Sintered material, method for producing same, electron source, and device provided with same

Abstract

A method for producing a sintered material comprising iridium and cerium, the method comprising: a step for preparing a sintered body comprising iridium and cerium; and a step for obtaining a sintered material by heat-treating the sintered body for 0.5 hours or more at a temperature of 1400-1800 DEG C in an atmosphere having an oxygen partial pressure of 10-1 Pa or less. And a sintered material comprising iridium and cerium and having a work function of 3.8 eV or less.

Description

Technical Field

[0001] This disclosure relates to sintering materials and methods for manufacturing them, as well as electronic sources and apparatus equipped with them. Background Technology

[0002] Electron-emitting emitters are used, for example, in electron microscopes and semiconductor inspection devices. An emitter includes an electron source and a heater for heating the electron source. The electron source is heated by energizing the heater, thereby generating an emission current. The electron source is composed of an electron-emitting material. Examples of electron-emitting materials include rare-earth borides such as lanthanum boride (LaB6) and cerium boride (CeB6); high-melting-point metals such as tungsten, tantalum, and hafnium, as well as their oxides, carbides, and nitrides. In recent years, the use of sintered bodies composed of iridium and cerium as electron sources has been investigated (see Patent Documents 1 and 2).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 6285254

[0006] Patent Document 2: Japanese Patent No. 6805306 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] The inventors of this application evaluated the performance of a sintered body composed of iridium and cerium as an electron source, and determined that the work function of the sintered body is large, and there is room for improvement in its practical use as an electron source.

[0009] One aspect of this disclosure is made in view of the aforementioned issues, with the aim of providing a sintered material composed of iridium and cerium with a sufficiently low work function, and a method for manufacturing the same. Another aspect of this disclosure is to provide an electronic source composed of the aforementioned sintered material and an apparatus equipped with such an electronic source.

[0010] Methods for solving problems

[0011] One aspect of this disclosure relates to a method for manufacturing a sintered material composed of iridium and cerium. The method includes: a step of preparing a sintered body composed of iridium and cerium; and a step of heat-treating the sintered body at a temperature of 1400–1800°C for at least 0.5 hours under a low-oxygen atmosphere to obtain the sintered material. It should be noted that in this disclosure, "sintered body" refers to the state before the heat treatment, and "sintered material" refers to the state after the heat treatment.

[0012] In the above manufacturing method, by heat-treating a sintered body composed of iridium and cerium under specified conditions, a sintered material with a sufficiently low work function can be obtained. For example, even if the work function of the sintered body is 4.1 to 4.3 eV, by undergoing the above heat treatment, a sintered material with a work function of 3.8 eV or less can be obtained. Although the mechanism by which the work function decreases through heat treatment is not necessarily fully understood, the inventors of this application speculate that the main reason is that, through heat treatment, the sintered body crystallizes to form crystals, and metallic iridium precipitates on the surface of these crystals. As a result, metallic iridium is dispersed in an island-like manner on the surface of the sintered material, or forms a layer of metallic iridium covering the entire surface of the crystals. The heat treatment only requires a low-oxygen atmosphere (oxygen partial pressure of 10) to the extent that the oxidation reaction of iridium and cerium does not occur. -1 It can be implemented in an atmosphere below Pa.

[0013] The sintered body described above can be composed of at least one crystalline phase selected from the group consisting of Ir₂Ce, Ir₃Ce, Ir₇Ce₂, and Ir₅Ce. From the viewpoint of easily forming iridium regions by precipitating metallic iridium on the surface of the sintered material, the composition of the sintered body is preferably iridium-rich; specifically, the sintered body is preferably composed of either the Ir₇Ce₂ or Ir₅Ce crystalline phases mentioned above. The cerium content can be 12.7 to 26.7 parts by mass relative to 100 parts by mass of the total mass of the sintered material manufactured from these sintered bodies.

