CN111364011B

CN111364011B - Sputtering target member, sputtering film, method for producing same, sputtering target, and film body

Info

Publication number: CN111364011B
Application number: CN201910746078.0A
Authority: CN
Inventors: 远藤瑶辅; 山本浩由; 桃井元; 角田浩二; 奈良淳史
Original assignee: JX Nippon Mining and Metals Corp
Current assignee: JX Nippon Mining and Metals Corp
Priority date: 2018-12-26
Filing date: 2019-08-13
Publication date: 2022-06-07
Anticipated expiration: 2039-08-13
Also published as: KR102274149B1; JP2020105558A; CN111364011A; KR20200080115A; TWI726340B; TW202024368A; JP6830089B2

Abstract

Provided is a sputtering target member suitable for obtaining a sputtering film having high work function and characteristics such as a refractive index at a wavelength of 633nm of 1.9 to 2.1. The sputtering target member is composed of Ga, In, O and unavoidable impurities, has a Ga/In atomic ratio of 0.90 or more and 1.11 or less, and has a surface analysis by EPMA In which (Ga, In) is compared with all crystal phases₂O₃The area ratio of the phases is 90% or more.

Description

Sputtering target member, sputtering film, method for producing same, sputtering target, and film body

Technical Field

The present invention relates to a sputtering target member, a method for producing a sputtering target member, a sputtering target, a sputtering film, a method for producing a sputtering film, a film body, a laminated structure, and an organic EL device.

Background

An organic Electroluminescent (EL) device includes an organic layer sandwiched between a pair of upper (cathode) and lower (anode) electrodes. As the organic layer, it is known that an organic hole transport layer and an organic light emitting layer are included, and holes injected from the lower electrode and electrons injected from the upper electrode are recombined in the organic light emitting layer to form an excited state, and light emission is generated when returning to a ground state. In order to efficiently inject holes and electrons into the organic hole transport layer and the organic light-emitting layer, typically, a metal having a low work function is used for the upper electrode, and a sputtered film of a metal composite oxide having a high work function is used for the lower electrode.

Here, in the case of forming a sputtering film as a lower electrode, a film having a high work function is formed on a substrate for film formation such as glass or plastic or on a metal film formed on the substrate by a sputtering method using a sputtering target member formed of an oxide sintered body. Therefore, in order to obtain a sputtering film having a high work function, attention is paid to a sputtering target member as a raw material.

For example, patent document 1 discloses a sintered body target for producing a transparent conductive film, which is mainly composed of Ga, In and O, contains 49.1 atomic% or more and 65 atomic% or less of Ga with respect to all metal atoms, and mainly consists of β -Ga₂O₃GaInO of type structure₃In of phase and ferromanganese structure₂O₃Phase constitution with In₂O₃Phase (400)/beta-GaInO₃X-ray diffraction peak intensity ratio of phase (111) × 100 (%) of 45% or less and density of 5.8g/cm³The above. It is also disclosed that a transparent conductive film obtained by a sputtering method using such a sintered target has a work function of 5.1eV or more and a refractive index of 1.65 to 1.85 at a wavelength of 633 nm.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2007-224386

Disclosure of Invention

Technical problem to be solved by the invention

In recent years, development of organic EL has been advanced, and various structures have been proposed by manufacturers of electronic devices. In view of this situation, since it is important to optimize optical characteristics in electronic devices, it is desirable to provide a sputtering target member capable of providing a sputtered film having a refractive index corresponding to the structure of various electronic devices. Therefore, it is considered that the sputtering target member of the related art still has room for improvement in order to obtain a sputtering film having a refractive index different from that disclosed in patent document 1.

Accordingly, an object of an embodiment of the present invention is to provide a sputtering target member suitable for obtaining a sputtered film having a high work function and a refractive index of 1.9 to 2.1 at a wavelength of 633 nm.

Means for solving the problems

That is, one aspect of the present invention is a sputtering target member comprising Ga, In, O and inevitable impurities, wherein the Ga/In atomic ratio is 0.90 or more and 1.11 or less, and In the surface analysis by EPMA, the atomic ratio is compared with the total crystal phase (Ga, In)₂O₃The area ratio of the phases is 90% or more.

In one embodiment of the sputtering target member of the present invention, the Ga/In atomic ratio is 0.95 or more and 1.05 or less.

In one embodiment of the sputtering target member of the present invention, the area ratio is 95% or more.

In one embodiment of the sputtering target member of the present invention, the relative density of the sputtering target member is 94% or more.

In one embodiment of the sputtering target member of the present invention, the sputtering target member has a volume resistivity of 1.0 × 10³Omega cm or less.

In one embodiment of the sputtering target member of the present invention, when the sputtering film is formed by changing the oxygen content in the sputtering gas from 0% by volume to 3% by volume, the work function of the sputtering film is in the range of 5.0 to 6.0 eV.

In one embodiment of the sputtering target member of the present invention, the sputtering target member is cylindrical or flat.

In another aspect of the present invention, there is provided a sputtering target comprising the sputtering target member described above and a base material.

In another aspect of the present invention, there is provided a method for manufacturing a sputtering target member described in any one of the above aspects, including: a mixing step of mixing In such a manner that the atomic ratio of Ga/In is 0.90 or more and 1.11 or less₂O₃Powder and Ga₂O₃Obtaining mixed powder; a sintering step of sintering the mixed powder at a sintering temperature of more than 1400 ℃ and less than 1600 ℃ to obtainTo a sintered body.

In one embodiment of the method for manufacturing a sputtering target member of the present invention, the sintering temperature is 1450 ℃ to 1550 ℃.

In one embodiment of the method for producing a sputtering target member of the present invention, in the sintering step, the sintering retention time is 5 to 20 hours.

In another aspect of the present invention, a sputtering film is formed of Ga, In, O, and unavoidable impurities, wherein the atomic ratio of Ga/In is 0.85 or more and 1.15 or less, the refractive index at a wavelength of 633nm is 1.9 to 2.1, and the work function is 5.0 to 6.0 eV.

In one embodiment of the sputtering film of the present invention, the volume resistivity of the sputtering film is 1.0 Ω · cm or less.

In one embodiment of the sputtered film of the present invention, the sputtered film has an extinction coefficient of 0.01 or less at a wavelength of 633 nm.

