KR101322800B1 - Oxide deposition material and transparent conductive film - Google Patents

Abstract

The oxide vapor deposition material of the present invention is composed of an oxide sintered body containing indium oxide as a main component and containing tin in an Sn / In atomic ratio of 0.001 to 0.614, wherein the L ^* value in the CIE1976 color system is 54 to 75. It is done. Since the oxide deposition material having an L ^* value of 54 to 75 has an optimum amount of oxygen, an oxygen gas introduction amount into the film forming vacuum chamber is at least low in resistance and a high permeability transparent conductive film in the visible range can be produced by vacuum deposition, Since the amount of oxygen gas introduced is small, the compositional difference between the film and the evaporation material can be made small, so that variations in film composition and characteristics in mass production can also be reduced.

Description

Oxide evaporation material and transparent conductive film {OXIDE DEPOSITION MATERIAL AND TRANSPARENT CONDUCTIVE FILM}

The present invention relates to an oxide vapor deposition material used when producing a transparent conductive film by various vacuum deposition methods such as an electron beam vapor deposition method, an ion plating method, a high density plasma assist vapor deposition method, and a transparent conductive film produced using the oxide vapor deposition material. For example, the present invention relates to an improvement of an oxide deposition material used for producing a transparent conductive film having low resistance useful as a transparent electrode of a solar cell and exhibiting high transmittance in the visible region.

The transparent conductive film has high conductivity and high light transmittance in the visible light region. Taking advantage of this characteristic, the transparent conductive film is used for solar cells, liquid crystal display elements, electrodes of various light receiving elements, and the like, and also utilizes heat absorbing characteristics in the near-infrared region and is used for window glass of automobiles and buildings. It is also used as an antifogging transparent heating element, such as a reflective film, various antistatic films, and a freezing showcase.

In addition, the transparent conductive film generally includes tin oxide (SnO ₂ ) containing antimony or fluorine as a dopant, zinc oxide (ZnO) containing aluminum, gallium, indium, tin as a dopant, tin, tungsten, titanium there is a widely used, such as indium oxide (In ₂ O ₃₎ containing as a dopant. In particular, an indium oxide film containing tin as a dopant, i.e., an In ₂ O ₃ -Sn-based film, is called an indium tin oxide (ITO) film, and a low-resistance transparent conductive film is easily obtained. Has been.

And as a manufacturing method of these transparent conductive films, the vacuum vapor deposition method, the sputtering method, the method of apply | coating the coating liquid for transparent conductive layer formation, etc. are generally used. Among them, the vacuum evaporation method and the sputtering method are effective methods when using materials with low vapor pressure or when precise film thickness control is required, and they are industrially useful because they are very easy to operate. In addition, when the vacuum deposition method and the sputtering method are compared, since the vacuum deposition method can form a film at high speed, it is excellent in mass productivity.

By the way, in general, the vacuum deposition method is a method of heating a solid or liquid as an evaporation source to decompose once into gas molecules or atoms in a vacuum of about 10 ^-3 to 10 ^-2 Pa, and then condensing it as a thin film on the substrate surface again. Moreover, although the heating method of the said evaporation source is various, the resistance heating method (RH method) and the electron beam heating method (EB method, electron beam vapor deposition method) are common. There are also known reactive evaporation deposition while introducing a reaction gas such as O ₂ gas into the film formation chamber (chamber).

In the case of depositing an oxide film such as ITO, the electron beam vapor deposition method has historically been well used. That is, using an oxide vapor deposition material (also called an ITO tablet or an ITO pellet) of ITO as an evaporation source, O ₂ gas, which is a reaction gas, is introduced into the film formation chamber (chamber), and is protruded from the filament for generating hot electrons (mainly W-line). When hot electrons are accelerated in an electric field and irradiated onto the oxide vapor deposition material of ITO, the irradiated portion becomes locally high temperature, and evaporates and is deposited on the substrate. In addition, an activated reactive vapor deposition method (ARE method) capable of producing a low-resistance film on a low temperature substrate by generating a plasma using a hot electron emitter or an RF discharge and activating an evaporate or a reaction gas (O ₂ gas, etc.) with the plasma. It is a useful method for ITO deposition. In recent years, high density plasma assist deposition (HDPE) using a plasma gun has also been found to be an effective method for ITO film formation, and has been widely used industrially ("Vacuum", Vol. 44, No. 4, 2001). , p. 435-439: See Non-Patent Document 1). In this method, arc discharge using a plasma generator (plasma gun) is used, but arc discharge is maintained between the cathode embedded in the plasma gun and the crucible (anode) of the evaporation source. Electrons emitted from the cathode are guided (guided) by the magnetic field and concentrated to irradiate the localized portions of the oxide deposition material of ITO charged into the crucible. From the portion where the electron beam is irradiated and locally hot, evaporates evaporate and are deposited on the substrate. Since the vaporized evaporate and the introduced O ₂ gas are activated in this plasma, an ITO film having good electrical characteristics can be produced. As another classification method of these various vacuum deposition methods, the ionization of evaporates or reaction gases is collectively called ion plating method (IP method), and is effective as a method of obtaining a low resistance and high light transmittance ITO film ("Transparent conductive film technology"). , Omsa, 1999, p. 205-211: see Non-Patent Document 2).

By the way, in any type of solar cell to which a transparent conductive film is applied, the transparent conductive film is indispensable to the electrode on the surface side where light hits, and conventionally, the above-described ITO film, aluminum or gallium-doped zinc oxide (ZnO) Membrane has been used. And these transparent conductive films are requested | required of characteristics, such as low resistance and the thing with high light transmittance of sunlight. As the method for producing these transparent conductive films, vacuum deposition methods such as the ion plating method and the high density plasma assist deposition method described above are used.

The oxide evaporation material used in the vacuum deposition method such as the electron beam deposition method, the ion plating method, or the high density plasma assist deposition method may be a sintered compact of a small size (for example, a cylindrical shape having a diameter of 10 to 50 mm and a height of about 10 to 50 mm). Therefore, there is a limit to the amount of film that can be formed by one oxide deposition material. When the amount of the oxide evaporation material consumed increases and the remaining amount decreases, the film formation is stopped, the film formation chamber in vacuum is introduced into the air, the film deposition chamber needs to be replaced with an unused oxide evaporation material, and the film formation chamber needs to be vacuumed again. It was a factor to make things worse.

Therefore, as an indispensable technique in the case of mass-producing a transparent conductive film by vacuum deposition methods, such as an electron beam vapor deposition method, an ion plating method, and a high density plasma assist vapor deposition method, the continuous supply method of the said oxide vapor deposition material is mentioned, The example is given by the nonpatent literature 1 It is described. In this continuous supply method, a cylindrical oxide vapor deposition material is continuously stored inside the cylindrical hearth, and the oxide vapor deposition material is pushed out one after another while the height of the lift screen is kept constant. By the continuous supply method of the oxide vapor deposition material, mass production of the transparent conductive film by the vacuum deposition method is realized.

And about the oxide vapor deposition material used as a raw material, the vapor deposition material of ITO is introduced by patent document 1 (Unexamined-Japanese-Patent No. 8-104978). Substantially granular in the form of an In ₂ O ₃ -SnO ₂ system composed of indium, tin, and oxygen, the volume of one particle is 0.01 to 0.5 cm ³ , the relative density is 55% or more, and when the container is filled A vapor deposition material of ITO having a bulk density of 2.5 g / cm ³ or less has been proposed. In this configuration, an ITO film having a low resistance can be formed stably by electron beam evaporation, and thus the utilization efficiency is 80% or more, and an ITO evaporation material capable of continuous supply without being blocked in the feeder can be obtained. It is.

In addition, Patent Document 2 (Japanese Patent Laid-Open No. 2007-84881) discloses a vapor deposition material of ITO made of indium oxide and tin oxide. The ITO vapor deposition material of patent document 2 is comprised from the cylindrical oxide sintered compact of density 4.9g / cm <^3> , diameter 30mm, and thickness 40mm, and it is described that continuous supply is possible in a feeder, without being damaged.

