JP2007284296A - Sintered compact, method of producing the same, transparent oxide film obtained by using the sintered compact and method of forming the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sintered compact for a sputtering target for stably forming a useful transparent oxide film at a high speed, the transparent oxide film and a gas-barrier transparent resin substrate. <P>SOLUTION: The sintered compact comprises a conductive oxide and silicon carbide and has a silicon content of 0.5-99.5 atom% based on the total metal element content in the sintered compact. The transparent oxide film is formed by a sputtering method using the sintered compact as a raw material and contains silicon. The gas-barrier transparent resin substrate is obtained by forming the transparent oxide film on at least one side of a resin film substrate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sintered body for a sputtering target for producing a transparent oxide thin film containing silicon. Furthermore, the present invention relates to a transparent oxide thin film containing silicon produced using the sintered body, and specifically, a transparent film having a low refractive index (from 1.48 to less than 1.6 in the visible range) as an optical thin film. It relates to oxide thin films, transparent oxide thin films having an intermediate refractive index (from 1.6 to 1.9 in the visible range), amorphous transparent conductive thin films with smooth surfaces, and transparent gas barrier thin films with smooth surfaces. is there.

  Transparent oxide thin films are always used in major electronic devices such as various optical components, displays, and solar cells. As a method for forming an oxide thin film, a sputtering method, a vapor deposition method, an ion plating method, and a solution coating method are often used. Among them, the sputtering method is effective when a material having a low vapor pressure is used or when precise film thickness control is required, and is most widely used industrially.

  In the sputtering method, an argon gas is generally used, and a voltage is applied using a substrate as an anode and a sputtering target as a raw material for an oxide transparent conductive film to be formed as a cathode under a gas pressure of about 10 Pa or less. A glow discharge occurs between the electrodes to which a voltage is applied to generate argon plasma, and argon cations in the plasma collide with the cathode sputtering target. Particles that are flipped one after another by this collision are sequentially deposited on the substrate to form a thin film. When an oxide thin film is formed by a sputtering method, oxygen is generally mixed in argon gas so that a predetermined amount of oxygen is introduced into the 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. In particular, the direct current sputtering method has the characteristics that the thermal damage to the substrate is small, high-speed film formation is possible, the power supply equipment is inexpensive, and the operation is simple. It is.

  In the high frequency sputtering method, not only a conductive material but also an insulating or high resistance film material can be stably formed from an insulating or high resistance target. In the high frequency sputtering method, an impedance matching circuit composed of a coil and a capacitor is usually inserted between the high frequency power source and the target so that electric power is efficiently introduced into the discharge. Further, since it is necessary to control the impedance matching circuit according to sputtering conditions, the high-frequency sputtering method is complicated in operation and inferior in reproducibility such as a film forming speed.

  On the other hand, the direct current sputtering method can generally form a conductive thin film from a conductive target, and is not suitable for forming an insulating or high resistance film because arcing is likely to occur. However, the direct current sputtering method is easier to operate than the high frequency sputtering method, and is excellent in reproducibility such as a film forming speed. Therefore, it is advantageous in terms of cost and controllability, and is widely used industrially.

  In addition, among DC sputtering methods, there is also a sputtering method (DC pulsing method) in which a negative voltage applied to a target is periodically stopped and a low positive voltage is applied therebetween to neutralize positive charging with electrons. It is possible to form a film while suppressing arcing of an insulating film (silicon oxide, silicon nitride oxide, titanium oxide, etc.) in reactive sputtering using a reactive gas of oxygen, and an impedance matching circuit like a high frequency sputtering method. Therefore, there is an advantage that the film forming speed is faster than that of the high frequency sputtering method. As a power source for performing sputtering film formation by the direct current pulsing method, for example, RPG series made by ENI, MDX-Sarc series and Pinnacle series made by Advanced Energy are known.

  Note that when an oxide film is formed by a direct current sputtering method, a conductive oxide sputtering target needs to be used. For example, when direct current sputtering is performed using a sputtering target in which a conductive oxide base material contains a high resistance or insulating material, the portion of the high resistance or insulating material is charged by the irradiation of argon cations and insulated. Breaking occurs and arc discharge occurs, and the film cannot be stably formed. In particular, as more DC power is applied, charging with a high resistance or insulating material is more likely to occur, and the frequency of arc discharge during film formation increases. Therefore, it is not possible to obtain a high film formation rate by applying high power. It becomes possible.

  The transparent conductive thin film has high conductivity and high transmittance in the visible light region. For this reason, transparent oxide conductive films are not only used for solar cells, liquid crystal display elements, and other light receiving element electrodes, but also by utilizing reflection absorption characteristics at wavelengths in the near infrared region, It is also used as a heat-reflecting film used for window glass of buildings, various antistatic films, and a transparent heating element for anti-fogging such as a freezer showcase.

Examples of transparent conductive thin films include tin oxide (SnO ₂ ) containing antimony and fluorine as dopants, zinc oxide (ZnO) containing aluminum and gallium as dopants, and indium oxide (In ₂ O ₃ ) containing tin as dopants. Is widely used. In particular, an indium oxide film containing tin as a dopant, that is, an In ₂ O ₃ —Sn-based film is called an ITO (Indium tin oxide) film, and since a low-resistance film can be easily obtained, it has been frequently used so far. Has been. Tin oxide-based transparent conductive thin films are mainly manufactured by the CVD method, but most of the In ₂ O ₃ and ZnO-based transparent conductive thin films are manufactured by the direct current sputtering method, and they are conductive as raw materials. An oxide sputtering target is used.

  In recent years, the field of application of transparent conductive films has been expanded, and mere high conductivity and high transmittance have become unsatisfactory. In particular, as an application of a transparent electrode of an organic electroluminescence element (hereinafter sometimes referred to as organic EL), excellent smoothness of the film surface is important in addition to excellent conductivity and excellent light transmittance. Yes.

  Organic EL is expected as a next-generation display because it has features such as high brightness, thinness and light weight, fast response speed, and wide viewing angle. An organic EL has an element structure in which an organic multilayer film is sandwiched between two types of electrodes having different work functions, and holes generated from an electrode (anode) having a high work function and electrons generated from an electrode having a small work function (cathode). Are combined in the light emitting layer in the organic multilayer film to emit light, and a transparent conductive film is used for the electrode on the light emitting direction side.

  A transparent conductive film in an organic EL is required to have a work function, surface smoothness, etc. in addition to high conductivity (for current driving) and high light transmittance. The work function of the transparent conductive film greatly affects the light emission characteristics, but can be adjusted to some extent by pretreatment such as UV ozone treatment or oxygen plasma treatment of the film surface. The surface smoothness of the transparent conductive film is also an important factor for obtaining good light emission characteristics. Since the organic light-emitting layer is a multi-layered ultrathin film (several hundreds of nanometers), if the surface roughness of the transparent conductive film in contact with the organic light emitting layer is large, the electric charge concentrates on the ultrathin organic layer in contact with the protrusion, and finally This is because the non-light emitting portion is generated due to the destruction.

  Patent Document 1 proposes an oxide sintered body for a sputtering target used for obtaining a transparent conductive thin film having a smooth surface. That is, in the oxide sintered body containing indium and silicon, the oxide sintered body for the sputtering target is characterized in that silicon element is dissolved in indium oxide. This oxide sintered body has a crystal phase of a bixbite type structure of indium oxide doped with silicon as a main phase, and a crystal phase of a tortobitite type structure of an indium silicate compound is mixed. This sputtering target is intended to obtain a low-resistance transparent conductive film, and the silicon element content is 0.01 to 0.17 in terms of Si / In atomic ratio, that is, oxidation of In It is described that the weight ratio of Si oxide to the total amount of the product and Si oxide is 0.431 to 6.87% by weight.

In relation to this, Patent Document 2 contains silicon oxide in an indium oxide sintered body suitable as a film forming material for a transparent conductive film, or a sintered body containing indium oxide and tin oxide. An indium oxide-based sintered body excellent in sinterability and characterized in that has been proposed. Furthermore, an indium oxide-based sintered body excellent in sinterability having a silicon and / or germanium content of 0.0001 to 0.6 per mole of indium has been proposed. Patent Document 2 includes, for example, an In ₂ O ₃ —SiO ₂ system as an indium oxide-based sintered body. In addition, as a starting material for silicon, an oxide such as SiO ₂ is generally used, but it is possible to use Si alone, a hydroxide of Si, and the like. It is described that it may be taken in in the form of Si, or partially in the form of Si or the like. Furthermore, in Patent Document 2, the silicon content is more preferably 0.01 to 0.3 mol, most preferably 0.02 to 0.1 mol, and 0.6 mol per mol of indium. It is described that if it exceeds the upper limit, the mobility of carrier electrons is lowered and the conductivity is deteriorated, which is not preferable.