[0014] Another aspect of this disclosure relates to a sintered material composed of iridium and cerium, having a work function of 3.8 eV or less. In one aspect, the sintered material comprises: a main body composed of iridium and cerium; and an iridium region formed on the surface of the main body. As described above, crystallization occurs in the sintered material after the aforementioned heat treatment. The degree of crystallization can be determined by X-ray diffraction (hereinafter referred to as XRD) analysis of the surface of the sintered material. That is, in the spectrum obtained by XRD analysis of the surface of the sintered material, the half-width at half-maximum (WHM) of the first peak at a scattering angle 2θ of 47.6° can be 0.5 or less, and the half-width at half-maximum (WHM) of the second peak at a scattering angle 2θ of 55.5° can be 0.5 or less.

[0015] Another aspect of this disclosure relates to an electronic source made of the aforementioned sintered material. Another aspect of this disclosure relates to an apparatus equipped with the aforementioned electronic source. Examples of apparatuses equipped with an electronic source include electron microscopes, semiconductor manufacturing apparatuses, inspection apparatuses, and processing apparatuses.

[0016] Invention Effects

[0017] According to one aspect of this disclosure, a sintered material composed of iridium and cerium with a sufficiently small work function and a method for manufacturing the same are provided. Furthermore, according to another aspect of this disclosure, an electronic source composed of the aforementioned sintered material and an apparatus equipping it are provided. Attached Figure Description

[0018] [ Figure 1 ] Figure 1 A top view illustrating an embodiment of this disclosure of an electronic source fixed to a filament.

[0019] [ Figure 2 ] Figure 2 A scanning electron microscope (SEM) image of the surface of the sintered body involved in Comparative Example 1.

[0020] [ Figure 3 ] Figure 3 The spectrum is obtained by XRD analysis of the surface of the sintered body involved in Comparative Example 1.

[0021] [ Figure 4 ] Figure 4 This is a SEM image of the surface of the sintered material involved in Example 1.

[0022] [ Figure 5 ] Figure 5 The spectrum is obtained by XRD analysis of the surface of the sintered material involved in Example 1.

[0023] [ Figure 6 ] Figure 6 This is an SEM image of the surface of the sintered material involved in Example 2.

[0024] [ Figure 7 ] Figure 7 The spectrum is obtained by XRD analysis of the surface of the sintered material involved in Example 2.

[0025] [ Figure 8 ] Figure 8 (a) and Figure 8 (b) is an image showing the mapping results of the surface of the sintered body involved in Comparative Example 1 based on energy dispersive X-ray analysis (hereinafter referred to as EDX).

[0026] [ Figure 9 ] Figure 9 (a) and Figure 9 (b) is an image showing the EDX-based mapping analysis results of the surface of the sintered material involved in Example 1.

[0027] [ Figure 10 ] Figure 10 (a) and Figure 10(b) is an image showing the EDX-based mapping analysis results of the surface of the sintered material involved in Example 2.

[0028] [ Figure 11 ] Figure 11 (a) and Figure 11 (b) is an image showing the analysis results of the surface of the sintered material involved in Example 1 based on electron backscatter diffraction (hereinafter referred to as EBSD).

[0029] [ Figure 12 ] Figure 12 (a) and Figure 12 (b) is an image showing the EBSD-based analysis results of the surface of the sintered material involved in Example 2. Detailed Implementation

[0030] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be noted that the present invention is not limited to the following embodiments.

[0031] Figure 1 This is a top view schematically showing the state in which the electron source according to this embodiment is fixed to the filament. The electron source 1 is a tip of a sintered material composed of iridium and cerium. The electron source 1 is fixed to the filament 2 at the junction 3. The junction 3 is located at the top of the filament 2, which is bent into a ring shape. Examples of devices equipped with the electron source 1 include electron microscopes, semiconductor manufacturing apparatuses, inspection apparatuses, and processing apparatuses.

[0032] Electron source 1 releases electrons by being heated. Electron source 1 is heated by energizing filament 2. Electron source 1 has a generally rectangular shape. The front end of electron source 1 can be machined into a conical or pyramidal shape. The shape of electron source 1 is not particularly limited and can be machined into the desired shape by electrical discharge machining or the like.