In one embodiment of the sputtered film of the invention, the sputtered film is amorphous.

In another aspect, the present invention provides a method for producing a sputtering film, including a film formation step of forming a sputtering film by using the sputtering target member described above.

In one embodiment of the method for manufacturing a sputtered film of the present invention, the method includes a step of annealing the sputtered film at 200 ℃ or lower after the film forming step.

In one embodiment of the method for producing a sputtered film of the present invention, in the film formation step, the sputtered film is formed while performing an annealing process at 200 ℃.

In one embodiment of the method for producing a sputtered film according to the present invention, the film formation step is performed with an oxygen content in a sputtering gas of 10 vol% or less.

In another aspect, the present invention provides a film body including the sputtering film described above.

In one embodiment of the film body of the present invention, the film body further includes a 1 st metal film in contact with the 1 st main surface of the sputtered film.

In one embodiment of the film body of the present invention, the film body further includes an oxide barrier film in contact with a main surface of the 1 st metal film.

In one embodiment of the film body of the present invention, the film body includes an oxide conductive film in contact with the 1 st main surface of the sputtered film.

In one embodiment of the film body of the present invention, the film body further includes a 1 st metal film in contact with a main surface of the oxide conductive film.

In one embodiment of the film body of the present invention, the volume resistivity of the oxide conductive film is 1.0 × 10^-3Omega cm or less.

In one embodiment of the film body of the present invention, the oxide conductive film is formed of at least 1 selected from the group consisting of ITO, IZO, and AZO.

In one embodiment of the film body of the present invention, the 1 st metal film is formed of a composition containing 90 mass% or more of 1 or 2 or more species selected from the group consisting of Ag, Cu, Ni, Fe, Cr, Al, and Co.

In another aspect, the present invention is a laminated structure including the film body described in any one of the above, and a glass substrate or a resin substrate in contact with the outermost main surface of the film body on the 1 st main surface side of the sputtered film.

In one embodiment of the laminated structure of the present invention, the laminated structure further includes an organic layer in contact with a 2 nd main surface of the sputtered film, the 2 nd main surface being located on an opposite side of the 1 st main surface.

In one embodiment of the laminated structure of the present invention, the laminated structure further includes a 2 nd metal film in contact with a main surface of the organic layer.

In one embodiment of the laminated structure of the present invention, the 2 nd metal film is formed of 1 or 2 or more kinds selected from the group of Al, In, W, Ti, Mo, Mg — Ag, and Ag — Al.

In another aspect, the present invention provides an organic EL device in which a sealing layer, the laminated structure described above, a thin film transistor, and a substrate are laminated in this order.

ADVANTAGEOUS EFFECTS OF INVENTION

The sputtering target member according to one embodiment of the present invention is suitable for obtaining a sputtering film having high work function and characteristics such as a refractive index of 1.9 to 2.1.

Drawings

Fig. 1 is a flowchart illustrating an embodiment of a method for manufacturing a sputtering target member according to the present invention.

Fig. 2 is a sectional view illustrating an embodiment of the laminated structure of the present invention.

Fig. 3 is a sectional view illustrating another embodiment of the laminated structure of the present invention.

Fig. 4 is a sectional view illustrating still another embodiment of the laminated structure of the present invention.

Fig. 5 is a sectional view illustrating still another embodiment of the laminated structure of the present invention.

Fig. 6 is a sectional view illustrating still another embodiment of the laminated structure of the present invention.

Fig. 7 is a sectional view illustrating still another embodiment of the laminated structure of the present invention.

Fig. 8(a) is a graph showing an SE image (500 times) of a target cross section of the sputtering target member obtained in example 1, and fig. 8(B) is a graph showing an analysis result of X-ray diffraction (XRD) of the sputtering target member obtained in example 1.

Detailed Description

Hereinafter, the present invention is not limited to the embodiments, and the constituent elements may be modified and embodied without departing from the scope of the invention. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiments. For example, several constituent elements may be deleted from all the constituent elements shown in the embodiments. Further, the constituent elements of the different embodiments may be appropriately combined.

[1. sputtering target Member ]

In one embodiment, the sputtering target member of the present invention is composed of Ga, In,A sputtering target member comprising O and unavoidable impurities, wherein the atomic ratio of Ga/In is 0.90 or more and 1.11 or less, and (Ga, In) is obtained In a surface analysis by EPMA analysis₂O₃The area ratio of the phases is 90% or more.

Hereinafter, examples of ideal conditions of the sputtering target member will be described.

(composition)

In one embodiment, the sputtering target member of the present invention is formed of Ga, In, O, and the balance unavoidable impurities. The inevitable impurities are impurities which are present in the raw materials or are inevitably mixed in the production process, substantially in the metal or metal oxide product, and include, for example, a medium for pulverizing the raw material powder. Although not required per se, trace amounts and do not affect the properties of the metal or metal oxide product and are therefore tolerable impurities. In the sputtering target member of the present invention, the total amount of the inevitable impurities, for example, Sn, is usually 1000 mass ppm or less, typically 500 mass ppm or less, and more typically 100 mass ppm or less.

The atomic ratio of Ga/In is 0.90 or more and 1.11 or less. The above-mentioned atomic ratio of Ga/In is based on increasing (Ga, In)₂O₃From the viewpoint of the phase ratio, the lower limit thereof is 0.90 or more, preferably 0.95 or more, and more preferably 0.97 or more. Similarly, the upper limit of the atomic ratio of Ga/In is 1.11 or less, preferably 1.05 or less, and more preferably 1.03 or less.

In one embodiment of the sputtering target member of the present invention, Ga and In may be present In the form of an oxide. In one embodiment of the sputtering target member of the present invention, from the viewpoint of adjusting the refractive index of the sputtered film to a target value, the refractive index is rated as (Ga, In) In X-ray diffraction₂O₃Peak of (2). Here, In ICDD (International Centre for Diffraction Data) card, (Ga, In)₂O₃Is No. 00-014-.

XRD measurements were performed according to the following procedure. A sputtering target member to be measured was cut in the thickness direction, and the measurement surface (target cross-sectional side) was processed by a method in accordance with JIS R6010: 2000 abrasive paper having an average sand particle size of #400 was used as a sample for measurement after polishing, and an X-ray diffraction pattern was obtained by the following measurement conditions using an X-ray diffraction method. The resolution software uses PDXL. PDXL has a function of automatically calculating the peak shift due to solid solution in software and moving the peak of ICDD card to facilitate calibration.

