JP4269986B2 - Oxide sintered compact target for manufacturing transparent conductive thin film, transparent conductive thin film, transparent conductive substrate, display device, and organic electroluminescence element - Google Patents

Description

  The present invention relates to a transparent conductive thin film used for a liquid crystal display (LCD) element, an organic electroluminescence (EL) element or the like, and an oxide firing used for producing a transparent conductive thin film by a sputtering method or an ion plating method. Concerning ligation target.

The transparent conductive thin film has high conductivity (for example, a specific resistance of 1 × 10 ⁻³ Ωcm or less) and high transmittance in the visible light region. In addition to being used as electrodes for devices, etc., it is also used as anti-fogging transparent heating elements such as heat ray reflective films, various antistatic films, freezing showcases, etc. used for automobile window glass, building window glass, etc. Yes.

The transparent conductive thin film includes a tin oxide (SnO ₂ ) film doped with antimony and fluorine, a zinc oxide (ZnO) film doped with aluminum and gallium, and an indium oxide (In ₂ O ₃ ) film doped with tin. Are widely used. In particular, an indium oxide film doped with tin, that is, an In ₂ O ₃ —Sn-based film is called an ITO (Indium Tin Oxide) film and is often used because a low-resistance transparent conductive thin film can be easily obtained. It has been.

  A sputtering method is often used as a method for producing these transparent conductive thin films. The sputtering method uses a material having a low vapor pressure to form a film on a material to be deposited (hereinafter simply referred to as “substrate”) or when precise film thickness control is required. Since it is an effective technique and the operation is very simple, it is widely used.

  In general, the sputtering method uses a substrate as an anode and a target as a cathode under an argon gas pressure of about 10 Pa or less to generate a glow discharge between them to generate an argon plasma. Then, it is made to collide with the target of the cathode, thereby repelling the particles of the target component and depositing the particles on the substrate to form a film.

  Sputtering methods are classified according to the method of generating argon plasma. Those using high-frequency plasma are called high-frequency sputtering methods, and those using direct-current plasma are called DC sputtering methods. A method of forming a film by arranging a magnet on the back side of the target so that argon plasma is concentrated directly on the target and increasing the collision efficiency of argon ions even at a low gas pressure is called a magnetron sputtering method. Usually, the direct current magnetron sputtering method is adopted as the method for producing the transparent conductive thin film.

  A transparent conductive thin film with a smooth surface is required for electrodes for LCDs and organic EL elements. In particular, in the case of an electrode for an organic EL element, an ultra-thin film of an organic compound is formed on the electrode, so that the transparent conductive thin film is required to have excellent surface smoothness. In general, the surface smoothness greatly depends on the crystallinity of the film. Even if the composition is the same, the transparent conductive thin film (amorphous film) with an amorphous structure with no grain boundaries is more smooth than the transparent conductive thin film (crystalline film) with a crystalline structure. Is good.

Even in the case of an ITO film having a conventional composition, for example, when a DC magnetron sputtering apparatus is used, the substrate temperature during film formation is lowered, and sputtering film formation is performed at a low temperature (150 ° C. or less) and a high gas pressure (1 Pa) or more. It has been confirmed by the present inventors that the obtained amorphous ITO film is superior in surface smoothness. However, the specific resistance of the amorphous ITO film is limited to 9 × 10 ⁻⁴ Ω · cm even if it can be lowered, and in order to form a film with low surface resistance, it is necessary to form the film itself thickly. . However, when the thickness of the ITO film is increased, a problem of coloring occurs.

  Even in the case of an ITO film formed at room temperature without heating the substrate, if the sputtering gas pressure is low, the kinetic energy of sputtered particles incident on the substrate is high, so the temperature rises locally, and the fine crystalline phase and non- A film composed of a crystalline phase is obtained. Presence of a fine crystal phase can be confirmed not only by X-ray diffraction but also by a transmission electron microscope or electron diffraction.

  If such a fine crystal phase is partially formed, the surface smoothness is greatly affected. Further, when the transparent conductive film is etched into a predetermined shape with a weak acid, only the crystal phase may remain unremoved, which is problematic.

  On the other hand, the amorphous ITO film has a problem of stability in addition to a problem of specific resistance. When an amorphous ITO film is used as an electrode for an LCD or an organic EL element, heating at 150 ° C. or more is performed during the manufacturing process due to the thermal history after the electrode is formed. It will crystallize. This is because the amorphous phase is a metastable phase. If the amorphous phase is crystallized, crystal grains are formed, resulting in poor surface smoothness and a large change in specific resistance.

  Next, the organic EL element will be described. An electroluminescence (EL) element uses electroluminescence, has high visibility because of self-emission, and is a completely solid element. For this reason, the EL element has advantages such as excellent impact resistance, and the use of the EL element as a light emitting element in various display devices has attracted attention.

  EL elements include an inorganic EL element using an inorganic compound as a light emitting material and an organic EL element using an organic compound. Among these, since organic EL elements can be easily reduced in size by greatly reducing drive voltage, practical application research as next-generation display elements has been actively conducted. The configuration of the organic EL element is basically a laminate of an anode / light emitting layer / cathode, and a configuration in which a transparent anode is formed on a substrate using a glass plate or the like is usually employed. In this case, the emitted light is extracted to the substrate side.

  In recent years, attempts have been made to extract light from the cathode side by making the cathode transparent for the following reasons. If the anode is made transparent together with the cathode, a transparent light emitting element as a whole can be obtained. Therefore, an arbitrary color can be adopted as the background color of the transparent light-emitting element, and a colorful display can be obtained even during light emission, and the decorativeness is improved. In addition, when black is used as the background color, there is an advantage that the contrast during light emission is improved. In addition, these can be placed on the light emitting element by using a color filter or a color conversion layer. For this reason, a light emitting element can be manufactured without considering a color filter or a color conversion layer. As an advantage, for example, it is not necessary to consider forming a transparent electrode on a color filter or color conversion layer having poor heat resistance, so that the substrate temperature can be increased when forming the anode. Thus, the resistance value of the anode can be lowered.

  Since such advantages can be obtained by making the cathode transparent, an attempt has been made to produce an organic EL device using a transparent cathode.

  For example, in an organic EL device described in JP-A-10-162959, an organic layer including an organic light emitting layer is interposed between an anode and a cathode, and the cathode is an electron injection metal layer and an amorphous transparent conductive material. And an electron injecting metal layer is in contact with the organic layer.

  Japanese Patent Application Laid-Open No. 2001-43980 describes an organic EL element that is devised so as to efficiently extract light from a cathode by making the cathode transparent and using a light-reflective metal film for the anode. .

  Here, the electron injection metal layer will be described. The electron injecting metal layer is a metal layer that can satisfactorily inject electrons into an organic layer including a light emitting layer. In order to obtain a transparent light-emitting element, the electron injection metal layer preferably has a light transmittance of 50% or more. For this purpose, the thickness of the layer needs to be an ultrathin film of about 0.5 to 20 nm. There is.

  Specifically, a metal having a work function of 3.8 eV or less (electron-injecting metal) such as Mg, Ca, Ba, Sr, Li, Yb, Eu, Y, and Sc is used as the electron-injecting metal layer. And a layer having a thickness of 1 nm to 20 nm. In this case, a configuration capable of obtaining a light transmittance of 50% or more, preferably 60% or more is desired.

  The organic layer interposed between the anode and the cathode includes at least a light emitting layer. The organic layer may be a layer composed only of the light emitting layer, or may have a multilayer structure in which a hole injecting and transporting layer and the like are laminated together with the light emitting layer. In the organic EL element, the organic layer is (1) a function that can inject holes from the anode or the hole transport layer when an electric field is applied, and can inject electrons from the electron injection layer, (2) Transport function to move injected charges (electrons and holes) by the force of electric field, (3) Functions such as light-emitting function that provides a recombination field of electrons and holes inside the light-emitting layer and connects them to light emission Have.

  The hole injection transport layer is a layer made of a hole transfer compound, and has a function of transferring holes injected from the anode to the light emitting layer. By interposing this hole injecting and transporting layer between the anode and the light emitting layer, many holes are injected into the light emitting layer with a lower electric field. In addition, electrons injected from the electron injection layer into the light emitting layer are accumulated near the interface in the light emitting layer due to an electron barrier existing at the interface between the light emitting layer and the hole injection transport layer. Thereby, the luminous efficiency of an organic EL element can be improved and the organic EL element excellent in the light emission performance is obtained.

  The anode is not particularly limited as long as it has a work function of 4.4 eV or more, preferably 4.8 eV or more. A metal having a work function of 4.8 eV or more, a transparent conductive thin film, or a combination thereof is preferable.

  The anode is not necessarily transparent and may be coated with a black carbon layer or the like. Suitable metals include, for example, Au, Pt, Ni and Pd. Examples of the conductive oxide include In—Zn—O, In—Sn—O, ZnO—Al, and Zn—Sn—O. Examples of the stacked body include a stacked body of Au and In—Zn—O, a stacked body of Pt and In—Zn—O, and a stacked body of In—Sn—O and Pt.

In addition, since the anode only needs to have a work function of 4.4 eV or more at the interface with the organic layer, the anode may be formed in two layers and a conductive film having a work function of 4.4 eV or less may be used on the side not in contact with the organic layer. Good. In this case, a metal such as Al, Ta, or W, or an alloy such as an Al alloy or Ta—W alloy can be used. In addition, conductive polymers such as doped polyaniline and doped polyphenylene vinylene, and amorphous semiconductors such as a-Si, a-SiC, and aC can also be used. Further, black semiconductor oxides such as Cr ₂ O ₃ , Pr ₂ O ₅ , NiO, Mn ₂ O ₅ and MnO ₂ can be used.

The transparent conductive layer constituting the cathode of the organic EL element is preferably an amorphous film with little internal stress and excellent smoothness. In order to eliminate the voltage drop and the light emission non-uniformity caused by the voltage drop, the specific resistance value is preferably 9 × 10 ⁻⁴ Ω · cm or less.