[0033] The filament 2 heats the electron source 1 by passing an electric current through it. The filament 2 can be, for example, a tungsten filament. The tungsten filament may contain elements other than tungsten (e.g., rhenium, aluminum, silicon, and potassium) depending on the desired performance. An alkali metal (e.g., potassium) may be doped into the tungsten filament for stabilization. If the tungsten filament contains rhenium, the rhenium content may be, for example, 2–30% by mass, 2–10% by mass, or 2–5% by mass. Rhenium increases the resistivity of the tungsten filament.

[0034] As described above, the sintered material is composed of iridium and cerium. The sintered material may contain at least one crystal phase selected from the group consisting of Ir2Ce, Ir3Ce, Ir7Ce2, and Ir5Ce.

[0035] The total content of iridium and cerium can be 97 parts by mass or more, 98 parts by mass or more, or 99 parts by mass or more, relative to 100 parts by mass of the total mass of the sintered material. The sintered material can be formed solely of iridium, cerium, and unavoidable impurities.

[0036] The contents of iridium and cerium are appropriately set according to the types of crystal phases constituting the sintered material. Relative to 100 parts by mass of the total sintered material, the iridium content can be 73.3 parts by mass or more, 77 parts by mass or more, or 80 parts by mass or more, or less than 87.3 parts by mass, less than 85 parts by mass, or less than 83 parts by mass. Relative to 100 parts by mass of the total sintered material, the cerium content can be 12.7 parts by mass or more, 15 parts by mass or more, or 17 parts by mass or more, or less than 26.7 parts by mass, less than 23 parts by mass, or less than 20 parts by mass.

[0037] The work function of the sintered material is 3.8 eV or less, preferably 3.7 eV or less or 3.6 eV or less, and can be 3.4 eV or less or 3.0 eV or less. By making this work function 3.8 eV or less, even under low vacuum conditions (e.g., 10 eV), the sintered material (electron source 1) can withstand low vacuum conditions (e.g., 10 eV). -3 ~10 -6 Even when using Pa), a sufficiently high current density can be achieved. The lower limit of the work function of the sintered material can be, for example, 2.7 eV or higher, 2.8 eV or higher, 2.9 eV or higher, 3.0 eV or higher, 3.1 eV or higher, 3.2 eV or higher, or 3.3 eV or higher.

[0038] In this publication, the work function refers to the value determined by ultraviolet photoelectron spectroscopy (UPS method) under the following conditions.

[0039] Test sample: 3mm in diameter × 2.5mm in length

[0040] [Heating conditions]

[0041] Maximum heating temperature: 1550℃

[0042] Cumulative heating time: 78 hours (of which, the heating time at 1550℃ is 24 hours)

[0043] [Ultraviolet photoelectron spectroscopy device]

[0044] Photon energy of ultraviolet light: 21.22 eV

[0045] Bias voltage: -6V

[0046] Measurement area: Central

[0047] Energy resolution of the photoelectron analyzer: 0.025 eV

[0048] Slot: 55μm

[0049] [Ion sputtering]

[0050] As a pretreatment for work function determination, ion sputtering was performed under the following conditions to remove contaminants from the outermost surface of the sample.

[0051] Type of ion: Argon ion

[0052] Accelerating voltage: 1kV

[0053] Time: 20-100 seconds

[0054] Sintered materials can be obtained by heat-treating a sintered body composed of iridium and cerium under a low-oxygen atmosphere. Specifically, the method for manufacturing sintered materials includes: a step of preparing a sintered body composed of iridium and cerium; and a step of heat-treating the sintered body at a temperature of 1400–1800°C for at least 0.5 hours under a low-oxygen atmosphere to obtain the sintered material. The low-oxygen atmosphere referred to here is an atmosphere to the extent that the oxidation reaction of iridium and cerium does not occur. Specifically, it is an atmosphere where the oxygen partial pressure is 10... -1 Pa and below, 10 -2 Pa or below, or 10 -3 Pa or less, preferably 10 -4 Pa or less, more preferably 10 Pa -5 Pa or below, further preferred 5×10 -5 Below Pa, 4×10 -5 Below Pa, or 3×10 -5 The sintered body can be heated in a gas below Pa. Such a low-oxygen atmosphere can be achieved by using an inert gas atmosphere, or by reducing the pressure in an air atmosphere to preferably 10 Pa. -5 Pa or less, more preferably 10 Pa -6 This can be achieved below Pa.