By the way, using a conventional ITO evaporation material (oxide evaporation material) described in the patent document and the like, by a variety of vacuum evaporation methods such as electron beam evaporation method, ion plating method, high-density plasma assist evaporation method, a transparent conductive film having low resistance and high light transmittance When manufacturing, since it is necessary to introduce a lot of oxygen gas into a film-forming vacuum chamber at the time of film-forming (for example, refer description of Paragraph 0007 and Paragraph 0108 of patent document 2), it is mainly as described below. There is a problem.

First, the composition deviation of a transparent conductive film and an oxide vapor deposition material becomes large, and the composition design of a transparent conductive film becomes difficult. It is because the composition difference of a transparent conductive film and an oxide vapor deposition material tends to become large, in general, when the amount of oxygen introduced into a film forming vacuum chamber increases. In the film-forming mass production step, variations in the amount of oxygen in the film forming vacuum chamber are also likely to occur, and therefore, variations in the film composition are also likely to occur, leading to variations in the film properties.

Moreover, in reactive vapor deposition using oxygen gas, when the amount of oxygen increases, not only the density of the film is lowered, but also the problem that the adhesion of the film to the substrate is weakened occurs. This is because when the evaporated metal oxide is oxidized until it reaches the substrate, energy is lost. Therefore, when the ratio of oxidation increases, it is difficult to obtain a dense and highly adherent film against the substrate.

In the case where a transparent conductive film is formed on a substrate covered with a metal film or an organic material film, the surface of which is likely to be oxidized, if the oxygen gas in the film forming vacuum chamber is large, the surface of the substrate is oxidized before film formation, whereby a high performance device can be manufactured. There will be no. This tendency becomes more remarkable as the substrate temperature at the time of film formation is higher. For example, when manufacturing a solar cell such as converting energy by injecting light from a surface opposite to the substrate, it is necessary to form a transparent conductive film on a PIN element formed of a metal thin film. In this case, the device is easily damaged, and a high performance device cannot be manufactured. Similarly, in the case of forming an organic thin film solar cell or a top emission type organic electroluminescent device, when the transparent conductive film is formed on the organic light emitting layer, the organic light emitting layer is oxidized and damaged in a situation where the amount of oxygen introduction is high. Can not be realized.

The present invention has been made in view of the above problems, and its object is to make indium oxide added with tin as a main component, and the amount of oxygen introduced at the time of film formation is at least low resistance and transparent having high light transmittance in the visible region. It is providing the oxide vapor deposition material which can manufacture a conductive film stably, and also provides the transparent conductive film manufactured using this oxide vapor deposition material.

That is, the oxide vapor deposition material according to the present invention is composed of an oxide sintered body containing indium oxide as a main component and containing tin, and the content of tin is 0.001 to 0.614 in the Sn / In atomic ratio, and L in the CIE1976 color system. ^* Value is 54-75, It is characterized by the above-mentioned.

The transparent conductive film according to the present invention containing indium oxide as a main component and containing tin is composed of a crystalline transparent conductive film formed by an electron beam deposition method, an ion plating method or a high density plasma assist deposition method using the oxide deposition material. Moreover, content of tin is 0.001-0.614 by Sn / In atomic ratio, It is characterized by the above-mentioned.

In addition, since the oxide vapor deposition material according to the present invention having an L ^* value of 54 to 75 in the CIE1976 colorimetric system has an optimum amount of oxygen, by applying this oxide vapor deposition material, the amount of oxygen gas introduced into the deposition vacuum chamber is at least low. It is possible to manufacture a transparent transparent conductive film in the visible range by vacuum deposition, and also because the amount of oxygen gas introduced into the deposition vacuum chamber is small, it is possible to reduce the compositional difference between the film and the oxide deposition material. As a result, not only the desired film composition can be easily obtained, but also variations in film composition and characteristics in mass production can be reduced. In addition, since the deposition amount of the oxygen gas into the film formation vacuum chamber is small, the damage to the substrate by the oxygen gas can be reduced, thereby realizing a high-performance device. In particular, it is possible to stably produce a high-performance film useful for solar cells without damaging the substrate.

Hereinafter, embodiments of the present invention will be described in detail.

(1) oxide vapor deposition material

The oxide vapor deposition material of the present invention contains indium oxide as a main component and has a composition in which tin is contained in a ratio of 0.001 to 0.614 in the Sn / In atomic ratio. Since the composition of the transparent conductive film produced by the vacuum deposition method using the oxide vapor deposition material of the present invention is very close to that of the oxide vapor deposition material, the film composition to be produced also has indium oxide as a main component and Sn / In atomic ratio. The tin is a composition containing only the ratio of 0.001 to 0.614. The reason for containing only tin in the above ratio is that the mobility of the indium oxide film can be increased. If the film composition, that is, the tin content (Sn / In atomic ratio) of the oxide vapor deposition material composition is less than 0.001, the effect of increasing the carrier concentration (that is, the effect of increasing mobility) is small and a low resistance film cannot be obtained. Moreover, when it exceeds 0.614, the amount of tin in a film will be too large, neutral impurity scattering at the time of electron transfer will become large, and mobility will fall and a low resistance film will not be obtained. The more preferable content of tin for exerting a higher carrier concentration and obtaining a low resistance film is 0.040 to 0.163 in the Sn / In atomic ratio, and the film is a crystal film.

By the way, although the transparent conductive film which has indium oxide as a main component is an n-type semiconductor, in order to exhibit high electroconductivity and high light transmittance, moderate oxygen deficiency is required. That is, in the case where the amount of oxygen in the film is large and the amount of oxygen deficiency is small, for example, even when a dopant is included, conductivity is not exhibited. In order to exhibit conductivity, it is necessary to introduce oxygen vacancies into the film. However, when the oxygen vacancies are excessively large, the absorption of visible light increases, causing coloration. Therefore, the membrane needs to have an optimum oxygen deficiency. Oxygen in the film is supplied not only from the oxide vapor deposition material which is a raw material, but also from the introduction of oxygen gas introduced into the film forming vacuum chamber during film formation into the film. And when there is little supply from an oxide vapor deposition material, it is necessary to make the amount of oxygen gas introduce | transduced into a film formation vacuum chamber a little, but when the amount of oxygen gas introduced into a film formation vacuum chamber is large, the said problem will arise. Therefore, an oxide vapor deposition material having an optimum amount of oxygen becomes useful.

The maximum feature of the oxide vapor deposition material according to the present invention is defined by the L ^* value in the CIE1976 colorimetric system. Here, the CIE1976 color system is the color space recommended in 1976 by the CIE. The color is also abbreviated as CIELAB when the color is represented by coordinates in the uniform color space composed of the brightness L ^* and the chromatic index a ^* and b ^* . L ^* which represents lightness shows the diffuse color of black at L ^* = 0 and white at L ^* = 100. In addition, a ^* represents green at a negative value, and magenta at a positive value, and b ^* represents a blue vicinity at a negative value, and yellow at a positive value.

In addition, although the color tone of the sintered compact surface and the inside of a sintered compact of the oxide vapor deposition material which concerns on this invention prescribed | regulated by the L ^* value in CIE1976 color system is preferable, for example, when it is an oxide vapor deposition material different from an outermost surface and inside, in this invention, in a sintered compact body, We set L ^* value for.

According to the experiment by the inventor etc., when the L ^* value in the inside of an oxide vapor deposition material is 54-75, the transparent conductive film which combines the electroconductivity high in at least high electroconductivity and the high transmittance of visible range can be obtained. Also, the more white the color, the higher the L ^* value. On the contrary, the blacker the color, the lower the L ^* value. It is considered that the L ^* value of the oxide vapor deposition material has a correlation with the amount of oxygen contained in the oxide vapor deposition material. The larger the L ^* value is, the larger the amount of oxygen is contained, and the smaller the L ^* value is, the smaller the amount of oxygen is. The present inventors have experimented with fabricating a transparent conductive film by vacuum deposition using various L ^* value oxide evaporation materials with varying manufacturing conditions. The larger the L ^* value, the lower the optimum amount of oxygen to be introduced during film formation. The amount of oxygen for obtaining a film with high transparency was small. This is because an oxide deposition material having a large L ^* value increases the amount of oxygen supplied from the oxide deposition material itself. In addition, the composition difference between the film and the oxide vapor deposition material tends to be larger as the amount of oxygen introduced increases. Therefore, the larger the L ^* value, the smaller the composition difference.