< measurement Condition >

An example of an XRD diffraction device: smart Lab (manufactured by Kabushiki Kaisha)

Tube voltage: 40kV

Tube current: 30mA

Measurement range: 2 theta is 10-90 DEG

Scanning shaft: 2 theta/theta

Scanning speed: 10 °/min

Step width: 0.01 degree

Analysis software: PDXL (attached to SmartLab)

In the area analysis of EPMA analysis, measurement is made on the cross-sectional side of the target (Ga, In)₂O₃Area ratio of phases. (Ga, In) from the viewpoint of obtaining a sputtered film having a high work function and a refractive index of 1.9 to 2.1₂O₃The area ratio of the phases is preferably 90% or more. This determination was made by comparing XRD. (Ga, In)₂O₃The area ratio of the phase is preferably 90% or more, more preferably 95% or more. However, the upper limit of the area ratio is typically 100% or less, more typically 99% or less.

Note that, the surface analysis of EPMA is described below.

The sputtering target member was cut out to prepare a test piece. Subsequently, the test piece was cut into a block of about 1cm × 1cm × 1cm by a microtome to be used as a measurement sample, and mirror-polished using an abrasive. The polished surface of the test piece is measured by surface analysis using an electron beam microanalyzer (for example, JXA-8500F, manufactured by Nippon electronics Co., Ltd.), and at least 3 points are arbitrarily selected for measurement.

< measurement Condition >

Pressurizing current: 15.0kv

Irradiation current: 1.0 to 2.0 x 10^-7A

Measurement multiplying power: 500 times of

Resolution ratio: 256X 256dpi

Scanning: beam scanning

In addition, the method is to obtain (Ga, In)₂O₃The area ratio of the phases is determined by the following procedure.

1. The results of the surface analysis are displayed.

2. The results of surface analysis of the metal elements were subjected to particle measurement to determine the region where Ga and In overlap. In this region, the sputtering target member was confirmed to have almost only (Ga, In) by the XRD₂O₃The existence of the phase, therefore, it can be judged that Ga and In recognized by EPMA are present together and are (Ga, In)₂O₃And (4) phase(s).

For particle measurement, the following conditions were used. In the case of particle measurement using software attached to JXA-8500F, it is necessary to select a filter, a binarization method, a labeling method, and the like, which are as follows.

< Condition for particle measurement >

A filter: smoothing filter

Binarization: automatic

The binarized labels are 8 linked, and the outer particles are also labeled.

Measuring occupied area ratio of mark image

The occupied area ratio indicates the area ratio of the region containing In and Ga of the marked particles.

3. Calculating (Ga, In)₂O₃Area ratio of phases. That is, In the present invention, (Ga, In)₂O₃The area ratio of the phases is expressed by the following ratio: measured by label-based particles (Ga, In)₂O₃Area of phase calculated (Ga, In)₂O₃The total area of the phases was compared with the total area in the measurement range in which at least 3 points were measured with respect to the polished surface of the test piece to obtain an area ratio.

(relative Density)

In one embodiment, the sputtering target member of the present invention has a relative density of preferably 94% or more, more preferably 95% or more, and still more preferably 95.5% or more. The relative density of the sputtering target member is related to the quality of the sputtered film. When the density of the sputtering target member is low, abnormal discharge or dust generation due to the hole portion may occur, and thus, particles may be generated on the sputtering film. When the relative density is 94% or more, the number of internal voids is within the allowable range of the work, and generation of fine particles due to voids can be reduced. However, the smaller the number of voids, the better.

Note that, a method of calculating the relative density of the sputtering target member is described below.

The "relative density" in the present invention is expressed by relative density (measured density/calculated density) × 100 (%). The calculated density is a value of density calculated from theoretical density of oxides of elements after removal of oxygen by shaving among the respective constituent elements of the sintered body. In the case of the Ga-In-O target of the present invention, gallium oxide (Ga) is used as an oxide of gallium and indium after oxygen is planed out from among the constituent elements gallium, indium and oxygen₂O₃) And indium oxide (In)₂O₃) The calculated density was calculated. Gallium oxide (Ga) was converted from elemental analysis values (at% or mass%) of gallium and indium in the sintered body₂O₃) And indium oxide (In)₂O₃) The mass ratio of (a). For example, as a result of conversion, the calculated density is expressed as (Ga) in the case of an IGO target in which gallium oxide is 50 mass% and indium oxide is 50 mass%₂O₃Density (g/cm)³)×50+In₂O₃Density (g/cm)³)×50)/100 (g/cm³) And (6) calculating. Using Ga₂O₃Has a theoretical density of 5.95g/cm³，In₂O₃Has a theoretical density of 7.18g/cm³And (4) performing calculation. On the other hand, measuring the density means a value obtained by dividing the volume by the weight. In the case of the sintered body, the volume was determined by the archimedes method and calculated.

(volume resistivity)

The sputtering target of the inventionIn one embodiment, the volume resistivity is preferably 1.0 × 10 from the viewpoint of increasing the film formation rate during sputtering³Omega cm or less, more preferably 5.0X 10²Omega cm or less, and still more preferably 1.0X 10²Omega cm or less, for example, 1.0 to 1.0X 10³Ω·cm。

In the present invention, the volume resistivity of the sputtering target member is measured by a four-probe method using a resistivity measuring instrument. On the surface of the sputtering target member, 1.0mm was ground off due to the presence of the deteriorated layer by sintering, and the thickness of the sputtering target member was measured using a thickness in accordance with JIS R6010: 2000 abrasive paper having an average sand particle size of #400 was finished. In the examples, the following devices were used for the measurement.

And (3) resistivity measurer: model number FELL-TC-100-SB-Sigma 5+ (manufactured by NPS Co., Ltd.)

Measuring a jig: test material table RG-5

In one embodiment, when the sputtering target member of the present invention is formed by changing the oxygen content in the sputtering gas from 0% by volume to 3% by volume, the work function of the sputtering film is preferably in the range of 5.0 to 6.0 eV. The film formation conditions are exemplified as follows.

