JP5761253B2 - Zn-Si-O-based oxide sintered body, method for producing the same, sputtering target, and tablet for vapor deposition - Google Patents

Description

  The present invention relates to a Zn-Si-O-based oxide sintered body used for a sputtering target, a deposition tablet, and the like, and a method for producing the Zn-Si-O-based oxide sintered body. In particular, when used in a sputtering method, abnormal discharge is suppressed, The present invention relates to a Zn—Si—O-based oxide sintered body capable of suppressing a splash phenomenon and enabling continuous film formation for a long time when used in a deposition method such as ion plating, and a manufacturing method thereof.

  Transparent conductive films having high conductivity and high transmittance in the visible light region are used for solar cells, liquid crystal display elements, surface elements such as organic electroluminescence and inorganic electroluminescence, and electrodes for touch panels. In addition, they are also used as various antifogging transparent heating elements such as automobile windows, architectural heat ray reflective films, antistatic films, and refrigerated showcases.

As the transparent conductive film, for example, a tin oxide (SnO ₂ ) -based thin film, a zinc oxide (ZnO) -based thin film, an indium oxide (In ₂ O ₃ ) -based thin film, and the like are known.

  In the tin oxide system, those containing antimony as a dopant (ATO) and those containing fluorine as a dopant (FTO) are often used. In addition, in zinc oxide systems, those containing aluminum as a dopant (AZO) and those containing gallium as a dopant (GZO) are often used. The most transparently used transparent conductive film is an indium oxide type. Among them, an indium oxide film containing tin as a dopant, that is, an In—Sn—O-based film is called an ITO (Indium tin oxide) film, and is particularly widely used because a low-resistance transparent conductive film can be easily obtained. Yes.

  A sputtering method is often used as a method for producing these transparent conductive films. The sputtering method is an effective method when film formation of a material having a low vapor pressure or precise film thickness control is required, and is widely used industrially because the operation is very simple.

  In the sputtering method, a sputtering target is used as a raw material for the thin film. In this method, generally, under a gas pressure of about 10 Pa or less, a substrate is used as an anode, a sputtering target is used as a cathode, glow discharge is generated between them to generate argon plasma, and argon cations in the plasma are converted into cathodes. The target component particles which are made to collide with the sputtering target and are repelled by this are deposited on the substrate to form a thin film. In addition, the above-described transparent conductive film is also manufactured using a vapor deposition method such as an ion plating method.

  By the way, although the indium oxide-based materials such as ITO described above are widely used industrially, the rare metal indium is expensive, and there are toxic components that adversely affect the environment and human body such as indium elements. Therefore, in recent years, a non-indium transparent conductive film material has been demanded. As non-indium materials, zinc oxide materials such as AZO and GZO described above and tin oxide materials such as FTO and ATO are known. In particular, zinc oxide-based materials are abundantly embedded as resources and are not only low-cost materials but also attracting attention as materials that are friendly to the environment and the human body. In addition, zinc oxide-based materials are attracting attention as materials exhibiting properties comparable to ITO.

  However, it is practically difficult to stably produce a transparent conductive film having a high transmittance and low specific resistance comparable to that of ITO using a zinc oxide-based material. There was abnormal discharge that occurred during filming. That is, when a transparent conductive film is formed by sputtering using a zinc oxide-based material, the above abnormal discharge (arcing) occurs frequently and stable film formation is difficult. The reason why the abnormal discharge frequently occurs is that a portion having a high specific resistance (phase having a high resistance value) is locally present in the zinc oxide-based material, and this portion is charged during film formation. On the other hand, even when a transparent conductive film is formed by a deposition method such as an ion plating method using a zinc oxide-based material (evaporation tablet), a high specific resistance exists locally in the zinc oxide-based material. Due to the part, uniform sublimation by plasma beam or electron beam becomes difficult, and the evaporation material (evaporation tablet) scatters in the size of several μm to 1000 μm when mixed with the uniform evaporation gas. The splash phenomenon that collides with the film was likely to occur. And since the pinhole defect etc. arise in the vapor deposition film by the splash phenomenon, it was difficult to stably manufacture a transparent film having a high transmittance and a low specific resistance even in the film formation by the vapor deposition method.

Therefore, in order to avoid such a problem, in Patent Document 1, zinc oxide-based sintering containing one or more additive elements of Al, Ga, In, Ti, Si, Ge, and Sn is included. Suggest body. That is, in Patent Document 1, zinc oxide and an oxide of an additive element are mixed in advance and calcined to form a spinel-type composite oxide phase such as ZnM ₂ O ₄ or Zn ₂ MO ₄ (M is an additive element). Then, the calcined powder and the uncalcined zinc oxide powder are mixed and subjected to main baking, thereby preventing the formation of a new spinel-type composite oxide phase in the main baking process. Is suppressed. When such a zinc oxide-based sintered body is used as a sputtering target, it is possible to reduce the abnormal discharge, but it is difficult to completely eliminate it. If abnormal discharge occurs even once in the continuous film forming line, the product at the time of film forming becomes a defective product, which has a problem of adversely affecting the manufacturing yield.