  As an amorphous film, indium oxide added with zinc (In-Zn-O) is described in JP-A-7-235219. This publication introduces that the Zn element is contained in an amount of 10 to 20 at% with respect to the total of the Zn element and the In element, and exhibits stable amorphousness and high conductivity.

  However, the film having the composition introduced here has a drawback that the light transmittance is low at a short wavelength side in the visible region, particularly at a wavelength near 400 nm. This is because, firstly, a large amount of Zn metal is contained, and light absorption by the Zn metal is remarkable. Second, since the carrier concentration is lower than that of ITO or the like, the Burstein-Moss effect. ("Transparent conductive film technology", Ohm Co., 1st edition, P74), there is little increase in the band gap and the accompanying shortening of the absorption edge.

  In addition, an indium oxide film containing tungsten is conventionally known. For example, Japanese Patent Publication No. 50-19125 describes a technique for producing a tungsten-added indium oxide film on a heated glass substrate at 350 ° C. by an electron beam evaporation method.

  However, the tungsten-added indium oxide film described here is intended to reduce the resistance of a conventional indium oxide film, and is not intended to improve surface smoothness or increase the crystallization temperature. Further, Japanese Patent Publication No. 50-19125 discloses nothing about making amorphous, improving surface smoothness, and raising the crystallization temperature by adding tungsten. Not. As in the tungsten-added indium oxide film described in this publication, it is impossible to form an amorphous film simply by adding tungsten, and it is amorphous under the film-forming conditions of heating to 350 ° C. as described above. No tungsten or zinc-added indium oxide film can be obtained. As described above, by simply adding tungsten, an amorphous film cannot be obtained, the surface smoothness is excellent, the low resistance and the transmittance cannot be increased.

  As described in Japanese Patent Application Laid-Open No. 2004-52102, the present inventors have obtained a low resistance amorphous film of indium oxide to which tungsten is added, and an organic EL element using the same. Discloses the invention. This publication shows that when tungsten element is added to indium oxide, the crystallization temperature rises, and an amorphous film that has been low resistance and could not be easily manufactured can be stably manufactured by sputtering. Further, the obtained tungsten-doped indium oxide film has a shorter visible light region than the amorphous film made of 10-20 at% Zn-doped indium oxide described in JP-A-7-235219. It is shown that it has the characteristic that the transmittance | permeability by the wavelength side is high.

Realizing a transparent conductive thin film that has excellent surface smoothness and is stable even with the heat history of the manufacturing process is impossible with conventional ITO materials. Therefore, it is transparent for display elements such as organic EL elements and LCDs. It was difficult to utilize for an electrode. As described above, an indium oxide thin film containing 10 to 20 at% of Zn with respect to the sum of In + Zn atoms (Japanese Patent Laid-Open No. 7-235219), or W in a W / In atomic ratio of 0.004 to 0 0.047 containing an indium oxide thin film (Japanese Patent Laid-Open No. 2004-52102) stably provides an amorphous film and exhibits high conductivity. However, the former has a defect that the transmittance on the short wavelength side (for example, 400 nm) in the visible light region is low, and the latter is manufactured by a sputtering method and has an absolute value of 1 × 10 ¹⁰ dyn / cm ² or less (ie, Low internal stress of −1 × 10 ¹⁰ dyn / cm ² to 1 × 10 ¹⁰ dyn / cm ² (for the internal stress of the film, see “Applied Physics Engineering Selection 3 Thin Film”, Baifukan, first edition, P107) and low It has a drawback that it is difficult to obtain a transparent conductive film having two characteristics of resistance. Japanese Patent Application Laid-Open No. 7-235219 and Japanese Patent Application Laid-Open No. 2004-52102 have no disclosure about the internal stress of the film.

Japanese Patent Laid-Open No. 10-162959 JP 2001-43980 A JP 7-235219 A Japanese Patent Publication No. 50-19125 JP 2004-52102 A "Technology of transparent conductive film", Ohmsha, 1st edition, P74 "Applied Physics Engineering Selection 3 Thin Film", Baifukan, First Edition, P107

  The present invention is excellent in that the surface smoothness is excellent, the specific resistance is low, and the properties of amorphousness, surface smoothness and specific resistance are not changed even by heating below 200 ° C., and the internal stress is low. An object of the present invention is to provide a transparent conductive thin film having a novel composition.

  Furthermore, it aims at providing the display device using the said transparent conductive thin film as an electrode.

  In particular, compared to conventional organic EL elements using transparent conductive thin films, high-quality organic EL elements that emit light with a high luminance, have a long half-life of light emission intensity, and are less prone to dark spots (non-light emitting parts). The purpose is to provide.

In the present invention, indium oxide is a main component, tungsten element is contained at a W / In atomic ratio of 0.0040 to 0.0230, and zinc element is Zn / In atomic ratio at 0.004 to 0.00. Transparent conductive thin film having a composition contained at a ratio of 100, preferably a transparent conductive film having a composition in which silver is further contained in the above composition at a ratio of 0.001 to 0.010 in terms of the Ag / In atomic ratio (1) Excellent surface smoothness, low specific resistance of 9.0 × 10 ⁻⁴ Ω · cm or less, and amorphous and surface even when heated below 200 ° C. The properties of smoothness and specific resistance do not change, (2) the transparency on the short wavelength side (400 nm) in the visible light region is extremely excellent, and (3) -1 × 10 ¹⁰ dyn / cm ² to 1 × 10 ¹⁰ Low internal stress of dyn / cm ² can be realized It has the feature that.

  The transparent conductive thin film according to the present invention can be used as a transparent electrode formed on an organic light emitting layer in a top emission type organic EL device or a transparent electrode formed on a resin film substrate.

  In one aspect of the transparent conductive thin film according to the present invention, indium oxide is the main component, tungsten element is contained in a W / In atomic ratio of 0.004 to 0.023, and zinc element is Zn / In atomic number. It is contained at a ratio of 0.004 to 0.100 in a ratio, and has an amorphous structure.

  The transparent conductive thin film according to another aspect comprises indium oxide as a main component, tungsten element is contained in a W / In atomic ratio of 0.004 to 0.023, and zinc element is Zn / In atomic ratio. The silver element is contained at a ratio of 0.004 to 0.100, and the silver element is contained at a ratio of 0.001 to 0.010 in terms of the Ag / In atom number ratio, and has an amorphous structure.

In the transparent conductive thin film, the specific resistance is preferably 9.0 × 10 ⁻⁴ Ωcm or less, and more preferably 6.0 × 10 ⁻⁴ Ωcm or less. Moreover, it is preferable that the crystallization temperature is 200 degreeC or more. Furthermore, the arithmetic average height (Ra) of the film surface is preferably 2.0 nm or less. In addition, the absolute value of the internal stress is preferably 1 × 10 ¹⁰ dyn / cm ² or less.

  The oxide sintered compact target for manufacturing a transparent conductive thin film according to one aspect of the present invention is used for manufacturing a transparent conductive thin film whose substantial constituent elements are indium, tungsten, zinc, and oxygen, and the tungsten element is used. W / In atom number ratio contains 0.004-0.023, and zinc element contains Zn / In atom number ratio 0.004-0.100.

  The oxide sintered compact target for manufacturing a transparent conductive thin film according to another aspect is used to manufacture a transparent conductive thin film whose substantial constituent elements are indium, tungsten, zinc, silver and oxygen, W / In atomic ratio is 0.004-0.023, zinc element is Zn / In atomic ratio is 0.004-0.100, silver element is Ag / In atom. It is contained at a ratio of 0.001 to 0.010 in the number ratio.

  Furthermore, according to the present invention, a transparent conductive thin film is formed on the surface of a transparent substrate using the oxide sintered compact target for manufacturing a transparent conductive thin film.

  In the transparent conductive substrate according to the present invention, the transparent substrate is a glass plate, a resin plate or resin film whose one or both sides are covered with a gas barrier film, or a resin plate or resin in which a gas barrier film is inserted. A film is preferred.

  The gas barrier film is preferably at least one selected from a silicon oxide film, a silicon oxynitride film, a magnesium aluminum oxide film, a tin oxide film, and a diamond-like carbon film.

  Further, the resin plate or the resin film is made of polyethylene terephthalate (PET), polyethersulfone (PES), polyarylate (PAR), polycarbonate (PC), or the surface of these materials is covered with an acrylic organic material. It preferably has a laminated structure.

  The display device of the present invention uses the transparent conductive thin film as an electrode.

  The organic EL device of the present invention comprises an organic layer sandwiched between an anode and a cathode, and the organic layer emits light by recombination of holes supplied from the anode and electrons supplied from the cathode. At least one layer including a light emitting layer and forming the anode and / or the cathode is composed of the transparent conductive thin film.

According to the present invention, the surface smoothness is excellent, the specific resistance is 9.0 × 10 ⁻⁴ Ω · cm or less, and depending on the production conditions, it is as low as 6.0 × 10 ⁻⁴ Ω · cm or less, and it is amorphous. A transparent conductive thin film can be obtained in a state of low internal stress (the absolute value of internal stress is 1 × 10 ¹⁰ dyn / cm ² or less). Since the transparent conductive thin film obtained by the present invention has a low internal stress, it can be deposited on a soft substrate (for example, a resin film or an organic film) without deforming the substrate. In particular, since a transparent conductive thin film can be formed as a cathode on a soft organic light emitting layer, a top emission type organic EL device capable of efficiently extracting light from the cathode as the upper surface electrode is realized. In addition, the present invention is useful.

  Further, if the transparent conductive thin film of the present invention is formed on a substrate maintained at a low temperature, it is possible to form a transparent electrode having low resistance and excellent surface smoothness. And, on a soft resin film substrate having no heat resistance, it can be formed as a low-resistance transparent electrode at low temperature without deforming the substrate, and / or a cathode of a flexible transparent organic EL element using the resin film substrate and / or It can be used as an anode.