Further, the oxide vapor deposition material according to the present invention has conductivity, and the conductivity of the oxide vapor deposition material depends on the amount of oxygen contained, but also on the density, grain size, and dopant efficiency of cerium. Therefore, the conductivity and L ^* value of the oxide deposited material do not correspond to one to one.

In addition, from the oxide vapor deposition material according to the present invention containing indium oxide as a main component and containing tin, evaporated particles are generated in the form of In ₂ O _{3 -X} , SnO _{2 -X} during vacuum deposition, and in the chamber It reacts with oxygen, absorbs oxygen, reaches the substrate, and forms a film. In addition, the energy possessed by the evaporated particles serves as a driving source of mass transfer when the particles reach the substrate and are deposited on the substrate, contributing to densification of the film and enhancement of adhesion to the substrate. Since the smaller the L ^* value of the oxide evaporation material, the less oxygen there is in the oxide evaporation material, so that the oxygen vacancies in the evaporated particles become larger. have. However, since evaporated particles are oxidized during flight and consume energy, it is difficult to obtain a film that is dense and has high adhesion to a substrate in a reactive film in which much oxygen is introduced. On the contrary, the reactive vapor deposition film which made the oxygen gas introduce | transduce as few as possible has high adhesion, and a high density film | membrane is easy to be obtained, and the oxide vapor deposition material of this invention can implement this.

Here, when the L ^* value is less than 54, since the amount of oxygen in the oxide vapor deposition material is too small, the optimum amount of oxygen introduced into the film formation vacuum chamber for obtaining a film having low resistance and high transparency increases, and the composition difference between the film and the oxide vapor deposition material is increased. It is not preferable because not only it becomes large but also a problem such as damage to the substrate increases during film formation. On the contrary, when the L ^* value exceeds 75, since the amount of oxygen contained in the oxide vapor deposition material is too large, the oxygen supplied to the film from the oxide vapor deposition material is excessively high, resulting in a highly conductive film having an optimum oxygen deficiency. You won't lose.

By the way, Japanese Unexamined Patent Publication No. 5-112866 (Reference), which discloses the invention according to the sputtering method, introduces a sputter target of an indium oxide sintered body containing tin, but is manufactured according to the manufacturing method described in the reference. L ^* value of the indium-oxide sintered compact containing this is 38-49, a low value (refer comparative example 3). Therefore, when such a sintered compact is used as the oxide vapor deposition material, it is necessary to increase the amount of oxygen introduced into the film forming vacuum chamber for obtaining the optimum film, and therefore, the above-mentioned problem occurs. Therefore, the object of the present invention has not been achieved.

Here, the oxide sinter for deposition (oxide vapor deposition material) of the present invention having the above L ^* value of 54 to 75 cannot be manufactured by a technique for producing a conventional ITO sintered body. An oxide vapor deposition material having an appropriate oxygen amount (or oxygen deficiency amount) suitable for use in mass production by vacuum deposition can be produced by the following method.

In other words, an oxide sintered body containing indium oxide as a main component and containing tin is mixed with each powder of indium oxide and tin oxide as a raw material, and molded to form a green compact, fired at high temperature, and reacted and sintered. Can be prepared. Each powder of indium oxide and tin oxide is not special, and what is necessary is just the raw material for oxide sinter currently used conventionally. Moreover, the average particle diameter of the powder to be used is 1.5 micrometers or less, Preferably it is 0.1-1.1 micrometers.

Although the ball mill mixing method is used as a mixing method of the general raw material powder at the time of manufacturing the said oxide sintered compact, it is effective also when manufacturing the sintered compact of this invention. A ball mill is a device for making fine mixed powder by grinding a material by crushing the material by rotating a hard ball (ball diameter of 10 to 30 mm) such as ceramic and powder of material in a container. The ball mill (crushing media) includes steel, stainless steel, nylon, etc. as a cylinder, and alumina, magnetic material, natural silica, rubber, urethane, etc. are used as a lining material. Balls include alumina-based alumina balls, natural silica, iron core nylon balls, and zirconia balls. There are wet and dry grinding methods and are widely used for mixing and grinding raw powders for obtaining sintered bodies.

As a method other than ball mill mixing, the bead mill method and the jet mill method are also effective. In particular, the tin oxide powder is a hard material, which is very effective when a raw material having a large average particle size is used or when it needs to be pulverized and mixed in a short time. In the bead mill method, 70-90% of beads (crushing media, bead diameters 0.005-3 mm) are filled in a vessel called a vessel, and the beads are moved by rotating the rotation axis in the center of the vessel at a circumferential speed of 7-15 m / sec. Here, the slurry which mixed the to-be-processed material, such as raw material powder, with a liquid is sent to a pump, and it grind | pulverizes and disperse | distributes by making a bead collide. In the case of a bead mill, when a bead diameter is made small according to a to-be-processed object, efficiency will become high. In general, the bead mill can realize pulverization and mixing at an acceleration close to 1000 times that of the ball mill. Bead mills having such a structure are called by various names, for example, sand grinders, aquamizers, attritors, pearl mills, Abaeks mills, ultrabiscomills, dynomills, agitator mills, coball mills, spike mills, SCs, etc. Mills and the like are known and can be used in the present invention. In addition, the jet mill is a method of colliding high-pressure air or steam injected from the nozzle before and after the speed of sound with a to-be-pulverized object such as raw material powder as an ultra-high-speed jet and pulverizing it into fine particles by impact of the particles.

As described above, first, the indium oxide powder and the tin oxide powder are added to a ball mill pot at a desired ratio, and dry or wet mixed to prepare a mixed powder. And in order to obtain the oxide sintered compact of this invention, it is prepared so that content of indium and tin may be 0.001-0.614 in Sn / In atomic ratio with respect to the compounding ratio of the said raw material powder.

The slurry is prepared by adding organic substances, such as water, a dispersing material, and a binder, to the mixed powder prepared in this way. The viscosity of the slurry is preferably 150 to 5000 cP, more preferably 400 to 3000 cP.

The granulated powder can be obtained by drying with a spray dryer or the like using the slurry thus obtained. However, in order to obtain a sintered compact with more uniform sinterability, it is more effective to carry out the pulverized mixing treatment by the following bead mill.

That is, the obtained slurry and beads are put into a container of a bead mill and subjected to pulverizing and mixing treatment. Although zirconia, alumina, etc. are mentioned as a bead material, Zirconia is preferable at the point of abrasion resistance. As for the diameter of a bead, 1-3 mm are preferable at the point of grinding | polishing efficiency. Although the number of passes may be one time, two or more times are preferable and sufficient effect is acquired at five times or less. Moreover, as processing time, Preferably it is 10 hours or less, More preferably, it is 4-8 hours.

By performing such a process, grinding and mixing of the indium oxide powder and tin oxide powder in a slurry become favorable.

Next, molding is performed using the slurry thus treated. As the molding method, both the injection molding method and the press molding method can be adopted. In the case of performing injection molding, the obtained slurry is poured into a mold for injection molding to produce a molded article. The time from the treatment of the bead mill to the injection is preferably within 10 hours. This is because the obtained slurry can be prevented from showing thixotropy. In the case of press molding, a binder such as polyvinyl alcohol or the like is added to the obtained slurry, and moisture control is carried out if necessary, followed by drying with a spray dryer or the like to assemble. The granulated powder thus obtained is filled into a mold having a predetermined size, and then subjected to uniaxial pressure molding at a pressure of 9.8 to 98 MPa (100 to 1000 kg / cm ² ) using a press machine to form a molded body. It is preferable to set the thickness of the molded object at this time to the thickness which can obtain the sintered compact of a predetermined magnitude in consideration of the shrinkage by a subsequent baking process.

