Cr-si-c sintered body

Abstract

Disclosed is a Cr-Si-C sintered body having a high density, and at least one of a Cr-Si-C sintered body having a high density, a sputtering target including the same, and a method for manufacturing a film using the sintered body. According to the present application, a Cr-Si-C sintered body having a relative density of 90% or more and a porosity of 13% or less can be provided.

Description

TECHNICAL FIELD

[0001] The present application relates to a Cr-Si-C sintered body for film formation. BACKGROUND

[0002] In recent years, a chromium silicide such as CrSi2, which is a representative of a silicide, is used as a film (thin film) in many uses such as semiconductors, solar cells, and the like due to its characteristics. In a method for producing a film, mainly a thin film, a sputtering method is generally used in industry. However, a composition (for example, a sintered body) containing a silicide such as CrSi2 generally has low strength, and thus, cracking and the like occur at the time of processing into a sputtering target and at the time of discharging for film formation. Therefore, it is known that a composition containing a silicide is difficult to use as a sputtering target. Thus, in Patent Literature 1, a sputtering target of a crystal phase of Cr and Si (an alloy target mainly composed of a Cr phase and a Si phase) is produced by a thermal spraying method. However, the sputtering target produced by the thermal spraying method does not have sufficient strength in a composition region in which the proportion of Cr is small. Similarly, a sputtering target produced by a thermal spraying method using a powder of a silicide phase also does not have sufficient strength.

[0003] In addition, in Patent Literature 2, a composition having a fine eutectic structure is produced by a melting method. However, the composition obtained by the melting method does not have sufficient strength in a composition region in which the proportion of the eutectic structure is small and the proportion of a primary crystal (that is, a crystal phase having the highest proportion in the composition) is large. Further, in the case where such a composition is made large, it is difficult to control the crystal structure due to the difference in cooling speed between phases, and the strength of the composition as a whole becomes uneven.

[0004] Note that, since a silicide phase is brittle, a system containing a large amount of a silicide is not mentioned in Patent Literatures 3 and 4.

[0005] In recent years, as a sputtering target of a Cr-Si system in which the temperature change characteristics of the resistivity of a film (thin film) are improved (that is, the temperature dependence of the resistivity is reduced), a sintered body in which a third element such as carbon or boron is added to a Cr-Si system sintered body has been studied. However, such a sintered body is difficult to be densified. Therefore, if a sintered body to which a third element is added is used as a sputtering target, a large amount of particles are generated, and the yield of a finished product, that is, the productivity of a film product is low.

[0006] PRIOR ART DOCUMENTS

[0007] PATENT LITERATURE

[0008] Patent Literature 1: Japanese Patent Application Laid-Open No. 2017-82314

[0009] Patent Literature 2: Japanese Patent Application Laid-Open No. 2013-502368

[0010] Patent Literature 3: Japanese Patent Application Laid-Open (JP A) No. 2002-173765

[0011] Patent Literature 4: Japanese Patent Application Laid-Open (JP A) No. 2003-167324 SUMMARY

[0012] PROBLEMS TO BE SOLVED BY THE INVENTION

[0013] An object of the present application is to provide at least any one of a Cr-Si-C sintered body containing chromium (Cr), silicon (Si), and carbon (C) having high density, a Cr-Si-C sintered body having high density, a sputtering target containing the same, and a method for manufacturing a film using the sintered body. In particular, an object of the present application is to provide at least any one of a Cr-Si-C sintered body in which generation of particles is suppressed as compared with a conventional Cr-Si sintered body, a method for manufacturing the sintered body, and a sputtering target containing the sintered body and a method for manufacturing a film using the sintered body.

[0014] MEANS FOR SOLVING THE PROBLEMS

[0015] The present inventors have intensively studied a Cr-Si-C sintered body and a manufacturing process thereof. As a result, it has been found that a Cr-Si-C sintered body having high density is obtained by using a rapidly cooled alloy powder (molten metal powder) such as a gas atomized powder, and that generation of particles is suppressed when a Cr-Si-C sintered body having a specific structure is used as a sputtering target, thereby completing the present application.

[0016] That is, the gist and the mode of the present application are as follows.

[0017] (1) A Cr-Si-C sintered body characterized by being a Cr-Si-C sintered body containing chromium (Cr), silicon (Si), and carbon (C), the sintered body having a relative density of 90% or more and a porosity of 13% or less.

[0018] (2) The Cr-Si-C sintered body according to (1), wherein, as a composition range, carbon is 1 to 20 wt%, silicon is 20 to 70 wt%, and the remainder is chromium.

[0019] (3) The Cr-Si-C sintered body according to (1) or (2), wherein chromium silicide and one or more selected from the group consisting of chromium carbide, silicon carbide, and carbon are contained.

[0020] (4) The Cr-Si-C sintered body according to any one of (1) to (3), wherein one or more selected from the group of CrSi, CrSi2, and Cr3Si is contained as a main phase.

[0021] (5) The Cr-Si-C sintered body according to any one of (1) to (4), wherein the oxygen content is 1 wt% or less.

[0022] (6) The Cr-Si-C sintered body according to any one of (1) to (5), wherein the bending strength is 100 MPa or more.

[0023] (7) A method for manufacturing a Cr-Si-C sintered body according to any one of (1) to (6), wherein the method comprises:

[0024]

[0025] mixing a gas atomized powder of chromium and silicon, and a carbon source containing at least either one of chromium and silicon and carbon to obtain an alloy raw material powder; and a sintering step in which the alloy raw material powder is hot-pressed at a pressure of 50 MPa or less and a sintering temperature of 1350°C or higher and 1800°C or lower in a vacuum atmosphere.

[0026] (8) The method for manufacturing according to (7), wherein the carbon source is a carbide containing at least either one of chromium and silicon.

[0027] (9) A sputtering target composed of the Cr-Si-C sintered body according to any one of (1) to (6).

[0028] (10) A method for manufacturing a film by sputtering using the sputtering target according to (9).

[0029] Effects of the Invention

[0030] According to the present application, it is possible to provide a Cr-Si-C sintered body containing chromium, silicon, and carbon, which has a high density, and further provide at least any one of a Cr-Si-C sintered body having a high density, a sputtering target containing the same, and a method for manufacturing a film using the sintering target. Preferably, the Cr-Si-C sintered body of the present application has a relative density of 90% or more, and when used as a sputtering target, has fewer particles when used as a sputtering target, and enables a higher productivity. In particular, the present application can provide at least any one of a Cr-Si-C sintered body in which the generation of particles has been suppressed compared to a conventional Cr-Si sintered body, a method for manufacturing the same, and a sputtering target containing the same and a method for manufacturing a film using the sputtering target. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a laser microscope observation image for measuring porosity. DETAILED DESCRIPTION

[0032] ​Hereinafter, an embodiment of the present application will be described in detail with reference to the drawings.

[0033] The present application is a Cr-Si-C sintered body characterized by being a Cr-Si-C sintered body containing chromium (Cr), silicon (Si), and carbon (C), and having a relative density of 90% or more and a porosity of 13% or less.

[0034] The Cr-Si-C sintered body of the present application (hereinafter also referred to as "the sintered body of the present application") is a sintered body mainly composed of chromium, silicon, and carbon, and is preferably a sintered body composed of chromium, silicon, and carbon.

[0035] The sintered body of the present application preferably contains chromium silicide and one or more selected from the group consisting of chromium carbide, silicon carbide, and carbon.