  Furthermore, if the transparent conductive thin film of the present invention has a crystallization temperature of 200 ° C. or higher and is heated below 200 ° C., the amorphous property and the surface smoothness are not impaired, and the property of specific resistance deteriorates. Therefore, even in the sputtering method in which the substrate easily receives heat from plasma, an amorphous film can be stably obtained if the substrate surface temperature is set to less than 200 ° C. Furthermore, even if a heating process at 200 ° C. is included in the manufacturing process after film formation, the transparent conductive thin film of the present invention can stably maintain its characteristics.

  As described above, the transparent conductive thin film of the present invention having excellent characteristics can be used not only as an organic EL element, but also as an inorganic EL element, a transparent electrode for LCD and electronic paper, and industrially. Extremely valuable. In addition, the organic EL device using the transparent conductive thin film of the present invention has high emission intensity and hardly generates dark spots, so that it is possible to produce a high-quality display and is extremely valuable industrially.

1. Transparent conductive thin film The transparent conductive thin film of the present invention contains indium oxide as a main component, tungsten element is contained at a W / In atomic ratio of 0.0040 to 0.0230, and zinc element is Zn / In. It has a composition that is contained at a ratio of 0.004 to 0.100 in atomic ratio, and has an amorphous structure.

  Tungsten contributes to improving the conductivity of the transparent conductive thin film and increasing the crystallization temperature. The reason why the range of the atomic ratio with respect to tungsten in the transparent conductive thin film is specified is that the resistance value of the obtained transparent conductive thin film increases when the range is deviated.

  Zinc also contributes to improving the conductivity of the transparent conductive thin film, increasing the crystallization temperature, and lowering the internal stress. The reason for defining the content is that the Zn / In atomic ratio is 0.100. If it exceeds, the transmittance at a short wavelength in the visible range (for example, a wavelength of 400 nm) is reduced. On the other hand, when it is less than 0.004, a film having low resistance and low internal stress cannot be obtained.

  Preferably, the transparent conductive thin film of the present invention contains indium oxide as a main component, tungsten element is contained at a W / In atomic ratio of 0.0040 to 0.0230, and zinc element is Zn / In atomic number. It is contained at a ratio of 0.004 to 0.100 in a ratio, and silver element is further contained at a ratio of 0.001 to 0.010 at an Ag / In atomic ratio, and has an amorphous structure.

  Although silver contributes to the improvement of conductivity, the reason for defining the range of the atomic ratio of silver to indium in the transparent conductive thin film is that the atomic ratio of tungsten and zinc to indium is in the above range, and Ag / When In is less than 0.001, there is no effect of lowering the resistance compared to the case where Ag is not added, and when the Ag / In atomic ratio exceeds 0.010, the short wavelength region in the visible light region (for example, wavelength This is because not only a decrease in transmittance at about 400 nm) is observed, but also the specific resistance increases as compared with the case where no Ag is added.

From the tests by the present inventors, the transparent conductive thin film having any of the above compositions has a completely amorphous structure and not only a smooth surface, but also 9.0 × 10 ⁻⁴ Ωcm or less, depending on conditions. Shows a low resistance of 6.0 × 10 ⁻⁴ Ωcm or less, and further, it was confirmed that their properties do not change even when heating at less than 200 ° C.

  Although the transparent conductive thin film of the present invention has an amorphous structure, the same effect can be obtained even if there are microcrystals of such a size and amount that a crystal phase is not detected by X-ray diffraction, This range is also included in the present invention.

Furthermore, the transparent conductive thin film of the present invention has an arithmetic average height (Ra) of the film surface of 2.0 nm or less depending on conditions, and an absolute value of internal stress of 1 × 10 ¹⁰ dyn / cm ² or less. It was confirmed that this was achieved.

  In order to obtain an amorphous film having low resistance and low internal stress, it is necessary not only to add tungsten and zinc but also to form a film under appropriate film forming conditions. In particular, the substrate temperature is 170 ° C. It is essential to maintain: The sputtering gas pressure is preferably about 0.3 to 1.5 Pa. In order to obtain a transparent conductive thin film having a low internal stress, a relatively high gas pressure side (0.8 to 1) is required under normal film formation conditions. DC magnetron sputtering film formation is desirable at 5 Pa).

The specific resistance is 9.0 × 10 ⁻⁴ Ωcm or less, preferably 6.0 × 10 ⁻⁴ Ωcm or less, and it is necessary to flow a large amount of current, especially for applications used in organic EL devices. It is preferable when used as an electrode of a certain device.

  In addition, the fact that the crystallization temperature of the amorphous film is 200 ° C. or higher means that the amorphous film can be stably manufactured by sputtering film formation in which film formation is performed while the substrate receives heat from the plasma during film formation. Therefore, it is preferable.

  Furthermore, when the arithmetic average height (Ra) of the film surface is 2.0 nm or less, particularly when used as an electrode for an organic EL device, the organic light emitting layer formed thereon is very thin (several hundred nm). Therefore, holes or electrons can be uniformly injected into the organic light emitting layer so that light can be emitted uniformly, which is preferable.

Also, the absolute value of the internal stress is 1 × 10 ¹⁰ dyn / cm ² or less when the electrode is formed on the organic light emitting layer as an electrode (top emission type organic EL) or on the resin film. In the case of forming as, since an electrode can be formed without deforming them, it is preferable for stabilizing the characteristics of the device.

As described above, the transparent conductive thin film of the present invention is composed only of an amorphous phase, is excellent in surface smoothness, and exhibits a low resistance of 9.0 × 10 ⁻⁴ Ω · cm or less, Since the characteristics are not changed even when heating is performed at a temperature of less than 200 ° C., it is extremely advantageous for application to display devices such as LCDs and organic EL elements. A transparent conductive thin film having low internal stress, low resistance, surface smoothness and characteristic stability below 200 ° C. has been achieved for the first time in the present invention.

2. Oxide sintered compact target for manufacturing transparent conductive thin film In one aspect, the oxide sintered compact target of the present invention is composed of indium, tungsten, zinc, and oxygen, and tungsten element has a W / In atomic ratio. The zinc element is contained in a ratio of 0.004 to 0.100 in terms of the Zn / In atom number ratio. Alternatively, in another aspect, the constituent elements are indium, tungsten, zinc, silver, and oxygen, the tungsten element is contained at a W / In atomic ratio of 0.004 to 0.023, and the zinc element is Zn It is contained at a ratio of 0.004 to 0.100 in the ratio of / In atoms, and silver is further contained at a ratio of 0.001 to 0.010 in the ratio of Ag / In atoms.

  Using these targets, it is possible to produce a transparent conductive thin film by sputtering or ion plating.

  In the sputtering method, a target having the above composition is used as a target, the substrate and the target are arranged in a sputtering apparatus, and the substrate is heated at a predetermined temperature in an argon inert gas atmosphere containing oxygen gas. The transparent conductive thin film of the present invention can be produced on a substrate by applying an electric field between the target and generating plasma between the target and the substrate.

  On the other hand, in the ion plating method, a target having the above composition is used as an ion plating tablet that is a raw material, a substrate and the tablet are placed in a copper hearth in an ion plating apparatus, and an argon gas containing oxygen gas is contained. In an active gas atmosphere, the substrate is heated to a predetermined temperature, and using an electron gun, the tablet is evaporated from the copper hearth, and plasma is generated near the substrate to ionize the tablet vapor. A transparent conductive thin film can be produced on a substrate. The term “tablet” is included in the term “target” as a sputtering material, and the use of a target in the composition range of the present invention for a tablet in an ion plating method is within the scope of the present invention. Included.

  Such a method is an example, and the transparent conductive thin film of the present invention is obtained by appropriately selecting the conditions even when the positional relationship between the substrate and the target is changed by the apparatus or the substrate is transported. be able to.

  In addition, each content of a transparent conductive thin film can be changed by changing content of tungsten, zinc, and silver in the said target (a tablet is included). At this time, the structure and crystallinity of the produced transparent conductive thin film depend on film forming conditions such as the composition of the transparent conductive thin film, the substrate heating temperature, the inert gas atmosphere, and the film forming speed.

  Although it is possible to easily produce the transparent conductive thin film of the present invention by sputtering, it is difficult to obtain an amorphous film, so it is necessary to form the film under suitable sputtering conditions.

  In particular, as described above, maintaining the substrate temperature at 170 ° C. or lower is indispensable for obtaining an amorphous film. If the substrate temperature is 170 ° C. or lower, the substrate surface temperature does not exceed the crystallization temperature (200 ° C. or higher) even when heat is applied to the substrate from the plasma during film formation. Is obtained.

  Further, in order to obtain a low-resistance transparent conductive thin film, the distance between the target and the substrate needs to be 50 to 70 mm, for example, and the sputtering gas pressure needs to be about 0.3 to 1.5 Pa. The sputtering gas pressure affects the kinetic energy of sputtered particles that reach the substrate being sputtered. For example, when the distance between the target and the substrate is 50 to 70 mm, when the film forming gas pressure is lower than 0.3 Pa, the kinetic energy of the sputtered particles is too high and is incident on the transparent conductive thin film being deposited. Re-sputtering occurs, resulting in a film with a rough surface. On the other hand, if it is higher than 1.5 Pa, the kinetic energy of the sputtered particles is too low, resulting in a low-density and non-dense film, and a low-resistance transparent conductive thin film cannot be obtained. Accordingly, when the distance between the substrates is 50 to 70 mm, a dense and low resistance transparent conductive thin film is obtained by carrying out sputtering film formation at a sputtering gas pressure of about 0.3 Pa to 1.5 Pa. be able to.