If the molded object produced from the said mixed powder is used, the oxide sintered compact of this invention can be obtained by an atmospheric pressure sintering method. Moreover, when baking by an atmospheric pressure sintering method and obtaining an oxide sintered compact, it becomes as follows.

First, about the obtained molded object is heated at a temperature of 300-500 degreeC for about 5 to 20 hours, and a binder removal process is performed. Thereafter, the temperature is raised and sintered, but the temperature increase rate is 150 ° C / hour or less, preferably 100 ° C / hour or less, more preferably 80 ° C / hour or less, in order to effectively bring out the internal bubble defects to the outside. . The sintering temperature is 1150 to 1300 ° C, preferably 1200 to 1250 ° C, and the sintering time is 1 to 20 hours, preferably 2 to 5 hours. It is important that the debinder treatment to the sintering step are performed by introducing oxygen into the furnace at a rate of 5 liters / minute or more per 0.1 m ³ of the furnace volume. The introduction of oxygen in the sintering step is intended to prevent this since the sintered body easily decomposes the oxygen at 1150 ° C or higher and easily proceeds to an excessive reduction state. Once the sintered compact in which oxygen deficiency was introduce | transduced in this process once is formed, it will become difficult to optimally adjust the oxygen deficiency amount of a sintered compact in a subsequent oxygen amount adjustment process. When the calcination temperature is performed at a temperature exceeding 1300 ° C., dissociation of oxygen becomes severe even under the oxygen atmosphere as described above, and it is easy to proceed to an excessive reduction state, which is not preferable for the same reason. If the firing temperature is less than 1150 占 폚, the temperature is too low, so that sintering is insufficient and a sintered compact of sufficient strength cannot be obtained.

After sintering, the oxygen amount adjustment process of the sintered compact is performed. It is important that the oxygen amount adjusting step is performed at a heating temperature of 900 to 1100 ° C, preferably 950 to 1050 ° C, and the heating time is 10 hours or more. Cooling to the heating temperature of the said oxygen amount adjustment process is performed, continuing oxygen introduction, and it temperature-falls at the temperature-fall rate of 0.1-20 degreeC / min, Preferably it is 2-10 degreeC / min.

In the oxygen amount adjustment process of the sintered body, the control of the atmosphere in the furnace is also particularly important, and the introduction gas into the furnace controls the mixing ratio (volume ratio) of oxygen and argon within the range of O ₂ / Ar = 40/60 to 90/10. in volume, it is important to introduce in the furnace to 0.1m ³ at least 5 liters / minute per ratio. By precisely adjusting such a temperature, an atmosphere, and time, the sintered compact which has L ^* value prescribed | regulated by this invention useful when using as an oxide vapor deposition material can be obtained.

The heating temperature in the oxygen amount adjusting step is not preferable because the reaction of dissociation and adsorption of oxygen is slow and takes time for uniform reduction treatment to the inside of the sintered body at less than 900 ° C. It is not preferable because the dissociation of is too severe and the optimum reduction treatment by the atmosphere becomes impossible. Moreover, since the uniform reduction process cannot be performed even inside the sintered compact when the heating temperature of an oxygen amount adjustment process is less than 10 hours, it is unpreferable. If the mixing ratio (O ₂ / Ar) of the introduction gas to the furnace is less than 40/60, reduction by oxygen dissociation is too predominant, and the L ^* value becomes less than 54, which is not preferable. On the contrary, when the mixing ratio (O ₂ / Ar) of the introduction gas into the furnace exceeds 90/10, the oxidation becomes excessively predominant and the L ^* value exceeds 75, which is not preferable.

In order to obtain the oxide vapor deposition material of the present invention, as described above, it is important to anneal the oxygen gas in the gas atmosphere in which the oxygen gas is precisely diluted with argon gas, that is, in the atmosphere in which the amount of oxygen is precisely controlled. It does not have to be a mixed gas of oxygen and argon. For example, another inert gas such as helium or nitrogen may be used instead of argon. Moreover, even when using air instead of argon, it is effective as long as oxygen content is precisely controlled in the mixed gas of the whole. However, as in the prior art, when oxygen gas is introduced into a furnace that is fired in the atmosphere, it is not effective because the oxygen content of the atmosphere in the furnace cannot be precisely controlled. As proposed in the present invention, an oxide vapor deposition material having an optimal reduction state can be obtained by introducing a mixed gas with an inert gas whose oxygen content is controlled precisely and filling the furnace.

And after completion | finish of an oxygen amount adjustment process, it can fall to room temperature at 10 degreeC / min, and can take out from a furnace at room temperature. The obtained sintered compact can be processed into a predetermined size by grinding or the like to form an oxide vapor deposition material. In addition, in consideration of the shrinkage of sintering, when a molded article having a predetermined size after firing is used, it can be used as an oxide vapor deposition material without performing grinding processing after sintering.

By the way, it is known that the hot press method is effective as a method of obtaining a high density sintered compact as one of the manufacturing methods of a sputtering target. However, when the hot press method is applied to the material of the present invention, only the sintered compact whose L ^* value is 40 or less and the reducibility is too strong is obtained. Such a sintered compact cannot achieve the object of the present invention.

Moreover, about the oxide vapor deposition material of this invention, although it is also possible to use it for the cylindrical tablet or pellet shape of 10-50 mm in diameter and 10-50 mm in height, for example, the granule shape of about 1-10 mm which crushed such a sintered compact was crushed. It can also be used.

In addition, about the oxide vapor deposition material which concerns on this invention, even if tungsten, molybdenum, zinc, cadmium, cerium, etc. are contained as other elements other than indium, tin, and oxygen, the characteristic of this invention is not impaired. Condition is allowed. However, among the metal ions, when the vapor pressure of the oxide is extremely high compared with the vapor pressure of indium oxide or tin oxide, it is preferable not to contain it because it is difficult to evaporate by various vacuum deposition methods. For example, metals such as aluminum, titanium, and silicon have extremely high vapor pressures of these oxides compared with indium oxide and tin oxide, so that when included in the oxide deposition material, it is difficult to evaporate with indium oxide or tin oxide. do. For this reason, it should not be contained since it will remain in the oxide vapor deposition material and become high concentration and will adversely affect the evaporation of indium oxide and tin oxide finally.

When the transparent conductive film is produced by various vacuum deposition methods by applying the oxide vapor deposition material of the present invention, since the oxygen content in the oxide vapor deposition material is optimally adjusted, the oxygen introduction amount into the film formation vacuum chamber is at least optimal. A transparent conductive film can be obtained. Therefore, the composition difference between a transparent conductive film and an oxide vapor deposition material is small, and there exists an advantage which is hard to be influenced by the characteristic deviation accompanying the fluctuation | variation of oxygen introduction amount.

(2) transparent conductive film

Oxide according to the present invention, which is composed of an oxide sinter containing tin as a main component of indium oxide, having a tin content of 0.001 to 0.614 in Sn / In atomic ratio, and a L ^* value of 54 to 75 in the CIE1976 colorimetric system. By applying a vapor deposition material, a crystal film (transparent conductive film) of indium oxide containing tin can be produced by various vacuum deposition methods such as an electron beam vapor deposition method, an ion plating method, or a high density plasma assist vapor deposition method.

By setting it as a crystal film, high mobility can be exhibited when tin substitutes and solidifies to the indium site of indium oxide. Although the said crystal film (transparent conductive film) is obtained by heating the board | substrate in film-forming at 180 degreeC or more, it can also be obtained by the method of annealing at 180 degreeC or more the film | membrane obtained by unheated film-forming which does not heat a board | substrate.