[0036] As the chromium silicide contained in the sintered body of the present application, one or more selected from the group consisting of monosilicide, disilicide, and trisilicide of chromium can be given, further one or more selected from the group consisting of CrSi, CrSi2, Cr3Si, and Cr5Si3 can be given, and still further one or more selected from the group consisting of CrSi, Cr3Si, and Cr5Si3 can be given. The sintered body of the present application can contain two or more kinds of chromium silicide, preferably two or more kinds selected from the group consisting of CrSi, CrSi2, Cr3Si, and Cr5Si3, more preferably two or more kinds selected from the group consisting of CrSi, Cr3Si, and Cr5Si3, and further preferably Cr5Si3 and CrSi or Cr3Si.

[0037] The sintered body of the present application preferably contains at least any one of chromium carbide (Cr3C2), silicon carbide (SiC), and carbon (C), further preferably at least any one of silicon carbide and carbon, and still further preferably silicon carbide.

[0038] The sintered body of the present application can be a sintered body composed of chromium silicide and one or more selected from the group consisting of chromium carbide, silicon carbide, and carbon, but in addition thereto, can contain at least any one of silicon (Si) and chromium (Cr), and further can contain silicon.

[0039] The sintered body of the present application preferably has chromium silicide as a main phase, more preferably one or more selected from the group consisting of CrSi, CrSi2, and Cr3Si as a main phase, and further preferably CrSi as a main phase. The main phase in the present application means a crystal phase having the highest proportion in the crystal phases of the sintered body, and for example, a mass proportion of the crystal phase of the main phase with respect to the mass of the sintered body can be more than 50 wt%, more than 60 wt%, or more than 70 wt%. Further, for example, the mass proportion (wt%) of chromium silicide in the sintered body of the present application can be more than 70 wt%, more than 75 wt%, or less than 80 wt%, or less than 95 wt%.

[0040] In the present application, the crystal phase contained in the sintered body of chromium silicide or the like can be determined from its powder X-ray diffraction (hereinafter, also referred to as "XRD") pattern. The XRD pattern can be measured by a general XRD device (for example, RINT Ultima III, manufactured by Rigaku Corporation). As the XRD measurement conditions in the present application, the following conditions can be cited.

[0041] Accelerating current / voltage: 40 mA / 40 kV

[0042] Radiation source: Cu Kα ray

[0043] Measurement mode: Continuous scan

[0044] Scanning condition: 2° / minute

[0045] Measurement range: 2θ = 20° to 80°

[0046] Divergence longitudinal limiting slit: 10 mm

[0047] Divergence / incidence slit: 1 / 2°

[0048] Receiving slit: 0.3 mm

[0049] By comparing the obtained XRD pattern with the database of ICDD, the crystal phase of the sintered body can be determined.

[0050] The sintered body of the present application is characterized in that the relative density is 90% or more, preferably 92% or more, more preferably 94% or more, and particularly preferably 96% or more. In addition, the relative density can be 100% or less or 99% or less. In the case where the relative density of the sintered body is less than 90%, a part of the sintered body is detached as a coarse particle (i.e., a particle is generated) when a film is produced (i.e., when a film is formed using the sintered body). Thus, a coarse pore (for example, a pore having a maximum length of 50 μm or more; hereinafter, also referred to as "coarse pore") is generated in the sintered body. At the same time, the particle is attached as a film and is formed into a film (i.e., a film into which the particle is mixed is formed). The film into which the particle is mixed is not uniform in physical properties and characteristics, and thus cannot be used. Thus, the sintered body having a relative density of less than 90% reduces the productivity of the film.

[0051] The "relative density" (%) in the present application is the ratio of the measured density to the true density, and is a value obtained by (measured density [g / cm 3 / true density [g / cm 3 ]) x 100.

[0052] The measured density is the bulk density measured by the Archimedes method according to JIS R 1634, which is calculated from the dry mass with respect to the volume. Before the Archimedes method, the pretreatment is preferably a boiling method, in which the sintered body is boiled in water.

[0053] The true density is the density calculated according to the following formula.

[0054] d = 1 / {(R1 / M1) + (R2 / M2) + (R3 / M3) + (R4 / M4) + (R5 / M5) + (R6 / M6) + (R7 / M7) + (R8 / M8) + (R9 / M9)}

[0055] In the above formula, d is the true density [g / cm 3 ] of the sintered body, M1 to M8 and R1 to R8 are the true densities [g / cm 3 ] of each crystal phase of Si, C, Cr, SiC, CrSi, CrSi2, Cr3Si, Cr3C2 and Cr5Si3 contained in the sintered body, and the mass proportions [wt%] of each crystal phase in the sintered body, respectively.

[0056] The true density of each crystal phase can be calculated using the values described in ICDD (Version 2.1502) for each crystal phase. As the true density, the following values can be exemplified.

[0057] Si: 2.33 g / cm 3 (= M1)

[0058] C: 2.28 g / cm 3 (= M2)

[0059] Cr: 7.20 g / cm 3 (= M3)

[0060] SiC: 3.12 g / cm 3 (= M4)

[0061] CrSi: 5.36 g / cm 3 (= M5)

[0062] CrSi2: 4.98 g / cm 3 (= M6)

[0063] Cr3C2: 6.66 g / cm 3 (= M7)

[0064] Cr5Si3: 5.87 g / cm 3 (= M8)

[0065] Cr3Si: 6.46 g / cm 3 (= M9)

[0066] Note that the ICDD number of each crystal phase can be mentioned as follows: Si is 00-026-1481, C is 00-026-1080, Cr is 01-077-759, SiC is 00-002-105, CrSi is 03-065-3298, CrSi2 is 01-072-6184, Cr3C2 is 01-071-2287, Cr5Si3 is 01-072-0347, and Cr3Si is 01-070-301.

[0067] The mass ratio of each crystal phase is the mass ratio [wt%] of each crystal phase determined based on the ratio of the crystal phases of the sintered body and the elements (Cr, Si, and C) constituting the sintered body, which is determined using the XRD pattern measured under the above conditions. For example, in the case where the crystal phases included in the XRD pattern of the sintered body are CrSi, Cr5Si3, and SiC, and the composition of the sintered body obtained from the composition analysis is X mol% Cr, Y mol% Si, and Z mol% C, the mass ratio [wt%] is obtained by multiplying the molar ratio [mol%] calculated from the following formula by the true density of each crystal phase.

[0068] X = 1 x M CrSi + 5 x M Cr5Si3

[0069] Y = 1 x M CrSi + 3 x M Cr5Si3 + 1 x M SiC

[0070] Z = 1 x M SiC

[0071] In the above formula, M CrSi is the molar ratio [mol%] of CrSi, M Cr5Si3 is the molar ratio [mol%] of Cr5Si3, and M SiC is the molar ratio [mol%] of SiC.

[0072] In addition, the true density of the sintered body of the present application including three crystal phases (crystal phases A to C) can be calculated from the following formula.

[0073] d = (a + b + c) / ((a / Ma) + (b / Mb) + (c / Mc))

[0074] or

[0075] d = 1 / ((Ra / Ma) + (Rb / Mb) + (Rc / Mc))

[0076] In the above formula, d is the true density [g / cm 3, a, b and c are the mass [g] of the crystal phases A, B and C contained in the sintered body, respectively, and, in addition, Ma, Mb and Mc are the true density [g / cm3] of the crystal phases A, B and C contained in the sintered body, respectively. The crystal phases A, B and C are three selected from the group of Si, C, Cr, SiC, CrSi, CrSi2, Cr3C2 and Cr5Si3, and are preferably (1) CrSi, Cr5Si3 and SiC, (2) Cr3Si, Cr5Si3 and SiC, or (3) CrSi2, Si and C, more preferably CrSi, Cr5Si3 and SiC. 3 , and, in addition, Ra, Rb and Rc are the mass ratio [wt%] of the crystal phases A, B and C contained in the sintered body, respectively. The crystal phases A, B and C are three selected from the group of Si, C, Cr, SiC, CrSi, CrSi2, Cr3C2 and Cr5Si3, and are preferably (1) CrSi, Cr5Si3 and SiC, (2) Cr3Si, Cr5Si3 and SiC, or (3) CrSi2, Si and C, more preferably CrSi, Cr5Si3 and SiC.