Furthermore, in order to produce a transparent conductive thin film having a low internal stress, it is desirable to perform sputtering film formation on the high-pressure gas region side (for example, 0.8 Pa to 1.5 Pa) in the gas pressure range. The absolute value of the internal stress is lower as the sputtering gas pressure is higher, and in order to obtain a dense low resistance transparent conductive thin film with a low internal stress of 1 × 10 ¹⁰ dyn / cm ² or less, the sputtering gas pressure is reduced. It is preferable to set it as 0.8 Pa-1.5 Pa. Note that as the distance between the target and the substrate becomes wider, the optimum sputtering gas pressure tends to be lower, so the sputtering gas pressure may be adjusted according to the distance.

  Note that it is preferable to use a mixed gas in which oxygen of about 0.5% to 5% is added to argon as the sputtering gas. Addition of oxygen suppresses the decrease in conductivity and transmittance due to the decrease in carrier electron mobility due to excessive introduction of oxygen vacancies into the film, and it is a transparent conductive thin film with low resistance and high permeability. To get.

3. Transparent conductive substrate In the transparent conductive substrate of the present invention, the transparent conductive thin film of the present invention is formed on the surface of the transparent substrate.

  The transparent substrate is a glass plate, a resin plate or a resin film in which one or both surfaces of the glass plate are covered with a gas barrier film, or a resin plate or a resin film in which a gas barrier film is inserted inside the glass plate. .

  Resin plates or resin films have higher gas permeability than glass plates, and light emitting layers of organic EL elements and inorganic EL elements, and liquid crystal layers of LCDs, etc., deteriorate with moisture and oxygen. Or when using a resin film as a board | substrate of these display elements, it is preferable to provide the gas barrier film which suppresses passage of gas.

  The gas barrier film may be formed on one side of the resin plate or the resin film, and if it is formed on both sides, the gas barrier property is good. Further, the gas barrier film can be inserted into the inside by forming the gas barrier film on one surface of the resin plate or the resin film and further laminating the resin plate or the resin film on the gas barrier film. Furthermore, it can also be set as the structure which repeated lamination | stacking several times.

  The resin plate or resin film is made of polyethylene terephthalate (PET), polyethersulfone (PES), polyarylate (PAR), polycarbonate (PC), or a laminated structure in which the surface of these materials is covered with an acrylic organic material. Consists of. The thickness of the resin plate or resin film is appropriately selected according to the following specific application.

  The gas barrier film is preferably at least one selected from a silicon oxide film, a silicon oxynitride (SiON) film, a magnesium aluminate film, a tin oxide film, and a diamond-like carbon (DLC) film. Here, the tin oxide film has a composition containing at least one additive element selected from, for example, Si, Ce, Ge and the like in tin oxide. By these additive elements, the tin oxide layer is made amorphous to form a dense film. In addition, at least one gas barrier film selected from a silicon oxide film, a silicon oxynitride film, a magnesium aluminum oxide film, a tin oxide-based film, and a diamond-like carbon film, and an organic or polymer film may be a resin substrate or The structure which gave the said transparent conductive thin film on the board | substrate of the structure laminated | stacked alternately on the surface of the resin film may be sufficient.

4). Display Device The display device of the present invention uses the transparent conductive thin film as an electrode, and includes, for example, an organic EL element, an inorganic EL element, a liquid crystal, a touch panel, and the like.

(A) Organic electroluminescence device (organic EL device):
The organic EL device of the present invention comprises an organic layer sandwiched between an anode and a cathode, and the organic layer emits light by recombination of holes supplied from the anode and electrons supplied from the cathode. At least one layer including a light emitting layer and forming the anode and / or the cathode is composed of the transparent conductive thin film. The organic layer of the organic EL element has a multi-layered structure with a very thin film thickness. If the surface of the transparent electrode used for the anode and / or the cathode is uneven or has protrusions, A current leak occurs between the electrodes and a non-light emitting portion (dark spot) is generated.

  An example of the organic EL element of the present invention is shown in FIG. The cathode (11) has a two-layer structure of the transparent conductive thin film (8) of the present invention and an electron injection metal layer (7), and a light emitting layer (6), a hole transport layer (5), a positive electrode and the anode. This is a structure in which an organic film (10) composed of a stack of hole injection layers (4) is formed. The light emitting layer (6) in the organic layer can be a low molecular weight material (for example, aluminum complex, anthracene, rare earth complex, iridium complex) or a high molecular weight material (for example, polyphenylene vinylenes, polyfluorenes, polythiophenes). ) May be used. The cathode electron injection metal layer (7) is made of a material having a low work function (3.8 eV or less) and is thin enough to transmit light (0.5 to 20 nm). It is. In addition, if the transparent conductive thin film of this invention is used for an anode (2), the organic EL element which can be light-emitted not only on the cathode (11) side but on the anode (2) side is realizable. As the substrate (1), not only a glass substrate but also a resin substrate or resin film provided with a gas barrier film, or a resin substrate or resin film having a gas barrier film inserted therein can be used.

  Since the transparent conductive thin film of the present invention having low resistance, low internal stress, excellent surface smoothness, and excellent thermal stability is used for the cathode and / or anode, no current leakage occurs, so dark Spot generation can be suppressed. In addition, since the transparent conductive thin film of the present invention has low internal stress, adhesion between the transparent electrode and the organic layer is improved without distorting the organic layer even when formed on the organic layer. An organic EL element with high quality and long life can be realized. In addition, since the transparent conductive thin film of the present invention has a low resistance, it is possible to eliminate a voltage drop for light emission and non-uniformity of light emission resulting therefrom, and to realize a high-quality organic EL element.

(B) Inorganic electroluminescence element (inorganic EL element):
An inorganic EL element can be manufactured using the transparent conductive thin film of the present invention.

  As an example, FIG. 2 shows a basic element structure of an AC thin film inorganic EL element having a double insulating layer structure. A transparent electrode (13), a first insulating layer (14), a light emitting layer (15), a second insulating layer (16), and a back electrode (17) are sequentially formed on a transparent substrate (12) such as glass or a resin substrate. Are laminated.

  The thickness of the light emitting layer (15) is about 0.5 μm to 1 μm, and the thickness of the first insulating layer (14) and the second insulating layer (16) is about 0.3 μm to 0.5 μm, respectively. The total film thickness is about 2 μm.

  When an AC voltage of about 200 V is applied between the transparent electrode (13) and the back electrode (17), EL light emission is obtained.

  By sandwiching the light emitting layer (15) between the first insulating layer (14) and the second insulating layer (16), the dielectric breakdown of the element is prevented, and a high voltage of 108 V / m or more is stably applied to the light emitting layer (15). Can be applied.

The light emitting layer (15) is obtained by adding Mn (orange yellow), TbF ₃ (green), SmF ₃ (red orange) or the like as a light emission center to a base material of zinc sulfide (ZnS).

  By using the transparent conductive thin film of the present invention having low resistance, excellent surface smoothness and excellent thermal stability as a transparent electrode, a voltage can be uniformly applied to the light emitting layer (15), and the light emission intensity is high. An inorganic EL element can be realized.

(C) Liquid crystal (LCD):
A liquid crystal element can be manufactured using the transparent conductive thin film of the present invention. As an example, a color LCD used in a personal computer or television will be described.

  A cross-sectional view of a color filter type LCD is shown in FIG. A liquid crystal cell having an optical shutter function and an RGB color filter are combined, and multi-color or full-color display is realized by additive color mixing of light from a color light source (backlight).

  A black matrix (27) is formed between the RGB pixels to improve contrast and color purity.

  The transparent electrode (18) on the upper part of the color filter (20) is formed as a stripe electrode in the simple matrix drive and as a whole surface integral electrode in the TFT (thin-film transistor) drive (active matrix drive).

  The backlight not only contributes to the improvement of the brightness of the color LCD but also can improve the color purity in combination with the color filter (20).

  The transparent conductive thin film of the present invention can be used not only as a transparent electrode (25) on a transparent substrate (18) (glass, resin substrate) but also as a transparent electrode (18) on a color filter (20). . In particular, when a transparent electrode (18) is formed on a soft organic layer having low heat resistance such as a color filter (20) by sputtering, a transparent conductive thin film having low internal stress and low resistance. However, the transparent conductive thin film of the present invention is easy to realize, and a high-quality LCD can be manufactured.

(D) Touch panel:
A touch panel can be manufactured using the transparent conductive thin film of the present invention. The structure of a resistive film type touch panel is shown in FIG.

  A transparent electrode (30) is formed on each of the opposing surfaces of the upper resin film (28) and the lower glass (29) (which may be a resin plate or a resin film). 31) through a certain distance. When the upper resin film (28) is pushed down with a finger or a pen, both the transparent electrodes (30) are in contact with each other and energized.

  The transparent conductive thin film of the present invention can be effectively used as both transparent electrodes (30). In particular, when the transparent electrode (30) is formed on the upper resin film (28), it is necessary to form the film at a low temperature in consideration of the low heat resistance of the film. Moreover, since an upper resin film (28) will deform | transform if an internal stress is high, it is necessary to form the transparent conductive thin film of a low internal stress.

  As such a transparent conductive thin film, the transparent conductive thin film of the present invention can be used effectively. Since the transparent conductive thin film of the present invention has a low resistance, it can be used by thinning it, so that it can have a high light transmittance and excellent visibility.

As described above, according to the present invention, the surface smoothness is excellent, the specific resistance is 9.0 × 10 ⁻⁴ Ω · cm or less, and depending on the manufacturing conditions, 6.0 × 10 ⁻⁴ Ω · cm. A low amorphous film can be obtained with a low internal stress (the absolute value of the internal stress is 1 × 10 ¹⁰ dyn / cm ² or less).

  The obtained transparent conductive thin film is a transparent conductive thin film with low internal stress. Therefore, the substrate itself is easily deformed, such as a film, or the outermost surface of a structure in which a multilayer structure is easily deformed. In addition, it is possible to deposit without deforming the substrate or the structure. In particular, since a transparent conductive thin film can be formed as a cathode on a soft organic light emitting layer, it is possible to realize a top emission type organic EL device capable of efficiently extracting light from a cathode as a top electrode. It is particularly useful. The top emission type organic EL element can be used as a cathode of an organic EL element having a high aperture ratio formed on a glass substrate on which a TFT is formed.