The crystalline transparent conductive film according to the present invention is an indium oxide film containing tin in an amount of 0.001 to 0.614 in the Sn / In atomic ratio because it can be produced from an oxide vapor deposition material having a small compositional difference between the film and the oxide vapor deposition material. . When the tin content (Sn / In atomic ratio) of the film is less than 0.001, the effect of increasing the carrier concentration (that is, the effect of increasing mobility) is small and a low resistance film cannot be obtained. If it exceeds 0.614, the amount of tin in the film is too large, and the neutral impurity scattering during electron transfer becomes large, and the mobility is lowered. Thus, a film of low resistance is not obtained. In order to obtain a transparent conductive film with a higher carrier concentration, the content of tin is more preferably 0.040 to 0.163 in the Sn / In atomic ratio, and the film is a crystal film. By obtaining a crystal film having such a composition range, a transparent conductive film having a carrier concentration of 7.2 × 10 ²⁰ cm ⁻³ or more and a specific resistance of 3.5 × 10 ⁻⁴ Ω cm or less can be realized. The transparent conductive film according to the present invention has a very high average transmittance of 90% or more at the wavelength of 400 to 800 nm.

EMBODIMENT OF THE INVENTION Hereinafter, the Example of this invention is described concretely.

(Example)

[Examples 1 to 4]

[Production of Oxide Deposition Materials]

An In ₂ O ₃ powder having an average particle diameter of 0.8 μm and a SnO ₂ powder having an average particle diameter of 1 μm were used as raw materials, and these In ₂ O ₃ powders and SnO ₂ powders had an atomic ratio of Sn / In of 0.048. It combined at the ratio similar to what was mentioned, and also put in the pot made of resin, and mixed by the wet ball mill. At this time, a hard ZrO ₂ ball was used and the mixing time was 20 hours.

After mixing, the slurry was taken out, the binder of polyvinyl alcohol was added to the obtained slurry, and it dried and granulated with the spray dryer etc.

Using this granulated material, uniaxial pressure molding was performed at a pressure of 98 MPa (1 ton / cm ² ) to obtain a cylindrical shaped body having a diameter of 30 mm and a thickness of 40 mm.

Next, the obtained molded object was sintered as follows.

That is, after performing a treatment to remove the binder of the molded product of, by heating at a temperature of 300 ℃ for 10 hours in the atmosphere in the sintering furnace, the furnace in a volume of 0.1m ³ per atmosphere introducing oxygen at a rate of 5 liter / min, 1 It heated up at the speed of ° C / min, and sintered at 1250 ° C for 2 hours (atmospheric pressure sintering method). At this time, even at the time of cooling after sintering, it cooled down to 1000 degreeC at 10 degreeC / min, introducing oxygen.

Next, the introduction gas was switched to a mixed gas of oxygen and argon, and heated and maintained at 1000 ° C. for 15 hours (hereinafter, this step is referred to as a sintered body oxygen amount adjusting step), and then, the temperature was lowered to 10 ° C./min to room temperature.

The oxide sintered body (oxide evaporation material) having various L ^* values was obtained by changing the mixing ratio of oxygen and argon of the mixed gas.

That is, the oxide vapor deposition material according to Example 1 is manufactured under the condition that the oxygen gas / argon gas flow rate ratio (that is, the volume ratio) is "40/60", and the oxide vapor deposition material according to Example 2 is such that the volume ratio is "60/40". The oxide vapor deposition material according to Example 3 was prepared under the condition that the volume ratio was "80/20", and the oxide vapor deposition material according to Example 4 was manufactured under the condition that the volume ratio was "90/10".

Moreover, it was 4.8-5.7 g / cm < ³ > when density and the density were computed by measuring the volume and weight of the obtained oxide sintered compact (oxide vapor deposition material). Moreover, when the average value of 100 grain diameters in the oxide sintered compact was calculated | required from the observation by the scanning electron microscope of the fracture surface of the said oxide sintered compact, all were 3-10 micrometers. Moreover, when the surface resistance was measured with the 4 needle resistivity meter about the electron beam irradiation surface of the oxide sintered compact, the specific resistance was computed and it was 1 k ohm cm or less. Furthermore, when all the oxide sintered compacts were analyzed by ICP emission spectrometry, it turned out that it has a charge composition. Moreover, about the surface of the sintered compact and the inside of the sintered compact, the L ^* value in CIE1976 colorimeter was measured using the color difference meter (Spectroguide, E-6834 by BYK-Gardner GmbH company), and showed substantially the same value.

The oxygen gas / argon gas flow rate ratio (that is, volume ratio) of the mixed gas introduced in the sintered body oxygen amount adjusting step and the L ^* values of the obtained oxide sintered body (oxide evaporation material) are shown in Tables 1 (a), 1 (b) and Table below. It shows in 1 (c).

[Production of Transparent Conductive Film, Evaluation of Film Characteristics, Film Formation Evaluation]

(1) The magnetic field deflection electron beam vapor deposition apparatus was used for preparation of a transparent conductive film.

The vacuum exhaust system consists of a low vacuum exhaust system by a rotary pump and a high vacuum exhaust system by a cryon pump, and can exhaust up to 5x10 <^-5> Pa. The electron beam is generated by the heating of the filament, accelerated by the electric field applied between the cathode and the anode, bent in the magnetic field of the permanent magnet, and then irradiated onto the oxide deposition material provided in the tungsten crucible. The intensity of the electron beam can be adjusted by changing the voltage applied to the filament. In addition, changing the accelerating voltage between the cathode and the anode can change the irradiation position of the beam.

Film formation was performed under the following conditions.

Ar gas and O ₂ gas were introduced into the vacuum chamber, and the pressure was maintained at 1.5 × 10 ⁻² Pa. At this time, the transparent conductive film was evaluated characteristics obtained by changing the mixing ratio of the Ar gas and O ₂ gas being introduced into the vacuum chamber. The cylindrical oxide deposition materials of Examples 1 to 4 were placed in a tungsten crucible and irradiated with an electron beam in the center of the circular surface of the oxide deposition material to form a transparent conductive film having a thickness of 200 nm on a Corning 7059 glass substrate having a thickness of 1.1 mm. did. The set voltage of the electron gun was 9 kV, the current value was 150 mA, and the board | substrate was heated to 250 degreeC.

(2) The characteristics of the obtained thin film (transparent conductive film) were evaluated in the following procedures.

First, the surface resistance of the thin film (transparent conductive film) was measured with a 4-needle resistivity meter LORESTAR EP (manufactured by Diamond Instruments, MCP-T360), and the film thickness of the thin film (transparent conductive film) was a contact surface roughness meter (manufactured by Tencol Corporation). ) Was evaluated from the step measurement of the unfilmed portion and the film-forming portion, and the "specific resistance (μΩcm)" was calculated. In addition, to measure the Hall effect measurement apparatus (manufactured by Toyo Technica ResiTest) by, "carrier concentration (cm ^-3)," "Hall mobility (cm ² / Vs)" in the film at room temperature by a Van der Pauw method using .

Next, the transmittance [T _{L + B} (%)] of the film (glass substrate B with film L) including the glass substrate was measured with a spectrophotometer (manufactured by Hitachi Sesakusho Co., Ltd., U-4000), and the glass was measured by the same method. From the transmittance [(T _B (%)) of the substrate only (glass substrate B), the transmittance of the film itself was calculated by [T _{L + B} ÷ T _B × 100 (%)].

In addition, the crystallinity of the film was evaluated by X-ray diffraction measurement. The X-ray diffraction apparatus used X'PertPROMPD (made by PANalytical), The measurement conditions were the wide area measurement, and it measured by the voltage of 45 kV and 40 mA using CuK alpha ray. The crystallinity of the film was evaluated from the presence or absence of the X-ray diffraction peak. This result is also shown in the "crystallinity of a film" column of Table 1 (c).

Next, the composition of the film (atomic ratio of Sn / In) was measured by ICP emission spectrometry. In addition, the adhesive force of the film | membrane to the board | substrate was evaluated based on JIS C0021. Evaluation was made into good (strong) when there was no peeling, and made into insufficient (weak) by having peeling. These results are also shown in each column of "the atomic ratio of Sn / In" of Table 1 (c), and "adhesion force of the film | membrane to the board | substrate."

