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US-20260128249-A1 - ELECTRON SOURCE

US20260128249A1US 20260128249 A1US20260128249 A1US 20260128249A1US-20260128249-A1

Abstract

According to one embodiment, an electron source includes a first member. The first member includes a first semiconductor layer and a second semiconductor layer. The first semiconductor layer has a first bandgap energy and is of p-type. The second semiconductor layer includes a first region. The first region has a second bandgap energy larger than the first bandgap energy, and is of n-type.

Inventors

  • Hisao Miyazaki
  • Shigeya Kimura
  • Shinya Nunoue
  • Akira Fujimoto
  • Yuma Yamaguchi

Assignees

  • KABUSHIKI KAISHA TOSHIBA

Dates

Publication Date
20260507
Application Date
20250723
Priority Date
20241101

Claims (20)

  1. 1 . An electron source, comprising: a first member including: a first semiconductor layer of p-type, the first semiconductor layer having a first bandgap energy; a second semiconductor layer including a first region, the first region having a second bandgap energy larger than the first bandgap energy, the first region being of n-type.
  2. 2 . The electron source according to claim 1 , wherein the first semiconductor layer includes In x Al y Ga 1-x-y N (0≤x≤1, 0≤y≤1, x+y≤1).
  3. 3 . The electron source according to claim 2 , wherein the first region includes diamond.
  4. 4 . An electron source comprising: a first member including: a first semiconductor layer including In x Al y Ga 1-x-y N (0≤x≤1, 0≤y≤1, x+y≤1) and including magnesium; a second semiconductor layer including a first region, the first region including diamond and including a first element including at least one selected from the group consisting of phosphorus and nitrogen.
  5. 5 . The electron source according to claim 4 , wherein the second semiconductor layer is configured to emit electrons in response to light incident on the first member.
  6. 6 . The electron source according to claim 1 , wherein the second semiconductor layer is configured to emit electrons in response to light incident on the first member.
  7. 7 . The electron source according to claim 6 , wherein energy of the light is greater than the first band gap energy.
  8. 8 . The electron source according to claim 7 further including: a light-emitting portion, the light-emitting portion being configured to cause the light to be incident on the first member.
  9. 9 . The electron source according to claim 8 , wherein a plurality of the light emitting portions are provided, the first semiconductor layer includes a first face facing the first region, and the plurality of the light emitting portions are arranged along the first face.
  10. 10 . The electron source according to claim 8 , wherein the first semiconductor layer is located between the light emitting portion and the first region.
  11. 11 . The electron source according to claim 8 , wherein peak wavelength of the light is not less than 230 nm and not more than 700 nm.
  12. 12 . The electron source according to claim 1 , wherein the second semiconductor layer further includes a second region, the first region is located between the first semiconductor layer and the second region, and the second region has a third band gap energy larger than the first band gap energy, and is p-type.
  13. 13 . The electron source according to claim 4 , wherein the second semiconductor layer further includes a second region, the first region is located between the first semiconductor layer and the second region, and the second region includes diamond and includes boron.
  14. 14 . The electron source according to claim 13 , wherein a second region thickness of the second region in the first direction from the first semiconductor layer to the first region is not less than 3 nm and not more than 100 nm.
  15. 15 . The electron source according to claim 1 , wherein a first region thickness of the first region in the first direction from the first semiconductor layer to the first region is 12 nm or more.
  16. 16 . The electron source according to claim 1 , wherein the n-type impurity concentration in the first region is 1×10 18 cm −3 or more.
  17. 17 . The electron source according to claim 1 , wherein a p-type impurity concentration in the first semiconductor layer is 1×10 18 cm −3 or more.
  18. 18 . The electron source according to claim 4 , wherein a concentration of the first element in the first region is 1×10 18 cm −3 or more, and a concentration of magnesium in the first semiconductor layer is 1×10 18 cm −3 or more.
  19. 19 . The electron source according to claim 4 , wherein x is not less than 0 and not more than 0.5, and y is not less than 0 and not more than 0.1.