  Moreover, since the transparent conductive thin film of the present invention can form a transparent electrode with low resistance and excellent surface smoothness on a low-temperature substrate, the substrate is deformed on a soft resin film substrate having no heat resistance. Without forming, it can be formed as a transparent electrode having a low temperature and a low resistance. Therefore, the transparent conductive thin film of the present invention can be used as a cathode and / or an anode of a flexible transparent organic EL device using a resin film substrate.

  The transparent conductive thin film of the present invention has a crystallization temperature of 200 ° C. or higher, and has characteristics that the properties of amorphousness, surface smoothness, and specific resistance are not deteriorated even when heated below 200 ° C. Therefore, it is easy to stably produce an amorphous film even by a sputtering method in which the substrate is easily subjected to heat from plasma. Moreover, even if the manufacturing process after film | membrane formation includes the heating process below 200 degreeC, it has the characteristics that the characteristic is stable.

  Since the transparent conductive thin film of the present invention can be used not only as an organic EL element but also as an inorganic EL element, a transparent electrode for LCD and electronic paper, it can be said to be extremely valuable industrially. In addition, the organic EL device using the transparent conductive thin film of the present invention has high emission intensity and hardly generates dark spots, so that it is possible to produce a high-quality display and is extremely valuable industrially.

(Examples 1 to 11)
Each predetermined amount of In ₂ O ₃ powder, WO ₃ powder and ZnO powder was weighed, mixed and molded so as to have the composition shown in Table 1. The obtained compact was heated and sintered, and W / In atomic ratio was 0.004 to 0.023, Zn / In atomic ratio was 0.004 to 0.100, and tungsten and zinc were mixed. The contained indium oxide sintered body was produced. The obtained sintered body was processed to 6 inches (Φ) × 5 mm (thickness), and bonded to a backing plate made of oxygen-free copper using an In-based alloy to obtain a sputtering target.

  The sputtering target is applied to a ferromagnetic target cathode of a DC magnetron sputtering apparatus (SPF503K, manufactured by Tokki Co., Ltd.) (maximum horizontal magnetic field strength at a position 1 cm away from the target surface is about 80 kA / m (1 kG)). A quartz glass substrate having a thickness of 1.1 mm was attached to the opposite surface of the sputtering target. The average light transmittance in the visible light wavelength region of the quartz glass substrate itself is 92%.

The distance between the sputtering target and the substrate was 130 mm. When the degree of vacuum in the chamber reaches 5 × 10 ⁻⁵ Pa or less, Ar gas having a purity of 99.9999% by mass is introduced into the chamber to a gas pressure of 0.3 to 1.5 Pa, and oxygen is supplied. Only 0.5 to 5% was introduced into the film forming gas. A direct current power of 300 W was applied between the target and the substrate to generate direct current plasma, and sputtering was carried out while the substrate was stationary immediately above the center of the target. As a result, a transparent conductive thin film having a thickness of 150 nm was formed on the substrate. The film thickness was determined by measuring the level difference between the part without the film and the part with the film with a contact-type surface shape measuring device (Dektak ³ ST). Note that the substrate was not heated during sputtering.

  The composition of the obtained transparent conductive thin film is quantitatively analyzed by ICP emission spectroscopic analysis (manufactured by Seiko Instruments Inc., SPS4000), and the presence or absence of crystallinity in the film is determined by an X-ray diffractometer (Mac Science Co., Ltd.) using CuKα rays. Made by M18XHF22), transmission electron microscope (manufactured by Hitachi, Ltd., HF-2200), and electron diffraction. Further, the specific resistance of each transparent conductive thin film was measured by a four-probe method using a resistivity meter Loresta EP (Dia Instruments MCP-T360 type). Furthermore, the light transmittance including the substrate was measured with a spectrophotometer (manufactured by Hitachi, Ltd., U-4000). The surface roughness of the film was measured with an atomic force microscope (manufactured by Digital Instruments, NS-III, D5000 system). For internal stress, a change in the warpage of the substrate (film thickness 150 to 400 nm) produced on a 100 μm thick quartz substrate and Si substrate under the same film formation conditions was measured using a thin film physical property evaluation apparatus (manufactured by NEC Saneisha, MH4000) and evaluated.

About each, film-forming was implemented, changing sputtering gas pressure and the amount of oxygen in sputtering gas. The specific resistance and internal stress of the film greatly depend on the sputtering gas pressure at the time of film production and the amount of oxygen in the sputtering gas, and particularly when the film is formed at a sputtering gas pressure of 0.8 Pa or higher, a film with low internal stress can be obtained. It was. Among them, the absolute value of the internal stress was 1 × 10 ¹⁰ dyn / cm ² or less, and the characteristics of the film having the lowest resistance were examined. The results are shown in Table 1.

The obtained transparent conductive thin film was annealed in nitrogen at 190 ° C. for 1 hour, and the change in characteristics after annealing was also examined by the same method. Table 1 shows the results of specific resistance and crystallinity after annealing.

As is apparent from Table 1, it was prepared by a sputtering method, containing indium oxide as a main component, containing tungsten at a ratio of 0.0040 to 0.0230 in terms of W / In atomic ratio, and further containing zinc as Zn / The transparent conductive thin film of the present invention having a composition contained at a ratio of 0.004 to 0.100 in terms of the number of In atoms, the structure judged from the XRD measurement does not include a crystal phase, and is composed only of an amorphous phase. Although the absolute value of the internal stress is 1 × 10 ¹⁰ dyn / cm ² or less, the specific resistance is 9.0 × 10 ⁻⁴ Ω · cm or less, and in many cases, 6.0 × 10 ⁻⁴ Ω · cm. The resistance was as low as cm or less.

  In top emission type organic EL devices (types that emit light on the opposite side of the substrate), it is necessary to form a transparent electrode on the organic light emitting layer, and it is transparent so that deformation due to stress does not occur in the thin organic light emitting layer. The electrode needs to have a low internal stress. Since the transparent conductive thin films of Examples 1 to 11 of the present invention have low internal stress, they are formed on the organic light emitting layer of the top emission type organic EL device and are useful as a transparent electrode having low internal stress and low resistance. It can be said. Moreover, in the case of the transparent conductive thin film formed on the resin film substrate, when the film thickness is increased, the resin film substrate is curved when the internal stress is large, but the transparent conductive thin film of Examples 1 to 11 of the present invention. Since the internal stress is small, the allowable amount of film thickness to be formed is large.

  Arithmetic mean height (Ra) measurement of a 1 μm × 1 μm region was measured with an atomic force microscope at 10 arbitrary points, and the average value was calculated. It was 2.0 nm. Moreover, the average visible light transmittance | permeability including a board | substrate was 85 to 90%, and the transmittance | permeability was also favorable. In particular, at a wavelength of 400 nm, the transmittance of the transparent conductive thin film including the substrate was 80 to 85%, which was higher than that of the conventional material described later.

  The transparent conductive thin films of Examples 1 to 11 did not crystallize even after annealing at 190 ° C. for 10 minutes in the atmosphere, and the specific resistance decreased. X-ray diffraction measurement was performed while raising the temperature of the film at a constant rate of 5 ° C./min, and the temperature at which the transparent conductive thin film crystallized was measured by high-temperature X-ray diffraction measurement. All transparent conductive thin films have a crystallization temperature of 200 ° C. or higher, and are materials that can stably obtain an amorphous film by a sputtering method. In addition, it was found that the characteristics were stable even when a heating step of less than 200 ° C. was included in the manufacturing process after film formation.

Table 1 shows only the characteristics of the low internal stress transparent conductive thin film whose absolute value of internal stress is 1 × 10 ¹⁰ dyn / cm ² or less. For example, the sputtering gas pressure is 0.3 to 0.00. Like 6 Pa, depending on the manufacturing conditions of the transparent conductive thin film, a film having an internal stress with a high absolute value is obtained. Like in Examples 1 to 11, the resistance is low, the transmittance is high, and the surface is smooth. An amorphous film is obtained.

  Moreover, these characteristics are stable even when heated to less than 200 ° C. in nitrogen. When manufacturing a transparent conductive thin film on a substrate that is not easily deformed by the internal stress of the formed transparent conductive thin film, such as glass, even if the internal stress is high, there is no problem. A thin film is also useful.

(Examples 12 to 18)
Next, an indium oxide thin film containing tungsten, zinc and silver was produced by the following procedure. Each predetermined amount of In ₂ O ₃ powder, WO ₃ powder, ZnO powder, and Ag powder was weighed, mixed, and molded so that the indium oxide thin film after preparation had the composition shown in Table 2. The obtained molded body was heated and sintered to produce an indium oxide sintered body containing tungsten, zinc and silver. The obtained sintered body was processed to 6 inches (Φ) × 5 mm (thickness), and bonded to a backing plate made of oxygen-free copper using an In-based alloy to obtain a sputtering target.

  A transparent conductive thin film was produced under the same film formation conditions as in Examples 1 to 11, and the evaluation was performed in the same manner as in Examples 1 to 11.

The specific resistance and internal stress of the transparent conductive thin film largely depended on the sputtering gas pressure at the time of production and the amount of oxygen in the sputtering gas. For each composition, the film was formed by changing the sputtering gas pressure and the amount of oxygen in the sputtering gas, and the absolute value of the internal stress was 1 × 10 ¹⁰ dyn / cm ² or less. The characteristics of the transparent conductive thin film having the lowest resistance were investigated.

  In Examples 12 to 14, Ag was added to Example 4 in an amount specified in the present invention, and in Examples 15 to 18, Ag was added to Example 5 in an amount specified in the present invention. Is.