The specific resistance and transmittance of each thin film (transparent conductive film) depended on the mixing ratio of Ar gas and O ₂ gas introduced into the film formation vacuum chamber during film formation. The mixing ratio of O ₂ gas [O ₂ / (Ar + O ₂ ) (%)] was changed from 0 to 50% in 1% intervals to determine the mixing ratio of O ₂ gas showing the lowest specific resistance as the optimum oxygen mixing amount. . This result is shown in the "Optimal oxygen mixing amount" column of Table 1 (a).

The thin film (transparent conductive film) produced with less oxygen than the optimum oxygen mixing amount was not only poor in conductivity but also low in transmittance in the visible range. The thin film (transparent conductive film) produced by the optimum oxygen mixing amount not only had good electrical conductivity but also had high transmittance in the visible region.

(3) The optimum oxygen mixing amount, the resistivity of the film at that time, and the film itself in the visible range (wavelength 400 to 800 nm) when the film formation evaluation was performed using the oxide vapor deposition materials of Examples 1 to 4 Average transmittance | permeability was calculated | required.

These evaluation results are shown in Table 1 (b) "Resistance (μΩcm)" and "Transmittance (%) of visible range of the film | membrane itself", respectively.

In the film formation using the oxide vapor deposition materials of Examples 1 to 4, the optimum amount of oxygen mixing to be introduced into the film formation vacuum chamber was very small in order to obtain the lowest resistance and high transparent transparent conductive film. This is because the optimum amount of oxygen was contained in each oxide vapor deposition material. In addition, the film produced at the optimum oxygen mixing amount exhibited the same composition as the oxide vapor deposition material, exhibited a very low resistivity, and a high transmittance in the visible region. Furthermore, it was confirmed that the film was a crystal film of indium oxide having a bixbite type structure, and the adhesion to the substrate was also strong and practically sufficient.

In addition, the set voltage of the electron gun was 9 kV and the current value was 150 mA. The oxide vapor deposition material after 60 minutes of electron beam irradiation was observed, and it observed visually whether the crack and the crack generate | occur | produced in the oxide vapor deposition material (oxide vapor deposition durability test). The oxide vapor deposition materials of Examples 1 to 4 did not produce cracks (evaluation of "no cracking") even when used continuously.

Such a transparent conductive film can be said to be very useful as a transparent electrode of a solar cell.

[Comparative Examples 1 and 2]

In Examples 1-4, only the mixing ratio of the introduction gas in the sintered compact oxygen amount adjustment process was changed, and the oxide sintered compact was manufactured. That is, in Comparative Example 1,, O ₂ / Ar flow ratio to 30/70, and in Comparative Example 2 was a 100/0. About the obtained sintered compact, although density, a specific resistance, a grain diameter, and a composition were evaluated similarly, it was equivalent to Examples 1-4. The color tone of the surface and the inside of the obtained oxide sintered body were equal, and when the L ^* value was measured, it showed the value similar to Table 1 (a).

Next, film-forming evaluation was performed similarly to Examples 1-4.

The results are also shown in Tables 1 (a) to (c) above.

Comparative Example 1 is an oxide vapor deposition material exhibiting a value 49 whose L ^* value is smaller than the prescribed ranges 54 to 75 of the present invention, and is optimum oxygen at the time of film formation as compared with the oxide vapor deposition materials of Examples 1 to 4. It had a large amount of mixing (15). Although the transmittance | permeability was equal compared with Examples 1-4 in the characteristic of the film | membrane in optimum oxygen mixing amount, the specific resistance was slightly high. This is considered to be the factor that the deviation of the film composition was large. In addition, the film of Comparative Example 1 had a weak adhesive force to the substrate as compared with Examples 1 to 4. This is considered to be because the film was formed by introducing a little oxygen at the time of film formation. Since such an oxide vapor deposition material has a large deviation of the composition of the film obtained, it is difficult to design the film composition. In addition, since it is necessary to introduce a little more oxygen into the film forming vacuum chamber, when it is used in the mass production process of film forming, the composition and the characteristic fluctuation become large due to the influence of the oxygen concentration variation in the vacuum chamber. Therefore, it is confirmed that the oxide vapor deposition material of Comparative Example 1 is not suitable for mass production.

Moreover, the comparative example 2 is an example of the oxide vapor deposition material which showed the value 79 whose L ^* value is larger than the prescribed range of this invention. Although the optimum oxygen mixing amount at the time of film-forming was 0%, the specific resistance of the film | membrane was high compared with Examples 1-4. This is considered to be because the amount of oxygen supplied to the film from the oxide vapor deposition material is too large, the amount of oxygen in the film is large, and an optimal amount of oxygen deficiency cannot be introduced. Therefore, even when it forms into a film using such an oxide vapor deposition material, it is confirmed that the film | membrane which exhibits the high conductivity which the composition of this vapor deposition material originally has cannot be obtained.

[Comparative Example 3]

Next, the indium oxide sintered compact containing tin was manufactured according to the sintered compact manufacturing technique of the sputter target introduced by Unexamined-Japanese-Patent No. 5-112866 (reference reference).

First, an In ₂ O ₃ powder having an average particle diameter of 1 µm or less and a SnO ₂ powder having an average particle diameter of 1 µm or less were used as raw materials, and the In ₂ O ₃ powder and SnO at a ratio such that the atomic ratio of Sn / In is 0.048. ₂ powders were combined, and also it put in the resin pot and mixed with the wet ball mill. At this time, a hard ZrO ₂ ball was used and the mixing time was 20 hours. After mixing, the slurry was taken out, filtered and dried, and then granulated.

Then, using the obtained granulated powder, a pressure of 196 MPa (2 ton / cm ² ) was applied to form a cold hydrostatic press, and the obtained molded product was placed in a sintering furnace and sintered at 1520 ° C. for 5 hours in air.

The obtained sintered compact was processed into the column shape of the diameter of 30 mm and the thickness of 40 mm. The density of the sintered compact was 6.0 g / cm <^3> and the specific resistance was 0.6 m (ohm) cm. Moreover, the grain diameter was 12-15 micrometers, and the composition was substantially the same as the charging composition. The surface and internal color tone of the obtained sintered compact were equivalent, and when the L ^* value was measured, it was the extremely low value 38 as shown in Table 1 (a). This shows that the amount of oxygen in the oxide vapor deposition material is very small.

In addition, film-forming evaluation was performed like Examples 1-4.

The results are also shown in Tables 1 (a) to (c) above.

The comparative example 3 has shown the value 38 which L ^* value is remarkably small compared with the prescribed range 54-75 of this invention. Compared with the oxide vapor deposition materials of Examples 1 to 4 of the same composition, the optimum amount of oxygen mixing during film formation is very large (42). Although the transmittance | permeability was equal compared with Examples 1-4 in the characteristic of the film | membrane in the optimum oxygen mixing amount, the specific resistance was high. This is considered to be the factor that the deviation of the film composition was large. In addition, the film of Comparative Example 3 had a weak adhesive force to the substrate as compared with Examples 1 to 4. This is considered to be because it was film-forming which introduce | transduced a little oxygen at the time of film-forming. Such oxide evaporation material is difficult to design the film composition because the deviation of the composition of the film obtained is large. In addition, since it is necessary to introduce a little more oxygen into the film forming vacuum chamber, when it is used in the mass production process of film forming, the composition and the characteristic fluctuation become large due to the influence of the oxygen concentration variation in the vacuum chamber. Moreover, when the oxide vapor deposition material endurance test was done on the conditions similar to Examples 1-4, the crack generate | occur | produced in the oxide vapor deposition material after continuous film-forming (evaluation of "cracking"). If the film is continuously formed using the cracked oxide vapor deposition material, problems such as large fluctuations in the film formation rate occur, and film formation cannot be performed stably.

Therefore, it was confirmed that the oxide vapor deposition material of Comparative Example 3 was not suitable for mass production.

[Examples 5 to 8]

When the In ₂ O ₃ powder and the SnO ₂ powder were combined, they were carried out under the same conditions as in Examples 1 to 4, including the conditions for adjusting the amount of oxygen in the sintered body, except that the ratio of Sn / In was 0.102. The oxide sintered compact (oxide vapor deposition material) of Examples 5-8 was produced.