< film Forming conditions >

A sputtering device: canon ANELVA corporation, model number: SPF-313H

Substrate: EAGLE XG (manufactured by KANGNING corporation)

Inputting: 1W/cm²

Substrate temperature: at room temperature

Reaching the vacuum degree: 2.0X 10^-4Torr below

Sputtering gas: ar + oxygen (0-3 vol%)

Gas flow rate: 50sccm

Film thickness: 100nm

The work function can be measured, for example, by photoelectron spectroscopy. The following apparatus and procedure were used for the measurement.

An example of an apparatus: atmospheric photoelectron spectrum device AC-3 (manufactured by RIKEN KEIKI)

The method comprises the following steps: after sputtering, the film formation substrate was vacuum-packed within 10 minutes and opened in the atmosphere before measurement. This is because, if the film is stored in the atmosphere, the surface deteriorates and an accurate value cannot be obtained.

The sputtering target member is not limited, and can be processed into a flat plate shape, a cylindrical shape, or the like.

[2. method for producing sputtering target Member ]

Next, a method for manufacturing a sputtering target member will be described with reference to the drawings. In one embodiment, the method for manufacturing a sputtering target member of the present invention includes, as shown in fig. 1, a mixing step S11, a pressure forming step S21, a sintering step S31, and a machining step S41. Hereinafter, each step is exemplified. Note that the contents overlapping with the above are omitted.

(mixing step S11)

In mixing step S11, Ga is weighed so that the Ga/In atomic ratio is 0.90 to 1.11₂O₃Powder and In₂O₃Powder as a raw material powder. In order to avoid adverse effects of impurities on electrical characteristics, it is preferable to use a raw material powder having a purity of 3N (99.9 mass%) or higher, and it is more preferable to use a raw material powder having a purity of 4N (99.99 mass%) or higher. Since the influence on the refined crystal phase is slight, Sn impurities of 1000 ppm by mass or less may be contained as impurities.

Then, Ga is mixed and finely pulverized by a wet method₂O₃Powder and In₂O₃And (3) powder. The median diameter of the mixed powder obtained by mixing and pulverizing is preferably 5 μm or less, more preferably 3 μm or less, and still more preferably 1 μm or less. The median diameter of the mixed powder is a volume-based median diameter (D50) when the cumulative distribution of particle sizes is measured by a laser diffraction scattering particle size measuring apparatus after ultrasonic dispersion for 1 minute using ethanol as a dispersion medium.

However, if the mixing and pulverization are insufficient, the sputtering target member produced contains components segregated, high resistivity region and low resistivity region, and the components are sputteredSince charging in the high resistivity region or the like at the time of film formation upon irradiation causes abnormal discharge such as arcing, it is preferable to sufficiently perform mixing and pulverization. As a preferable method of mixing and pulverizing, for example, a method of dispersing a raw material powder in water to form a slurry, and finely pulverizing the slurry by using a wet media agitation mill (bead mill or the like) is cited. In addition, in the case of manufacturing a large sputtering target member, the warpage after sintering is large, and in this case, the Ga mixed therein may be performed at 800 to 1250 ℃₂O₃Powder and In₂O₃The powder obtained from the powder is pre-sintered and then micro-pulverized.

Then, PVA (polyvinyl alcohol) was put into the obtained slurry as a binder. The amount of PVA is not particularly limited, and can be appropriately adjusted.

Next, the slurry containing PVA was dried and granulated by a spray dryer to obtain a mixed powder. The drying is not limited, and may be performed, for example, at 150 to 200 ℃. After drying, coarse particles are preferably separated by screening. The screening is preferably performed using a sieve having a mesh size of 500 μm or less, and more preferably, using a sieve having a mesh size of 250 μm or less. Here, the mesh complies with JIS Z8801-1: 2006 to take measurements.

(pressure Forming step S21)

In the press molding step S21, the mixed powder is filled into a mold having a desired shape, and is pressed to obtain a molded body. The surface pressure during pressing can be, for example, 400 to 1000kgf/cm². In addition, cold isostatic pressing may be performed.

(sintering step S31)

In the sintering step S31, the compact is sintered at a heating temperature exceeding 1400 ℃ for 5 hours or more In an oxygen-containing atmosphere, for example, to obtain a sintered body containing a Ga — In — O composite oxide phase.

Heating in an oxygen-containing atmosphere is employed in order to suppress evaporation of the oxide and to increase the density of the sintered body. Examples of the oxygen-containing atmosphere include an oxygen atmosphere and an air atmosphere, and an oxygen atmosphere is preferable from the viewpoint of further increasing the density. Heating temperature in sintering step S31The temperature exceeding 1400 ℃ is selected so that the reaction speed of sintering is sufficiently fast and (Ga, In) is generated₂O₃. As described in patent document 1, beta-Ga is produced in sintering at 1400 ℃ or lower₂O₃. That is, the lower limit of the heating temperature is more than 1400 ℃, preferably 1450 ℃ or more, and more preferably 1500 ℃ or more. On the other hand, if the temperature is too high, there is a concern that the components may be different due to volatilization of the oxide, and therefore, it is preferable to perform sintering at a heating temperature of less than 1600 ℃, and more preferably 1550 ℃ or less. The heating holding time at the heating temperature exceeding 1400 ℃ is preferably 5 hours or more in order to sufficiently progress the sintering. The heating retention time is more preferably 10 hours or more, but even if the heating retention time is extended to 10 hours or more, the rise in relative density is small, and therefore, it is preferably 20 hours or less.

(machining step S41)

In the machining step S41, the formed sintered body is machined into a desired shape using machining equipment such as a surface grinder, a cylinder grinder, a lathe, a cutter, a machining center, or the like, to obtain a sputtering target member.

[3. sputtering target ]

In one embodiment, the sputtering target of the present invention is used by bonding the above-described sputtering target member to a base material such as a backing plate or a backing tube. The sputtering target member and the base material may be joined by any known method, and for example, a low melting point solder, such as indium solder, may be used. Any known material may be used as the material of the base material, and for example, copper (e.g., oxygen-free copper), a copper alloy, an aluminum alloy, titanium, stainless steel, or the like can be used.

[4. sputtered film ]

In one embodiment, the sputtering film of the present invention is a sputtering film formed of Ga, In, O, and inevitable impurities, and the Ga/In atomic ratio is 0.85 or more and 1.15 or less. In order to prevent a part of the crystallized film from remaining as an etching residue, the sputtered film of the present invention is preferably amorphous.