[0077] The sintered body of the present application is characterized in that the porosity is 13% or less. If the porosity is more than 13%, the productivity of the film will be drastically reduced when the film is produced (i.e., when the film is produced using the sintered body). In order to stably obtain high productivity, the porosity is preferably 8% or less, more preferably 6% or less, and particularly preferably 4% or less. The sintered body of the present application can contain pores, but preferably contains no pores (i.e., the porosity is 0%), and the porosity of the sintered body of the present application can be 0% or more, more than 0%, 0.5% or more, or 1% or more.

[0078] In the present application, the "porosity" refers to the proportion of pores obtained from an observation chart of the surface of the sintered body, and is the proportion of pores measured by image analysis of an observation chart of the surface of the sintered body having a surface roughness Ra of 0.02 μm or less. The porosity can be obtained from an observation chart of the surface of the sintered body in either state before or after sputtering, but is preferably obtained from an observation chart of the surface of the sintered body in either state before or after sputtering. In the observation chart, the shape of the pores is arbitrary, and examples include, for example, substantially spherical, substantially polyhedral or indefinite shapes. The observation chart is obtained by laser microscope observation using a general laser microscope (e.g., VX-250, manufactured by Keyence Corporation). As the observation conditions for laser microscope observation, the following conditions can be mentioned.

[0079] Observation magnification: 200x

[0080] Observation field: 5 fields or more, preferably 5 to 8 fields, more preferably 5 fields

[0081] Figure 1 One field of the observation chart obtained by laser microscope observation is shown. As Figure 1In the observation image (100), as shown, the pores are identified as black regions (10), and the sintered body is identified as white regions (11). As for the porosity (%) of each field of view, only the proportion (%) of the black regions in each observation image relative to the total area of the black regions and the white regions is required. As long as the average value of the porosities of the observed fields of view is taken as the porosity of the present application, it is acceptable. The image analysis can be performed by using a general image analysis software (for example, Image-Pro, manufactured by Media Cybernetics Corporation) on the obtained observation image. As the image analysis conditions, the following conditions can be cited. Note that the contrast is a value taken from any value in the range of 0 to 100.

[0082] Number of fields of view to be measured: 5 or more, preferably 5 to 8, more preferably 5

[0083] The amount of silicon (Si) in the sintered body of the present application is preferably in the range of 20 to 70 wt%, more preferably 25 to 65 wt%, more preferably 30 to 60 wt%, and further preferably 35 to 55 wt%. When the amount of silicon is less than 20 wt%, the amount of the semiconductor phase (i.e., the SiC phase and the Si phase) of the sintered body as a whole tends to decrease, and the temperature dependence of the resistivity tends to increase. In addition, when the amount of silicon is more than 70 wt%, and further more than 50 wt%, the amount of the semiconductor phase increases, and the temperature dependence of the resistivity of the obtained film tends to increase. As the preferable amount of silicon in the sintered body of the present application, 20 wt% or more, 25 wt% or more, or 30 wt% or more can be cited, and 70 wt% or less, 65 wt% or less, 50 wt% or less, 45 wt% or less, or 40 wt% or less can be cited.

[0084] The amount of silicon in the sintered body of the present application is the mass ratio (wt%) of silicon relative to the mass of the sintered body of the present application obtained by mass measurement. The silicon contained in the sintered body of the present application can be measured by a general method used in the technical field, for example, measurement by ICP analysis can be cited.

[0085] The amount of carbon (C) in the sintered body of the present application is preferably in the range of 1 to 20 wt%, more preferably 1 to 15 wt%, further preferably 1 to 10 wt%, and still further preferably 5 to 10 wt%. When the amount of carbon is less than 1 wt%, the temperature dependence of the resistivity of the film is not improved (i.e., the temperature dependence is difficult to reduce). On the other hand, when the amount of carbon is more than 20 wt%, the amount of SiC phase exhibiting high resistivity close to insulating property tends to increase in the sintered body, which tends to become a cause of particle generation in the case of DC discharge. As the preferable amount of carbon in the sintered body of the present application, 1 wt% or more, 3 wt% or more, or 4 wt% or more can be given, and, in addition, 20 wt% or less, 15 wt% or less, 10 wt% or less, or 9 wt% or less can be given.

[0086] The content of carbon in the sintered body of the present application is the mass ratio (wt%) of carbon with respect to the mass of the sintered body. The carbon can be measured by a general method used in the technical field, and, for example, the carbon can be exemplified by a combustion-infrared absorption method using a general carbon / sulfur analysis device (e.g., LECO-CS844 carbon / sulfur analysis device).

[0087] The sintered body of the present application can contain, as the remaining portion of silicon and carbon, chromium, and, as the content of chromium in the sintered body of the present application, 10 wt% or more and less than 79 wt%, further 15 to 75 wt%, and still further 35 to 70 wt% can be given. In addition, as the preferable composition range of the sintered body of the present application, 1 to 20 wt% of carbon, 20 to 70 wt% of silicon, and the remaining portion of chromium can be given.

[0088] The metal elements (including semi-metal elements. In the present specification, the same applies hereinafter) contained in the sintered body of the present application are preferably chromium and silicon. However, the sintered body of the present application can contain, in addition to chromium (Cr), silicon (Si), and carbon (C), metal impurities such as iron (Fe) and aluminum (Al). The metal elements such as iron and aluminum are contained as inevitable impurities. That is, the sintered body of the present application can contain inevitable impurities, can contain metal impurities (metal elements other than chromium and silicon) as inevitable impurities, and further can contain iron and aluminum as inevitable impurities. These metal impurities (metal elements other than chromium and silicon) can be contained in a total amount of 1 wt% or less, preferably 0.5 wt% or less, and further preferably 0.3 wt% or less. The sintered body of the present application preferably does not contain metal impurities, and, as the total amount of metal elements other than chromium and silicon, 0 wt% or more, more than 0 wt%, or 0.1 wt% or more can be given.

[0089] Further, the sintered body of the present application can contain oxygen, as long as the properties when used as a sputtering target are not reduced to an extent that is not acceptable. The amount of oxygen (O) in the sintered body of the present application is preferably small, for example, preferably 1 wt% or less. If the amount of oxygen is more than 1 wt%, a large number of particles derived from insulating oxides are likely to be generated in film formation. The amount of oxygen in the sintered body of the present application is further preferably 0.5 wt% or less, particularly preferably 0.1 wt% or less. The sintered body of the present application preferably contains no oxygen (i.e., the amount of oxygen is 0 wt%), but can contain more than 0 wt% or 0.01 wt% or more.

[0090] The amount of oxygen in the sintered body of the present application is the mass ratio (wt%) of oxygen with respect to the mass of the sintered body. The oxygen contained in the sintered body of the present application can be measured by a general method used in the technical field. For example, the content of oxygen can be measured by analysis based on the inert gas fusion-infrared absorption method. In the inert gas fusion-infrared absorption method, a general oxygen / nitrogen analysis device (e.g., LECO-ON736 oxygen / nitrogen analysis device) can be used.

[0091] The sintered body of the present application can have any shape as appropriate for the purpose, and one or more selected from the group consisting of a round plate shape, a cylindrical shape, a plate shape, a cuboid shape, a cubic shape, a polyhedral shape, and a substantially polyhedral shape can be exemplified.

[0092] The bending strength of the sintered body of the present application is preferably 100 MPa or more, particularly preferably 150 MPa or more. By having the bending strength in this range, even in the case where the sintered body of the present application is manufactured as a large-sized sintered body exceeding 300 mm, the generation of defects at the time of processing, such as the risk of breakage due to processing, can be reduced, and the generation of defects such as cracks when used as a sputtering target can also be easily suppressed. The bending strength of the sintered body of the present application can be 300 MPa or less, 250 MPa or less, or 200 MPa or less, for example.