That is, the oxide vapor deposition material according to Example 5 is prepared under the condition that the oxygen gas / argon gas flow rate ratio (that is, the volume ratio) is "40/60", and the oxide vapor deposition material according to Example 6 has the condition that the volume ratio is "60/40". The oxide vapor deposition material according to Example 7 was prepared under the condition of the volume ratio of "80/20", and the oxide vapor deposition material according to Example 8 was manufactured under the condition of the volume ratio of "90/10".

And about the obtained oxide sintered compact (oxide vapor deposition material) of Examples 5-8, density, specific resistance, a grain diameter, and a composition were evaluated similarly, and all were equivalent to Examples 1-4. Moreover, the color tone of the surface and the inside of the obtained oxide sintered compact were equivalent. The result of having measured the L ^* value was shown to the said Table 1 (a).

In addition, film-forming evaluation was performed like Examples 1-4.

The results are also shown in Tables 1 (a) to (c) above.

In the film formation using the oxide vapor deposition materials of Examples 5 to 8, the optimum amount of oxygen mixing to be introduced into the film formation vacuum chamber was very small as in Examples 1 to 4 in order to obtain the lowest resistance and high transparent transparent conductive film. This is because the optimum amount of oxygen was contained in the oxide vapor deposition material. In addition, the film produced at the optimum oxygen mixing amount exhibited the same composition as that of the oxide vapor deposition material, exhibited not only a very low specific resistance, but also a high transmittance in the visible region. Moreover, all the films were made into the crystal film of the bixbite type crystal structure of indium oxide, and the adhesive force of the film | membrane to the board | substrate was also strong enough, and it was practically enough. Moreover, even if it used continuously, the oxide vapor deposition material of Examples 5-8 did not generate a crack.

Such a transparent conductive film can be said to be very useful as a transparent electrode of a solar cell.

Comparative Examples 4 to 5

In Comparative Examples ₁ and ₂ , oxide deposition materials were prepared under the same conditions as in Comparative Examples 1 and 2 except that the atomic ratio of Sn / In when the In ₂ O ₃ powder and the SnO ₂ powder were combined was 0.102. That is, the conditions of adjusting the amount of sintered oxygen were set to 30/70 in the O ₂ / Ar flow rate ratio in Comparative Example 4, and set to 100/0 in Comparative Example 5. About the obtained sintered compact, density, specific resistance, a grain diameter, and a composition were evaluated similarly, but it was equivalent to Examples 5-8. Moreover, the color tone of the surface and the inside of the obtained sintered compact were equal, and when the L ^* value was measured, the value similar to Table 1 (a) was shown.

Next, film-forming evaluation was performed similarly to Examples 1-4.

The results are also shown in Tables 1 (a) to (c).

Comparative Example 4 is an oxide vapor deposition material exhibiting a value 50 in which the L ^* value is smaller than the prescribed ranges 54 to 75 of the present invention, and compared with the case where the oxide vapor deposition material of Examples 5 to 8 is used. The optimum oxygen mixing amount at the time was (15). Although the transmittance | permeability was nearly equal compared with Examples 5-8 in the characteristic of the film | membrane in optimum oxygen mixing amount, the specific resistance was slightly high. This is considered to be because the film is out of composition and the tin is excessively contained in the film. In addition, the film of Comparative Example 4 was weak in adhesion to the substrate as compared with Examples 5 to 8. The reason for such large compositional deviation and low adhesion was because the film was formed by introducing a little oxygen at the time of film formation. Such oxide evaporation material is difficult to design the film composition because the deviation of the composition of the film obtained is large. In addition, since it is necessary to introduce a little oxygen into the film forming vacuum chamber, when it is used in the mass production process of film forming, it is easy to receive a change in composition and characteristics remarkably under the influence of the oxygen concentration variation in the vacuum chamber. Therefore, it was confirmed that the oxide vapor deposition material of Comparative Example 4 was also unsuitable for mass production.

Moreover, the comparative example 5 is an example of the oxide vapor deposition material which showed the value 82 whose L ^* value is larger than the prescribed range of this invention. Although the optimum oxygen mixing amount at the time of film-forming was 0%, the specific resistance of the film | membrane was high compared with Examples 5-8. This is considered to be because the amount of oxygen supplied to the film from the oxide vapor deposition material is too large, the amount of oxygen in the film is large, and an optimal amount of oxygen deficiency cannot be introduced. Therefore, even when it forms into a film using such an oxide vapor deposition material, it is confirmed that the film | membrane which exhibits the high electroconductivity originally having the composition of this oxide vapor deposition material cannot be obtained.

[Comparative Example 6]

In Comparative Example 3, an oxide vapor deposition material was produced under the same conditions as in Comparative Example 3, except that the atomic ratio of Sn / In when the In ₂ O ₃ powder and the SnO ₂ powder were combined was 0.102. About the obtained sintered compact, density, specific resistance, a grain diameter, and a composition were evaluated similarly, but it was equivalent to the comparative example 3. Moreover, the color tone of the surface and the inside of the obtained sintered compact were equivalent, and when the L ^* value was measured, it showed the same value as Table 1 (a).

Next, film-forming evaluation was performed similarly to Examples 1-4.

The results are also shown in Tables 1 (a) to (c).

Comparative Example 6 also shows a value 49 whose L ^* value is significantly smaller than the prescribed ranges 54 to 75 of the present invention. Compared with the oxide vapor deposition materials of Examples 5 to 8 of the same composition, the optimum oxygen mixing amount at the time of film formation is very large (42). Although the transmittance | permeability was equal compared with Examples 5-8 in the characteristic of the film | membrane in the optimum oxygen mixing amount, the specific resistance was high. This is considered to be the factor that the deviation of the film composition was large. In addition, the film of Comparative Example 6 had a weak adhesion to the substrate as compared with Examples 5-8. This is because the film was formed by introducing a little oxygen during the film formation. Such oxide evaporation material is difficult to design the film composition because the deviation of the composition of the film obtained is large. In addition, since it is necessary to introduce a little oxygen into the film forming vacuum chamber, when it is used in the mass production process of film forming, the composition and the characteristic fluctuation become large due to the influence of the oxygen concentration variation in the vacuum chamber. Moreover, when the oxide vapor deposition material endurance test was done on the conditions similar to Examples 1-4, a crack generate | occur | produced in the oxide vapor deposition material after continuous film-forming (evaluation of "cracking"). If the film is continuously formed using the cracked oxide vapor deposition material, problems such as large fluctuations in the film formation rate occur, and film formation cannot be performed stably.

In view of the above, it is confirmed that the oxide vapor deposition material of Comparative Example 6 is also not suitable for mass production.

EXAMPLES 9-14

The compounding ratio when combining In ₂ O ₃ powder and SnO ₂ powder is 0.001 (Example 9), 0.009 (Example 10), 0.028 (Example 11), 0.163 (Example 12) in Sn / In atomic ratio. , Except that the values were changed to 0.230 (Example 13) and 0.614 (Example 14), in the same manner as in Example 2 (that is, under the condition that the oxygen gas / argon gas flow rate was "60/40"). An oxide sintered body (oxide vapor deposition material) of 14 was produced.

And about the obtained oxide sintered compacts (oxide vapor deposition materials) of Examples 9-14, the density, specific resistance, grain diameter, and composition were evaluated similarly, and all were equivalent to Example 2. Moreover, the color tone of the surface and the inside of the obtained oxide sintered compact were equivalent. The result of having measured the L ^* value was shown to the said Table 1 (a).

In addition, film-forming evaluation was performed similarly to Examples 1-4.

The results are also shown in Tables 1 (a) to (c) above.

In the film formation using the oxide vapor deposition materials of Examples 9 to 14, the optimum amount of oxygen mixing to be introduced into the film formation vacuum chamber was very small as in Examples 1 to 4 in order to obtain the lowest resistance and high transmissive transparent conductive film. This is because the optimum amount of oxygen was contained in the oxide vapor deposition material. In addition, the film produced at the optimum oxygen mixing amount exhibited the same composition as the oxide vapor deposition material, exhibited a very low specific resistance, and a high transmittance in the visible region. In addition, it was confirmed that all the films were crystal films of the bixbite type crystal structure of indium oxide, and the adhesion of the films to the substrate was also strong and practically sufficient. Moreover, although the oxide vapor deposition material durability test was done on the conditions similar to Examples 1-4, even if it used continuously, the oxide vapor deposition material of Examples 9-14 did not generate a crack.