[0055] The crystal phase constituting the sintered body can be at least one selected from the group consisting of Ir2Ce, Ir3Ce, Ir7Ce2, and Ir5Ce. From the viewpoint that it is easy to precipitate metallic iridium on the surface of the sintered material to form an iridium region, it is preferred to be at least one selected from the group consisting of Ir7Ce2 and Ir5Ce.

[0056] The total content of iridium and cerium, relative to 100 parts by mass of the sintered body, can be 97 parts by mass or more, 98 parts by mass or more, or 99 parts by mass or more. The sintered body may be formed solely of iridium, cerium, and unavoidable impurities. The content of iridium and cerium are appropriately set according to the type of crystal phase constituting the sintered body. The content of iridium, relative to 100 parts by mass of the sintered body, can be 73.3 parts by mass or more, 77 parts by mass or more, or 80 parts by mass or more, or less than 87.3 parts by mass, less than 85 parts by mass, or less than 83 parts by mass. The content of cerium, relative to 100 parts by mass of the sintered body, can be 12.7 parts by mass or more, 15 parts by mass or more, or 17 parts by mass or more, or less than 26.7 parts by mass, less than 23 parts by mass, or less than 20 parts by mass.

[0057] In the XRD pattern obtained by XRD analysis of the surface of the sintered body, two peaks (the first peak) and the second peak (the second peak) are observed as peaks originating from Ir, located at a scattering angle of 2θ of 47.6°. In this pattern, the half-width at half-maximum (WHM) of the first peak at 2θ of 47.6° is greater than 0.5, and can be 0.5 or greater than 0.55. The upper limit of the WHM of the first peak can, for example, be less than 0.55. Similarly, the WHM of the second peak at 2θ of 55.5° is greater than 0.5, and can be 0.6 or greater than 0.65. The upper limit of the WHM of the second peak can, for example, be 0.69. Such a sintered body can be obtained, for example, by sintering powder composed of iridium and cerium using hot pressing or spark plasma sintering (see Patent Documents 1 and 2).

[0058] As described above, the heat treatment temperature for the sintered body is 1400–1800°C, preferably 1400–1600°C or 1500–1800°C, more preferably 1500–1600°C. By setting the temperature above 1400°C, crystallization is promoted; by setting the temperature below 1800°C, material dissolution is inhibited.

[0059] As described above, the heat treatment time is 0.5 hours or more, preferably 1 hour or more, 2 hours or more, or 2.5 hours or more, and can be 100 hours or more. By making the heat treatment time 0.5 hours or more, crystallization is promoted, and by making the heat treatment time 100 hours or more, iridium is more easily deposited on the surface. The upper limit of the heat treatment time can be, for example, 240 hours or less.

[0060] As described above, the work function of the sintered material after the heat treatment is 3.8 eV or less, while the work function of the sintered body before the heat treatment is, for example, 4.1 to 4.3 eV. The decrease in work function due to the heat treatment is presumably due to the crystallization of the sintered body, resulting in the formation of crystals and the precipitation of metallic iridium on the surface of these crystals. Consequently, metallic iridium is either dispersed in island-like patterns on the surface of the sintered material or forms a layer of metallic iridium covering the entire surface of the crystals.

[0061] The crystallization process induced by the aforementioned heat treatment can be confirmed by the full width at half maximum (FWHM) of the peaks from Ir in the XRD patterns of the sintered body and the sintered material, respectively, before and after the heat treatment. Specifically, in one embodiment, as described above, the sintered body (before heat treatment) exhibits a peak with a FWHM greater than 0.5 (first peak) at a scattering angle 2θ of 47.6° and a peak with a FWHM greater than 0.5 (second peak) at a scattering angle 2θ of 55.5°. In contrast, the sintered material (after heat treatment) may exhibit a peak with a FWHM less than 0.5 at a scattering angle 2θ of 47.6° (first peak) and a peak with a FWHM less than 0.5 at a scattering angle 2θ of 55.5° (second peak).