[0093] The bending strength in the present application can be measured by the method according to JIS R 1601.

[0094] As a preferable embodiment of the sintered body of the present application, a sintered body characterized by a porosity of 13% or less and containing chromium silicide and one or more selected from the group consisting of chromium carbide, silicon carbide, and carbon can be given, and it is preferable that the porosity be 11% or less, 10% or less, or 6% or less, and be 0% or more, more than 0%, or 0.3% or more. Furthermore, the chromium silicide preferably contains two or more selected from the group consisting of CrSi, CrSi2, Cr3Si, and Cr5Si3, more preferably one or more selected from the group consisting of CrSi, CrSi2, and Cr3Si, and is more preferably CrSi, Cr3Si, and Cr5Si3. In addition, the sintered body more preferably contains CrSi, Cr3Si, and silicon carbide. In addition, the relative density of the sintered body is preferably 90% or more, further preferably 93% or more and 100% or less. In addition, the bending strength of the sintered body is preferably 150 MPa or more and 250 MPa or less, more preferably 180 MPa or more and 220 MPa or less.

[0095] As for the method for manufacturing the sintered body of the present application, it can be manufactured by the following steps, which include: (1) an alloy raw material powder preparation step in which chromium, silicon, and carbon are mixed as powders; and (2) a sintering step in which the obtained alloy raw material powder is sintered at a sintering temperature of 1200°C to 1800°C and a pressure of 50 MPa or less using a pressurized sintering furnace such as a hot press.

[0096] Hereinafter, the method for manufacturing the sintered body of the present application will be described for each step.

[0097] (1) Alloy raw material preparation step

[0098] The raw material supplied to the alloy raw material preparation step (hereinafter, also referred to as "starting raw material") is chromium, silicon, and carbon.

[0099] The chromium is preferably high-purity chromium, and chromium of, for example, 3N (purity of 99.9% or more), and further 4N (purity of 99.99% or more) can be given.

[0100] The silicon is preferably high-purity silicon, and silicon of, for example, 3N (purity of 99.9% or more), and further 4N (purity of 99.99% or more), and still further 5N (purity of 99.999% or more) can be given.

[0101] The carbon (carbon source) can be any carbon (C) and its compound, and is preferably a carbide of at least any one of chromium and silicon, and one or more selected from the group consisting of chromium carbide (Cr3C2), silicon carbide (SiC), and carbon (C) can be given, and further at least any one of chromium carbide and silicon carbide can be given. The chromium carbide and the silicon carbide can be regarded as the starting raw material of chromium and silicon, respectively.

[0102] The starting material can use, for example, chromium (Cr), silicon (Si), chromium carbide (Cr3C2), silicon carbide (SiC), carbon (C).

[0103] Further, the starting material can contain an alloy of chromium and silicon, in addition to or instead of chromium and silicon, preferably a molten metal powder of chromium and silicon.

[0104] In the present application, the "molten metal powder" is a powder in a state in which a molten metal is cooled, further a powder in a state in which a molten metal is rapidly cooled, and is a powder having a fine structure. As the molten metal powder, for example, a powder obtained by one or more selected from the group consisting of a quenching thin strip, arc melting, gas atomization, water atomization, centrifugal atomization, and vacuum atomization can be given, further a powder obtained by one or more selected from the group consisting of a quenching thin strip, arc melting, and gas atomization can be given, and still further a powder obtained by gas atomization can be given. The molten metal powder is a powder obtained without a pulverization process, further a powder obtained without a pulverization process, and thus impurities are likely to be less than a powder obtained with a pulverization process.

[0105] The starting material preferably contains a powder obtained by gas atomization (hereinafter, also referred to as "gas atomized powder"), and particularly preferably contains a gas atomized powder of chromium and silicon. A particle produced by a gas atomization method is spherical with a diameter of about several tens of μm, and has a fine crystal phase in the spherical shape. The gas atomized powder is a powder composed of particles with a small surface area and a fine structure, and thus can provide a sintered body after firing with low oxygen and high strength, i.e., can provide an alloy raw material powder from which a sintered body with less oxygen and high strength can be obtained.

[0106] As the gas atomized powder, for example, a powder having an average particle diameter of 5 μm or more and 100 μm or less can be given, a powder having at least any one shape of a spherical shape and a substantially spherical shape can be given, a powder composed of polycrystalline grains of chromium silicide can be given, and further a powder composed of particles of polycrystalline chromium silicide having different crystal phases from each other can be given.

[0107] The gas atomized powder preferably contains at least CrSi2in a crystal phase, more preferably contains CrSi2and one or more selected from the group consisting of Si, Cr, CrSi, Cr3C2, and Cr5Si3in a crystal phase, and further preferably contains CrSi2and at least any one selected from Si and CrSi in a crystal phase.

[0108] The conditions of the gas atomization method are arbitrary, and for example, the treatment temperature at which chromium and silicon are dissolved is preferably a melting temperature + 50 to 300°C, and further preferably a melting temperature + 100 to 250°C. Thus, a molten metal, i.e., a metal in a liquid state is obtained.

[0109] Here, the "melting temperature" refers to the temperature at which the precursor of the raw material powder, flake, or the like of chromium and silicon melts, and is an inherent value of the material. As the melting temperature, 1300°C to 1500°C can be exemplified. Thus, the processing temperature can be exemplified as 1350°C or higher and 1800°C or lower, and 1350°C or higher, 1370°C or higher, or 1390°C or higher can be cited, and 1800°C or lower, 1700°C or lower, 1550°C or lower, or 1470°C or lower can be cited. In the case where the difference between the melting temperature and the processing temperature is small (for example, in the case where the difference is less than 50°C), it is difficult to make the alloy particles constituting the obtained powder fine, for example, because the phase having a higher melting point among the two phases is precipitated first. On the other hand, in the case where the difference between the melting temperature and the processing temperature is large, the particles after atomization are sintered to each other, and the particles are adhered to the wall surface of the gas atomization device, and thus the recovery rate of the powder (the yield of the product) is deteriorated.

[0110] In the gas atomization method, the precursor of the gas atomized powder of chromium and silicon, which is supplied as a starting material, is sufficient. The precursor is at least any one of chromium and silicon and a compound thereof, and is a powder, flake, or block of chromium and silicon, and is preferably a flake of chromium and silicon.

[0111] The precursor of chromium is preferably a flake of high-purity chromium, and a flake of, for example, 3N (purity of 99.9% or more), and further 4N (purity of 99.99% or more) can be cited.

[0112] The precursor of silicon is preferably a flake of high-purity silicon, and a flake of, for example, 3N (purity of 99.9% or more), and further 4N (purity of 99.99% or more), and still further 5N (purity of 99.999% or more) can be cited.

[0113] In the gas atomization method, the obtained molten metal is dropped toward a gas stream in such a manner that the gas stream passes therethrough, and thereby a gas atomized powder is obtained.

[0114] The gas stream is a non-reactive gas, and one or more selected from the group of argon (Ar), nitrogen (N2), and helium (He) can be cited, and further argon can be cited.

[0115] The pressure of the gas stream (hereinafter, also referred to as "gas pressure") is 1 MPa or more, 4 MPa or more, or 6 MPa or more, and is 10 MPa or less, and further 9 MPa or less.

[0116] The gas atomization method can be either of at least one of a crucible type and an electrode type, and is preferably the crucible type. As for the crucible used in the gas atomization method based on the crucible type, for example, a crucible composed of one or more selected from the group consisting of carbon, alumina, magnesia, silicon nitride, zirconia, and boron nitride is preferred; or a crucible in which at least one of boron nitride and silicon carbide is coated on a main body composed of one or more selected from the group consisting of carbon, alumina, magnesia, and zirconia is preferred.