Many optically useful oxide films are known, and are applied as a laminate in which the characteristics of each oxide film are well combined. A typical application example is a multilayer antireflection film designed to selectively reflect or transmit light of a specific wavelength. In addition, there are many application examples such as a reflection increasing film, an interference film, and a polarizing film, which are very diverse. Also, functional multilayer films with added values such as antistatic properties, heat ray shielding properties, electromagnetic wave shielding properties as well as optical properties have been proposed.
The spectral characteristics of the oxide multilayer film are determined by the refractive index n and the film thickness d in the visible region of each layer when the extinction coefficient k can be regarded as almost zero. Therefore, when designing a laminate using an oxide film, optical design is generally performed by calculation based on n and d data of each layer constituting the multilayer film. In this case, in addition to combining a high refractive index film and a low refractive index film, a multilayer film having superior optical characteristics can be obtained by adding a film having an intermediate refractive index (intermediate refractive index film). Is easy to realize.

In general, as a high refractive index film (n> 1.9), TiO ₂ (n = 2.4), CeO ₂ (n = 2.3), ZrO ₂ (n = 2.2), Nb ₂ O ₅ (N = 2.1), Ta ₂ O ₅ (n = 2.1), WO ₃ (n = 2.0) and the like are known. Further, as the low refractive index film (n <1.6), SiO ₂ (n = 1.46), MgF ₂ (n = 1.38), etc. are known. In general, as the intermediate refractive index film (n = 1.6 to 1.9), Al ₂ O ₃ (n = 1.64), MgO (n = 1.72), Y ₂ O ₃ (n = 1). .87) is known.

  Incidentally, the usefulness of the intermediate refractive index film in the antireflection film is described in detail, for example, in Patent Document 3. That is, in the antireflection film, the greater the number of types of film material having an available refractive index, the greater the degree of design freedom including the substrate. For example, when considering a three-layer antireflection film, an intermediate refractive index film (n = 1.80), a high refractive index film (n = 2.10), a low refractive index on a glass substrate (n = 1.52). By laminating the rate films (n = 1.46) in order, the reflectivity can theoretically be made zero.

However, the above-described general intermediate refractive index films such as Al ₂ O ₃ , MgO, and Y ₂ O ₃ are all poor in conductivity, and when an oxide sputtering target is used, stable film formation by a DC sputtering method is possible. A membrane cannot be obtained. Therefore, in order to obtain an intermediate refractive index film by film formation by direct current sputtering, sputtering is performed while reacting metal particles and oxygen in an oxygen-rich atmosphere using a conductive metal target (reactive sputtering method). It is necessary to do. However, since the deposition rate by the reactive sputtering method containing a large amount of oxygen is extremely slow, productivity is significantly impaired. As a result, the cost of the intermediate refractive index film is high, which is a serious problem in manufacturing.

  In order to solve such a problem, Patent Document 4 proposes an oxide film containing Nb oxide and silicon oxide and having a refractive index of 1.6 to 1.9, a method for forming the oxide film, and a sputtering target. Has been. An oxide film having an intermediate refractive index (n = 1.6 to 1.9), a sputtering target used when the oxide film is formed by a direct current (DC) sputtering method, and the sputtering target are used. A method of forming the oxide film is described.

  However, the oxide of Nb and the oxide of silicon do not react to form a composite oxide during sintering, and each exists as a single oxide in the sputtering target obtained by sintering, Since a single silicon oxide is an insulator, the oxide film forming method described in Patent Document 1 is easily charged with silicon oxide, causing arc discharge in DC sputtering and being stable. There was a problem that the film could not be formed.

  Patent Document 4 states that conductivity is obtained when oxygen deficiency is formed in an oxide of Nb. However, since Nb is naturally easily oxidized, the formation of the oxide film described in Patent Document 1 is described. The method has a problem that the target surface is oxidized while the film forming process is repeated, the conductivity is remarkably lowered, and stable discharge becomes impossible.

  Further, the inventors of the present application proposed an oxide sintered body capable of stably forming an oxide film having an intermediate refractive index by a direct current sputtering method in Japanese Patent Application No. 2005-242788. Yes. This oxide sintered body is mainly composed of an oxide containing indium and silicon, the atomic ratio of silicon to indium is 0.65 to 1.75, does not contain silicon dioxide, and is a tortovite type. A crystal phase of an indium silicate compound having a structure is configured as a main phase, and when used as a sputtering target, a film can be formed by a direct current sputtering method.

  Unlike a glass substrate, a plastic substrate or a film substrate transmits gas such as water vapor or oxygen. Therefore, a gas barrier film (transparent) whose surface is covered with a metal oxide film such as silicon oxide or aluminum oxide is used for packaging purposes in order to prevent alteration of food and chemicals that require blocking of gas such as water vapor and oxygen. Resin substrates) have been used. Also, in the field of electronic equipment, for example, in the fields of liquid crystal display elements, solar cells, electroluminescence (EL) display elements, etc., a transparent resin film substrate is used instead of a glass substrate that is heavy and easily broken. Adoption is being considered.

  In addition, gas barrier films used in liquid crystal display elements and EL display elements have recently been required to be lighter and larger in size in accordance with the development of display elements, as well as to have excellent surface smoothness. It is appearing. The organic EL element has the structure as described above, and if the surface of the gas barrier film is uneven, the surface of the electrode formed on the surface also becomes uneven, which adversely affects the light emission characteristics.

  Patent Document 5 proposes a transparent resin substrate having better surface smoothness, higher transparency and higher water vapor barrier performance than before, and a flexible display element using the same. For this purpose, a transparent oxide film made of a tin oxide-based amorphous film in which silicon element is contained in tin oxide at a ratio of 0.2 to 45 atomic% with respect to the sum of Si and Sn is used as a gas barrier. An example of using it as a layer has been proposed. Unlike conventional gas barrier thin films such as silicon oxide, aluminum oxide, and silicon oxynitride films, this tin oxide-based amorphous film has not only excellent gas barrier properties but also excellent surface smoothness. A tin oxide sintered body containing silicon at a ratio of 45 atomic% or less with respect to the sum of silicon and tin for producing such a gas barrier thin film is described.

JP 2004-123479 A JP-A-61-136954 JP 2004-287274 A JP 2000-160331 A JP 2005-103768 A

  As described above, the transparent oxide thin film containing silicon element has a low refractive index (from 1.48 to less than 1.6 in the visible range) and an intermediate refractive index (from 1.6 to 1 in the visible range). .9 or less) for transparent oxide thin films for optical thin films, amorphous transparent conductive thin films with smooth surfaces, and transparent gas barrier thin films with excellent gas barrier properties and smooth surfaces. It is manufactured by a sputtering method using a sintered oxide target.

  In the prior art, in order to produce a sputtering target for obtaining a transparent oxide thin film containing silicon, silicon oxide powder (Patent Document 1, Patent Document 2) or metal silicon powder (Patent Document) is used as a raw material for the silicon component. 5, Patent Document 2) has been used. However, when metallic silicon powder is used as a raw material and mixed with oxide powder and sintered, the oxidizing power of metallic silicon is strong, so metallic silicon and atmospheric oxygen and surrounding oxide particles during firing The silicon oxide phase is likely to be generated by reacting with oxygen taken from the silicon, and when the silicon oxide phase is present in the sintered body, the silicon oxide is an insulating material, so such a sintered body is used as a sputtering target. Arcing occurs and DC sputtering cannot be performed stably.

The indium oxide sintered body containing silicon described in Patent Document 1 and Patent Document 2 is obtained by mixing and firing metal silicon powder and indium oxide powder, or silicon oxide powder and indium oxide powder, Metallic silicon reacts with oxygen to form silicon oxide as an intermediate product, and silicon oxide reacts with indium oxide to finally form an indium silicate compound such as In ₂ Si ₂ O ₇ . In addition, when silicon oxide powder is used as a raw material, unreacted silicon oxide particles may be present in the sintered body, and silicon oxide is an insulating material. Therefore, such a sintered body is used as a sputtering target. Arcing occurs and DC sputtering cannot be performed stably.

When fabricated from silicon oxide and indium oxide, the silicon oxide ultimately forms an indium silicate compound such as In ₂ Si ₂ O ₇ . If silicon oxide remains in the sintered body as a starting material or an intermediate organism, problems such as arcing may occur during direct current sputtering and stable film formation may occur.

  When the direct current pulsing method is used, a film can be stably formed when a slight silicon oxide phase is included. The DC pulsing method is a sputtering method in which a negative voltage applied to a target is periodically stopped, and a low positive voltage is applied between them to neutralize positive charging with electrons. included. In this method, it is possible to form a film while suppressing arcing, and it is not necessary to control the impedance matching circuit unlike the high frequency sputtering method, and there is an advantage that the film formation rate is faster than the high frequency sputtering method.