[0062] In the XRD pattern obtained by analyzing the surface of the sintered material, the half-width at half-maximum (WHM) of the first peak at a scattering angle 2θ of 47.6° is preferably 0.5 or less, more preferably 0.48 or less, 0.46 or less, 0.44 or less, 0.43 or less, or 0.42 or less, and can be 0.39 or more, 0.40 or more, or 0.41 or more. In the XRD pattern obtained by analyzing the surface of the sintered material, the half-width at half-maximum (WHM) of the second peak at a scattering angle 2θ of 55.5° is preferably 0.5 or less, more preferably 0.49 or less, and can be 0.43 or more, 0.44 or more, or 0.45 or more. By keeping the WHMs of the first and second peaks below the upper limit, the sintered material easily achieves a sufficiently small work function value.

[0063] Furthermore, the state in which metallic iridium is dispersed in an island-like pattern on the surface of the sintered material can be observed through EDX (Energy Dispersive X-ray) mapping analysis of the sintered body surface and EBSD (Electron Back Scatter Diffraction) analysis of the sintered material surface. That is, based on such observations, it can be seen that in one embodiment, the sintered material may have: a main body portion constituting the core of the sintered material; and iridium regions formed on the surface of the main body portion.

[0064] The main body can be made of iridium and cerium. The iridium regions can be regions made of iridium or regions without cerium. Multiple iridium regions can be distributed on the surface of the main body. The size of each iridium region (the maximum length of the straight line connecting two points on the outer perimeter of an iridium region) can be, for example, 0.1 μm or more, 0.5 μm or more, or 1 μm or more, or less than 30 μm, less than 20 μm, or less than 10 μm.

[0065] Example

[0066] The present invention will now be described in more detail with reference to the embodiments, but the present invention is not limited to the embodiments described below.

[0067] (Comparative Example 1)

[0068] Sintered bodies made directly using Ir7Ce2 as the main crystalline phase, and also containing Ir5Ce and Ir3Ce crystalline phases (made by Kobelco Research Institute). Figure 2 This is a SEM image of the surface of the sintered body. Figure 3 The XRD pattern is shown for the surface of the sintered body. In the XRD pattern, ○ indicates a peak from Ir, □ indicates a peak from Ir5Ce, △ indicates a peak from Ir7Ce2, and × indicates a peak from Ir3Ce (the same applies below). The half-width at half-maximum (WHM) of the first peak at a scattering angle of 2θ of 47.6° is 0.543, and the half-width at half-maximum (WHM) of the second peak at a scattering angle of 2θ of 55.5° is 0.690. It should be noted that in Comparative Example 1 and the following embodiments, XRD patterns were obtained using an XRD apparatus manufactured by Rigaku Corporation, and the WHM was determined using XRD analysis software (JADE, manufactured by MDI Corporation). Specifically, after background subtraction from the XRD pattern, the WHM of each peak was determined using the first and second peaks separated by peak fitting. It should be noted that Kα2 subtraction was not performed.

[0069] Furthermore, the work function of the sintered body described above is 4.27 eV. It should be noted that in Comparative Example 1 and the following embodiments, an ultraviolet photoelectron spectroscopy apparatus manufactured by Kratos Analytical was used to measure the work function.

[0070] (Example 1)

[0071] The sintered body used in Comparative Example 1 (a sintered body composed of Ir7Ce2 crystal phase, manufactured by Kobelco Research Institute) was subjected to a decompression of 10 °C. -5 In air at Pa (oxygen partial pressure: approximately 2 × 10⁻⁶ Pa), -6 The material is heated at 1750℃ for 3 hours to obtain sintered material. Figure 4The image shows a SEM image of the surface of the obtained sintered material. Figure 5 The XRD pattern is shown for the surface of the obtained sintered material. The full width at half maximum (FWHM) of the first peak at a scattering angle of 2θ of 47.6° is 0.415, and the FWHM of the second peak at a scattering angle of 2θ of 55.5° is 0.489. The work function of the obtained sintered material is 3.67 eV. Furthermore, relative to 100 parts by mass of the total mass of the obtained sintered material, the content of iridium is 82.8 parts by mass and the content of cerium is 17.2 parts by mass.