Such a transparent conductive film can be said to be very useful as a transparent electrode of a solar cell.

[Comparative Example 7]

Next, the ITO oxide vapor deposition material introduced in Unexamined-Japanese-Patent No. 8-104978 (patent document 1) was manufactured, and the same evaluation was performed.

That is, tin oxide powder with an average particle diameter of 1 micrometer was mix | blended so that it might become 0.102 by Sn / In atomic ratio in the indium oxide powder of average particle diameter 0.1 micrometer, and the 2 mass% vinyl acetate type binder was added. This was mixed for 16 hours in a wet ball mill, dried and pulverized, and it was granulated powder. Moreover, using this granulated powder, the pressure of 49 MPa (500 kgf / cm <^2> ) was apply | coated by the cold hydrostatic press, and it was set as the cylindrical shaped object. This molded object was sintered in air. In the sintering step, the temperature was raised from room temperature to 600 ° C in 10 hours, and the temperature was raised to 1450 ° C in 4 hours and 40 minutes. And it hold | maintained at 1450 degreeC for 10 hours, and obtained the sintered compact.

The obtained sintered compact was processed into the column shape of the diameter of 30 mm and the thickness of 40 mm, and it was set as the ITO oxide vapor deposition material. The density of the sintered compact was 4.4 g / cm <^3> and the specific resistance was 1.2 m (ohm) cm. The grain diameter was 12-16 micrometers, and the composition was substantially the same as the charging composition. The color tone of the surface and the inside of a sintered compact was equal, and when the L ^* value was measured, it was the extremely low value 49, as shown in Table 1 (a). This indicates that the amount of oxygen in the oxide vapor deposition material is very small.

In addition, film-forming evaluation was performed similarly to Examples 1-4.

The results are also shown in Tables 1 (a) to (c) above.

Comparative Example 7 FIG., The L ^* value is compared with the oxide evaporation material of Examples 5 to 8 show a remarkably small value (49) as described above as compared with the specified range, (54-75) of the present invention, the film-forming The optimum oxygen mixing amount at the time is very large (42). Although the transmittance | permeability of visible range was equal compared with Examples 5-8 in the characteristic of the membrane in the optimum oxygen mixing amount, the specific resistance was high. This is considered to be a factor that the deviation of the film composition was large. In addition, the film of Comparative Example 7 had a weak adhesion to the substrate as compared with Examples 5 to 8. This is because the film was formed by introducing a little oxygen during the film formation. Such oxide evaporation material is difficult to design the film composition because the deviation of the composition of the film obtained is large. In addition, since it is necessary to introduce a little oxygen into the film forming vacuum chamber, when it is used in the mass production process of film forming, the composition and the characteristic fluctuation become large due to the influence of the oxygen concentration variation in the vacuum chamber. Moreover, when the oxide vapor deposition material endurance test was done on the conditions similar to Examples 1-4, the crack generate | occur | produced in the oxide vapor deposition material after continuous film-forming (evaluation of "cracking"). If the film is continuously formed using the cracked oxide vapor deposition material, problems such as large fluctuations in the film formation rate occur, and film formation cannot be performed stably.

In view of the above, it is confirmed that the oxide vapor deposition material of Comparative Example 7 is also unsuitable for mass production.

[Comparative Example 8]

Moreover, the ITO oxide vapor deposition material introduced by Unexamined-Japanese-Patent No. 2007-84881 (patent document 2) was manufactured, and the same evaluation was performed.

That is, tin oxide powder with an average particle diameter of 1 micrometer or less was mix | blended so that it might become 0.102 by Sn / In atomic ratio in the indium oxide powder of average particle diameter of 1 micrometer or less, and the 2 mass% vinyl acetate type binder was added. This was mixed for 18 hours in a wet ball mill using a hard ZrO ₂ ball, dried and pulverized to obtain a granulated powder. Moreover, using this granulated powder, the pressure of 94 MPa (3 ton / cm <^2> ) was applied by the cold hydrostatic press and it was set as the cylindrical shaped object.

The obtained molded product was put into a sintering furnace, oxygen was introduced at a rate of 5 liters / minute per 0.1 m ^{3 of the} furnace volume, and the atmosphere was formed, followed by atmospheric pressure sintering at 1100 ° C. for 2 hours. At this time, it heated up at 1 degree-C / min, the oxygen introduction was stopped at the time of cooling after sintering, and it heated up to 1000 degreeC at 10 degree-C / min.

The obtained oxide sintered compact was processed into the cylindrical shape of the diameter of 30 mm and the thickness of 40 mm using a vertical machining center, the volume and the weight were measured, and the density was computed. The density of the sintered compact was 4.8 g / cm <^3> . In addition, the color tone of the surface of the sintered compact and the inside were equivalent, and when the L ^* value was measured, as shown in Table 1 (a), the large value 79 was shown compared with the prescribed range 54-75 of this invention. . This shows that the amount of oxygen in the oxide vapor deposition material is very large.

Film formation evaluation was performed like Example 1-4 using the oxide vapor deposition material produced in this way.

Although the optimum oxygen mixing amount at the time of film-forming was 0% similarly to the comparative example 2, the specific resistance of a film | membrane was high compared with Examples 5-8.

This is considered to be because the amount of oxygen supplied to the film from the oxide evaporation material is too large, the amount of oxygen in the film is large, and an optimal amount of oxygen deficiency cannot be introduced. Therefore, even when it forms into a film using such an oxide vapor deposition material, it is confirmed that the film | membrane which exhibits the high electroconductivity originally having the composition of this vapor deposition material cannot be obtained.

By applying the oxide deposition material according to the present invention, it becomes possible to manufacture a transparent conductive film showing high conductivity while showing high light transmittance in the visible region by vacuum deposition, and thus oxide deposition for forming transparent electrodes of various solar cells. Has industrial applicability as ash.

Claims (4)

In the oxide vapor deposition material used when manufacturing a transparent conductive film by the vacuum deposition method, indium oxide and tin are included, and it is comprised by the oxide sinter manufactured by the normal pressure sintering method, and tin content is Sn / In atom. It is 0.001-0.614 by the number and L ^* value in CIE1976 color system is 54-75, The oxide vapor deposition material characterized by the above-mentioned. The oxide vapor deposition material according to claim 1, wherein the tin content is 0.040 to 0.163 in a Sn / In atomic ratio. The oxide sintered body is produced by an atmospheric pressure sintering method of firing at a temperature of 1150 to 1300 ° C while introducing oxygen in a furnace at a rate of 5 liters / minute or more per 0.1 m ³ of the furnace. Oxide deposition material. In the method for producing an oxide deposited material according to claim 1,
A molded article preparation step of forming the granulated powder obtained by mixing each powder of indium oxide and tin oxide as a raw material, mixing the tin content so as to be 0.001 to 0.164 in a Sn / In atomic ratio, and obtaining granulated powder;
The binder was subjected to a debinder treatment at a temperature of 300 to 500 ° C. with the introduction of oxygen at a rate of 5 liters / minute or more per 0.1 m ³ in the furnace, followed by 5 liters / minute or more per 0.1 m ^{3 in the} furnace. A debinder-baking step of firing at a temperature of 1150 to 1300 ° C while introducing a ratio of oxygen into the furnace;
Mixed gas (volume ratio) of oxygen and argon is in a range of O ₂ / Ar = 40/60 to 90/10, and a mixed gas of oxygen and argon at a ratio of 5 liters / minute or more per 0.1 m ^{3 in the} furnace. Amount adjusting step of adjusting the amount of oxygen for 10 hours or more at a temperature of 900 to 1100 ° C with respect to the sintered body while introducing into the furnace.
Each process of the manufacturing method of the oxide vapor deposition material characterized by the above-mentioned.