A method of confirming the crystallinity of the sputtered film is exemplified below. When XRD is performed on the sputtered film, a specific crystal peak is not observed, and a wide open-halo pattern is observed, the sputtered film to be observed can be said to be amorphous.

< measurement Condition >

Tube voltage: 40kV

Tube current: 30mA

Measurement range: 2 theta is 10-90 DEG

Scanning shaft: 2 theta/theta

Scanning speed: 10 °/min

Step width: 0.01 degree

Analysis software: PDXL (attached to SmartLab)

(refractive index)

In one embodiment, the sputtered film has a refractive index of 1.9 to 2.1 at a wavelength of 633 nm. The refractive index can be measured, for example, using a spectroscopic ellipsometer.

(extinction coefficient)

In one embodiment, the extinction coefficient at a wavelength of 633nm of the sputtered film of the present invention is preferably 0.01 or less, more preferably 0.001 or less, and still more preferably 0.0005 or less, from the viewpoint of improving the transmittance. However, the lower limit is typically 0 or more, more typically 0.00001 or more. The extinction coefficient can be measured, for example, using a spectroscopic ellipsometer.

(work function)

In one embodiment, the work function of the sputtering film of the present invention is preferably 5.0 to 6.0 eV. The lower limit of the work function is preferably 5.0eV or more, more preferably 5.2eV or more, and still more preferably 5.5eV or more. The value of the work function cannot be determined in a general way which value is better depending on the equipment employed, but it is preferable to be able to control within this range. The work function can be measured, for example, using photoelectron spectroscopy. The following apparatus and procedure were used for the measurement.

The device comprises the following steps: photoelectron spectroscopy device in the atmosphere AC-3 (manufactured by RIKEN KEIKI)

(volume resistivity)

In one embodiment, the sputtered film of the present invention has a volume resistivity of preferably 1.0 Ω · cm or less, more preferably 1.0 × 10^-1Omega cm or less, and still more preferably 5.0X 10^-2Omega. cm or less, for example, 1.0X 10^-31.0. omega. cm. This can be suitably used as a conductive film.

In the present invention, the volume resistivity is measured by a four-probe method using a resistivity measuring instrument. In the examples, the following devices were used for the measurement.

Measuring a jig: test material table RG-5

[5. method for producing sputtered film ]

In one embodiment, the method for producing a sputtering film of the present invention includes a film formation step of forming a sputtering film by using the sputtering target member described above. The sputtering apparatus to which the sputtering target member can be applied is not particularly limited. For example, a magnetron sputtering apparatus, an RF application type magnetron DC sputtering apparatus, or the like can be used.

In the film formation step, the oxygen content in the sputtering gas is preferably 10 vol% or less, more preferably 5 vol% or less, and still more preferably 3 vol% or less, from the viewpoint of obtaining a sputtered film having a low volume resistivity. It is preferable to carry out the sputtering with the oxygen content of 0% by volume or more, and since the work function tends to decrease when oxygen is not contained, it is preferably carried out with 1% by volume or more, and more preferably carried out with 2% by volume or more.

After the film forming step, a step of annealing the sputtered film may be further included in order to reduce the volume resistivity. In the film formation step, a sputtered film may be formed while performing annealing. The annealing is carried out at 60 to 200 ℃ for 0.2 to 5 hours in the air, for example.

[6. laminated Structure ]

Fig. 2 is a sectional view for explaining an embodiment of the laminated structure of the present invention. Fig. 3 to 7 are sectional views for explaining another embodiment of the laminated structure of the present invention. Hereinafter, an embodiment of a laminated structure according to the present invention will be described with reference to the drawings.

As shown in fig. 2 to 7, the

multilayer structure

10A, 10B, 10C, 10D, 10E, 10F includes a 2 nd metal film 11, an organic layer 12, a film body 13, and a substrate 14.

The 2 nd metal film 11 is in contact with the main surface 12-1 of the organic layer 12 on the side opposite to the film body 13. The 2 nd metal film has a function as a cathode when used in an organic EL device, for example. The 2 nd metal film 11 is not particularly limited as long as it is a metal, but is preferably formed of 1 or 2 or more selected from the group consisting of Al, In, W, Ti, Mo, Mg — Ag, and Ag — Al, from the viewpoint of using a metal having a low work function to facilitate electron injection and improve light emission efficiency. For example, the 2 nd metal film 11 is formed by a vacuum evaporation method or a sputtering method. The thickness of the 2 nd metal film 11 is typically 5 to 20nm, and more typically 7 to 17 nm.

And an organic layer 12 in contact with a 2 nd main surface 13 a-2 of the sputtered film 13a, the 2 nd main surface 13 a-2 being located on the opposite side of the 1 st main surface 13 a-1. The organic layer 12 includes an organic hole transport layer and an organic light emitting layer, and the organic hole transport layer is provided on the sputtering film 13a and the organic light emitting layer is provided on the organic hole transport layer.

The film body 13 functions as an anode when used in an organic EL device, for example. The film body 13 shown in fig. 2 includes the sputtered film 13a described above. The film body 13 shown in fig. 3 includes a sputtered film 13a and a 1 st metal film 13b in contact with a 1 st main surface 13 a-1 of the sputtered film 13 a. The film body 13 shown in fig. 4 includes: the sputtered film 13a, a 1 st metal film 13b in contact with a 1 st main surface 13 a-1 of the sputtered film 13a, and an oxide barrier film 13c in contact with a main surface 13 b-1 of the 1 st metal film 13 b. The film body 13 shown in fig. 5 includes: the sputtered film 13a, and an oxide conductive film 13d in contact with the 1 st main surface 13 a-1 of the sputtered film 13 a. The film body 13 shown in fig. 6 includes: the sputtered film 13a, the oxide conductive film 13d in contact with the 1 st main surface 13 a-1 of the sputtered film 13a, and the 1 st metal film 13b in contact with the main surface 13 d-1 of the oxide conductive film 13 d. The film body 13 shown in fig. 7 includes: the sputtered film 13a, the oxide conductive film 13d in contact with the 1 st main surface 13 a-1 of the sputtered film 13a, the 1 st metal film 13b in contact with the main surface 13 d-1 of the oxide conductive film 13d, and the oxide barrier film 13c in contact with the main surface 13 b-1 of the 1 st metal film 13 b.