As shown in Table 2, when Ag contained only 0.001 to 0.010 in terms of the Ag / In atomic ratio, the specific resistance decreased as compared with Examples 4 and 5 that did not contain Ag. This tendency is the same for the films of Examples 1 to 3 and Examples 6 to 11, and when Ag contains 0.001 to 0.010 in Ag / In atomic ratio, the specific resistance decreases, An amorphous film having a smooth surface of 3.5 × 10 ⁻⁴ Ωcm to 8.5 × 10 ⁻⁴ Ωcm was obtained.

  Indium oxide is the main component, tungsten element is contained in a W / In atomic ratio of 0.0040 to 0.0230, and zinc element is Zn / In atomic ratio in 0.004 to 0.100. In addition, the transparent conductive thin film of the present invention having a composition in which silver element is contained at a ratio of 0.001 to 0.010 in terms of Ag / In atomic ratio, the structure judged from the XRD measurement has a crystalline phase. It was comprised only by the amorphous phase.

Moreover, since the absolute value of internal stress is as low as 1 × 10 ¹⁰ dyn / cm ² or less and a low resistance film can be realized, the top emission type is used for the same reason as the transparent conductive thin films of Examples 1 to 11. It can be said that it is useful as a transparent electrode formed on the organic light emitting layer of the organic EL element or a transparent conductive thin film formed on the resin film substrate.

  When arithmetic mean height (Ra) measurement was performed in an area of 1 μm × 1 μm, and an arbitrary value was calculated by measuring 10 arbitrary points with an atomic force microscope, Examples 12 to 18 were all 0.4 to 1. It was 8 nm.

  Moreover, the average visible light transmittance | permeability including a board | substrate was 85 to 90%, and the transmittance | permeability was also favorable. In particular, at a wavelength of 400 nm, the transmittance of the transparent conductive thin film including the substrate was 80 to 85%, which was higher than that of the conventional material described later.

  Although not shown in Table 2, when the Ag / In atomic ratio exceeded 0.010, the specific resistance increased as compared with the case where Ag was not added, and the transmittance at a wavelength of 400 nm decreased.

  The transparent conductive thin films of Examples 12 to 18 did not crystallize even when annealed at 190 ° C. for 10 minutes in nitrogen, and the specific resistance decreased. X-ray diffraction measurement was performed while raising the temperature of the film at a constant rate of 5 ° C./min, and the temperature at which the transparent conductive thin film crystallized was measured by high-temperature X-ray diffraction measurement. All transparent conductive thin films have a crystallization temperature of 200 ° C. or higher, and are materials that can stably obtain an amorphous film by a sputtering method. In addition, it was found that characteristics such as specific resistance, crystallinity, and surface smoothness are stable even when a heating process of less than 200 ° C. is included in the manufacturing process after film formation.

In Table 2, only the characteristics of the transparent conductive thin film having a low internal stress whose absolute value of the internal stress is 1 × 10 ¹⁰ dyn / cm ² or less among the obtained films are shown. In particular, in a low gas pressure region of 0.3 Pa to 0.6 Pa, a transparent conductive thin film having a high internal stress is obtained. Like in Examples 12 to 18, the surface has a low resistance and a high transmittance. A smooth amorphous film is obtained. In these, these characteristics are stable even when heated to less than 200 ° C. in nitrogen, and on a substrate that is not easily deformed by internal stress of the formed transparent conductive thin film, such as glass, In the production of a conductive thin film, such a transparent conductive thin film can be said to be useful because a high internal stress does not cause a problem.

(Comparative Examples 1-14)
As a comparative example, in the transparent conductive thin film after fabrication, each predetermined amount of In is used so that the content of tungsten and zinc deviates from the ratio range of the W / In atomic ratio and the Zn / In atomic ratio according to the present invention. _A transparent conductive thin film was produced under the same conditions as in Example 1 except that ₂ O ₃ powder, WO ₃ powder and / or ZnO powder were weighed. The obtained transparent conductive thin film was evaluated in the same manner as in Example 1.

The specific resistance and internal stress of the transparent conductive thin film largely depended on the sputtering gas pressure at the time of production and the amount of oxygen in the sputtering gas. For each, film formation was carried out by changing the sputtering gas pressure and the oxygen amount in the sputtering gas. Among them, the absolute value of the internal stress was 1 × 10 ¹⁰ dyn / cm ² or less, which was the lowest resistance. The characteristics of the membrane were investigated. The results are shown in Table 3.

Comparative Examples 1 to 3 are indium oxide films containing no tungsten and containing tungsten. In the case of a transparent conductive film which is amorphous and has a low resistance of 9.0 × 10 ⁻⁴ Ωcm or less and a transmittance of 80% or more including the substrate at a wavelength of 400 nm, the absolute value is 1 × 10 ¹⁰ dyn / cm Only high internal stress exceeding ² was obtained. Depending on the sputtering conditions, a film having an absolute value of internal stress of 1 × 10 ¹⁰ dyn / cm ² or less was obtained, but the specific resistance of the film was an amorphous film of 12 × 10 ⁻⁴ Ωcm to The value was as high as 15 × 10 ⁻⁴ Ωcm. That is, a transparent conductive film having a low resistance of 9 × 10 ⁻⁴ Ωcm or less and a low internal stress of 1 × 10 ¹⁰ dyn / cm ² or less could not be obtained.

  Comparative Examples 4 to 8 are indium oxide films containing no zinc and containing zinc. In Comparative Example 4 in which the Zn / In atomic ratio is 0.003, even when the film is formed without heating the substrate, the film contains a fine crystal phase, and the arithmetic average height of the film surface measured in the same manner. The thickness (Ra) was 4.2 nm, and the unevenness was severe. Further, it was completely crystallized by annealing at 200 ° C.

  Further, Comparative Example 5 having a Zn / In atomic ratio of 0.051 and Comparative Example 6 having a Zn / In atomic ratio of 0.098 have a high crystallization temperature and provide a stable amorphous film. However, it was crystallized by heating at 200 ° C. in nitrogen. In Comparative Example 7 where the Zn / In atomic ratio is 0.130 and Comparative Example 8 where the Zn / In atomic ratio is 0.198, the crystallization temperature is high, and a stable amorphous film can be obtained. Even when heated at 190 ° C. in nitrogen, the amorphousness was maintained.

  The films of Comparative Examples 1 to 6 had an average visible light transmittance of 85 to 90% and a transmittance at a wavelength of 400 nm of 80 to 85%. However, the films of Comparative Examples 7 and 8 in which stable amorphousness was obtained have a transmittance at a wavelength of 400 nm of 70% or less including the substrate. Compared with Examples 1 to 18 of the present invention, It had the disadvantage of being extremely low.

The film of Comparative Example 9 is an indium oxide thin film containing tungsten and zinc, and the W / In atomic ratio and the Zn / In atomic ratio in the film are both smaller than the range defined in the present invention. A low internal stress of 9 × 10 ⁹ dyn / cm ² was obtained. However, before annealing, it was crystalline, the arithmetic average height Ra was 2.5 nm, the surface unevenness was large, and the specific resistance was significantly higher than that of the film of the present invention. Although not described as a comparative example, the absolute value of the internal stress exceeds 1 × 10 ¹⁰ dyn / cm ² and the film having the same composition is crystalline before annealing, and the arithmetic average height Ra is 2.5 nm. Thus, the surface irregularities are large and the specific resistance is significantly higher than that of the film of the present invention, and an amorphous film having a low resistance and excellent surface smoothness as in the present invention was not obtained. Therefore, the film like Comparative Example 9 cannot be used as an electrode of a display device such as a high quality organic EL device.

The films of Comparative Examples 10 and 11 are indium oxide thin films containing tungsten and zinc, and the W / In atomic ratio in the film is within the range defined in the present invention, but the Zn / In atomic ratio is More than the range specified in the present invention, it was amorphous before annealing, and this amorphousness was maintained by annealing, and the crystallization temperature was 200 ° C. or higher. However, in Comparative Example 11 in which the absolute value of the internal stress is 1 × 10 ¹⁰ dyn / cm ² or less, the specific resistance value exceeds 9.0 × 10 ⁻⁴ Ωcm, which is higher than that of the example of the present invention. At 400 nm, the transmittance including the substrate was 80% or less, which was lower than that of the film of the present invention. Although not shown in Table 3, the same tendency is observed for films having the same composition in which the absolute value of internal stress exceeds 1 × 10 ¹⁰ dyn / cm ² , which is produced under other production conditions, and is 9.0 × 10 ⁻ A film having a low resistance of ⁴ Ωcm or less and a high permeability at a wavelength of 400 nm was not obtained. Such a film cannot be used as an electrode of a display device such as a high-quality organic EL device.

  The films of Comparative Examples 12 and 13 are indium oxide thin films containing tungsten, zinc, and silver, and the Zn / In atomic ratio and W / In atomic ratio in the film are within the range defined in the present invention. However, the Ag / In atomic ratio is larger than the range defined in the present invention. It was amorphous before annealing, and this amorphousness was maintained by annealing. However, the transmittance including the substrate at a wavelength of 400 nm was 80% or less, which was lower than that of the film of the present invention. Such a film cannot be used as an electrode of a display device such as a high-quality organic EL device. Further, from the comparison between Example 4 and Comparative Example 12 and the comparison between Example 5 and Comparative Example 13, no improvement in specific resistance was found by adding Ag.

The film of Comparative Example 14 is an indium oxide thin film containing tungsten, zinc, and silver. The Zn / In atomic ratio, W / In atomic ratio, and Ag / In atomic ratio in the film are all the present invention. More than the range specified in. Before annealing, it was amorphous, and this amorphousness was maintained by annealing. The specific resistance before annealing was 9.8 × 10 ⁻⁴ Ωcm, which was higher than that of the film of the present invention. Further, the transmittance including the substrate at a wavelength of 400 nm was 65%, which was lower than that of the film of the present invention (80% or more). Although not shown in Table 3, the same tendency is observed for films having the same composition and having an absolute value of internal stress exceeding 1 × 10 ¹⁰ dyn / cm ² , which is produced under other production conditions. A film having a low resistance of ⁻⁴ Ωcm or less and a high permeability at a wavelength of 400 nm was not obtained. Such a film cannot be used as an electrode of a display device such as a high-quality organic EL device.