[0117] The atomized powder (gas atomized powder) is preferably managed (stored) in a vacuum atmosphere or in an inert atmosphere such as nitrogen or argon, and is preferably not exposed to an oxidizing atmosphere until it is supplied to the subsequent sintering process. If the powder is left under the atmosphere and exposed to an oxidizing atmosphere, oxidation occurs from the surface of the atomized powder, and the oxygen content of the powder increases.

[0118] Note that, instead of using a molten metal powder, a mixed powder obtained by mixing chromium and silicon by a powder mixing method has been known as a starting material for a sintered body. For example, a high-strength sintered body can be produced in a fine powder mixing (physical mixing of fine powders). However, the oxygen content of a sintered body obtained by sintering a powder obtained by this method increases. In contrast, by coarse particle mixing (physical mixing of powders containing coarse particles), low oxidation of a sintered body can be achieved, but the strength decreases. As other production methods of a raw material (molten metal powder), methods such as rapid cooling of a thin strip by arc melting can be given.

[0119] It is preferable that the oxygen content of the starting material be low. If the oxygen content of the starting material is high, the oxygen content of the sputtering target using the sintered body of the present application increases. Such a large amount of oxygen easily causes the generation of particles. It is preferable that the oxygen content of the starting material be 0.5 wt% or less, further 0.1 wt% or less, and can be exemplified as 0 wt% or more, more than 0 wt%, or 0.01 wt% or more, respectively.

[0120] As a particularly preferable starting material to be supplied to the alloy raw material preparation process, a gas atomized powder of chromium and silicon, and a carbide of chromium and silicon can be given, and further a gas atomized powder of chromium and silicon, and chromium carbide can be given.

[0121] The shape of the starting material is arbitrary, and a powder can be given.

[0122] As a mixing method of the powder (starting material), a method in which the starting materials are uniformly mixed can be used, and all mixers such as a V-type mixer, a mixer, and the like can be used. The mixing method can be at least one of dry mixing and wet mixing, and is preferably dry mixing, and more preferably dry mixing using a V-type mixer. Thereby, an alloy raw material powder is obtained.

[0123] The mixed atmosphere is preferably an atmosphere in which the starting material is not easily oxidized, and at least any one of a vacuum atmosphere and an inert atmosphere can be given, and at least any one of a nitrogen atmosphere and an argon atmosphere can be further given, and an argon atmosphere can be further given.

[0124] As the rotation speed of the mixer, the stirring speed, etc., a mixing speed of 10 rpm or more and 200 rpm or less, further 50 rpm or more and 100 rpm or less can be given. In addition, as the mixing time, 30 minutes or more and 5 hours or less, further 45 minutes or more and 3 hours or less can be given.

[0125] The purity of the raw material obtained by the alloy raw material preparation step (alloy raw material powder) is preferably 99% or more, and more preferably 99.9% or more. If a large amount of impurities is contained in the raw material alloy powder (i.e., the purity is low), the impurities easily become a cause of abnormal grain growth in the sintering step. In addition, the abnormal growth grains easily become a source of generation of particles at the time of film formation.

[0126] As the preferred alloy raw material preparation step, a step in which a molten metal powder of chromium and silicon (molten alloy powder of chromium and silicon), and a starting material containing a carbon source are mixed in at least any one of a vacuum atmosphere and an inert atmosphere to obtain an alloy raw material powder can be given. The molten metal powder is preferably a gas atomized powder of chromium and silicon. The carbon source preferably contains a carbide containing at least any one of chromium and silicon, and more preferably at least any one of chromium carbide (Cr3C2) and silicon carbide (SiC), and further preferably chromium carbide.

[0127] (2) Sintering Step

[0128] In the sintering step, the obtained alloy raw material powder is sintered at a sintering temperature of 1200°C to 1800°C at a pressure of 50 MPa or less using a pressure sintering furnace such as a hot press. The sintering is preferably performed using a pressure sintering furnace such as a hot press. The diffusion coefficient of silicon is low, and thus it is difficult to densify the obtained sintered body in a non-pressure furnace.

[0129] In the sintering step, the alloy raw material powder is sintered by pressure sintering. As the pressure sintering in this step, at least any one of hot pressing and hot isostatic pressing can be given, and hot pressing is preferably given.

[0130] The hot pressing pressure at the time of sintering (hereinafter, also simply referred to as "pressure") is preferably 50 MPa or less. If it exceeds 50 MPa, it is difficult to prepare a hot press mold (die) that can be pressurized (it is difficult to use a general mold). As the general mold, a mold made of carbon can be given.

[0131] In the production of a large sintered body, the hot-pressing pressure is preferably 5 to 45 MPa, further preferably 10 to 40 MPa, and particularly preferably 15 to 40 MPa. In this process, the preferable hot-pressing pressure is, for example, 5 MPa or higher, 10 MPa or higher, or 15 MPa or higher, and 50 MPa or lower, 45 MPa or lower, or 40 MPa or lower.

[0132] The firing temperature is 1350°C to 1800°C. If the firing temperature is less than 1350°C, the density of the resulting sintered body cannot be sufficiently increased. On the other hand, if the firing temperature exceeds 1800°C, the material (sintered body) can be melted during firing. As a particularly preferable firing temperature, for example, 1300°C or higher, 1325°C or higher, or 1350°C or higher, and 1800°C or lower, 1600°C or lower, or 1400°C or lower can be given.

[0133] The temperature increase rate and the temperature decrease rate are not particularly limited and can be appropriately determined in consideration of the volume of the firing furnace, the size and shape of the sintered body, the ease of breakage, and the like. As the temperature increase rate, for example, 100°C / hour or higher or 150°C / hour or higher can be given, and as the temperature decrease rate, for example, 300°C / hour or lower or 250°C / hour or lower can be given.

[0134] As an example, the holding time during firing is 1 to 5 hours, and further 1.5 hours or more and 3.5 hours or less. By being 1 hour or more, temperature unevenness in the firing furnace and the mold (press mold) for hot-pressing can be suppressed, and a sintered body having a uniform structure can be easily obtained. By being 5 hours or less, sintering can be performed with industrial productivity.

[0135] The firing atmosphere is preferably a vacuum atmosphere, a vacuum-reduced pressure atmosphere, or an inert gas atmosphere such as an argon atmosphere, and more preferably an argon atmosphere or a vacuum atmosphere, and further preferably a vacuum atmosphere. By firing in a vacuum atmosphere, a sintered body having the same composition as the raw material alloy powder can be easily obtained. Note that in the present application, a vacuum atmosphere and a vacuum-reduced pressure atmosphere are used interchangeably.

[0136] As a particularly preferable firing process, a process in which the alloy raw material powder is pressure-sintered at a pressure of 50 MPa or lower and a firing temperature of 1350°C or higher and 1800°C or lower in a vacuum atmosphere can be given. The pressure-sintering is preferably a hot-pressing process, and the alloy raw material powder preferably contains a molten metal powder of chromium and silicon, and more preferably a powder composition containing a molten metal powder of chromium and silicon and a carbide powder of at least either of chromium and silicon.

[0137] As a particularly preferable production method of the sintered body of the present application, a production method having the following steps can be given: a step of mixing a gas atomized powder of chromium and silicon, and a carbon source containing at least either one of chromium and silicon and carbon to obtain an alloy raw material powder; and a sintering step of hot-pressing the alloy raw material powder at a pressure of 50 MPa or less and a sintering temperature of 1350°C or higher and 1800°C or lower in a vacuum atmosphere. The carbon source is preferably a carbide containing at least either one of chromium and silicon, and more preferably chromium carbide.