  In addition, since zinc oxide-based transparent conductive films generally have poor heat resistance and moisture resistance, characteristics such as transmittance and specific resistance deteriorate over time in an environment where heat and humidity are applied. It tends to be easy. Therefore, Patent Document 2 proposes an oxide-based sputtering target containing a predetermined amount of Ga and Si and containing zinc oxide as a main component for the purpose of improving the moisture resistance of the obtained transparent conductive film. However, in the invention described in Patent Document 2, the discharge is stabilized by making the crystal grains of the Si oxide 200 μm or less, but the abnormal discharge cannot be completely extinguished.

  Under such technical background, the present applicant optimizes the content of aluminum and gallium in an oxide sintered body containing zinc oxide as a main component and further containing aluminum and gallium as additive elements, and Optimal control of the type and composition of the crystal phase produced during firing, especially the spinel crystal phase, makes it difficult for particles to form even when continuous film formation is performed for a long time with a sputtering device, and high DC power A target oxide sintered body has been proposed in which abnormal discharge does not occur even when charged (see Patent Document 3).

  And, by using the zinc oxide-based sintered body described in Patent Document 3, it has become possible to form a high-quality transparent conductive film with lower resistance and higher permeability than before, but high transmission comparable to ITO It was still difficult to produce a transparent conductive film with a high rate.

JP 2008-63214 A (see paragraphs 0022-0032) Japanese Patent No. 4067141 (see claims 1 and 2) Japanese Patent No. 4231967 (see paragraph 0013)

  The present invention has been made paying attention to such problems, and the problem is that it is used for sputtering targets and evaporation tablets, and when used for sputtering targets, the abnormal discharge described above is suppressed. The Zn-Si-O-based oxide sintered body that can suppress the above-described splash phenomenon when used in a deposition tablet and can stably form a transparent conductive film having a high transmittance comparable to that of ITO. And providing a manufacturing method thereof.

Therefore, as a result of intensive studies to solve the above-mentioned problems, the present inventors have found that Zn--contains zinc oxide as a main component, contains Si having high oxygen affinity as an additive element, and does not contain other additive elements. With regard to the Si—O-based oxide sintered body, the manufacturing method is optimized, and a single oxide phase (SiO ₂ phase) of an additive element generated during firing, a composite spinel crystal phase, particularly in the sintered body By controlling the precipitation of the oxide phase in the vicinity of the grain boundaries, abnormal discharge and particle generation are suppressed even when continuous film formation is performed for a long time with a sputtering device, and stable film formation is possible even when high DC power is applied. It can be used as a sputtering target that can be used, and it can also be used as a deposition tablet that suppresses the above-mentioned splash phenomenon even when film deposition is performed for a long time using a deposition device such as ion plating. It has been found that a Zn-Si-O-based oxide sintered body can be obtained. Moreover, the transparent conductive film obtained by using the obtained Zn-Si-O-based oxide sintered body for a sputtering target or a tablet for vapor deposition has excellent permeability, and is useful as an electrode of a display, a touch panel, a solar cell, or the like. I came to find out.

That is, the invention according to claim 1
In a Zn—Si—O-based oxide sintered body containing zinc oxide as a main component and containing no additional elements other than Si,
The oxide sintered body is produced at a firing temperature of 900 to 1400 ° C. while raising the temperature range of 700 to 900 ° C. at a temperature rising rate of 5 ° C./min or more , and
The Si content is 0.1 to 10 atomic% in terms of Si / (Zn + Si) atomic ratio,
Si element is dissolved in the wurtzite zinc oxide phase,
Two detection methods by X-ray diffraction of sintered powder using CuKα rays and electron diffraction of sintered flakes using a transmission electron microscope, with SiO ₂ phase and zinc silicate (Zn ₂ SiO ₄ ) A certain spinel type complex oxide phase is not detected.

Next, the invention according to claim 2
In sputtering target,
It is obtained by processing the Zn—Si—O-based oxide sintered body according to claim 1,
The invention according to claim 3
In the tablet for vapor deposition,
It consists of the Zn-Si-O type oxide sintered compact of Claim 1.

The invention according to claim 4
In the manufacturing method of the Zn-Si-O type oxide sintered compact according to claim 1,
A first step of drying and granulating a slurry obtained by mixing ZnO powder and SiO ₂ powder with pure water, an organic binder, and a dispersing agent;
A second step of pressure-molding the obtained granulated powder to obtain a molded body,
While having the third step of firing the obtained molded body to obtain a sintered body,
The third step of obtaining the sintered body is a step of raising the temperature range of 700 to 900 ° C. at a rate of temperature rise of 5 ° C./min or more, and the molded body at 900 to 1400 ° C. in a firing furnace. It consists of a process of firing,
The invention according to claim 5
In the manufacturing method of the Zn-Si-O type oxide sintered compact according to claim 4,
In the third step, the temperature range from 900 ° C. to the sintering temperature is raised at a rate of temperature rise of 3 ° C./min or less,
The invention according to claim 6
In the manufacturing method of the Zn-Si-O type oxide sintered compact according to claim 4,
In the first step, ZnO powder and SiO ₂ powder, calcined powder obtained by mixing and calcining ZnO powder and SiO ₂ powder, and pure water, an organic binder, and a dispersant are raw material ZnO powder. , Mixing so that the total concentration of the SiO ₂ powder and the calcined powder is 50 to 80 wt%, and mixing and stirring for 10 hours or more to obtain the slurry,
The invention according to claim 7 provides:
In the manufacturing method of the Zn-Si-O type oxide sintered compact according to claim 6,
ZnO powder and SiO ₂ powder are mixed and calcined at 900 ° C. to 1400 ° C. to obtain the calcined powder,
The invention according to claim 8 provides:
In the manufacturing method of the Zn-Si-O type oxide sintered compact according to any one of claims 4 to 7,
ZnO powder and SiO ₂ powder having an average particle size of 1.0 μm or less are used.