  However, when high-speed film formation is performed by applying high input power even in the direct current pulsing method, if the silicon oxide phase is included, charging cannot be neutralized and arcing occurs. Further, when the ratio of the silicon component in the sintered body is increased and the silicon oxide phase is increased, it is impossible to suppress arcing even by a low-power DC pulsing method. In such a case, the film must be formed by high frequency sputtering which is not industrially practical. Moreover, although compounds such as indium silicate are conductive, sputtering efficiency is very low. A transparent oxide film having a large amount of silicon component is obtained from a sintered body of indium oxide containing a large amount of silicon component, and the refractive index in the visible region of the film is decreased (refractive index of silicon oxide film (n = 1.46)). The transmittance is improved, but silicon oxide remains in the sintered body and cannot be stably deposited by the DC sputtering method. The ratio of indium silicate in the sintered body increases. When it was used as a sputtering target, such as a rapid decrease in the film formation rate, there were significant problems in practical use.

  The tin oxide sintered body containing silicon as shown in Patent Document 5 is exactly the same as the above-mentioned indium oxide sintered body containing silicon. If the silicon oxide phase is contained in the sintered body as a starting material residue or as an intermediate product, arcing occurs during direct current sputtering and stable film formation cannot be achieved. If the direct current pulsing method is used, stable film formation can be achieved, but if the silicon component is large and the silicon oxide phase is contained in a large amount in the sintered body, arcing cannot be avoided, and this is not possible with high-frequency sputtering, which is not practical. It must be filmed. Moreover, if high power is applied to perform high-speed film formation, it is impossible to suppress arcing.

Silicon oxide and tin oxide react to form a silicon stannate compound such as SiSnO ₃ . In a sintered body having a large amount of silicon component, since the ratio of such a compound is increased, there arises a problem that the sputtering efficiency is lowered and a practical film formation rate cannot be obtained.

  The zinc oxide sintered body containing silicon is exactly the same as the above-described indium oxide sintered body containing silicon. If the silicon oxide phase is contained in the sintered body as a starting material residue or as an intermediate product, arcing occurs during direct current sputtering and stable film formation cannot be achieved. If the direct current pulsing method is used, a stable film can be formed, but the amount of silicon is increased and a silicon oxide phase is included in the sintered body, and arcing cannot be avoided. Therefore, the film must be formed by high frequency sputtering which is not practical.

  In the present invention, as the conductive oxide such as an indium oxide thin film, a tin oxide thin film, or a zinc oxide thin film contains more silicon elements, the refractive index in the visible region decreases, and the refractive index of silicon oxide (n = 1). .46), a useful film having a high transmittance in the visible region is obtained, is useful as an optical thin film such as an intermediate refractive index film or a low refractive index film, and is also useful as a gas barrier film having a high transmittance. In addition, it is made by paying attention to the fact that when a small amount of silicon element is contained, the high conductivity of the conductive oxide is maintained, and a transparent oxide thin film having excellent conductivity and surface smoothness can be obtained. The target is a sputtering target capable of producing these useful transparent oxide thin films stably and at high speed even when high power is applied by a direct current sputtering method (including a direct current pulsing method). It is to provide a sintered body, a transparent oxide thin film, and the gas-barrier transparent plastic substrate.

  In order to achieve the above object, a sintered body according to the present invention is a sintered body composed of a conductive oxide and silicon carbide, and the silicon content in the sintered body is less than that in the sintered body. It is a ratio of 0.5 to 99.5 atomic% with respect to the total metal element content.

  The sintered body according to the present invention is preferably characterized in that the silicon carbide contains at least one additive element selected from nitrogen, boron, phosphorus and aluminum.

  The sintered body according to the present invention is preferably characterized in that the conductive oxide has as a main component at least one material selected from the group of indium oxide, zinc oxide, and tin oxide.

  The method for producing a sintered body according to the present invention is characterized in that a conductive oxide powder and a silicon carbide powder are used as starting materials, they are mixed, and the mixture is sintered to obtain a sintered body. .

  The method for producing a sintered body according to the present invention is preferably characterized in that the conductive oxide has at least one material selected from the group of indium oxide, zinc oxide and tin oxide as a main component. To do.

  The method for producing a sintered body according to the present invention is preferably characterized in that the conductive oxide powder has an average particle size of 50 μm or less and the silicon carbide powder has an average particle size of 50 μm or less. To do.

  The method for producing a sintered body according to the present invention is preferably characterized in that the mixture is sintered by a hot press method.

  The transparent oxide thin film according to the present invention is a transparent oxide thin film produced by a sputtering method using any one of the above sintered bodies as a raw material, and contains silicon.

  In addition, the transparent oxide thin film according to the present invention is preferably characterized in that the refractive index of light at a wavelength of 633 nm has an intermediate refractive index of 1.6 or more and 1.9 or less.

  In addition, the transparent oxide thin film according to the present invention is preferably characterized in that the refractive index of light at a wavelength of 633 nm has a low refractive index of 1.48 or more and less than 1.6.

In addition, the transparent oxide thin film according to the present invention is preferably characterized by having a specific resistance of 5.5 × 10 ⁻³ Ωcm or less.

In addition, the transparent oxide thin film according to the present invention is preferably characterized in that the specific resistance is 5.6 × 10 ⁻¹ Ωcm or less.

  The transparent oxide thin film according to the present invention is preferably characterized in that the center line average surface roughness Ra of the film surface is 2.5 nm or less.

  A gas barrier transparent resin substrate according to the present invention is characterized in that the transparent oxide thin film described above is formed on at least one surface side of a resin film substrate.

In addition, the gas barrier transparent resin substrate according to the present invention is preferably characterized in that the water vapor transmission rate by the Mocon method measured in accordance with the JIS standard K7129 method is less than 0.01 g / m ² / day.

  The method for producing a transparent oxide thin film according to the present invention is characterized in that the transparent oxide thin film according to any one of the above is obtained by forming a film by a direct current sputtering method using the sintered body according to any of the above as a raw material. And

The sintered body of the present invention is a sintered body composed of at least one conductive oxide selected from the group of indium oxide, zinc oxide, and tin oxide and silicon carbide, and in the sintered body. The silicon content is a ratio of 0.5 to 99.5 atomic% with respect to the total metal element content in the sintered body. If this sintered body is used, a transparent oxide thin film containing silicon can be formed stably and at high speed by a direct current sputtering method.
The obtained transparent oxide thin film containing silicon has an intermediate refractive index (from 1.6 to 1.9 in the visible range) and a low refractive index (from 1.48 to less than 1.6 in the visible range) for optical thin films. Transparent oxide thin film, high-transparency amorphous transparent conductive thin film with a smooth surface and low resistance, and a transparent gas barrier thin film with a smooth surface and excellent moisture resistance. When the body is used, these thin films can be produced with high productivity by the direct current sputtering method widely used in the industry, and therefore, it is extremely valuable industrially.

  Hereinafter, prior to the description of the examples, the background of the inventors to the present invention, the sintered body of the present invention, the production method thereof, and the transparent oxide thin film will be described in detail.

  The inventors of the present invention show that the more the silicon element is contained in the conductive oxide such as an indium oxide thin film, a tin oxide thin film, or a zinc oxide thin film, the lower the refractive index in the visible region, and the refractive index (n = 1.46), a useful film having a high transmittance in the visible region is obtained, and it is useful as an optical thin film such as an intermediate refractive index film or a low refractive index film, and also useful as a gas barrier film having a high transmittance. In addition, when containing a small amount of silicon element, the high conductivity of the conductive oxide is maintained, and a transparent oxide thin film having excellent conductivity and surface smoothness can be obtained. Silica that can be used to produce a sintered body target containing a silicon element as a sintered body for a sputtering target for producing a transparent oxide thin film stably and at high speed by a direct current sputtering method System powder intensively studied, focusing on the silicon carbide powder as a raw material for the silicon component, the sintered body of the conductive oxide and silicon carbide can be solved by using a sputtering target, have completed the present invention.

Regarding the sintered body, even if the silicon component amount in the sintered body of the present invention, that is, the silicon carbide content is large, even if it is used as a target for direct current sputtering, arcing does not occur, and a transparent oxide thin film containing silicon is used. It is characterized by being obtained at a high film formation rate.
The silicon carbide in the sintered body of the present invention preferably contains a trace amount of additive elements such as B, Al, P, and N. This is because silicon carbide becomes a semiconductor when it contains a trace amount of additives (B, Al, P, N, etc.) and has conductivity. Also, silicon carbide is less susceptible to oxidation than metal silicon. Therefore, when silicon carbide powder and conductive oxide powder are mixed and baked, a composite oxide containing insulating silicon oxide or high-resistance silicon is difficult to be formed, and is composed of silicon carbide and conductive oxide. A sintered body is obtained. When such a sintered body of silicon carbide and conductive oxide is used as a sputtering target, arcing does not occur even when high DC power is applied because the sintered body does not contain an insulating or high-resistance material. . In addition, when oxygen gas is introduced into the argon gas of the sputtering gas, carbon atoms jumping out from the target as sputtering particles are oxidized and become carbon dioxide gas molecules, which are excluded from the system without being a constituent element of the film. Thus, a conductive oxide thin film containing only silicon element is obtained. Silicon carbide may have a C / Si atom number ratio close to 1, but may have a composition in which the C / Si atom number ratio deviates from 1. The above characteristics can be obtained if silicon carbide has a composition with a C / Si atomic ratio in the range of 0.4 to 1.2.