[0138] The sintered body of the present application can be ground into a plate-like shape using a surface grinder, a cylindrical grinder, a lathe, a cutting machine, a machining center, or the like. Thereby, an arbitrary shape corresponding to the purpose can be produced.

[0139] The sintered body of the present application can be used for the known uses of suicides, such as structural materials, electrode materials, semiconductor materials, and the like, and is particularly preferably used as a sputtering target (hereinafter, also simply referred to as "target").

[0140] A sputtering target composed of the sintered body of the present application can be produced.

[0141] The production method of the sputtering target is arbitrary, and the sintered body of the present application can be directly used as a sputtering target. Alternatively, as needed, the sintered body of the present application can be bonded to a back plate composed of oxygen-free copper or titanium or the like using indium solder or the like, and thereby the sintered body of the present application can be produced into a sputtering target.

[0142] In addition, a film (thin film) can be produced by sputtering using the obtained sputtering target. That is, the sintered body of the present application can be produced into a sputtering target having the sintered body of the present application, a back plate, and a liner tube, and in addition, can be used in a film production method using sputtering of the sputtering target.

[0143] The conditions of sputtering are arbitrary, and for example, the following conditions can be given.

[0144] Film forming power: 100 W or more and 800 W or less, preferably 150 W or more and 300 W or less

[0145] Gas pressure: 0.2 Pa or more and 1.0 Pa or less, preferably 0.3 Pa or more and 0.7 Pa or less

[0146] Gas atmosphere: inert gas atmosphere, preferably argon atmosphere

[0147] Film forming time: 0.5 hours or more and 3 hours or less, preferably 0.5 hours or more and 1.5 hours or less

[0148] In order to reduce the temperature dependence of the resistivity, it is preferable that the film after sputtering is subjected to heat treatment (annealing treatment). As the conditions of annealing treatment, the following conditions can be given.

[0149] Annealing atmosphere: vacuum atmosphere

[0150] Annealing time: 1 hour

[0151] Annealing temperature: any temperature from 200°C to 600°C

[0152] The film obtained using the sintered body of the present application (hereinafter, also referred to as "film of the present application") can have any thickness, and examples thereof include a film thickness of 5 nm or more or 10 nm or more, and further, 1 μm or less or 500 nm or less.

[0153] The film of the present application is a Si-Cr-C-based film, and is an amorphous film of chromium silicide and one or more selected from the group consisting of chromium carbide, silicon carbide, and carbon, and is preferably an amorphous film of chromium silicide and silicon carbide or carbon.

[0154] The film of the present application is a film present on a substrate, that is, a film in a state formed on a substrate, and is particularly a sputtered film. Therefore, the film of the present application can also be considered as a laminate in which the film of the present application and a substrate are laminated, unlike a free-standing film. The substrate can be any substrate composed of a material corresponding to the purpose, and examples thereof include a substrate composed of one or more selected from the group consisting of a metal, a semimetal, a ceramic, a glass, and a polymer, further, a substrate composed of one or more selected from the group consisting of a metal, a semimetal, and a glass, and still further, a substrate composed of a glass.

[0155] For the film of the present application, it is preferable that the change ratio of the resistivity when the temperature of the film changes by 1°C, so-called Temperature Coefficient of Resistance (hereinafter, also referred to as "TCR") is small, and it is preferable that the maximum value of the TCR at a measurement temperature of 40°C to 150°C (hereinafter, also referred to as "maximum TCR") is 100 ppm / °C or less or 98 ppm / °C or less.

[0156] Further, it is preferable that the minimum value of the TCR at a measurement temperature of 40°C to 150°C (hereinafter, also referred to as "minimum TCR") is -25 ppm / °C or more or 0 ppm / °C or more.

[0157] In the present application, the TCR can be calculated from the following formula using the value of the resistivity of the film measured using a general resistivity measuring device (for example, 8403 type AC / DC Hall measurement system, manufactured by Toyo Technica Corporation).

[0158] TCR = (R - R 30 ) / {R 30 × (T - 30)} x 10 6

[0159] In the above formula, TCR is a temperature coefficient of resistance [ppm / °C], R is a specific resistance at a measurement temperature [Ω-cm], R 30 is a specific resistance at 30°C [Ω-cm], and T is a measurement temperature [°C].

[0160] The film of the present application preferably has an average value of TCR (hereinafter, also referred to as "average TCR") at a measurement temperature of 40°C to 150°C of 100 ppm / °C or less, 50 ppm / °C or less, or 15 ppm / °C or less. The average TCR can be 0 ppm / °C or more, 1 ppm / °C or more, or 10 ppm / °C or more, for example.

[0161] The average TCR is an average value of absolute values of TCRs measured at 10°C intervals in a temperature range of 40°C to 150°C at a measurement temperature, and can be calculated from the following formula.

[0162] Average TCR = (TCR 40 + TCR 50 +... + TCR 150 ) / 12

[0163] In the above formula, TCR 40 is an absolute value of TCR at a measurement temperature of 40°C [ppm / °C], TCR 50 is an absolute value of TCR at a measurement temperature of 50°C [ppm / °C], and the like, and is an absolute value of TCR at each measurement temperature measured at 10°C intervals.

[0164] The film of the present application preferably has a slope (hereinafter, also referred to as "TCR slope") of a straight line of a first approximation formula (approximate straight line) obtained from plotting points of 13 TCRs measured at 10°C intervals in a temperature range of 30°C to 150°C of ±0.7 ppm / °C 2 , preferably ±0.5 ppm / °C 2 , ±0.3 ppm / °C 2 , ±0.2 ppm / °C 2 , ±0.1 ppm / °C 2 , or 0 (zero) ppm / °C 2 . By making the TCR slope within this range, detection sensitivity is stabilized in a sensor use in an environment where temperature changes greatly, such as a vehicle-mounted sensor.

[0165] Example

[0166] Hereinafter, the present application will be described more specifically by way of examples, but the present application is not limited thereto. Note that each measurement in the present examples was performed as follows.

[0167] (1) Crystal phase of sintered body

[0168] As for the crystal phase of the sintered body, the XRD pattern measured under the above conditions was determined and characterized.

[0169] (2) Relative density of sintered body

[0170] The relative density of the sintered body was calculated as a ratio (%) of the measured density to the true density. First, the bulk density calculated from the dry mass with respect to the volume measured by the Archimedes method was determined according to JIS R 1634, and was used as the measured density.

[0171] The true density was calculated by the following equation.

[0172] d = 1 / {(R1 / M1) + (R2 / M2) + (R3 / M3) + (R4 / M4) + (R5 / M5) + (R6 / M6) + (R7 / M7) + (R8 / M8) + (R9 / M9)}

[0173] In the above equation, d is the true density [g / cm 3 ] of the sintered body, and M1 to M9 and R1 to R9 are the true densities [g / cm 3 ] and mass proportions [wt%] of Si, C, Cr, SiC, CrSi, CrSi2, Cr3Si, Cr3C2, and Cr5Si3 contained in the sintered body, respectively.

[0174] As for the crystal phase contained in the sintered body, the XRD pattern measured under the above conditions was determined, and the composition of the sintered body was analyzed by ICP. For the measured elements, the mass proportions of each crystal phase were calculated from the obtained crystal phase.

[0175] In addition, in the case of the sintered body composed of three phases, the true density of the sintered body was calculated from the mass a [g] of the crystal phase A, the mass b [g] of the crystal phase B, the mass c [g] of the crystal phase C, the respective true densities Ma [g / cm 3 ], Mb [g / cm 3 ], and Mc [g / cm 3 ] by the following equation.