The Zn—Si—O-based oxide sintered body according to the present invention is:
The oxide sintered body is produced at a firing temperature of 900 to 1400 ° C. while raising the temperature range of 700 to 900 ° C. at a temperature rising rate of 5 ° C./min or more , and
The Si content is 0.1 to 10 atomic% in terms of Si / (Zn + Si) atomic ratio,
Si element is dissolved in the wurtzite zinc oxide phase,
Two detection methods by X-ray diffraction of sintered powder using CuKα rays and electron diffraction of sintered flakes using a transmission electron microscope, with SiO ₂ phase and zinc silicate (Zn ₂ SiO ₄ ) It is characterized in that a certain spinel type complex oxide phase is not detected.

  When a sputtering target obtained by processing this Zn—Si—O-based oxide sintered body is used, even when direct current sputtering is performed by increasing direct current power density in order to increase production efficiency, conventional AZO, GZO, etc. The abnormal discharge (arcing), which has been a problem with the target, is not generated. Further, even when used for a long time in continuous film formation, particles due to film peeling attached to the surface of a target or the like are hardly generated. For this reason, it has the effect of enabling mass production film formation with a high yield with almost no defective products.

  Moreover, when the tablet for vapor deposition which consists of a Zn-Si-O type oxide sintered compact of this invention is used, even if it forms a continuous film formation for a long time with vapor deposition apparatuses, such as ion plating, the above-mentioned splash phenomenon does not occur. Therefore, as in the case of using as a sputtering target, it has the effect of enabling mass production film formation with a high yield with almost no defective products.

  Furthermore, the transparent conductive film formed by using the sputtering target or the deposition tablet obtained from the Zn—Si—O-based oxide sintered body of the present invention contains Si that has a high bondability with oxygen. Therefore, since it has excellent transmittance, it has an effect that can be suitably used as a transparent electrode for flat panel displays, touch panels, light emitting devices, solar cells and the like.

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

1. Zn-Si-O-based oxide sintered body The Zn-Si-O-based oxide sintered body according to the present invention, which contains zinc oxide as a main component and contains no additional elements other than Si, has a temperature range of 700 to 900 ° C. Is heated at a heating rate of 5 ° C./min or more, and the above oxide sintered body is manufactured at a firing temperature of 900 to 1400 ° C., and the Si content is Si / (Zn + Si) atomic ratio. 0.1 to 10 atomic%, Si element is dissolved in the wurtzite type zinc oxide phase, and X-ray diffraction of sintered powder using CuKα ray and transmission electron microscope are used. It is characterized in that a spinel type complex oxide phase which is SiO ₂ phase and zinc silicate (Zn ₂ SiO ₄ ) is not detected by two detection methods by electron beam diffraction of a sintered flake, and a sputtering target or ion plating, etc. Table for deposition It is used as a door. In the Zn—Si—O-based oxide sintered body according to the present invention, the constituent elements may be substantially composed of zinc (Zn), silicon (Si), and oxygen (O). It does not limit contamination.

In the Zn-Si-O-based oxide sintered body according to the present invention, when the Si content exceeds 10 atomic% in terms of the Si / (Zn + Si) atomic ratio, the Zn-Si-O-based oxide sintered body An oxide phase such as a spinel type is generated in the body. Since these oxide phases are high-resistance or insulating materials, they induce abnormal discharge during the above-described sputtering film formation, and also induce the above-described splash phenomenon during deposition such as ion plating. In particular, SiO ₂ also tends to precipitate at the grain boundaries in the Zn—Si—O-based oxide sintered body. If this precipitation cannot be suppressed, the above-described abnormal discharge and splash phenomenon can be completely eliminated. Is impossible.

  On the other hand, if the Si content is less than 0.1 atomic% in terms of the Si / (Zn + Si) atomic ratio, the free electron carriers described below are poor, and the conductivity becomes insufficient regardless of the compound phase to be produced. Abnormal discharge occurs during film formation.

  Further, in the Zn-Si-O-based oxide sintered body according to the present invention, the wurtzite type zinc oxide phase in the oxide sintered body indicates a hexagonal wurtzite structure, oxygen deficiency, zinc deficiency Non-stoichiometric compositions are also included. The zinc oxide phase takes such a non-stoichiometric composition to generate free electrons and improve conductivity. Therefore, abnormal discharge during sputtering film formation and splash phenomenon during deposition such as ion plating can occur. Has the effect of suppressing. In addition, the wurtzite zinc oxide phase contains Si element as a solid solution as described above. When this element dissolves in the zinc site (wurtzite zinc oxide phase), free electron carriers are generated and the conductivity is improved. Therefore, abnormal discharge during sputtering deposition and splash during deposition such as ion plating. Contributes to the suppression of the phenomenon.