  First, the sintered body according to the present invention is characterized in that silicon carbide particles are dispersed in a conductive oxide sintered body. The conductive oxide in the present invention is more preferably, for example, indium oxide, zinc oxide, tin oxide, but not only this, but also titanium oxide, niobium oxide, tungsten oxide, molybdenum oxide, iridium oxide, ruthenium oxide, vanadium oxide, The present invention can also be applied to materials that exhibit n-type or p-type semiconductor conductivity by introducing oxygen vacancies or containing additional elements such as cerium oxide and antimony oxide, and materials that exhibit metallic conductivity. Also included are compounds of these oxides and conductive oxides of solid solutions.

  In the case of indium oxide as a semiconducting conductive oxide containing an additive element, for example, tin, titanium, tungsten, molybdenum, zirconium, silicon, germanium, etc. Corresponds to an effective additive element for improving conductivity. In the case of tin oxide, elements such as antimony, tungsten, molybdenum, niobium, and tantalum that tend to have a valence of 5 or more correspond to effective additive elements that improve conductivity. In the case of zinc oxide, for example, an element that tends to have a valence of 3 or more, such as gallium, aluminum, boron, tin, titanium, tungsten, molybdenum, zirconium, silicon, and germanium, is effective in exerting conductivity. Corresponds to additive element. Similarly, for conductive oxides such as titanium oxide, niobium oxide, tungsten oxide, molybdenum oxide, iridium oxide, ruthenium oxide, vanadium oxide, cerium oxide, and antimony oxide, the valence is larger than that of the constituent metal elements. It is preferable to contain an additive element that can be easily removed to improve conductivity.

Regarding the manufacturing method of the sintered body, the sintered body according to the present invention is obtained by mixing and firing a conductive oxide powder represented by indium oxide, zinc oxide, tin oxide, etc. and silicon carbide powder. Can do. The firing method may be either a normal pressure firing method or a hot press method, but the hot press method can be sintered at a lower temperature, higher density and higher strength than the normal pressure firing method. It is preferable because generation of silicon oxide that causes arcing caused by oxidation of silicon carbide can be prevented.
In order to improve the sinterability, the conductive oxide powder preferably has an average particle size of 50 μm or less, and the silicon carbide powder preferably has an average particle size of 50 μm or less. If any of the powders exceeds the above average particle diameter, not only the relative density of the sintered body is lowered but also the strength of the sintered body is lowered. In particular, when the average particle size of the silicon carbide powder exceeds 50 μm, the specific surface area of the powder decreases, so that the necking of the particles becomes insufficient during the sintering process, resulting in cracking of the sputtering target. It tends to happen.

  Further, by using the hot pressing method, it is possible to apply a high pressure in a reducing atmosphere, and as a result, a high-density sintered body not containing silicon oxide can be obtained. As hot press conditions, a temperature of 800 to 1000 ° C. and a pressure of 4.9 to 49.0 MPa are preferable. When the sintering temperature is less than 800 ° C., it is not sufficiently sintered. On the other hand, when the temperature exceeds 1000 ° C., indium oxide is reduced to metal indium having a low melting point, and oozes into the melt. Further, when the pressure is less than 4.9 MPa, it is not sufficiently sintered, but when it is 4.9 MPa or more, it is sufficiently sintered. However, if it exceeds 49.0 MPa, a problem arises that the carbon container used as a mold cannot be tolerated in strength and breaks.

Regarding the transparent oxide thin film, the transparent oxide thin film of the present invention contains silicon, but the sintered body of the present invention is composed of a conductive oxide such as indium oxide, zinc oxide, tin oxide and silicon carbide. Can be obtained by a direct current sputtering method. In this case, the sintered body of the present invention requires that the silicon element content in the sintered body is 0.5 to 99.5 atomic% with respect to the total metal element content.

In the case of a sintered body composed of indium oxide and silicon carbide, when the content of silicon element in the sintered body is 0.5 atomic% or more and 35 atomic% or less with respect to the total metal element content, the specific resistance is It is possible to obtain a transparent oxide film having a smooth surface with a high conductivity of 3.8 × 10 ⁻⁴ or more and 5.5 × 10 ⁻³ Ωcm or less and a centerline surface average roughness Ra of 2.5 nm or less. This is preferable. When the content of silicon element is less than 0.5 atomic% with respect to the total metal element content, a transparent oxide film having a smooth surface cannot be obtained, and therefore cannot be used for a transparent electrode for organic EL. Moreover, when the silicon element content is 8 atomic% or more and less than 60 atomic% with respect to the content of all metal elements, an intermediate refractive index film having a refractive index of 1.6 to 1.9 at a wavelength of 633 nm can be obtained. A low refractive index film having a refractive index of 1.48 or more and less than 1.60 at a wavelength of 633 nm when the silicon element content is 60 atomic% or more and 99.5 atomic% or less in terms of the atomic ratio with respect to the total metal element content. It can be obtained and is preferable.

In the case of a sintered body composed of tin oxide and silicon carbide, the surface of the center line when the silicon element content is a ratio of 0.5 atomic% or more and 99.5 atomic% or less with respect to the content of all metal elements A transparent oxide film having a smooth surface with an average roughness Ra of 2.5 nm or less can be obtained. However, when the content of silicon element is less than 0.5 atomic% with respect to the content of all metal elements, or 99.5 atoms If it exceeds 50%, the surface roughness becomes large, so it cannot be used as a moisture-proof film for organic EL applications. When the silicon element content is 0.5 atomic% or more and 25 atomic% or less with respect to the content of all metal elements, the specific resistance is 1.5 × 10 ⁻³ Ωcm or more and 5.6 × 10 ⁻¹ Ωcm. The following transparent conductive film can be obtained, and when the silicon element content is 5 atomic% or more and 63 atomic% or less with respect to the content of all metal elements, the refractive index at a wavelength of 633 nm is 1.6 or more and 1. An intermediate refractive index film of 9 or less can be obtained, and a low refractive index film having a refractive index of 1.48 or more and less than 1.60 at a wavelength of 633 nm can be obtained when it is more than 63 atomic% and 99.5 atomic% or less. Is preferable.

In the case of a sintered body composed of zinc oxide and silicon carbide, when the silicon element content is 0.5 atomic% or more and 23 atomic% or less with respect to the content of all metal elements, the specific resistance is 8.5. A transparent oxide film having a conductivity of × 10 ⁻⁴ or more and 5.3 × 10 ⁻¹ Ωcm or less can be obtained. When the silicon element content is 10 atomic% or more and 55 atomic% or less with respect to the content of all metal elements, an intermediate refractive index film having a refractive index of 1.6 to 1.9 at a wavelength of 633 nm can be obtained. When it is more than atomic percent and 99.5 atomic percent or less, a low refractive index film having a refractive index of 1.48 or more and less than 1.60 at a wavelength of 633 nm can be obtained, which is preferable.

  The sintered body according to the present invention basically does not contain silicon oxide, but does not impair the characteristics of the present invention at the interface between silicon carbide and conductive oxide (that is, DC sputtering method with high power input). Or to the extent that arcing does not occur in the DC pulsing method).

Hereinafter, the present invention will be described more specifically with reference to examples.
(In ₂ O ₃ —SiC sintered body)
Example 1
An average particle size including B as an additive element and an In ₂ O ₃ powder having an average particle size of 10 μm so that the atomic ratio of silicon element is 50 atomic% with respect to the total number of atoms of indium element and silicon element A 10 μm SiC powder was blended and subsequently stirred in a three-dimensional mixer to obtain a raw material powder. The obtained mixed powder was fed into a carbon container and sintered using a hot press method. Sintering was performed in an Ar gas atmosphere in order to prevent deterioration of the carbon container due to oxidation. First, the pressure was fixed at 4.9 MPa, the sintering temperature was 1000 ° C., and the sintering time was 3 hours.

  Powder X-ray diffraction measurement was performed on the end material of the obtained sintered body. As a result, only diffraction peaks of bixbite type indium oxide and silicon carbide were confirmed. Also, scanning electron microscope (SEM) mounted on energy dispersive X-ray fluorescence analyzer (EDX), electron diffraction using transmission electron microscope (TEM), and analysis by X-ray photoelectron spectrometer (XPS) As a result, the presence of a silicon oxide phase was not observed in the sintered body, and it was confirmed that the sintered body was composed of an indium oxide phase and a silicon carbide phase. When the composition of the sintered body was analyzed by ICP emission analysis, the content ratio of each metal element (In, Si) was the same as the charged ratio.