The sputtered film 13a, as described above, has a high work function. The film is formed on the 1 st metal film 13b or the oxide conductive film 13d by a sputtering method using the sputtering target member described above. Needless to say, when manufacturing an organic EL device described later, the 1 st metal film 13b may not be formed, but a film may be formed on the substrate 14 such as a glass substrate or a resin substrate. The thickness of the sputtered film 13a is typically 1 to 20nm, and more typically 2 to 10 nm.

The 1 st metal film 13b is not particularly limited, but is preferably formed of a composition containing 90 mass% or more of 1 or 2 or more species selected from the group consisting of Ag, Cu, Ni, Fe, Cr, Al, and Co, from the viewpoint of using a metal having excellent reflectance and high conductivity. For example, the 1 st metal film 13b is formed by a vacuum vapor deposition method or a sputtering method. The thickness of the 1 st metal film 13b is typically 10 to 200nm, and more typically 20 to 150 nm.

The oxide barrier film 13c is not particularly limited, but is preferably formed of an oxide or nitride of 1 or 2 or more elements selected from the group consisting of Al, Mg, Si, Sn, Zr, Ti, Ga, Nb, Ta, Hf, W, Zn, and In, from the viewpoint of preventing oxidation or corrosion of the 1 st metal film 13 b. The thickness of the oxide barrier film 13c is typically 5 to 100nm, and more typically 10 to 60 nm.

The oxide conductive film 13d is not particularly limited, and preferably has a thickness of 1.0 × 10^-3High conductivity not more than Ω · cm selected from ITO, IZO and1 or more than 2 AZO groups. The thickness of the oxide conductive film 13d is typically 1 to 20nm, and more typically 2 to 10 nm. Since the oxide conductive film 13d is disposed, a better conductivity can be obtained without disposing the 1 st metal film 13 b.

In the case where the oxide conductive film 13d is formed of ITO, for example, In is a main component₂O₃In SnO₂Contains 5 to 15 mass% of Sn in terms of Sn.

In the case where the oxide conductive film 13d is formed of IZO, for example, In is a main component₂O₃The zinc oxide composition contains 2.5 to 15 mass% of Zn in terms of ZnO.

In the case where the oxide conductive film 13d is formed of AZO, for example, ZnO is a main component, and Al is used₂O₃Contains 0.5 to 10 mass% of Al in terms of Al content.

And a substrate 14 in contact with the outermost main surface of the film body 13, the outermost main surface of the film body 13 being located on the 1 st main surface 13 a-1 side of the sputtered film 13 a. Here, the outermost main surface of the film body 13 is represented by the 1 st main surface 13 a-1 of the sputtered film 13a shown in fig. 2, by the 1 st metal film 13b shown in fig. 3, by the 1 st main surface 13 b-1 of the oxide barrier film 13c shown in fig. 4, by the oxide conductive film 13 d-1 shown in fig. 5, by the 1 st metal film 13b shown in fig. 6, and by the oxide conductive film 13 d-1 shown in fig. 7. The substrate 14 may be, for example, a glass substrate or a resin substrate.

The

stacked structures

10A, 10B, 10C, 10D, 10E, and 10F can be used for top emission organic EL devices. More specifically, in an organic EL device (not shown), a sealing layer, a laminated structure, a Thin Film Transistor (TFT), and a substrate are laminated in this order. When a voltage is applied to the lower electrode and the upper electrode by the driving circuit, electrons flow from the upper electrode to the organic layer 12, holes flow from the lower electrode to the organic layer 12, and the electrons and the holes are recombined to emit light through the light-emitting molecules of the organic layer 12. Light from the organic layer 12 is emitted from the sealing layer side on the opposite side of the substrate.

[ examples ] A method for producing a compound

The present invention will be specifically described based on examples and comparative examples. The following examples and comparative examples are merely specific examples for facilitating understanding of the technical contents of the present invention, and the technical scope of the present invention is not limited to these specific examples.

(example 1)

Weighing commercially available Ga₂O₃Powder and In₂O₃The powders were mixed and finely pulverized by a wet method so as to obtain the atomic ratio of Ga/In shown In table 1, and then dried and granulated by a spray dryer to obtain a mixed powder.

Next, the mixed powder was filled into a mold and press-molded using a press machine (surface pressure: 300 kgf/cm)²The retention time is as follows: 1 minute), a compact having a thickness of 13mm was produced. Thereafter, the obtained molded article was subjected to CIP molding (surface pressure: 1500 kgf/cm)²The retention time is as follows: 20 minutes).

Subsequently, the obtained molded body was charged into a sintering furnace, sintered at 1500 ℃ for 10 hours in an oxygen atmosphere, and then naturally cooled to room temperature to obtain a sintered body having a thickness of 10 mm.

Then, the upper surface, the lower surface and the side surfaces of the obtained sintered body were cut by machining, and each surface was ground by a surface grinder to obtain a flat sputtering target member having a diameter of 203.2mm × 5 mmt. The obtained sputtering target members were evaluated as follows.

< EPMA analysis >

As described above, the structure of the sputtering target member was observed using an electron beam microanalyzer, and as a result, as shown In FIG. 8A, it was confirmed that (Ga, In) composed of Ga, In and O was formed₂O₃And (4) phase(s). In addition, with respect to the (Ga, In)₂O₃The area ratio was determined by the method described above. The area ratio is shown in table 1.

< relative Density >

The measured density of the target member to be measured is obtained by the archimedes method, and the relative density is obtained by the measured density/calculated density. And, the relative density is shown in table 1.

< crystal phase >

For the sputtering target member, the crystal phase was judged by performing X-ray diffraction measurement (XRD) by the method described above. As a result, an XRD pattern as shown in fig. 8(B) was obtained. By ICDD, (Ga, In) can be observed as No. 00-014-₂O₃Ga as No. 00-051-₂In₆Sn₂O₁₆Ga as No. 00-051-_2.4In_5.6Sn₂O₁₆As In of No. 01-089-4595-₂O₃And Ga as No. 01-087-1901₂O₃。

< volume resistivity >

The volume resistivity of the sputtering target member was measured by the method described above using a resistivity measuring instrument (model number FELL-TC-100-SB- Σ 5+, manufactured by NPS corporation, measurement jig RG-5) using a direct current four-probe method. Also, the volume resistivity is shown in table 1.