[0072] (Example 2)

[0073] The sintered body used in Comparative Example 1 (a sintered body composed of Ir7Ce2 crystal phase, prepared by Kobelco Research Institute) was subjected to a decompression of 10 °C. -5 The material is sintered by heating it in air at 1600°C for 80 hours. Figure 6 The image shows a SEM image of the surface of the obtained sintered material. Figure 7 The XRD pattern is shown for the surface of the obtained sintered material. The full width at half maximum (FWHM) of the first peak at a scattering angle of 2θ of 47.6° is 0.429, and the FWHM of the second peak at a scattering angle of 2θ of 55.5° is 0.457. The work function of the obtained sintered material is 3.52 eV. Furthermore, relative to 100 parts by mass of the total mass of the obtained sintered material, the content of iridium is 82.8 parts by mass and the content of cerium is 17.2 parts by mass.

[0074] Figure 8 (a) and Figure 8 (b) is an image showing the EDX mapping analysis results of the surface of the sintered body of Comparative Example 1. Figure 8 Image (a) shows the distribution of Ce elements. Figure 8 Image (b) shows the distribution of Ir elements. Based on these images, it can be seen that Ce and Ir elements are relatively uniformly distributed on the surface of the sintered body of Comparative Example 1.

[0075] Figure 9 (a) and Figure 9 (b) is an image showing the EDX mapping analysis results of the surface of the sintered material obtained in Example 1. Figure 9 Image (a) shows the distribution of Ce elements. Figure 9 Image (b) shows the distribution of Ir elements. Based on these images, it can be seen that the surface of the sintered material obtained in Example 1 is scattered with iridium regions R1 (…). Figure 9 (b) The bright area in (b).

[0076] Figure 10 (a) and Figure 10 (b) is an image showing the EDX mapping analysis results of the surface of the sintered material obtained in Example 2. Figure 10 Image (a) shows the distribution of Ce elements. Figure 10 Image (b) shows the distribution of Ir elements. Based on these images, it can be seen that the surface of the sintered material obtained in Example 2 is scattered with iridium regions R2 (…). Figure 10 (b) The bright area in (b).

[0077] In Example 1, the iridium region R1 in the sintered material is more uniformly dispersed, while in contrast, the iridium region R2 in the sintered material of Example 2 appears to be more prevalent. Furthermore, the size of the iridium region R2 in the sintered material of Example 2 appears to be larger than the size of the iridium region R1 in the sintered material of Example 1.

[0078] Figure 11 (a) and Figure 11 (b) is an image showing the EBSD analysis results of the surface of the sintered material obtained in Example 1. Figure 11 (a) is an IQ (Image Quality) mapping of the surface of the sintered material obtained in Example 1. Figure 11 Image (b) shows the distribution of Ir elements and Ir7Ce2 crystal phase on the surface of the sintered material obtained in Example 1. Based on these images, it can be seen that Example 1 comprises a main body M1 (...) composed of Ir elements and the Ir7Ce2 crystal phase. Figure 11 (b) the bright area); and the iridium region R1, which is scattered in an island-like pattern on the surface of the main body M1. Figure 11 (The bright area in (a)). It is speculated that the iridium region R1 is mainly composed of iridium.

[0079] Figure 12 (a) and Figure 12 (b) is an image showing the EBSD analysis results of the surface of the sintered material obtained in Example 2. Figure 12 (a) is the IQ mapping diagram of the surface of Example 2. Figure 12 Image (b) shows the distribution of Ir elements and the Ir7Ce2 crystal phase on the surface of Example 2. Based on these images, it can be seen that the sintered material obtained in Example 2 comprises: a main body M2 composed of Ir elements and the Ir7Ce2 crystal phase. Figure 12 (b) the bright area); and the iridium region R2, which is scattered in an island-like pattern on the surface of the main body M2. Figure 12 (The bright area in (a)). It is speculated that the iridium region R2 is mainly composed of iridium.

[0080] In Example 1, the iridium region R1 in the sintered material is more uniformly dispersed on the surface of the main body M1. In contrast, in Example 2, the iridium region R2 appears to be more predominantly distributed on the surface of the main body M2. Furthermore, the size of the iridium region R2 in the sintered material of Example 2 appears to be larger than that of the iridium region R1 in the sintered material of Example 1.