2. Manufacturing method of Zn-Si-O-based oxide sintered body The manufacturing method of the Zn-Si-O-based oxide sintered body according to the present invention is to mix raw material powder with pure water, an organic binder, and a dispersant. The resulting slurry is dried and granulated in a “first step”, the obtained granulated powder is pressure-molded to obtain a molded body, and the resulting molded body is fired and fired. It consists of a “third step” for obtaining a knot.

[First step]
The “granulated powder” obtained in the first step can be produced by two methods.
(First method)
ZnO powder and SiO ₂ powder are used as raw material powder, mixed with pure water, an organic binder, and a dispersant, mixed so that the raw material powder concentration is 50 to 80 wt%, preferably 60 wt%, and the average particle size is 0 Wet pulverize to 5 μm or less. At this time, the average particle diameter of both the ZnO powder and the SiO ₂ powder used as raw materials is 1.0 μm or less, and the average particle diameter of the mixed powder is refined to 0.5 μm or less. Furthermore, in the above-mentioned wet pulverization, the “ball mill” using balls having a particle diameter of more than 2.0 mm is not suitable for crushing particles having a particle diameter of 1.0 μm or less. It is preferable to use a “bead mill” using the above. By this manufacturing method, aggregation of ZnO powder, SiO ₂ powder and the like can be reliably removed, and aggregation of Si-based oxides generated in the subsequent process can be prevented. After pulverization, the slurry obtained by mixing and stirring for 30 minutes or more is dried and granulated to obtain “granulated powder”.

(Second method)
ZnO powder and SiO ₂ powder, and calcined powder obtained by mixing and calcining ZnO powder and SiO ₂ powder are used as raw material powders. When the calcined powder is produced, it is calcined at 900 ° C. to 1400 ° C., preferably 900 ° C. to 1200 ° C., but expressed in a spinel phase such as ZnM ₂ O ₄ or Zn ₂ MO ₄ (M is an additive element). It is important that the temperature range of 700 to 900 ° C. at which the intermediate compound phase is most easily generated is increased at a temperature increase rate of 5 ° C./min or more.

Next, ZnO powder and SiO ₂ powder and the calcined powder are used as raw material powder, mixed with pure water, an organic binder, and a dispersant, so that the raw material powder concentration is 50 to 80 wt%, preferably 70 wt%. The slurry obtained by mixing and mixing and stirring for 10 hours or more is dried and granulated to obtain “granulated powder”. Also in this second method, the aggregation of ZnO powder, SiO ₂ powder, etc. is surely removed by setting both the average particle diameters of the ZnO powder and SiO ₂ powder used as raw materials to 1.0 μm or less. Aggregation of Si-based oxides generated in the process can be prevented.

[Second step]
When the sputtering target is molded, the above-mentioned “granulated powder” is subjected to pressure molding at a pressure of 98 MPa (1.0 ton / cm ² ) or more to obtain a molded body. When the molding is performed at 98 MPa or less, it becomes difficult to remove the pores existing between the particles, and the density of the sintered body is lowered. In addition, since the strength of the compact is reduced, stable production becomes difficult. Here, when performing pressure molding, it is desirable to use a cold isostatic press (CIP) that can obtain a high pressure.

On the other hand, when molding a tablet for vapor deposition, the above-mentioned “granulated powder” is pressure-molded by, for example, a mechanical press method in which pressure is applied in a mold to obtain a molded body. When the step of obtaining a molded body is molded at a pressure of "granulated powder" ^{49MPa (0.5ton / cm 2) ~147MPa} (1.5ton / cm 2), the sintered body is liable to give with the desired relative density preferable. In addition, the mold used in the above press molding can prevent chipping or the like when handling a molded body or a sintered body obtained by sintering the molded body when the edge portion has a C-chamfered shape and the molded body is chamfered. ,preferable.

[Third step]
By firing the molded body obtained in the second step at normal pressure, a Zn—Si—O-based oxide sintered body is obtained. Sintering is performed at a firing temperature of 900 to 1400 ° C, preferably 1100 to 1300 ° C. If the sintering temperature is less than 900 ° C., the necessary sintering shrinkage cannot be obtained, resulting in a sintered body having a low mechanical strength. In addition, since the sintering shrinkage is not sufficiently advanced, the density and size variation of the obtained sintered body are increased. In the region of 900 ° C. or higher, sintering proceeds and Si atoms are uniformly present inside the crystal grains in the sintered body. However, if heat energy is applied at a temperature higher than necessary, a region having a high Si concentration added as an impurity is formed inside the crystal grain adjacent to the grain boundary, and this may impede conductivity as a sintered body. However, the present inventors have confirmed that this phenomenon starts to occur at a temperature exceeding 1400 ° C. On the other hand, if the sintering temperature exceeds 1400 ° C., volatilization of zinc oxide (ZnO) is activated, which is not preferable because it deviates from a predetermined zinc oxide composition.