[0176] d = (a + b + c) / ((a / Ma) + (b / Mb) + (c / Mc))

[0177] (3) Porosity of sintered body

[0178] Mirror polishing was performed, and observation was performed using a laser microscope, and the obtained sintered body structure image was measured by image analysis. DP-suspension 1 μm (manufactured by Marumoto Struers Co., Ltd.) was used, and mirror polishing was performed in a manner such that the surface roughness Ra was 2 μm or less. At least 5 fields of view were observed, the area of the pores was calculated by image analysis, and the porosity was measured 5 times (i.e., 1 time for each field of view), and the average of the measurement results of the porosity of each field of view was used as the porosity.

[0179] Measurement field of view (magnification of observation): 200 times

[0180] Porosity (%) of each field of view = (area of pores calculated by image analysis / measured area) x 100

[0181] (4) Number of macro-pores

[0182] A sintered body having a diameter of 10.16 cm was cut out from an arbitrary position of the sintered body, and In bonding was performed to obtain a sputtering target. A sputtering test was performed according to the following conditions, and the number of pores having a maximum length of 50 μm or more in the sputtered target was counted using a laser microscope, and was used as the number of macro-pores.

[0183] (5) Oxygen amount

[0184] After the surface of the sintered body was ground by 1 mm or more, the content of oxygen in a sample (square shape having a length of 3 mm, a width of 20 mm, and a thickness of 4 mm) cut out from an arbitrary part of the sintered body was measured by a fusion-infrared absorption method.

[0185] Measurement method: pulse furnace fusion-infrared absorption method

[0186] Apparatus: LECO ON 736 oxygen / nitrogen analyzer

[0187] (6) Bending strength

[0188] The bending strength of the sintered body was measured by a method according to JIS R 1601.

[0189] Test method: 3-point bending test

[0190] Distance between supports: 30 mm

[0191] Sample size: 3 x 4 x 40 mm

[0192] Speed of indenter: 0.5 mm / minute.

[0193] (Example 1)

[0194] As the precursor, Cr flakes (4N): 33 wt% and Si flakes (5N): 67 wt% were used. The Cr flakes and the Si flakes were melted in a carbon crucible at a processing temperature of 1650°C to obtain a molten metal of chromium and silicon. Then, the molten metal was added dropwise by a flow of argon gas at a pressure of 7 MPa, whereby a powder (gas atomized powder) was produced by a gas atomization method as a starting material of chromium and silicon. The gas atomized powder had a crystal phase composed of CrSi2and Si. Then, the gas atomized powder and Cr3C2powder (product name: Chromium Carbide, manufactured by PPM Corporation) were dry mixed at 60 rpm for 1 hour in an argon atmosphere using a V-type mixer in a manner of 62 wt% of the gas atomized powder and 38 wt% of the Cr3C2powder, whereby the mixing was performed to produce an alloy raw material powder of 55 wt% of Cr, 39 wt% of Si, and 6 wt% of C.

[0195] Next, the alloy raw material powder was put into a carbon mold (mold: diameter 15.2 cm) and sintered by a hot-pressing method to obtain the sintered body of the present embodiment. The sintering conditions are shown below.

[0196] Sintering furnace: hot-pressing furnace

[0197] Temperature increasing rate: 200°C / hour

[0198] Temperature increasing atmosphere: vacuum reduced pressure atmosphere (vacuum atmosphere)

[0199] Sintering atmosphere: vacuum reduced pressure atmosphere (vacuum atmosphere)

[0200] Sintering temperature: 1350°C

[0201] Pressure: 40 MPa

[0202] Sintering time: 3 hours

[0203] Thus, a sintered body having a size of a round plate of diameter 15.2 cm x thickness 7 mm without microcracks was obtained.

[0204] From the results of the XRD measurement, it was confirmed that the sintered body of the present embodiment was a Cr-Si-C sintered body composed of CrSi, Cr5Si3, and SiC. From the results of the XRD measurement, the relative density of the sintered body of the present embodiment was calculated using the true density calculated in a manner of 52 wt% of crystal phase A: CrSi (true density 5.36 [g / cm 3 ]), 27 wt% of crystal phase B: Cr5Si3 (true density 5.87 [g / cm 3 ]), and 21 wt% of crystal phase C: SiC (true density 3.21 [g / cm 3 ]).

[0205] (Examples 2 to 7)

[0206] The sintering conditions were changed to those shown in Table 1, and otherwise, the same method as in Example 1 was used to produce sintered bodies (Cr-Si-C sintered bodies). The sintered bodies obtained were all Cr-Si-C sintered bodies composed of CrSi, Cr5Si3, and SiC.

[0207] (Example 8)

[0208] As the precursor materials, Cr flakes (4N): 59 wt% and Si flakes (5N): 41 wt% were used. In a carbon crucible, they were melted by setting the processing temperature to 1650°C to obtain a molten metal. The molten metal was dropped through an argon gas stream at a gas pressure of 7 MPa, whereby a gas atomized powder was produced by a gas atomization method. The gas atomized powder had a crystal phase composed of CrSi2and CrSi. Then, Cr3C2powder was mixed with the above gas atomized powder in a manner of 36 wt% of Cr3C2powder and 62 wt% of the gas atomized powder, and otherwise, the same method as in Example 1 was used for the mixing to produce an alloy raw material powder of Cr: 69 wt%, Si: 26 wt%, and C: 5 wt% of the present example.

[0209] Using the alloy raw material powder, the same method as in Example 1 was used for the sintering, whereby a Cr-Si-C sintered body was obtained, which was used as the sintered body of the present example. From the results of the XRD measurement, the relative density of the sintered body was calculated using the true density calculated in a form of 23 wt% of crystal phase A: Cr5Si3(true density 5.87 [g / cm3]), 61 wt% of crystal phase B: Cr3Si (true density 6.46 [g / cm3]), and 16 wt% of crystal phase C: SiC (true density 3.21 [g / cm3]). 3 ]) for 61 wt% of crystal phase B: Cr3Si (true density 6.46 [g / cm 3 ]) for 61 wt% of crystal phase B: Cr3Si (true density 6.46 [g / cm 3 ]) for 61 wt% of crystal phase B: Cr3Si (true density 6.46 [g / cm

[0210] (Example 9)

[0211] As the precursor materials, Cr flakes (4N): 59 wt% and Si flakes (5N): 41 wt% were used. In a carbon crucible, they were melted by setting the processing temperature to 1650°C to obtain a molten metal. The molten metal was dropped through an argon gas stream at a gas pressure of 7 MPa, whereby a gas atomized powder was produced by a gas atomization method. The gas atomized powder had a crystal phase composed of CrSi2and CrSi. Then, Cr3C2powder was mixed with the above gas atomized powder in a manner of 36 wt% of Cr3C2powder and 62 wt% of the gas atomized powder, and otherwise, the same method as in Example 1 was used for the mixing to produce an alloy raw material powder of Cr: 69 wt%, Si: 26 wt%, and C: 5 wt% of the present example.

[0212] Using this alloy raw material powder, other than this, a sintered body having a sintered body size of a circular plate shape of 15.2 cm in diameter x 7 mm in thickness without microcracks was obtained by sintering in the same manner as in Example 1, and this was used as the sintered body of the present example.

[0213] From the results of the XRD measurement, it was confirmed that the sintered body of the present example was a Cr-Si-C sintered body composed of CrSi2, Si and C. From the results of the XRD measurement, the relative density of the sintered body of the present example was calculated using the true density calculated on the basis of CrSi2 being 83 wt%, Si being 12 wt% and C being 5 wt%.

[0214] (Example 10)

[0215] C powder and gas atomized powder were mixed in a manner such that the C powder was 15 wt%, and other than this, the alloy raw material powder of the present example in which Cr was 36 wt%, Si was 49 wt% and C was 15 wt% was produced in the same manner as in Example 9.