Next, these sintered bodies are processed into a diameter of 152 mm and a thickness of 5 mm, the sputtering surface is polished with a cup grindstone to be a target surface, bonded to an oxygen-free copper backing plate using metallic indium, and sputtering is performed. Got the target.
Next, direct current sputtering was performed by processing the sintered body manufactured under the conditions of Example 1 as described above and using it as each sputtering target. The sputtering apparatus used was a DC magnetron sputtering apparatus manufactured by Tokki. Ar gas having a purity of 99.9999% by weight and O ₂ gas were introduced to make the total gas pressure 0.8 Pa, and the flow rate ratio of O ₂ gas was set to 2 to 10%. The input power was DC 100 W, DC plasma was generated with a normal DC power supply (without a pulse function), and then the power was gradually increased to determine the power at which arcing occurred. However, even when DC power is applied up to 600 W (power density applied to the target sputtering surface is 3.308 W / cm ² ), arc discharge does not occur, stable discharge is possible, and high-speed film formation is possible. . The refractive index at a wavelength of 633 nm of the transparent oxide thin film obtained on the quartz substrate at room temperature was 1.67 when measured with an ellipsometer.

Comparative Example 1
A sintered body was produced under the same conditions as in Example 1 except that metal silicon powder having an average particle size of 10 μm was used instead of SiC powder having an average particle size of 10 μm. When the end material of the sintered body was analyzed in the same manner as in Example 1, a silicon oxide phase was formed between the metal silicon phase and the indium oxide phase in addition to the metal silicon phase and the indium oxide phase. When the composition of the sintered body was analyzed by ICP emission analysis, the content ratio of each metal element (In, Si) was the same as the charged ratio.
In the same manner as in Example 1, a sputtering target having a diameter of 152 mm and a thickness of 5 mm was prepared and evaluated by direct current sputtering. Arcing occurred when the input power was 300 W (the input power density to the target sputtering surface was 1.654 W / cm ² ), and no DC power could be input. Therefore, high-speed film formation cannot be performed using such a sintered body.
Next, an RPG-50 manufactured by ENI was used as the DC power source, DC power using 200 kHz DC pulsing was applied, plasma was generated by DC pulsing, and deposition was attempted. Arcing occurred when the input power density was 2.481 W / cm ² ) or more. Therefore, even with the direct current pulsing method, high-speed film formation cannot be achieved by using such a sintered body.
In addition, the film formation rate when the sintered body of Comparative Example 1 was used to form a film at an input power of 200 W where arcing did not occur was the same under the same film formation conditions using the sintered body of Example 1. As compared with the film forming speed at the time of the above, it is about 90%, and it has been found that it is more effective to use the sintered body of Example 1 as a target in terms of productivity.

Comparative Example 2
A sintered body was produced under the same conditions as in Example 1 except that SiO ₂ powder having an average particle size of 10 μm was used instead of SiC powder having an average particle size of 10 μm. As a result of analyzing the sintered compacts in the same manner as in Example 1, a compound phase (described in JCPDS card 31-600) of silicon oxide phase and In ₂ Si ₂ O ₇ was formed in addition to the indium oxide phase. It was. When the composition of the sintered body was analyzed by ICP emission analysis, the content ratio of each metal element (In, Si) was the same as the charged ratio.
In the same manner as in Example 1, a sputtering target having a diameter of 152 mm and a thickness of 5 mm was prepared, and evaluation by normal (without pulse function) direct current sputtering was performed. Arcing occurred when the input power was 300 W (the input power density to the target sputtering surface was 1.654 W / cm ² ), and no DC power could be input. As in Comparative Example 1, film formation was attempted by the direct current pulsing method, but arcing occurred at an input power of 450 W (power density applied to the target sputtering surface was 2.481 W / cm ² ) or more. Therefore, high-speed film formation cannot be performed using such a sintered body.
In addition, when the sintered body of Comparative Example 2 was used to form a film at a DC input power of 200 W (using a normal DC power supply having no pulse function) in which arcing did not occur, the film formation rate was as in Example 1. It is about 85% compared to the film formation rate when the sintered body is formed under the same film formation conditions. From the viewpoint of productivity, it is more effective to use the sintered body of Example 1 as a target. I found out.

Example 2
A sintered body was produced in the same manner as in Example 1 except that the atomic ratio of silicon was set to 75 atomic% with respect to the total number of silicon and indium atoms. An analysis of the end material of the sintered body revealed that it was composed of an indium oxide phase and a silicon carbide phase. When the composition of the sintered body was analyzed by ICP emission analysis, the content ratio of each metal element (In, Si) was the same as the charged ratio.
In the same manner as in Example 1, a sputtering target having a diameter of 152 mm and a thickness of 5 mm was prepared and evaluated by direct current sputtering (using a normal direct current power source having no pulse function). It was found that arcing did not occur at a DC input power of 100 to 600 W, and a sintered body that could cope with high-speed film formation was obtained.
Moreover, when the refractive index in wavelength 633nm was measured with the ellipsometer about the transparent conductive thin film obtained by sputtering on the quartz substrate at room temperature, it turned out that it is 1.53 and is a low refractive index film | membrane. Therefore, it is a film that can be used as a low refractive index film when producing an antireflection film having a three-layer structure of “on glass substrate / intermediate refractive index film / high refractive index film / low refractive index film”.

Comparative Example 3
A sintered body was produced under the same conditions as in Example 2 except that metal silicon powder having an average particle size of 10 μm was used instead of SiC powder having an average particle size of 10 μm. As a result of analysis of the end material of the sintered body in the same manner as in Example 1, a compound phase of silicon oxide phase and In ₂ Si ₂ O ₇ was formed in addition to the indium oxide phase. When the composition of the sintered body was analyzed by ICP emission analysis, the content ratio of each metal element (In, Si) was the same as the charged ratio.
In the same manner as in Example 1, a sputtering target having a diameter of 152 mm and a thickness of 5 mm was prepared and evaluated by direct current sputtering. Arcing occurred when the input power was 300 W, and no more DC power could be input. Further, as in Comparative Example 1, film formation was attempted by the direct current pulsing method, but arcing occurred at an input power of 400 W (power density applied to the target sputtering surface was 2.205 W / cm ² ) or more. Therefore, high-speed film formation cannot be performed using such a sintered body.
Moreover, the film formation speed when using the sintered body of Comparative Example 3 at a DC input power of 200 W (using a normal DC power supply) in which arcing did not occur was the same as that of the sintered body of Example 2. It is about 75% compared to the film formation rate when the film is formed under the same film formation conditions, and it is understood that it is more effective to use the sintered body of Example 2 as a target in terms of productivity. It was.

Example 3
A sintered body was produced in the same manner as in Example 1 except that the atomic ratio of silicon was 95 atomic% with respect to the total number of silicon and indium atoms. As for the end material of the sintered body, an analysis was performed in the same manner as in Example 1. As a result, it was found that it was composed of an indium oxide phase and a silicon carbide phase.
In the same manner as in Example 1, a sputtering target having a diameter of 152 mm and a thickness of 5 mm was prepared, and evaluation by direct current sputtering using a normal direct current power source (without a pulse function) was performed. It was found that arcing did not occur at an input power of 100 to 600 W, and a sintered body that could cope with high-speed film formation was obtained. Further, when the composition of the sintered body was analyzed by ICP emission analysis, the content ratio of each metal element (In, Si) was the same as the charged ratio.
In the same manner as in Example 1, a sputtering target having a diameter of 152 mm and a thickness of 5 mm was prepared and evaluated by direct current sputtering. A sintered body that does not generate arcing at an input power of 100 to 600 W (an input power density to the target sputtering surface of 0.551 to 3.308 W / cm ² ) and can handle high-speed film formation is obtained. all right.
Moreover, when the refractive index in wavelength 633nm was measured with the ellipsometer about the transparent conductive thin film obtained by sputtering on the quartz substrate at room temperature, it turned out that it is 1.48 and is a low refractive index film | membrane. Therefore, it is a film that can be used as a low refractive index film when producing an antireflection film having a three-layer structure of “on glass substrate / intermediate refractive index film / high refractive index film / low refractive index film”.

Comparative Example 4
A sintered body was produced under the same conditions as in Example 3 except that metal silicon powder having an average particle size of 10 μm was used instead of SiC powder having an average particle size of 10 μm. As a result of analysis of the end material of the sintered body in the same manner as in Example 1, a compound phase of silicon oxide phase and In ₂ Si ₂ O ₇ was formed in addition to the indium oxide phase. Further, when the composition of the sintered body was analyzed by ICP emission analysis, the content ratio of each metal element (In, Si) was the same as the charged ratio.
As in Example 1, a sputtering target having a diameter of 152 mm and a thickness of 5 mm was produced. In DC sputtering, arcing occurred at 300 W (power density applied to the target sputtering surface is 1.654 W / cm ² ) or more, and it was difficult to input power exceeding 300 W. In addition, DC sputtering by the 200 kHz DC pulsing method was attempted using an ENI RPG-50 as the DC pulsing power source, but the power input was 500 W (power density applied to the target sputtering surface was 2.757 W / cm ² ) or more. And arcing has occurred. Therefore, high-speed film formation cannot be performed using such a sintered body.
In addition, when the sintered body of Comparative Example 4 was used to form a film at an input power of 200 W where arcing did not occur in the direct current pulsing method, the same film formation rate was obtained using the sintered body of Example 3. It was about 72% compared with the film formation rate when the film was formed by the direct current pulsing method, and it was found that it is more effective to use the sintered body of Example 3 as a target in terms of productivity. .