In addition, a temperature range of 700 to 900 ° C. at which an intermediate compound phase represented by a spinel phase such as ZnM ₂ O ₄ or Zn ₂ MO ₄ (M is an additive element) is most easily generated is set at a temperature rising rate of 5 ° C./min. It is important to raise the temperature at the above speed. Generation of an intermediate compound phase is suppressed by increasing the temperature at the above temperature increase rate, and diffusion solid solution of Si element is promoted by setting the temperature increase rate in a temperature range other than 700 to 900 ° C. to 3 ° C./min or less. The present inventors have confirmed that this is done. And by producing a sintered body with these firing programs, it is possible to suppress the precipitation of Si-based oxides and the generation of intermediate compound phases including spinel phases.

  The obtained sintered body is processed into a predetermined shape and size as required, and when used as a sputtering target, bonding is performed to a predetermined backing plate.

3. Transparent conductive film and manufacturing method thereof The transparent conductive film is formed on a substrate such as glass by a sputtering method using a sputtering target or an evaporation method such as ion plating using an evaporation tablet in a film forming apparatus. Since the composition of the transparent conductive film obtained is made from the Zn—Si—O-based oxide sintered body according to the present invention, the composition of the oxide sintered body is reflected. In addition, the transparent conductive film obtained by the present invention is composed of a crystalline phase, is substantially composed of a wurtzite zinc oxide phase, and all Si elements are contained in the wurtzite zinc oxide phase. preferable.

  Further, the obtained wurtzite zinc oxide phase is c-axis oriented in a direction perpendicular to a substrate such as glass. And the better the crystallinity (that is, the larger the crystal grain), the higher the mobility of carrier electrons and the better the conductivity. In addition, the mobility of carrier electrons increases because the crystallinity is improved by increasing the film thickness.

  In the present invention, by using a sputtering target or a deposition tablet obtained from the Zn-Si-O-based oxide sintered body and adopting film forming conditions such as a specific substrate temperature and pressure, an oxidation containing Si element is performed. A transparent conductive film made of zinc can be formed on the substrate.

  As described above, the composition of the transparent conductive film obtained by vapor deposition such as sputtering or ion plating using the Zn—Si—O-based oxide sintered body according to the present invention is the same as the composition of the oxide sintered body. It is the same. With regard to this composition, if the amount of Si element is too large, it cannot be dissolved in the zinc oxide phase, the Si oxide phase is precipitated and the crystallinity of the thin film is inferior, and the conductivity deteriorates due to the decrease in mobility of electron carriers. Becomes prominent. In this case, it is possible to improve the solid solubility of the Si element by heating the substrate. However, high-temperature film formation is a special film formation condition, and in order to obtain a highly conductive transparent conductive film under a wide range of mass production film formation conditions including room temperature film formation, the Si element content is in the above-mentioned range. Of these, that is, the Si content needs to be suppressed to 0.1 to 10 atomic% in terms of the Si / (Zn + Si) atomic ratio.

  Next, the substrate used for film formation is not particularly limited depending on the material such as glass, resin, metal, ceramic, and may be transparent or non-transparent. preferable. Further, when the substrate is a resin, various shapes such as a plate shape and a film can be used. For example, a substrate having a low melting point of 150 ° C. or less can be applied. However, in this case, it is desirable to perform film formation without heating.

  The transparent conductive film obtained from the Zn—Si—O-based oxide sintered body containing no additive element other than Si is composed mainly of zinc oxide in which ions of the above-described elements are substituted with zinc ion sites as dopants. Type semiconductor conductive crystal film. Silicon (Si) ions are positive tetravalent, but trivalent or higher elements replace positive divalent zinc ion sites to generate free electron carriers in the film and have excellent conductivity.

Next, in order to produce a transparent conductive film by a sputtering method using a sputtering target, it is preferable to use an inert gas such as argon as the sputtering gas and also use direct current sputtering. For example, after evacuating to 5 × 10 ⁻⁵ Pa or less, pure Ar gas is introduced, and the gas pressure is set to 0.1 to 1 Pa, particularly 0.2 to 0.8 Pa, and 0.55 to 5.0 W. Pre-sputtering can be performed by applying a DC power density (DC power / target area) of / cm ² to generate DC plasma. After performing this pre-sputtering for 5 to 30 minutes, it is preferable to perform sputtering after correcting the substrate position if necessary. When the sputtering target obtained from the Zn—Si—O-based oxide sintered body according to the present invention is used, there is an advantage that stable high-speed film formation is possible without occurrence of abnormal discharge even when high DC power is applied. .

In addition, a similar transparent conductive film can be formed even when a deposition tablet (also called a pellet or a target) produced from a Zn—Si—O-based oxide sintered body according to the present invention is used. is there. For example, in the ion plating method, when an evaporation tablet serving as an evaporation source is irradiated with heat from an electron beam or arc discharge, the irradiated portion becomes locally hot, and the evaporated particles are evaporated and deposited on the substrate. Is done. At this time, the evaporated particles are ionized by an electron beam or arc discharge. There are various ionization methods, and the high-density plasma-assisted deposition method (HDPE method) using a plasma generator (plasma gun) is suitable for forming a high-quality transparent conductive film. In this method, arc discharge using a plasma gun is used, but arc discharge is maintained between a cathode built in the plasma gun and a crucible (anode) of the evaporation source. Electrons emitted from the cathode are introduced into the crucible by magnetic field deflection, and concentrated and irradiated on the local area of the deposition tablet charged in the crucible. By this electron beam, the evaporated particles are evaporated and deposited on the substrate from the portion where the temperature is locally high. Vaporized evaporated particles and O ₂ gas introduced as a reactive gas are ionized and activated in the plasma, and thus a high-quality transparent conductive film can be formed.