  20. 20 . The electron source according to claim 4 , wherein x is not less than 0 and not more than 0.1, and y is not less than 0.1 and not more than 0.5.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2024-193064, filed on Nov. 1, 2024; the entire contents of which are incorporated herein by reference. FIELD Embodiments described herein relate generally to an electron source. BACKGROUND For example, electrons emitted from an electron source are used in electronic devices such as an electron beam drawing device. Improved performance is desired in electron sources. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view illustrating an electron source according to a first embodiment; FIG. 2 is a schematic diagram illustrating the electron source according to the first embodiment; FIGS. 3A and 3B are schematic diagrams illustrating the electron sources according to the first embodiment; FIG. 4 is a schematic cross-sectional view illustrating an electron source according to a second embodiment; FIG. 5 is a schematic diagram illustrating an electron source according to the second embodiment; and FIGS. 6A to 6C are schematic diagrams illustrating electron sources according to the second embodiment. DETAILED DESCRIPTION According to one embodiment, an electron source includes a first member. The first member includes a first semiconductor layer and a second semiconductor layer. The first semiconductor layer has a first bandgap energy and is of p-type. The second semiconductor layer includes a first region. The first region has a second bandgap energy larger than the first bandgap energy, and is of n-type. Various embodiments are described below with reference to the accompanying drawings. The drawings are schematic and conceptual; and the relationships between the thickness and width of portions, the proportions of sizes among portions, etc., are not necessarily the same as the actual values. The dimensions and proportions may be illustrated differently among drawings, even for identical portions. In the specification and drawings, components similar to those described previously or illustrated in an antecedent drawing are marked with like reference numerals, and a detailed description is omitted as appropriate. First Embodiment FIG. 1 is a schematic cross-sectional view illustrating an electron source according to the first embodiment. As shown in FIG. 1, an electron source 110 according to the embodiment includes a first member 10M. The first member 10M includes a first semiconductor layer 10 and a second semiconductor layer 20. The second semiconductor layer 20 includes a first region 21. A first direction D1 from the first semiconductor layer 10 to the second semiconductor layer 20 is defined as a Z-axis direction. One direction perpendicular to the Z-axis direction is defined as an X-axis direction. A direction perpendicular to the Z-axis direction and the X-axis direction is defined as a Y-axis direction. The first semiconductor layer 10, the second semiconductor layer 20, and the first region 21 are layered along the X-Y plane. The first semiconductor layer 10 includes a first face 10F facing the first region 21. The first face 10F is aligned along the X-Y plane. In the embodiment, the first semiconductor layer 10 includes InxAlyGa1-x-yN (0≤x≤1, 0≤y≤1, x+y≤1) and includes magnesium. The first semiconductor layer 10 is, for example, a p-type nitride layer. The first region 21 included in the second semiconductor layer 20 includes diamond and a first element. The first element includes at least one selected from the group consisting of phosphorus and nitrogen. The first region 21 includes, for example, n-type diamond. When light L1 is incident on such a first member 10M, electrons 81 are emitted. In the embodiment, highly efficient electron emission is obtained. For example, mobile carriers (electrons) are generated in the first semiconductor layer 10 by irradiation with light L1. The generated electrons 81 move efficiently to the second semiconductor layer 20 (for example, the first region 21). The electrons 81 are efficiently emitted from the second semiconductor layer 20 (for example, the first region 21) to the outside. High electron emission efficiency is obtained. According to the embodiment, an electron source capable of improving characteristics is provided. For example, by combining the first semiconductor layer 10 of p-type and the first region 21 of n-type, the electrons 81 can move efficiently to the first region 21. Thus, the second semiconductor layer 20 is configured to emit electrons 81 in response to the light L1 incident on the first member 10M. As shown in FIG. 1, the electron source 110 may further include a light emitting portion 50. The light emitting portion 50 is configured to emit light L1 to the first member 10M. The light emitting portion 50 may include, for example, a semiconductor light emitting element (for example, an LED, etc.). In one example, the first semiconductor layer 10 is located between the light emitting