Example 4
A sintered body was produced in the same manner as in Example 1 except that the atomic ratio of silicon was 0.5 atomic% with respect to the total number of silicon and indium atoms. An analysis of the end material of the sintered body revealed that it was composed of an indium oxide phase and a silicon carbide phase. Further, when the composition of the sintered body was analyzed by ICP emission analysis, the content ratio of each metal element (In, Si) was the same as the charged ratio.
In the same manner as in Example 1, a sputtering target having a diameter of 152 mm and a thickness of 5 mm was prepared and evaluated by direct current sputtering. A sintered body that does not generate arcing at an input power of 100 to 600 W (an input power density to the target sputtering surface of 0.551 to 3.308 W / cm ² ) and can handle high-speed film formation is obtained. all right.
Further, when the refractive index at a wavelength of 633 nm was measured with an ellipsometer on the transparent conductive thin film obtained by sputtering on a quartz substrate at room temperature, it was 1.98, which was a high refractive index film. Further, when the surface smoothness of the transparent oxide thin film having a thickness of 200 nm was examined with an atomic force microscope, the center line average roughness Ra was 1.5 nm, and the ITO film ( Ra value of 10 wt% SnO ₂ -containing target) is lower than 3.5 nm, and it was revealed that the surface smoothness was improved by adding Si. Further, the specific resistance was 5.5 × 10 ⁻⁴ Ωcm, the average transmittance of the visible region of the film itself was 91% or more, and it was found that the film had excellent characteristics as a transparent conductive film.

Comparative Example 5
A sintered body was produced under the same conditions as in Example 4 except that metal silicon powder having an average particle size of 10 μm was used instead of SiC powder having an average particle size of 10 μm. When the end material of the sintered body was analyzed in the same manner as in Example 1, a slight silicon oxide phase and an In ₂ Si ₂ O ₇ compound phase were formed in addition to the indium oxide phase. Further, when the composition of the sintered body was analyzed by ICP emission analysis, the content ratio of each metal element (In, Si) was the same as the charged ratio.
As in Example 1, a sputtering target having a diameter of 152 mm and a thickness of 5 mm was produced. Arcing did not occur at a DC input power of 100 to 600 W. The reason why arcing did not occur is that the proportion of the silicon oxide phase was very small. The properties (surface smoothness, conductivity, light transmittance) of the obtained film were almost the same as those obtained in Example 4.
However, the film forming speed when the film was formed by the direct current sputtering method using the sintered body of Comparative Example 5 was compared with that when the film was formed under the same film forming conditions using the sintered body of Example 4. In view of productivity, it was found that it was more effective to use the sintered body of Example 4 as a target.

Example 5
A sintered body was prepared in the same manner as in Example 1 except that the atomic ratio of silicon was changed to 10 atomic% with respect to the total number of silicon and indium atoms. An analysis of the end material of the sintered body revealed that it was composed of an indium oxide phase and a silicon carbide phase. Further, when the composition of the sintered body was analyzed by ICP emission analysis, the content ratio of each metal element (In, Si) was the same as the charged ratio.
In the same manner as in Example 1, a sputtering target having a diameter of 152 mm and a thickness of 5 mm was prepared, and evaluation by direct current sputtering using a normal direct current power source (without a pulse function) was performed. A sintered body that does not generate arcing at an input power of 100 to 600 W (an input power density to the target sputtering surface of 0.551 to 3.308 W / cm ² ) and can handle high-speed film formation is obtained. all right.
Moreover, when the refractive index in wavelength 633nm was measured with the ellipsometer about the transparent conductive thin film obtained by sputtering on the quartz substrate of room temperature, it was 1.88 and was a high refractive index film | membrane. Further, when the surface smoothness of the transparent oxide thin film having a film thickness of 200 nm was examined with an atomic force microscope, the center line average roughness Ra was 1.2 nm, and an ITO film produced under the same film formation conditions ( 10% by weight of SnO ₂ -containing target) was lower than the Ra value of 3.8 nm, and it was revealed that the surface smoothness was improved by the addition of Si. The specific resistance was 6.6 × 10 ⁻⁴ Ωcm, the average transmittance in the visible region of the film itself was 91% or more, and it was found that the film had excellent characteristics as a transparent conductive film.

Comparative Example 6
A sintered body was produced under the same conditions as in Example 5 except that metal silicon powder having an average particle size of 10 μm was used instead of SiC powder having an average particle size of 10 μm. When the end material of the sintered body was analyzed in the same manner as in Example 1, a silicon oxide phase and an In ₂ Si ₂ O ₇ compound phase were formed in addition to the indium oxide phase. Further, when the composition of the sintered body was analyzed by ICP emission analysis, the content ratio of each metal element (In, Si) was the same as the charged ratio.
As in Example 1, a sputtering target having a diameter of 152 mm and a thickness of 5 mm was produced. Arcing did not occur at a DC input power of 100 to 600 W. The characteristics (surface smoothness, conductivity, light transmittance) of the obtained film were almost the same as those of the film obtained in Example 5.
However, the film formation rate when the direct current sputtering method was used to form a film using the sintered body of Comparative Example 6 was higher than when the film was formed under the same film formation conditions using the sintered body of Example 5. From the viewpoint of productivity, it was found that it was more effective to use the sintered body of Example 5 as a target.

Example 6
The mixing ratio of indium oxide and silicon carbide was changed so that the content of silicon element was in the range of 0.5 atomic% to 99.5 atomic% with respect to the total content of indium element and silicon element. The sintered body was prepared in the same manner as in No. 1, but a sintered body composed of an indium oxide phase and a silicon carbide phase was obtained, and the room temperature was obtained by a direct current sputtering method using a normal direct current power source (without a pulse function). A transparent oxide film was prepared on the quartz substrate. When the ratio of the silicon atomic quantity to the sum of the atomic quantities of indium and silicon in the sintered body and in the transparent oxide film was compared, it was the same. When the content of silicon element in the sintered body is 0.5 atomic% or more and 35 atomic% or less with respect to the total content of indium element and silicon element, the specific resistance is 3.8 × 10 ⁻⁴ or more and 5.5. A transparent oxide film having a high conductivity of × 10 ⁻³ Ωcm or less and a smooth surface smoothness with a centerline average surface roughness Ra of 2.5 nm or less can be obtained, and the silicon element content is 8 atomic%. When the content is less than 60 atomic%, an intermediate refractive index film having a refractive index of 1.6 to 1.9 at a wavelength of 633 nm can be obtained, and the silicon element content is 60 atomic% to 99.5 atomic%. It was found that a low refractive index film having a refractive index of 1.48 or more and less than 1.60 at a wavelength of 633 nm can be obtained.

(SnO ₂ —SiC sintered body)
Example 7
Formulated with SnO ₂ powder with an average particle size of 10 μm and SiC powder with an average particle size of 10 μm containing Al as a trace additive element so that the atomic ratio of silicon is 28 atomic% with respect to the total number of silicon and tin atoms Subsequently, the mixture was stirred with a three-dimensional mixer to obtain a raw material powder. The obtained mixed powder was fed into a carbon container and sintered using a hot press method with different temperature conditions in each example. Sintering was performed in an Ar gas atmosphere in order to prevent deterioration of the carbon container due to oxidation. First, the pressure was fixed at 4.9 MPa, the sintering temperature was 1000 ° C., and the sintering time was 3 hours.
About the end material of the obtained sintered body, as in Example 1, powder X-ray diffraction measurement (XRD), scanning electron microscope (SEM) equipped with an energy dispersive X-ray fluorescence analyzer (EDX), transmission type Analysis was performed using electron diffraction using an electron microscope (TEM), and further using an X-ray photoelectron spectrometer (XPS). As a result, the sintered body was composed of a tin oxide phase and a silicon carbide phase, and the presence of a silicon oxide phase was not observed in the sintered body. Further, when the composition of the sintered body was analyzed by ICP emission analysis, the content ratio of each metal element (Sn, Si) was the same as the charged ratio.

  Next, these sintered bodies are processed into a diameter of 152 mm and a thickness of 5 mm, the sputtering surface is polished with a cup grindstone to be a target surface, bonded to an oxygen-free copper backing plate using metallic indium, and sputtering is performed. Got the target.