  Examples of the present invention will be specifically described below with reference examples, comparative examples, and reference comparative examples. However, the technical configuration of the present invention is not limited by the following examples.

[Example 1]
[Preparation of sintered oxide]
ZnO powder with an average particle size of 1.0 μm or less and SiO ₂ powder are used as raw material powders, and are prepared at a ratio of Si / (Zn + Si) atomic ratio of 3.0 atomic%, and pure water, organic binder, dispersion The slurry was mixed with an agent and mixed so that the raw material powder concentration was 60 wt%, and a slurry was prepared in a mixing tank.

Next, using a bead mill apparatus (manufactured by Ashizawa Finetech Co., Ltd., LMZ type) into which hard ZrO ₂ balls having a particle diameter of 0.5 mm are introduced, the average particle diameter of the raw material powder becomes 0.5 μm or less. After the wet pulverization, the slurry obtained by mixing and stirring for 30 minutes or more was sprayed and dried with a spray dryer (Okawara Kako Co., Ltd., ODL-20 type) to obtain “granulated powder”. Obtained. A laser diffraction particle size distribution measuring device (SALD-2200, manufactured by Shimadzu Corporation) was used to measure the average particle size of the raw material powder.

Next, the obtained “granulated powder” was molded by applying a pressure of 294 MPa (3 ton / cm ² ) with a cold isostatic press, and the resulting molded body of about 200 mmφ was subjected to an atmospheric pressure firing furnace. The temperature range of 700 to 900 ° C. is increased at a rate of temperature increase of 5 ° C./minute, the temperature increase rate in a temperature range other than 700 to 900 ° C. is set to 3 ° C./minute, and the maximum firing temperature is 1300. The oxide sintered body according to Example 1 was obtained by baking at 20 ° C. for 20 hours.

Here, the end material of the obtained oxide sintered body was pulverized, and the product phase was identified by powder X-ray diffraction measurement using CuKα rays. As a result, the peak of the ZnO phase having a hexagonal wurtzite structure was obtained. Only the peaks due to the SiO ₂ phase alone or the spinel type complex oxide phase of zinc silicate (Zn ₂ SiO ₄ ) were not detected.

Further, the end material of the obtained oxide sintered body was sliced by FIB processing and observed with a transmission electron microscope (TEM) mounted on an energy dispersive X-ray fluorescence spectrometer (EDX). As a result, it was confirmed from the electron diffraction that the oxide sintered body did not have a single SiO ₂ phase in the parent phase having a wurtzite structure.

[Preparation of transparent conductive film]
The obtained oxide sintered body according to Example 1 was processed to have a diameter of 152.4 mm (6 inches) and a thickness of 5 mm, and was bonded to an oxygen-free copper backing plate using metal indium. A sputtering target according to Example 1 was obtained.

  Next, using the obtained sputtering target according to Example 1, film formation by direct current sputtering was performed. The sputtering target was attached to a non-magnetic target cathode of a direct current magnetron sputtering apparatus (manufactured by Tokki, SPF-530K).

  On the other hand, a non-alkali glass substrate (Corning # 7059, thickness t is 1.1 mm) was used as the substrate for film formation, and the target-substrate distance was fixed to 60 mm.

Then, after evacuating to 5 × 10 ⁻⁵ Pa or less, pure Ar gas was introduced, the gas pressure was set to 0.3 Pa, DC power 200 W was applied to generate DC plasma, and pre-sputtering was performed. .

  After sufficient pre-sputtering, the substrate was placed immediately above the center (non-erosion part) of the sputtering target, and sputtering was performed without heating to form a transparent conductive film having a thickness of 200 nm.

  As a result, no crack was generated in the sputtering target, and no abnormal discharge or the like occurred in 10 minutes from the initial stage of film formation.

  Moreover, when the transmittance | permeability of the obtained film | membrane was measured with the spectrophotometer (made by Hitachi, Ltd.), the transmittance | permeability of visible region (400 nm-800 nm) including a board | substrate is 87%, and the board | substrate was included. The transmittance in the near infrared region (800 nm to 1200 nm) was 85%. Here, when the transmittance of the film itself was calculated by [(transmittance including the substrate) / (transmittance only of the substrate)] × 100 (%), the transmittance of the transparent conductive film according to Example 1 was The visible region was 89% and the near infrared region was 92%.

Moreover, when the specific resistance of the obtained film | membrane surface was measured using the four deep needle method resistivity meter Loresta EP (Mitsubishi Chemical Analytech Co., Ltd. make, MCP-T360 type | mold), a specific resistance value is 8.5x. 10 ⁻⁴ Ω · cm.

  Therefore, the transparent conductive film according to Example 1 is excellent not only in the visible region but also in the near infrared region, and not only for device applications such as displays that require visible light transmission, but also in the near infrared region. It has been confirmed that it is also useful as a solar cell application requiring high performance.