[0216] Using this alloy raw material powder, other than this, a sintered body having a sintered body size of a circular plate shape of 15.2 cm in diameter x 7 mm in thickness without microcracks was obtained by sintering in the same manner as in Example 1.

[0217] From the results of the XRD measurement, it was confirmed that the sintered body of the present example was a Cr-Si-C sintered body composed of CrSi2, Si and C. From the results of the XRD measurement, the relative density of the sintered body of the present example was calculated using the true density calculated on the basis of CrSi2 being 74 wt%, Si being 11 wt% and C being 15 wt%.

[0218] (Comparative Example 1)

[0219] Powder mixing was performed using a V-type mixer in a manner such that Cr powder: 31 wt%, CrSi2 powder: 48 wt%, SiC powder: 21 wt%, and other than this, a sintered body composed of crystal phases of CrSi, Cr5Si3 and SiC was obtained in the same manner as in Example 1.

[0220] (Comparative Example 2)

[0221] A gas atomized powder in which Cr was 42 wt% and Si was 58 wt% and which had crystal phases composed of CrSi2 and Si was obtained in the same manner as in Example 9.

[0222] Using this gas atomized powder, the sintering temperature was set to 1250°C and the pressure was set to 15 MPa, and other than this, a sintered body was produced in the same manner as in Comparative Example 1.

[0223] From the results of the XRD measurement, it was determined that the sintered body of this example was a Cr-Si-based sintered body (sintered body of chromium silicide) composed of CrSi2and Si. From the results of the XRD measurement and the composition analysis using ICP, the relative density of the sintered body of this comparative example was calculated using the true density calculated as 87 wt% of CrSi2and 13 wt% of Si.

[0224] The manufacturing conditions of Examples 1 to 10 and Comparative Examples 1 and 2 are shown in Table 1, and the evaluation results of the obtained sintered bodies are shown in Table 2.

[0225] [Table 1]

[0226]

[0227] [Table 2]

[0228]

[0229] <Confirmation of macro-pores>

[0230] The sintered bodies of Examples 1 and 8 and Comparative Example 1 were each subjected to lathe processing, and a round plate-shaped sintered body having a diameter of 10.16 mm and a thickness of 5 mm was cut out from the sintered body. The obtained sintered body was joined to a back plate, thereby producing a sputtering target. Film formation (sputtering) on a glass substrate (product name: Alkali-free glass C, manufactured by Mitsuru Optical Laboratory) was performed under the following conditions.

[0231] Film formation power: 800 W

[0232] Gas pressure: 0.5 Pa

[0233] Gas atmosphere: Ar only (argon atmosphere)

[0234] Film formation time: 1 hour

[0235] The target after film formation was subjected to surface observation using a laser microscope. As a result, it was confirmed that no pores (macro-pores) having a diameter of 50 μm or more were generated in the target of the example.

[0236] [Table 3]

[0237] Coarse pores (number) Example 1 0 Example 8 0 Comparative Example 1 43

[0238] <Film formation>

[0239] The sintered bodies of Examples 7, 9 and 10 and Comparative Example 2 were used, and sputtering was performed using the same method as in the <Confirmation of macro-pores> under the following conditions, except for the film formation conditions.

[0240] Film forming power: 200 W

[0241] Gas pressure: 0.5 Pa

[0242] Gas atmosphere: argon atmosphere

[0243] Film forming time: 1 hour

[0244] A plurality of films (sputtered films) were obtained by performing film formation a plurality of times. For the obtained films (sputtered films), annealing treatment was performed at any temperature at intervals of 10°C under the conditions of a vacuum atmosphere, 1 hour, and a temperature range of 200°C to 600°C, respectively. Thus, for each example, a plurality of sputtered films having a film thickness of 100 nm were obtained. The films after the annealing treatment were evaluated under the following conditions.

[0245] (Electrical resistivity)

[0246] The electrical resistivity of the film was measured at 30°C using an 8403 type AC / DC Hall measurement system (manufactured by Toyo Technica). The measurement was performed on a sample obtained by cutting a glass substrate having a sputtered film into a 1 cm square.

[0247] (TCR)

[0248] The electrical resistivity of the film was measured at intervals of 10°C from 30°C to 150°C, and the TCR at each temperature was calculated from the following equation.

[0249] TCR (ppm / °C) = (R-R 30 ) / (R 30 x (T-30)) x 10 6

[0250] The maximum value in the TCR measured at 40°C to 150°C was taken as the maximum TCR, the minimum value was taken as the minimum TCR, and the average of the absolute values of the TCR was taken as the average TCR.

[0251] (TCR slope)

[0252] The values of the TCR from 40°C to 150°C obtained in the measurement of the temperature-TCR pair TCR were plotted, and a first linear approximation equation obtained from the plot was calculated. The value of the slope of the first linear approximation equation was taken as the TCR slope.

[0253] The following table shows the annealing temperature at which the average TCR value is the smallest, and the evaluation results of the film after the annealing treatment at the annealing temperature.

[0254] [Table 4]

[0255]

[0256] From the above table, it is seen that, in comparison with the examples, the relative density of Comparative Example 2 is high, and although the porosity is low, the TCR slope of the resulting film is large, and the change in resistivity in the temperature change is large.

[0257] The entire contents of the specification, claims, and summary of Japanese Patent Application No. 2020-129947 filed on July 31, 2020, and Japanese Patent Application No. 2021-63955 filed on April 5, 2021 are hereby incorporated by reference into the present disclosure as published.

[0258] Explanation of Reference Numerals

[0259] 100 observation chart

[0260] 10 black region (pore)

[0261] 11 white region (sintered body)

Claims

1. A Cr-Si-C sintered body, characterized in that, The Cr-Si-C sintered body contains Cr, Si, and C, has a relative density of 90% or more and a porosity of 13% or less, contains CrSi and one or more selected from chromium carbide, silicon carbide, and carbon, the mass ratio of CrSi in the sintered body is more than 50 wt%, and the content of carbon in the sintered body is 1 to 20 wt%.

2. The Cr-Si-C-based sintered body according to claim 1, wherein The Cr-Si-C sintered body contains Cr, Si, and C, has a relative density of 90% or more and a porosity of 13% or less, contains CrSi and one or more selected from chromium carbide, silicon carbide, and carbon, the mass ratio of CrSi in the sintered body is more than 50 wt%, and the content of carbon in the sintered body is 1 to 20 wt%.

3. The Cr-Si-C-based sintered body according to claim 1 or 2, wherein The content of Cr in the Cr-Si-C sintered body is more than 10 wt% and less than 79 wt%.

4. The Cr-Si-C-based sintered body according to claim 1 or 2, wherein The content of oxygen in the Cr-Si-C sintered body is 1 wt% or less.

5. The Cr-Si-C-based sintered body according to claim 1 or 2, wherein The content of oxygen in the Cr-Si-C sintered body is 0.5 wt% or less.

6. The Cr-Si-C-based sintered body according to claim 1 or 2, wherein The bending strength of the Cr-Si-C sintered body is 100 MPa or more.

7. The method of producing a Cr-Si-C-based sintered body according to any one of claims 1 to 6, characterized by, including: a step of mixing a chromium and silicon gas atomized powder and a carbon source containing Cr3C2 to obtain an alloy raw material powder; and a sintering step of hot-pressing the alloy raw material powder at a pressure of 50 MPa or less and a sintering temperature of 1350°C or higher and 1800°C or lower in a vacuum atmosphere, the gas atomized powder contains CrSi2 and Si in a crystal phase.

8. The manufacturing method according to claim 7, wherein The mixing is dry mixing using a V-type mixer.

9. A sputtering target, characterized by, a Cr-Si-C sintered body according to any one of claims 1 to 6.

10. A method for producing a film, characterized by sputtering using the sputtering target according to claim 9.

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