(Comparative Examples 15 and 16)
Conventionally, the transparent conductivity of non-doped indium oxide using the indium oxide sintered body target that is often used and containing no impurities and the indium oxide (ITO) sintered body target containing tin under the same conditions as in the examples. A thin film (Comparative Example 15) and an ITO transparent conductive thin film (Comparative Example 16) were produced under the same conditions as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Table 4. In addition, when the transparent conductive thin film of the comparative example 16 analyzed the composition by ICP, Sn / In atomic ratio was 0.075.

  As shown in Table 4, Comparative Example 9 has a high specific resistance and cannot be used as a transparent electrode of an organic EL element that allows a large amount of current to flow. Each of the transparent conductive thin films obtained in Comparative Example 9 and Comparative Example 10 includes a mixture of an amorphous film and a crystalline film, even if sputtering film formation is performed without heating the substrate, The specific resistance was high. In Comparative Example 10, it was confirmed that an amorphous phase and a crystalline phase were mixed by a transmission electron microscope and electron diffraction. The arithmetic average height (Ra) of the film surfaces of Comparative Example 9 and Comparative Example 10 was measured in the same manner as in Example 1. As a result, it was 5 to 6 nm, which was very large compared with Examples 1 to 18. The transparent conductive thin films obtained in Comparative Example 9 and Comparative Example 10 were annealed in nitrogen at 200 ° C. for 1 hour to form a complete crystalline film, resulting in severe surface irregularities and organic EL. It cannot be used as a transparent electrode of an element.

  Moreover, the internal stress of the comparative example 9 and the comparative example 10 is high compared with Examples 1-18 of this invention. This is presumably because it contains a crystalline phase. Therefore, it cannot be used as a transparent electrode formed on the organic light emitting layer of the top emission type organic EL element or a transparent conductive thin film formed on the resin film substrate.

Example 19
A silicon oxynitride film having a thickness of 57 nm is applied as a gas barrier film on a PES film having a thickness of 200 μm by a high-frequency magnetron sputtering method, and films having the same 18 kinds of compositions as in Examples 1 to 18 are formed thereon. It was formed under the same production conditions as 1-18.

All of the obtained transparent conductive thin films were amorphous, the arithmetic average height (Ra) measured by the same method was 0.6 to 2.0 nm, and the specific resistance was 4.5 to 5. 9 × 10 ⁻⁴ Ωcm, and the visible light average transmittance was 85% or more. Further, when the film thickness was increased under the same conditions, no film warpage was observed until the film thickness reached 400 nm. This shows that the internal stress of the transparent conductive thin film of the present invention is small.

(Example 20)
A transparent conductive thin film was obtained in the same manner as in Example 19 except that a silicon oxide film, a silicon-doped tin oxide film, or a diamond-like carbon film was formed as a gas barrier film by a high-frequency magnetron sputtering method.

All of the obtained transparent conductive thin films were amorphous, the arithmetic average height (Ra) measured by the same method was 0.6 to 2.0 nm, and the specific resistance was 4.5 to 5. It was 9 × 10 ⁻⁴ Ωcm. Further, when the film thickness was increased under the same conditions, no film warpage was observed until the film thickness reached 400 nm. This shows that the internal stress of the transparent conductive thin film of the present invention is small.

  In addition, instead of the PES film, a PC film having a thickness of 100 μm, a PET film having a thickness of 100 μm, 125 μm, 188 μm, and a cycloolefin film having a thickness of 100 μm can be used. When a conductive thin film was formed, no film warping was observed up to a film thickness of 400 nm.

(Comparative Example 17)
A silicon oxynitride film having a thickness of 57 nm is applied as a gas barrier film on a PES film having a thickness of 200 μm by a high-frequency magnetron sputtering method, and a film having the same six types of compositions as Comparative Examples 1 to 4, 15 and 16 is formed thereon. Were formed under the same manufacturing conditions.

  When the film thickness was increased, the film thickness was 250 nm, the film warped, and could not be used as a transparent conductive film substrate. From this, it turns out that the internal stress of the transparent conductive thin film of Comparative Examples 1-4, 15, 16 is large.

(Production of organic EL element)
Examples of the organic EL device of the present invention are shown below.

(Example 21)
An organic EL element in which the organic layer having the structure shown in FIG. An organic EL element in which chromium having a work function of 4.5 eV is used as an anode made of metal will be described below.

  A glass substrate is used as the substrate (1), and chromium (Cr) is formed thereon by DC sputtering with a film thickness of 200 nm. A 6-inch (Φ) chromium target was used, argon (Ar) was used as the sputtering gas, the pressure was 0.4 Pa, and the DC output was 300 W. Furthermore, it was patterned into a predetermined shape using a normal lithography technique. Thereby, an anode (2) having a predetermined shape was obtained.

Next, a silicon dioxide (SiO ₂ ) film was formed as an insulating layer (3) on the substrate (1) on which chromium was processed into a predetermined pattern. Si0 ₂ film by reactive sputtering with oxygen using a Si target, and formed with a film thickness of 200 nm, using the usual lithography, an opening on the chromium. For etching the SiO ₂ film, a mixed solution of hydrofluoric acid and ammonium fluoride can be used. Also, processing by dry etching is possible. The opening becomes a light emitting portion of the organic EL element.

  Subsequently, the glass substrate (1) on which the anode (2) and the insulating layer (3) are formed is put into a vacuum deposition apparatus, and the electron injection metal layer (7) of the organic layer (10) and the cathode (11). Was formed by vapor deposition.

Here, the organic layer (10) is 4,4 ′, 4 ″ -tris (3-methylphenylphenylamino) triphenylamine (MTDATA) as the hole injection layer (4), and the hole transport layer (5). Bis (N-naphthyl) -N-phenylbenzidine (α-NPD) and 8-quinolinol aluminum complex (Alq ₃ ) were used as the light emitting layer (6).

An alloy of magnesium and silver (Mg: Ag) was used for the electron injection metal layer (7) of the cathode (11). 0.2 g of each material belonging to the organic layer (10) was filled in a resistance heating boat and attached to a predetermined electrode of a vacuum evaporation apparatus. Each material belonging to the electron injecting metal layer (7) was filled with 0.1 g of magnesium and 0.4 g of silver in a boat and attached to a predetermined electrode of a vacuum deposition apparatus. Thereafter, the vacuum chamber was evacuated to 1.0 × 10 ⁻⁴ Pa, and then a voltage was applied to each boat, which was sequentially heated and evaporated. For the vapor deposition, an organic layer (10) and an electron injection metal layer (7) made of Mg: Ag were vapor-deposited only at predetermined portions by using a metal mask. The predetermined portion is a portion where chromium is exposed on the substrate. However, it is difficult to deposit with high precision only on the exposed part of chromium, so that it covers the entire exposed part of chromium, in other words, covers the edge of the insulating layer. A mask was designed. First, 30 nm of MTDATA was deposited as the hole injection layer (4), 20 nm of α-NPD was deposited as the hole transport layer (5), and 50 nm of Alq was deposited as the light emitting layer (6). Further, by co-evaporating magnesium and silver, Mg: Ag was formed on the organic layer (10) as the electron injection metal layer (7) of the cathode (11). Magnesium and silver had a film formation rate ratio of 9: 1 and a Mg: Ag film thickness of 10 nm.

Furthermore, it moved to another vacuum chamber, and the transparent conductive thin film layer (8) was formed into a film using DC sputtering through the same mask. Here, an In—W—Zn—O-based transparent conductive thin film having the same composition as that of Example 4 was formed. The film formation conditions were as follows: as a sputtering gas, a mixed gas of argon and oxygen (volume ratio Ar: O ₂ = 99: 1), a pressure of 0.8 Pa, a DC output of 300 W, and a film thickness of 150 nm. As described above, the obtained transparent conductive thin film exhibited good conductivity and transmission characteristics despite the room temperature film formation.

Finally, SiO ₂ was sputtered to a thickness of 200 nm so as to cover the surface of the transparent conductive layer to form a protective film (9) to obtain an organic EL element. The configuration is such that each of two balanced stripe cathodes and eight balanced stripe anodes are alternately alternated so that a single element (pixel) of 2 mm × 2 mm has an interval of 2 mm. An organic EL element having a configuration of 16 pixels was obtained.

The obtained organic EL device was applied with a DC voltage in a nitrogen atmosphere and continuously driven at a constant current density of 10 mA / cm ^2. The initial average light emission luminance of 160 pixels (for 10 devices), the number of current leaks between the electrodes, The light emission half-life and the presence or absence of dark spots after 400 hours from the start of light emission were measured. The results are shown in Table 5.

(Example 22)
Except that the In—W—Zn—O-based transparent conductive thin film obtained in Example 5 was formed on the transparent conductive thin film layer (8) of the cathode (11), the production method was the same as in Example 21. A 16-pixel organic EL device was manufactured. Furthermore, Table 5 shows the results measured in the same manner as in Example 21.

(Example 23)
Except that the In—W—Zn—O-based transparent conductive thin film obtained in Example 8 was formed on the transparent conductive thin film layer (8) of the cathode (11), the production method was the same as in Example 21. A 16-pixel organic EL device was manufactured. Furthermore, Table 5 shows the results measured in the same manner as in Example 21.

(Example 24)
The same production method as in Example 21, except that the In—W—Zn—Ag—O-based transparent conductive thin film obtained in Example 13 was formed on the transparent conductive thin film layer (8) of the cathode (11). Thus, an organic EL element having 16 pixels was manufactured. Furthermore, Table 5 shows the results measured in the same manner as in Example 21.

(Comparative Example 18)
Except that the In—W—O-based transparent conductive thin film obtained in Comparative Example 2 was formed on the transparent conductive thin film layer (8) of the cathode (11), the production method was the same as that in Example 21, and 16 pixels The organic EL element was manufactured. Furthermore, Table 5 shows the results measured in the same manner as in Example 21.