[0081] (Example 3)

[0082] In addition to changing the oxygen partial pressure during heat treatment to 10 -1 Except for Pa, the same procedure as in Example 1 was followed to obtain the sintered material. The work function of the obtained sintered material was 3.8 eV or less.

[0083] This public document addresses the following matters.

[0084] [1] A method for manufacturing a sintered material, wherein the sintered material is composed of iridium and cerium, comprising: a step of preparing a sintered body composed of iridium and cerium; and a step of manufacturing a sintered material with an oxygen partial pressure of 10... -1 The process of obtaining sintered materials by heating the sintered body at a temperature of 1400–1800°C for more than 0.5 hours under an atmosphere below Pa.

[0085] [2] The method for manufacturing sintered materials as described in [1], wherein the sintered body is composed of at least one crystal phase selected from the group consisting of Ir2Ce, Ir3Ce, Ir7Ce2 and Ir5Ce.

[0086] [3] The method for manufacturing sintered materials as described in [1] or [2], wherein the work function of the sintered body is 4.1 to 4.3 eV.

[0087] [4] Sintered material, which is a sintered material composed of iridium and cerium, and has a work function of less than 3.8 eV.

[0088] [5] The sintering material as described in [4] comprises: a main body made of iridium and cerium; and an iridium region formed on the surface of the main body.

[0089] [6] The sintered material as described in [4] or [5], wherein the sintered material, in the spectrum obtained by XRD analysis of the surface of the sintered material, shows a peak with a half width of less than 0.5 at a scattering angle 2θ of 47.6°.

[0090] [7] The sintered material as described in any one of [4] to [6], wherein the sintered material, in the spectrum obtained by XRD analysis of the surface of the sintered material, shows a peak with a half width of less than 0.5 at a position where the scattering angle 2θ is 55.5°.

[0091] [8] The sintering material as described in any one of [4] to [7], wherein the cerium content is 12.7 to 26.7 parts by mass relative to 100 parts by mass of the total mass of the sintering material.

[0092] [9] An electronic source, which is composed of any one of the sintered materials described in [4] to [8].

[0093]

[10] A device having the electronic source described in [9].

[0094] Explanation of reference numerals in the attached figures

[0095] 1…Electron source, 2…Filament, 3…Joint, M1, M2…Main body, R1, R2…Iridium region.

Claims

1. A method for manufacturing a sintered material, comprising: The process of preparing a sintered body composed of iridium and cerium; and At an oxygen partial pressure of 10 -1 The process of obtaining the sintered material by heating the sintered body at a temperature of 1400-1800°C for more than 0.5 hours under an atmosphere below Pa.

2. The method for manufacturing sintered materials as described in claim 1, wherein, The sintered body is composed of at least one crystal phase selected from the group consisting of Ir2Ce, Ir3Ce, Ir7Ce2, and Ir5Ce.

3. The method for manufacturing the sintered material as described in claim 1 or 2, wherein, The work function of the sintered body is 4.1 to 4.3 eV.

4. Sintered materials, which are sintered materials composed of iridium and cerium, and have a work function of less than 3.8 eV.

5. The sintering material as described in claim 4, comprising: The main body is composed of iridium and cerium; and An iridium region formed on the surface of the main body.

6. The sintered material as described in claim 4, wherein, In the XRD pattern obtained by analyzing the surface of the sintered material, a peak with a half-width of less than 0.5 is observed at a scattering angle 2θ of 47.6°.

7. The sintered material as described in claim 4, wherein, In the spectrum obtained by XRD analysis of the surface of the sintered material, a peak with a half width at half maximum (WWHM) of less than 0.5 is observed at a scattering angle 2θ of 55.5°.

8. The sintering material as described in claim 4, wherein, The cerium content is 12.7 to 26.7 parts by mass relative to 100 parts by mass of the total mass of the sintered material.

9. An electronic source comprising the sintered material according to any one of claims 4 to 8.

10. An apparatus comprising the electronic source of claim 9.

Images