< composition >

The sputtering target member was analyzed by ICP emission spectrometry (high frequency inductively coupled plasma emission spectrometry). A part of the sputtering target member was dissolved with an acid as a sample, and diluted with ultrapure water as a measurement sample. The solution was analyzed for various metal elements. As a result, Ga and In among various metal elements and Ga-based₂O₃Powder and In₂O₃The atomic ratios of Ga and In calculated from the mixing ratios of the powders were approximately the same. Although Sn was present in an extremely small amount, several hundred mass ppm was detected.

Next, the obtained sputtering target member was bonded to a copper backing plate with indium solder to obtain a sputtering target. The sputtering targets were formed under the above-described film formation conditions using a DC (direct current) sputtering apparatus under the conditions of containing oxygen in an amount of 0 vol%, 1 vol%, 2 vol%, and 3 vol% in argon gas.

< work function >

The work function of the obtained sputtered film under the condition of 0% by volume to 3% by volume of oxygen was measured by arbitrarily selecting 2 positions by the method described above using the atmospheric photoelectron spectroscopy device AC-3 (manufactured by RIKEN KEIKI). The average of the measurements is recorded as a work function.

< refractive index >

The refractive index of the sputtered film was measured using a spectroscopic ellipsometer (manufactured by J.A. Woollam, model: ESM-300), and a value of 633nm was used. Further, the sputtered film was annealed at 150 ℃ for 1 hour in the atmosphere, and the refractive index of the sputtered film after the annealing was measured.

< extinction coefficient >

The extinction coefficient of the sputtered film was measured using a spectroscopic ellipsometer (manufactured by j.a. woollam, model: ESM-300) and a value of a wavelength of 633nm was used. Further, the sputtered film was annealed at 150 ℃ for 1 hour in the air, and then the extinction coefficient of the sputtered film after the annealing was measured.

< volume resistivity of thin film >

The volume resistivity of the surface of the sputtered film was measured by the method described above using a resistivity measuring instrument (model number FELL-TC-100-SB- Σ 5+, manufactured by NPS corporation, measurement jig RG-5) using a direct current four-probe method. Further, the sputtered film was annealed at 150 ℃ for 1 hour in the atmosphere, and then the volume resistivity of the sputtered film after the annealing was measured.

< crystallinity >

The crystallinity of the sputtered film was observed by the method described above. Further, the sputtered film was annealed at 150 ℃ for 1 hour in the air, and then the crystallinity of the sputtered film after the annealing was observed.

(example 2)

The procedure of example 2 was carried out In the same manner as In example 1 except that the atomic ratio of Ga/In was changed to 0.905. The manufacturing conditions and the evaluation results of the sputtering target member are shown in table 1, and the evaluation results of the sputtered film are shown in table 2.

(example 3)

The procedure of example 3 was carried out In the same manner as In example 1 except that the atomic ratio of Ga/In was changed to 1.105. The manufacturing conditions and the evaluation results of the sputtering target member are shown in table 1, and the evaluation results of the sputtered film are shown in table 2.

(example 4)

In example 4, the same procedure as in example 1 was repeated except that the sintering conditions were changed to atmospheric air. The manufacturing conditions and the evaluation results of the sputtering target member are shown in table 1, and the evaluation results of the sputtered film are shown in table 2.

(example 5)

The process was carried out in the same manner as in example 1, except that the sintering temperature in example 5 was changed to 1550 ℃. The manufacturing conditions and the evaluation results of the sputtering target member are shown in table 1, and the evaluation results of the sputtered film are shown in table 2.

(example 6)

The process was carried out in the same manner as in example 1, except that the sintering temperature was changed to 1450 ℃. The manufacturing conditions and the evaluation results of the sputtering target member are shown in table 1, and the evaluation results of the sputtered film are shown in table 2.

Comparative example 1

The process was carried out in the same manner as in example 1, except that the sintering temperature in comparative example 1 was changed to 1400 ℃. The manufacturing conditions and the evaluation results of the sputtering target member are shown in table 1, and the evaluation results of the sputtered film are shown in table 2.

Comparative example 2

In comparative example 2, the sintering temperature was changed to 1600 ℃. The sintered body reacts with the base plate, and thus a sputtering target member cannot be produced. The manufacturing conditions of the sputtering target member are shown in table 1.

Comparative example 3

In comparative example 3, the same procedure as In example 1 was repeated except that the atomic ratio of Ga/In was changed to 0.667. The manufacturing conditions and the evaluation results of the sputtering target member are shown in table 1, and the evaluation results of the sputtered film are shown in table 2.

Comparative example 4

In comparative example 4, the same procedure as In example 1 was repeated except that the atomic ratio of Ga/In was changed to 1.500. The manufacturing conditions and the evaluation results of the sputtering target member are shown in table 1, and the evaluation results of the sputtered film are shown in table 2.

[ TABLE 1 ]

[ TABLE 2 ]

(examination of examples)

The sputtered films produced in examples 1 to 6 had a work function of 5.0 to 6.0eV and a refractive index at a wavelength of 633nm of 1.9 to 2.1, and thus it is considered that they can be used in organic EL devices.

In comparative example 1, the target refractive index was not obtained because the sintering temperature was low. In comparative example 3, since Ga/In was low, the In2O3 phase having a ferromanganese structure was formed more In the crystal phase. As a result, the work function was lower than in examples 1 to 6, and the target refractive index was not obtained. In comparative example 4, since Ga/In was high, a β -GaInO 3 phase was formed more In the crystal phase. As a result, the volume resistivity was higher and the work function was lower than those of examples 1 to 6, and the target refractive index was not obtained.

Description of the reference numerals

10A, 10B, 10C, 10D, 10E, 10F laminated structure

11 nd 2 nd metal film

1 organic layer

12-1 major surface

13 film body

13a sputtered film

13 a-1 st major surface

13 a-2 nd major surface

13b 1 st metal film

13 b-1 major surface

13c oxide barrier film

13 c-1 major surface

13d oxide conductive film

13 d-1 major surface

14 substrate

S11 mixing step

S21 filling step

S31 sintering step

S41 machining step

Claims

1. A sputtering target member which is formed from Ga, In, O and inevitable impurities,

the atomic ratio of Ga/In is 0.90 or more and 1.11 or less, and the surface analysis of EPMA shows that the crystal phase contains (Ga, In) In comparison with the entire crystal phase₂O₃The area ratio of the phases is 90% or more.