Next, direct current sputtering was performed by processing the sintered body manufactured under the conditions of Example 1 as described above and using it as each sputtering target. The sputtering apparatus used was a DC magnetron sputtering apparatus manufactured by Tokki. Ar gas having a purity of 99.9999% by weight and O ₂ gas were introduced to make the total gas pressure 0.5 Pa, and the flow rate ratio of O ₂ gas was set to 2 to 10%. Using RPG-50 manufactured by ENI as a DC power source, DC power employing 200 kHz DC pulsing was applied between the target and the substrate to generate plasma by DC pulsing. DC power was generated at an input power of 100 W, and then the power was gradually increased to determine the power at which arcing occurred. However, even when DC power is applied up to 600 W (power density applied to the target sputtering surface is 3.308 W / cm ² ), arc discharge does not occur, stable discharge is possible, and high-speed film formation is possible. .
When the refractive index at a wavelength of 633 nm was measured with an ellipsometer on the transparent conductive thin film obtained by sputtering on a quartz substrate at room temperature, it was 1.80, which was an intermediate refractive index film.

Next, a PES film with an undercoat (manufactured by Sumitomo Bakelite Co., Ltd., FST-UCPES, thickness 0.2 mm) is used as a resin film substrate, and is placed on the surface facing the target of the above magnetron sputtering apparatus. A DC power of 400 W (power input per unit area of the target sputtering surface is 2.205 W / cm ² ) was applied, and a film thickness of 200 nm was formed on the film substrate at room temperature from the oxide sintered body of the present invention. A transparent oxide film was formed. The transmittance in the visible region of the transparent oxide film decreased as the amount of oxygen introduced into the argon gas decreased, but a transparent oxide film having a high transmittance was obtained with an oxygen amount of 8% or more.

When the film composition of a highly permeable transparent oxide film obtained with an oxygen content of 8% or more was measured by ICP emission analysis, the silicon content was almost the same as the composition of the oxide sintered body. Further, when the crystallinity of the obtained transparent oxide film was measured by X-ray diffraction, no diffraction peak was observed, and it was confirmed to be an amorphous structure. In addition, when the center line average surface roughness Ra of the 1 μm × 1 μm region of the film surface was measured at 20 points in the sample with an atomic force microscope (Digital Instruments, NS-III, D5000 system), the average value was obtained. A film having a surface smoothness of 2.2 nm was obtained.
The water vapor transmission rate was measured based on the JIS standard K7129 method (temperature 40 ° C., humidity 90% RH) using the MOCON method and PERMATRAN-W3 / 33 manufactured by MOCON. The water vapor permeability of the obtained film was less than the measurement limit (0.01 g / m ² / day) of the Mocon method, and it was found that the film sufficiently functions as a moisture-proof film.

Comparative Example 7
A sintered body was produced under the same conditions as in Example 7 except that metal silicon powder having an average particle size of 10 μm was used instead of SiC powder having an average particle size of 10 μm. When the end material of the sintered body was analyzed in the same manner as in Example 7, a silicon oxide phase was formed between the metal silicon phase and the tin oxide phase in addition to the tin oxide phase and the metal silicon phase. Further, when the composition of the sintered body was analyzed by ICP emission analysis, the content ratio of each metal element (Sn, Si) was the same as the charged ratio.
In the same manner as in Example 7, a sputtering target having a diameter of 152 mm and a thickness of 5 mm was produced, and evaluation by direct current sputtering using a direct current pulsing method of 200 kHz was performed. When the input power was 300 W (the input power density to the target sputtering surface was 1.654 W / cm ² ), arcing occurred vigorously, and no more DC power could be input. Therefore, high-speed film formation cannot be performed using such a sintered body.
In addition, when the sintered body of Comparative Example 7 was used and the film was formed stably at 200 W by the DC sputtering method, the film formation rate was the same as that of the sintered body of Example 7 under the same film forming conditions. It is about 85% compared with the time, and it can be said that it is inferior to the sintered body of Example 7 also in terms of productivity.
Under such circumstances, a transparent oxide film having a film thickness of 200 nm is formed on a PES film with an undercoat (Sumitomo Bakelite, FST-UCPS, thickness 0.2 mm) under the same conditions as in Example 7. Then, the water vapor transmission rate by the Mocon method was measured under the same conditions as in Example 7. However, it was 15.6 g / m ² / day or more, and the moisture resistance was insufficient. This is because a transparent oxide that is damaged and has defects is produced by arcing during film formation.

Comparative Example 8
A sintered body was produced under the same conditions as in Example 7 except that SiO ₂ powder having an average particle size of 10 μm was used instead of SiC powder having an average particle size of 10 μm. When the end material of the sintered body was analyzed in the same manner as in Example 7, a compound phase of the silicon oxide phase and SnSiO ₃ (described in the JCPDS card) was formed in addition to the tin oxide phase. When the composition of the sintered body was analyzed by ICP emission analysis, the content ratio of each metal element (Sn, Si) was the same as the charged ratio.
In the same manner as in Example 5, a sputtering target having a diameter of 152 mm and a thickness of 5 mm was prepared, and evaluation by direct current sputtering using a direct current pulsing method of 200 kHz was performed. Arcing occurred when the input power was 300 W (the input power density to the target sputtering surface was 1.654 W / cm ² ), and no DC power could be input. Therefore, high-speed film formation cannot be performed using such a sintered body.
In addition, when the sintered body of Comparative Example 8 was used and the film was formed stably at 200 W by the direct current sputtering method, the film formation rate was the same as that of the sintered body of Example 7 under the same film forming conditions. It is about 83% compared to the time, and it can be said that it is inferior to the sintered body of Example 7 in terms of productivity.

Example 8
Sintered body in the same manner as in Example 7 except that the mixing ratio of tin oxide and silicon carbide was changed within the range of 0.5 to 99.5 atomic% with respect to the total content of tin and silicon. Was made. Sintered bodies composed of tin oxide and silicon carbide can be obtained. In all the sintered bodies, input power is 100 to 600 W (power density applied to the target sputtering surface is 0.551 to 3.308 W / cm ^2. It was found that a sintered body capable of handling high-speed film formation was obtained without arcing. And using these, the transparent oxide film was produced by the direct current | flow sputtering method of the 200 kHz direct current | flow pulsing method. When the ratio of the silicon content to the total content of tin and silicon in the sintered body and in the transparent oxide film was compared, the results were the same. When the silicon content in the sintered body is in the range of 0.5 to 99.5 atomic% with respect to the total content of tin and silicon, the surface smooth transparency with a centerline surface average roughness Ra of 2.5 nm or less An oxide film was obtained. When the silicon content of the sintered body is 0.5 atomic% or more and 25 atomic% or less with respect to the total content of tin and silicon, the specific resistance is 1.5 × 10 ⁻³ Ωcm or more and 5.6 × 10 ^−1. A transparent conductive film of Ωcm or less can be obtained, and an intermediate refractive index film having a refractive index of 1.6 to 1.9 at a wavelength of 633 nm can be obtained when it is 5 atomic% to 63 atomic%. It was found that a low refractive index film having a refractive index of 1.48 or more and less than 1.60 at a wavelength of 633 nm can be obtained when it is super 99.5 atomic% or less.

Example 9
By changing the compounding ratio of tin oxide and silicon carbide, the number of silicon atoms was 0.5, 5, 15, 63, 82, 99.5 atomic% (all in the total amount of tin and silicon) as in Example 7. (Analytical value) sintered body, transparent oxide with a film thickness of 200 nm on a PES film substrate (manufactured by Sumitomo Bakelite, FST-UCPES, thickness 0.2 mm) with an undercoat under the same conditions as in Example 7. A material film was prepared. When the ratio of the number of silicon atoms to the total number of tin and silicon atoms in the sintered body and the transparent oxide film was compared, it was almost the same. When the center line average surface roughness Ra was measured by the same method in all composition regions, a film having a good surface smoothness of 1.1 to 2.5 nm was obtained. _{2. When} a SiO ₂ film (formed from an Si target by RF sputtering), which is conventionally used as a moisture-proof film, is formed on the same substrate by a film thickness of 200 nm and the center line average surface roughness Ra value is measured. It was 9 nm, and it became clear that the surface smoothness of the thin film of the present invention was remarkably good. In addition, Example 7 regarding a film substrate with a film obtained by performing film formation under the same conditions as Example 7 on a PES film with an undercoat (manufactured by Sumitomo Bakelite, FST-UCPES, thickness 0.2 mm) When the moisture resistance was evaluated under the same conditions as those described above, it was found that all were less than the measurement limit (0.01 g / m ² / day) of the Mokon method and functioned sufficiently as a moisture barrier film.

(ZnO-SiC sintered body)
Example 10
SiC powder having an average particle diameter of 10 μm containing N as a trace additive element so that the atomic ratio of silicon is 28 atomic% with respect to the total number of atoms of all metal elements (Zn, Si, Ga), and barium atoms A Ga ₂ O ₃ powder with an average particle diameter of 10 μm and a ZnO powder with an average particle diameter of 10 μm are blended so that the number ratio is 5 atomic% with respect to the total number of atoms of all metal elements (Zn, Si, Ga). Subsequently, the mixture was stirred with a three-dimensional mixer to obtain a raw material powder. The obtained mixed powder was fed into a carbon container and sintered using a hot press method with different temperature conditions in each example. Sintering was performed in an Ar gas atmosphere in order to prevent deterioration of the carbon container due to oxidation. First, the pressure was fixed at 4.9 MPa, the sintering temperature was 1000 ° C., and the sintering time was 3 hours.