(Comparative Example 19)
Except that the In—Zn—O-based transparent conductive thin film obtained in Comparative Example 8 was formed on the transparent conductive thin film layer (8) of the cathode (11), the production method was the same as that in Example 21 with 16 pixels. The organic EL element was manufactured.
Table 5 shows the results of measurement in the same manner as in Example 21 except that the presence or absence of dark spots was measured after 200 hours from the start of light emission.

(Comparative Example 20)
Except that the In—Sn—O-based transparent conductive thin film obtained in Comparative Example 16 was formed on the transparent conductive thin film layer (8) of the cathode (11), the production method was the same as that in Example 21 with 16 pixels. The organic EL element was manufactured. Furthermore, Table 5 shows the results measured in the same manner as in Example 21.

"Evaluation"
As shown in Table 5, the organic EL elements of Examples 21 to 24 using the transparent conductive thin film of the present invention as the cathode are more initial than the organic EL elements of Comparative Examples 18 to 20 using conventional materials. The average light emission luminance was high, and light emission of 400 cd / m ² or more was confirmed. Also, the luminance half time was clearly long, and the luminance half time was 800 hours.

  The occurrence of dark spots (non-light emitting points) after 400 hours from the start of light emission also occurred in large numbers in the organic EL elements of Comparative Examples 18 to 20 using conventional materials, but the transparent conductive thin film of the present invention was used. None of the organic EL devices of Examples 21 to 24 used for the cathode. In addition, in the organic EL device of Comparative Example 19, no dark spots (non-light emitting points) were observed after 200 hours from the start of light emission, and the luminance half-life was also the organic EL of Examples 21 to 24 of the present invention. Although it was long like the element, the initial light emission luminance was lower than that of the organic EL elements of Examples 21 to 24 of the present invention. This is because the transmittance on the short wavelength side in the visible region of the transparent conductive thin film (In—Zn—O, Zn / In = 0.198) of Comparative Example 8 was inferior.

  Further, when the organic EL elements of Examples 21 to 24 and Comparative Examples 18 to 20 were placed in an atmosphere of 95% humidity and 80 ° C. for 100 hours and then subjected to the same light emission test, Comparative Example 18 In the organic EL elements of ˜20, many dark spots were observed at the initial light emission, but in the organic EL elements of Examples 21 to 24, the dark spots were observed even after 400 hours from the start of light emission. There wasn't. This shows that the heat resistance of the transparent conductive thin film of this invention is excellent.

(Example 25)
An organic EL element was fabricated and measured in the same manner as in Examples 21 to 24 using tungsten, zinc, tantalum or niobium instead of chromium used for the anode, and the same tendency was observed.

(Example 26)
Instead of the metal used for the anode, the In—W—Zn—O amorphous thin films of Examples 1 to 11 and the In—W—Zn—Ag—O amorphous thin films of Examples 12 to 18 were used as anodes. An organic EL device having the structure shown in FIG. 1 was produced in the same manner as in Examples 21 to 24 except that the organic EL device was used. The obtained organic EL element can emit light not only to the cathode but also to the anode.

  The light emission characteristics were examined. As in Examples 21 to 24, good light emission characteristics were observed, and no dark spots were observed even after 200 hours.

  However, in the organic EL device produced in the same manner as in Example 21 except that the In—Sn—O system of Comparative Example 16 was used for the anode, many dark spots were observed after 200 hours.

(Example 27)
FIG. 1 shows a substrate in which a 50 nm silicon oxynitride film is formed on the surface of a PES (polyethersulfone) film (the thickness of the entire film is 0.2 mm) on which an acrylic hard coat layer having a thickness of 1 μm is formed. Such an organic EL element was produced.

  An In-W-Zn-O-based amorphous thin film of Examples 1 to 11 and an In-W-Zn-Ag-O-based amorphous thin film of Examples 12 to 18 were used for the anode (2) and the cathode (11). As a result, the emission characteristics were good.

(Example 28)
Similar to Examples 21 to 27 of the organic EL element in which the organic layer is a low molecular system, the same effect is obtained even when the organic layer is a polymer organic EL element, and the transparent conductive thin film of the present invention is used. Accordingly, dark spots are hardly generated, the light emission luminance is good, and the light emission lifetime is longer than that of a conventional organic EL element using a transparent conductive thin film.

It is sectional drawing which shows the basic composition of the organic EL element of this invention. It is sectional drawing which shows the basic composition of the inorganic EL element of this invention. It is sectional drawing which shows the basic composition of LCD of this invention. It is sectional drawing which shows the basic composition of the touch panel of this invention.

Explanation of symbols

1 substrate (glass plate or resin plate or resin film)
2 Anode 3 Insulating layer 4 Hole injection layer 5 Hole transport layer 6 Light emitting layer 7 Electron injection metal layer 8 Transparent conductive thin film layer 9 Protective film 10 Organic layer 11 Cathode 12 Transparent substrate (glass plate or resin plate or resin film)
13 Transparent electrode 14 First insulating layer 15 Light emitting layer 16 Second insulating layer 17 Back electrode (Al)
18 Transparent substrate (glass plate or resin plate or resin film)
19 Transparent electrode 20 Color filter (RGB)
21 Alignment film 22 Liquid crystal 23 Polarizing plate 24 Backlight 25 Transparent electrode (on color filter)
26 Sealant 27 Black matrix 28 Resin film 29 Glass 30 Transparent electrode 31 Spacer

Claims (20)

Mainly containing indium oxide, tungsten element is contained at a W / In atomic ratio of 0.004 to 0.023, and zinc element is Zn / In atomic ratio at a ratio of 0.004 to 0.100. contained amorphous a structure and a transparent conductive thin film, wherein the absolute value of the internal stress is 1 × 10 ¹⁰ dyn / cm ² or less. 2. The transparent conductive thin film according to claim 1, wherein the specific resistance is 9.0 × 10 ⁻⁴ Ωcm or less. 2. The transparent conductive thin film according to claim 1, wherein the specific resistance is 6.0 × 10 ⁻⁴ Ωcm or less.   The transparent conductive thin film according to any one of claims 1 to 3, wherein the crystallization temperature is 200 ° C or higher.   The transparent conductive thin film according to any one of claims 1 to 4, wherein the arithmetic average height (Ra) of the film surface is 2.0 nm or less.   An oxide sintered compact target for producing a transparent conductive thin film in which substantial constituent elements are indium, tungsten, zinc, and oxygen, wherein the tungsten element is 0.004 to 0.00 in terms of W / In atomic ratio. An oxide sintered compact target for producing a transparent conductive thin film, characterized in that it is contained at a ratio of 023, and zinc element is contained at a Zn / In atomic ratio of 0.004 to 0.100. The transparent conductive thin film according to any one of claims 1 to 5 is formed on a surface of a transparent substrate using the oxide sintered compact target for producing a transparent conductive thin film according to claim 6. A transparent conductive substrate.   Mainly containing indium oxide, tungsten element is contained at a W / In atomic ratio of 0.004 to 0.023, and zinc element is Zn / In atomic ratio at a ratio of 0.004 to 0.100. A transparent conductive thin film characterized by containing silver element in a ratio of 0.001 to 0.010 in terms of Ag / In atomic ratio and having an amorphous structure. 9. The transparent conductive thin film according to claim 8 , wherein the specific resistance is 9.0 × 10 ⁻⁴ Ωcm or less. 9. The transparent conductive thin film according to claim 8 , wherein the specific resistance is 6.0 × 10 ⁻⁴ Ωcm or less. The transparent conductive thin film according to any one of claims 8 to 10 , wherein the crystallization temperature is 200 ° C or higher. The transparent conductive thin film according to any one of claims 8 to 11 , wherein the arithmetic average height (Ra) of the film surface is 2.0 nm or less. The transparent conductive thin film according to any one of claims 8 to 12 the absolute value of the internal stress is equal to or is 1 × 10 ¹⁰ dyn / cm ² or less.   It is an oxide sintered compact target for producing a transparent conductive thin film whose substantial constituent elements are indium, tungsten, zinc, silver and oxygen, and the tungsten element has a W / In atomic ratio of 0.004 to 0 0.023, a zinc element is contained in a Zn / In atomic ratio of 0.004 to 0.100, and a silver element is an Ag / In atomic ratio in a ratio of 0.001 to 0.010. The oxide sintered compact target for transparent conductive thin-film manufacture characterized by being contained by these. The transparent conductive thin film according to any one of claims 8 to 13 is formed on a surface of a transparent substrate using the oxide sintered compact target for manufacturing a transparent conductive thin film according to claim 14. Transparent conductive substrate. Transparent substrate, a glass plate, a resin plate or resin film one side or both sides are covered with the gas barrier film according to claim 7 or was characterized by a resin plate or resin film inside the gas barrier film is inserted, Or 15. The transparent conductive substrate according to 15 . The transparent conductive film according to claim 16 , wherein the gas barrier film is at least one selected from a silicon oxide film, a silicon oxynitride film, a magnesium aluminum oxide film, a tin oxide film, and a diamond-like carbon film. Substrate. The material of the resin plate or resin film is polyethylene terephthalate (PET), polyethersulfone (PES), polyarylate (PAR), polycarbonate (PC), or a laminated structure in which an acrylic organic material is covered on the surface of these materials. The transparent conductive substrate according to claim 16 or 17 , characterized by the above. The display device using the transparent conductive thin film in any one of Claims 1-5 and 8-13 as an electrode. An organic electroluminescent device comprising an organic layer sandwiched between an anode and a cathode, wherein the organic layer emits light by recombination of holes supplied from the anode and electrons supplied from the cathode An organic electroluminescent device, wherein at least one layer forming the anode and / or the cathode is composed of the transparent conductive thin film according to any one of claims 1 to 5 and 8 to 13. .

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