  Here, the constituent components and manufacturing conditions of the oxide sintered bodies according to all examples and reference examples, the presence or absence of cracks in the manufacturing process, the use of the sintered body, etc. are shown together in Table 1, and Analysis results, film deposition conditions (however, “abnormal discharge during film deposition, etc.” column indicates the presence or absence of abnormal discharge or particles in the case of sputtering film deposition, and splash in the case of ion plating film deposition. Table 2 summarizes the characteristics and the like of the transparent conductive film.

[Examples 2 and 3, Comparative Examples 1 and 2]
The oxide firing was performed under the same conditions as in Example 1 except that the firing temperature was 1400 ° C. (Example 2), 900 ° C. (Example 3), 1500 ° C. (Comparative Example 1), and 800 ° C. (Comparative Example 2). A ligature was obtained.

As in Example 1, powder X-ray diffraction measurement of the obtained oxide sintered body was performed. As a result, only the peak of the ZnO phase having a hexagonal wurtzite structure was detected in all the sintered bodies, and SiO ₂ No peaks were detected due to the single phase or the spinel complex oxide phase of zinc silicate (Zn ₂ SiO ₄ ).

Further, the end material of the obtained oxide sintered body was sliced by FIB processing and observed with a transmission electron microscope (TEM) mounted on an energy dispersive X-ray fluorescence spectrometer (EDX). As a result, the oxide sintered bodies obtained in Examples 2 and 3 and Comparative Example 2 do not have a single SiO ₂ phase in the parent phase having a wurtzite type structure, also from electron diffraction. Was confirmed. However, in Comparative Example 1, a region having a high Si concentration was formed inside the crystal grain adjacent to the grain boundary because the firing temperature was too high, and the SiO ₂ phase was present.

  Next, the obtained oxide sintered body was processed to have a diameter of 152.4 mm (6 inches) and a thickness of 5 mm to obtain a sputtering target.

After these sputtering targets were mounted on a sputtering apparatus (SPF-530K, manufactured by Tokki), after being used for film formation by sputtering under the same conditions as in Example 1, the state of the target was confirmed. In both No. 3 and No. 3, no cracks occurred, and no abnormal discharge or the like occurred in 10 minutes from the initial stage of film formation. On the other hand, in Comparative Examples 1 and 2, abnormal discharge occurred 20 to 30 times in 10 minutes. In Comparative Example 1, it is considered that the presence of the SiO ₂ phase having poor conductivity contributes to abnormal discharge in Comparative Example 2 due to the low strength of the sintered body due to insufficient sintering. In Comparative Example 1, since the crystal grains are coarsened, the strength of the sintered body is low, and cracks occur in 4 of 20 sheets during processing. In addition, in Comparative Example 2, sintering did not proceed because the firing temperature was low, and cracks occurred in 12 of 20 sheets during processing. The oxide sintered bodies according to Comparative Examples 1 and 2 cannot be used in a mass production process that requires high productivity.

  Next, when the transmittance and specific resistance value of the film itself obtained in the same manner as in Example 1 were measured and calculated, 89% (Example 2), 88% (Example 3), 77 in the visible range. % (Comparative Example 1), 81% (Comparative Example 2), and 93% (Example 2), 92% (Example 3), 79% (Comparative Example 1), 81% (Comparative Example) in the near infrared region. 2).

The specific resistance values were 8.6 × 10 ⁻⁴ Ω · cm (Example 2), 9.0 × 10 ⁻⁴ Ω · cm (Example 3), 8.5 × 10 ⁻⁴ Ω · cm ( Comparative Example 1) and 8.8 × 10 ⁻⁴ Ω · cm (Comparative Example 2).

  The transparent conductive films obtained in Comparative Examples 1 and 2 are considered to have deteriorated transmittance due to the influence of abnormal discharge, and such transparent conductive films are applied as transparent electrode films that require high permeability. It was confirmed that it was not possible.

  In addition, regarding the comparative examples, the constituent components and production conditions of the oxide sintered bodies according to all comparative examples and reference comparative examples, the presence or absence of cracks in the production process, the usage of the sintered bodies, etc. are summarized in Table 3, As a result of the analysis of the sintered body, the situation at the time of film formation (however, the “abnormal discharge during film formation, etc.” column indicates the presence or absence of abnormal discharge or particle generation in the case of sputtering film formation. Table 4 summarizes the characteristics and the like of the transparent conductive film.

[Examples 4 and 5, Comparative Examples 3 and 4]
ZnO powder and SiO ₂ powder having an average particle size of 1.0 μm or less are used as raw material powders, and the Si / (Zn + Si) atomic ratio is 0 atomic% (Comparative Example 3), 0.1 atomic% (Example 4), 10 An oxide sintered body was obtained under the same conditions as in Example 1 except that the atomic% (Example 5) and 15 atomic% (Comparative Example 4) were used.

As in Example 1, the obtained oxide sintered body was subjected to powder X-ray diffraction measurement. The sintered bodies of Examples 4 and 5 and Comparative Example 3 had a ZnO phase having a hexagonal wurtzite structure. Only the peak was detected, and no peak due to the SiO ₂ phase alone or the spinel complex oxide phase of zinc silicate (Zn ₂ SiO ₄ ) was detected. On the other hand, in the sintered body of Comparative Example 4, in addition to the ZnO phase, a peak attributed to the spinel complex oxide phase of zinc silicate (Zn ₂ SiO ₄ ) was confirmed.