2. The sputtering target member according to claim 1, wherein the atomic ratio of Ga/In is 0.95 or more and 1.05 or less.

3. The sputtering target member according to claim 1, wherein the area ratio is 95% or more.

4. The sputtering target member according to claim 2, wherein the area ratio is 95% or more.

5. A sputtering target member according to any one of claims 1 to 4, wherein the relative density of the sputtering target member is 94% or more.

6. A sputtering target member according to any one of claims 1 to 4, wherein the volume resistivity of the sputtering target member is 1.0 x 10³And omega is seeded to less than cm.

7. A sputtering target member according to claim 5, wherein the volume resistivity of the sputtering target member is 1.0 x 10³And omega is seeded to less than cm.

8. The sputtering target member according to any one of claims 1 to 4, wherein when the film formation of the sputtering film is performed while changing the oxygen content in the sputtering gas from 0% by volume to 3% by volume, the work function of the sputtering film is in the range of 5.0 to 6.0 eV.

9. A sputtering target member according to any one of claims 1 to 4, wherein the sputtering target member is cylindrical or flat.

10. A sputtering target comprising the sputtering target member according to any one of claims 1 to 4 and a base material.

11. A method of manufacturing a sputtering target member according to any one of claims 1 to 9, comprising:

a mixing step of mixing In such a manner that the atomic ratio of Ga/In is 0.90 or more and 1.11 or less₂O₃Powder and Ga₂O₃Obtaining mixed powder by powder;

and a sintering step of sintering the mixed powder at a sintering temperature of more than 1400 ℃ and less than 1600 ℃ to obtain a sintered body.

12. A sputter target member manufacturing method as recited in claim 11 wherein said sintering temperature is 1450 ℃ to 1550 ℃.

13. The method of manufacturing a sputtering target member according to claim 11 or 12, wherein in the sintering step, the sintering retention time is 5 to 20 hours.

14. A method for producing a sputtering film, comprising a film formation step of forming a sputtering film by using the sputtering target member according to any one of claims 1 to 9, wherein the sputtering film:

formed of Ga, In, O and inevitable impurities,

the atomic ratio of Ga/In is 0.85 to 1.15, the refractive index at a wavelength of 633nm is 1.9 to 2.1, and the work function is 5.0 to 6.0 eV.

15. The method for manufacturing a sputtering film according to claim 14, wherein the sputtering film has a volume resistivity of 1.0 Ω & seeds & cm or less.

16. The method for producing a sputtering film according to claim 14, wherein the sputtering film has an extinction coefficient of 0.01 or less at a wavelength of 633 nm.

17. The method for producing a sputtering film according to claim 15, wherein the sputtering film has an extinction coefficient of 0.01 or less at a wavelength of 633 nm.

18. The method of manufacturing a sputtering film according to any one of claims 14 to 17, wherein the sputtering film is amorphous.

19. A method for producing a sputtering film, comprising a film formation step of forming a sputtering film by using the sputtering target member according to any one of claims 1 to 9.

20. A method for producing a sputtering film, comprising a film formation step of forming a sputtering film by using the sputtering target according to claim 10.

21. The method of manufacturing a sputtering film according to claim 19, wherein the film forming step is followed by a step of annealing the sputtering film at 200 ℃ or lower.

22. The method of manufacturing a sputtered film according to claim 19, wherein in the film forming step, the sputtered film is formed while performing an annealing process at 200 ℃ or lower.

23. The method of manufacturing a sputtering film according to any one of claims 19 to 22, wherein the film formation step is performed with an oxygen content in a sputtering gas of 10 vol% or less.

24. A method of manufacturing a membrane body, comprising:

the step of forming a sputtered film by using the method for producing a sputtered film according to any of claims 14 to 17.

25. The method of manufacturing a membrane body according to claim 24, further comprising: a step of disposing a 1 st metal film in contact with a 1 st main surface of the sputtered film.

26. The method of manufacturing a membrane body of claim 25, further comprising: a step of disposing an oxide barrier film in contact with a main surface of the 1 st metal film.

27. The method of manufacturing a membrane body of claim 24, further comprising: and a step of disposing an oxide conductive film in contact with the 1 st main surface of the sputtered film.

28. The method of manufacturing a membrane body of claim 27, further comprising: and a step of disposing a 1 st metal film in contact with a main surface of the oxide conductive film.

29. The method of manufacturing a membrane body of claim 28, further comprising: a step of disposing an oxide barrier film in contact with a main surface of the 1 st metal film.

30. The method for producing a film body according to any one of claims 27 to 29, wherein the volume resistivity of the oxide conductive film is 1.0 x 10^-3And omega is seeded to less than cm.

31. The method according to any one of claims 27 to 29, wherein the conductive oxide film is formed of at least one selected from the group consisting of ITO, IZO, and AZO.

32. The method of manufacturing a film body according to any one of claims 25, 26, 28, and 29, wherein the 1 st metal film is formed of a composition containing 90 mass% or more of 1 or 2 or more selected from the group consisting of Ag, Cu, Ni, Fe, Cr, Al, and Co.

33. A method of manufacturing a laminated structure, comprising:

a step of forming a film body using the method for manufacturing a film body according to any one of claims 24 to 32, and

a step of forming a glass substrate or a resin substrate in contact with the outermost main surface of the film body on the 1 st main surface side of the sputtered film.

34. The method of manufacturing a laminated structure according to claim 33, further comprising a step of forming an organic layer in contact with a 2 nd main surface of the sputtered film, the 2 nd main surface being on an opposite side of the 1 st main surface.

35. The method of manufacturing a laminated structure according to claim 34, further comprising a step of forming a 2 nd metal film in contact with a main surface of the organic layer.

36. The method of manufacturing a laminated structure according to claim 35, wherein the 2 nd metal film is formed of 1 or 2 or more selected from the group of Al, In, W, Ti, Mo, Mg-Ag, and Ag-Al.

37. A method of manufacturing an organic EL device, comprising: a step of sequentially laminating a sealing layer, a laminated structure manufactured by the method for manufacturing a laminated structure according to any one of claims 33 to 36, a thin film transistor, and a substrate.