About the end material of the obtained sintered body, as in Example 1, powder X-ray diffraction measurement, scanning electron microscope (SEM) equipped with energy dispersive X-ray fluorescence spectrometer (EDX), transmission electron microscope (TEM) ) Analysis using an X-ray photoelectron spectrometer (XPS). As a result, it was confirmed that it was composed of zinc oxide and silicon carbide. In addition, the presence of a silicon oxide phase was not observed in the sintered body. Further, when the composition of the sintered body was analyzed by ICP emission analysis, the content ratio of each metal element (Zn, Si, Ga) was the same as the charged ratio.
Next, these sintered bodies are processed into a diameter of 152 mm and a thickness of 5 mm, the sputtering surface is polished with a cup grindstone to be a target surface, bonded to an oxygen-free copper backing plate using metallic indium, and sputtering is performed. Got the target.

Next, the sintered body manufactured under the conditions of Example 1 as described above was processed and used as each sputtering target, and normal (pulseless) direct current sputtering was performed. The sputtering apparatus used was a DC magnetron sputtering apparatus manufactured by Tokki. Ar gas having a purity of 99.9999% by weight and O ₂ gas were introduced to make the total gas pressure 0.5 Pa, and the flow rate ratio of O ₂ gas was set to 2 to 10%. DC power was generated with an input power of DC 100 W, and then the power was gradually increased to determine the power at which arcing occurred. However, even when DC power is applied up to 600 W (power density applied to the target sputtering surface is 3.308 W / cm ² ), arc discharge does not occur, stable discharge is possible, and high-speed film formation is possible. .

A PES film with an undercoat (manufactured by Sumitomo Bakelite Co., Ltd., FST-UCPES, thickness 0.2 mm) is used as the resin film substrate, and is installed on the surface facing the target of the above magnetron sputtering apparatus. The input power per unit area of the sputtering surface was 2.205 W / cm ² ), and a transparent oxide film having a thickness of 200 nm was formed on the film substrate at room temperature from the oxide sintered body of the present invention. . The transmittance in the visible region of the transparent oxide film decreased as the amount of oxygen introduced into the argon gas decreased, but a transparent oxide film having a high transmittance was obtained when the oxygen amount was 5% or more.
When the film composition of a highly permeable transparent oxide film obtained with an oxygen content of 5% or more was measured by ICP emission analysis, the silicon content was almost the same as the composition of the oxide sintered body. Further, when the crystallinity of the obtained transparent oxide film was measured by X-ray diffraction, no diffraction peak was observed, and it was confirmed that the film had an amorphous structure. In addition, when the center line average surface roughness Ra of the 1 μm × 1 μm region of the film surface was measured at 20 points in the sample with an atomic force microscope (Digital Instruments, NS-III, D5000 system), the average value was obtained. A film having a surface smoothness of 0.8 to 2.5 nm was obtained.
The water vapor transmission rate was measured based on the JIS standard K7129 method (temperature 40 ° C., humidity 90% RH) using the MOCON method and PERMATRAN-W3 / 33 manufactured by MOCON. The water vapor permeability of the obtained film was less than the measurement limit (0.01 g / m ² / day) of the Mocon method, and it was found that the film sufficiently functions as a moisture-proof film.

Example 11
The compounding ratio of zinc oxide and silicon carbide was changed within the range of 0.5 to 99.5 atomic% with respect to the total content of all metal elements, and the sintered body was obtained in the same manner as in Example 10. The transparent oxide film was produced by direct current sputtering. The sintered body was composed of zinc oxide and silicon carbide, and no silicon oxide phase was present. When the ratio of the silicon content to the total content of zinc, silicon and gallium in the sintered body and in the transparent oxide film was compared with the ratio of the gallium content, the results were the same. When the silicon content is 0.5 atomic% or more and 23 atomic% or less with respect to the total content of zinc, silicon and gallium, the specific resistance is 8.5 × 10 ⁻⁴ Ωcm or more and 5.3 × 10 ^−. A transparent conductive film of ¹ Ωcm or less can be obtained, and an intermediate refractive index film having a refractive index of 1.6 to 1.9 at a wavelength of 633 nm when it is 10 atomic% to 55 atomic% can be obtained. It was found that a low refractive index film having a refractive index of 1.48 or more and less than 1.60 at a wavelength of 633 nm can be obtained when the atomic percentage is more than 9% and not more than 99.5 atomic%.

Comparative Example 9
A sintered body was produced under the same conditions as in Example 10 except that silicon oxide powder having an average particle size of 10 μm was used instead of SiC powder having an average particle size of 10 μm. When the end material of the sintered body was analyzed in the same manner as in Example 10, a silicon oxide phase was formed in addition to the zinc oxide phase.
In the same manner as in Example 10, a sputtering target having a diameter of 152 mm and a thickness of 5 mm was prepared and evaluated by direct current sputtering. When the input power was 300 W (the input power density to the target sputtering surface was 1.654 W / cm ² ), arcing occurred vigorously, and no more DC power could be input. In addition, as in Comparative Example 1, film formation was attempted by the direct current pulsing method, but arcing occurred with an input power of 400 W or more. Therefore, when such a sintered body is used, not only high-speed film formation cannot be performed, but also a high-quality film cannot be obtained.
In addition, when the sintered body of Comparative Example 9 was used and the film was formed stably at 200 W by the DC sputtering method, the film formation rate was the same as that of the sintered body of Example 10 under the same film forming conditions. It is about 75% compared to the time, and it can be said that the productivity is inferior to the sintered body of Example 10 in terms of productivity.

Comparative Example 10
A sintered body was produced in the same manner as in Comparative Example 9 by changing the compounding ratio of zinc oxide and silicon oxide within the range of 0.5 to 99.5 atomic% of silicon element with respect to the total of zinc element and silicon element. However, in any case, a silicon oxide phase was generated, and the film could not be stably formed by direct current sputtering. Similarly to Comparative Example 1, even when film formation was attempted by the direct current pulsing method, arcing occurred at an input power of 350 W (the power density applied to the target sputtering surface was 1.930 W / cm ² ) or more. Therefore, when the sintered body of Comparative Example 10 was used, high-speed film formation could not be performed, and a high-quality film could not be obtained.

Claims (16)

  A sintered body composed of a conductive oxide and silicon carbide, wherein the silicon content in the sintered body is 0.5 to 99.5 with respect to the total metal element content in the sintered body. A sintered body characterized by a ratio of atomic%.   The sintered body according to claim 1, wherein the silicon carbide contains at least one additive element selected from nitrogen, boron, phosphorus, and aluminum.   The sintered body according to claim 1, wherein the conductive oxide has at least one material selected from the group of indium oxide, zinc oxide, and tin oxide as a main component.   2. The method for producing a sintered body according to claim 1, wherein a conductive oxide powder and a silicon carbide powder are used as starting materials, they are mixed, and the mixture is sintered.   The method for producing a sintered body according to claim 4, wherein the conductive oxide has at least one material selected from the group of indium oxide, zinc oxide, and tin oxide as a main component.   6. The method for producing a sintered body according to claim 4 or 5, wherein the conductive oxide powder has an average particle size of 50 [mu] m or less, and the silicon carbide powder has an average particle size of 50 [mu] m or less.   The method for producing a sintered body according to any one of claims 4 to 6, wherein the mixture is sintered by a hot press method.   A transparent oxide thin film produced by a sputtering method using the sintered body according to any one of claims 1 to 3 as a raw material, wherein the transparent oxide thin film contains silicon. Thin film.   9. The transparent oxide thin film according to claim 8, having a refractive index of light at a wavelength of 633 nm having an intermediate refractive index of 1.6 or more and 1.9 or less.   The transparent oxide thin film according to claim 8, wherein the transparent oxide thin film has a low refractive index of 1.48 or more and less than 1.6 at a wavelength of 633 nm. The transparent oxide thin film according to claim 8, wherein the transparent oxide thin film has a specific resistance of 5.5 × 10 ⁻³ Ωcm or less. The transparent oxide thin film according to claim 8, wherein the transparent oxide thin film has a specific resistance of 5.6 × 10 ⁻¹ Ωcm or less.   9. The transparent oxide thin film according to claim 8, wherein the center line average surface roughness Ra of the film surface is 2.5 nm or less.   A gas barrier transparent resin substrate, wherein the transparent oxide thin film according to any one of claims 8 to 13 is formed on at least one surface side of a resin film substrate. 15. The gas barrier transparent resin substrate according to claim 14, wherein the water vapor permeability measured by the Mocon method measured according to JIS standard K7129 is less than 0.01 g / m ² / day.   A transparent oxide thin film according to any one of claims 8 to 13 obtained by a direct current sputtering method using the sintered body according to any one of claims 1 to 3 as a raw material. Method of manufacturing a thin film.