classification number: H01J37/073 ,  G02B3/04 ,  H01J37/1474 ,  H01J37/22 ,  H01J37/28 ,  H01J2237/0473

Abstract: A scanning electron beam apparatus which two-dimensionally scans a sample by an electron beam to achieve high resolution even with a photoexcited electron source. The electron beam apparatus includes a photocathode including a substrate having a refractive index of more than 1.7 and a photoemissive film, a focusing lens configured to focus an excitation light toward the photocathode, an extractor electrode disposed facing the photocathode and configured to accelerate an electron beam generated from the photoemissive film by focusing the excitation light by the focusing lens and emitting the excitation light through the substrate, and an electron optics including a deflector configured to two-dimensionally scan a sample by the electron beam accelerated by the extractor electrode. For a spherical aberration of the focusing lens, a root mean square of the spherical aberration on the photoemissive film is equal to or less than 1/14 of a wavelength of the excitation light.

公开(公告)号：US20220165536A1

公开(公告)日：2022-05-26

申请号：US17425872

申请日：2019-01-28

Applicant: Hitachi High-Tech Corporation

Inventor： Takashi Ohshima ,  Tatsuro Ide ,  Hideo Morishita ,  Yoichi Ose ,  Tsunenori Nomaguchi ,  Toshihide Agemura

IPC: H01J37/073 ,  H01J37/147 ,  H01J37/22 ,  G02B3/04

Abstract: A scanning electron beam apparatus which two-dimensionally scans a sample by an electron beam, to achieve high resolution even with a photoexcited electron source. The electron beam apparatus includes a photocathode including a substrate having a refractive index of more than 1.7 and a photoemissive film, a focusing lens configured to focus an excitation light toward the photocathode, an extractor electrode disposed facing the photocathode and configured to accelerate an electron beam generated from the photoemissive film by focusing the excitation light by the focusing lens and emitting the excitation light through the substrate, and an electron optics including a deflector configured to two-dimensionally scan a sample by the electron beam accelerated by the extractor electrode. For a spherical aberration of the focusing lens, a root mean square of the spherical aberration on the photoemissive film is equal to or less than 1/14 of a wavelength of the excitation light.