Further, the end material of the obtained oxide sintered body was sliced by FIB processing and observed with a transmission electron microscope (TEM) mounted on an energy dispersive X-ray fluorescence spectrometer (EDX). As a result, in the oxide sintered bodies obtained in Examples 4 and 5 and Comparative Example 3, the SiO ₂ phase does not exist alone in the matrix phase having a wurtzite structure, also from electron diffraction. Was confirmed. However, in Comparative Example 4, there was a SiO ₂ phase that was not dissolved because the Si concentration added as an impurity was high.

  Next, the obtained oxide sintered body was processed to have a diameter of 152.4 mm (6 inches) and a thickness of 5 mm to obtain a sputtering target.

  After mounting these sputtering targets on a sputtering apparatus (made by Tokki, SPF-530K), after using them for film formation by the sputtering method under the same conditions as in Example 1, the results of checking the state of the targets were shown. In Nos. 4 and 5, no cracks occurred, and no abnormal discharge occurred in 10 minutes from the initial stage of film formation. On the other hand, abnormal discharge generated in 10 minutes occurred 20 to 30 times in Comparative Example 3, and 100 to 120 times in Comparative Example 4. The oxide sintered bodies according to Comparative Examples 3 and 4 cannot be used in a mass production process that requires high productivity.

  Next, when the transmittance and specific resistance value of the film itself obtained in the same manner as in Example 1 were measured and calculated, it was 89% (Comparative Example 3), 88% (Example 4), and 90% in the visible range. (Example 5), 78% (Comparative Example 4), 90% (Comparative Example 3), 94% (Example 4), 89% (Example 5), 76% (Comparative Example 4) in the near infrared region. )Met.

The specific resistance values are 7.8 × 10 ² Ω · cm (Comparative Example 3), 9.0 × 10 ⁻⁴ Ω · cm (Example 4), 8.1 × 10 ⁻⁴ Ω · cm (implementation). Example 5) and 8.2 × 10 ⁻⁴ Ω · cm (Comparative Example 4).

  The transparent conductive films obtained in Comparative Examples 3 and 4 are considered to have deteriorated transmittance due to the influence of abnormal discharge, and such transparent conductive films should be applied as transparent electrode films that require high permeability. It was confirmed that it was not possible.

[Reference Examples 6 to 12, Reference Example 7-2, Reference Example 9-2, Reference Example 12-2]
ZnO powder having an average particle size of 1.0 μm or less, SiO ₂ powder, oxide powder of a third metal element as an additive element is used as a raw material powder, Si / (Zn + Si) atomic ratio is 3.0 atomic%, third metal When the element is M and the M / (Zn + Si + M) atomic ratio is 2.0 atomic%, the third additive element is Mg (Reference Example 6), Al (Reference Example 7), Ti (Reference Example 8), Ga (Reference Example 9), In (Reference Example 10), Sn (Reference Example 11), Al + Ga (Reference Example 12), and M / (Zn + Si + M) atomic ratio is 10 atomic%, and the third additive element is An oxide sintered body was obtained under the same conditions as in Example 1 except that Al (reference example 7-2), Ga (reference example 9-2), and Al + Ga (reference example 12-2) were used.

As in Example 1, powder X-ray diffraction measurement of the obtained oxide sintered body was performed. As a result, only the peak of the ZnO phase having a hexagonal wurtzite structure was detected in all the sintered bodies, and SiO ₂ No peaks were detected due to the single phase or the spinel complex oxide phase of zinc silicate (Zn ₂ SiO ₄ ).

Further, the end material of the obtained oxide sintered body was sliced by FIB processing and observed with a transmission electron microscope (TEM) mounted on an energy dispersive X-ray fluorescence spectrometer (EDX). As a result, it was confirmed by electron beam diffraction that the obtained oxide sintered body did not have a single SiO ₂ phase in the parent phase having a wurtzite structure.

  Next, the obtained oxide sintered body was processed to have a diameter of 152.4 mm (6 inches) and a thickness of 5 mm to obtain a sputtering target.

  After mounting these sputtering targets on a sputtering apparatus (SPF-530K, manufactured by Tokki), after using them for film formation by the sputtering method under the same conditions as in Example 1, all the results of confirming the state of the target No cracks occurred on the target, and no abnormal discharge occurred in 10 minutes from the initial stage of film formation.

  Next, when the transmittance and specific resistance value of the film itself obtained in the same manner as in Example 1 were measured and calculated, 90% (Reference Example 6), 90% (Reference Example 7), and 88% in the visible region. (Reference Example 8), 88% (Reference Example 9), 89% (Reference Example 10), 89% (Reference Example 11), 88% (Reference Example 12), 83% (Reference Example 7-2), 81% (Reference Example 9-2), 82% (Reference Example 12-2), and 91% (Reference Example 6), 91% (Reference Example 7), 91% (Reference Example 8), 91% in the near infrared region. (Reference Example 9), 90% (Reference Example 10), 91% (Reference Example 11), 92% (Reference Example 12), 82% (Reference Example 7-2), 80% (Reference Example 9-2), It was 80% (reference example 12-2).

The specific resistance values are 8.0 × 10 ⁻⁴ Ω · cm (Reference Example 6), 5.7 × 10 ⁻⁴ Ω · cm (Reference Example 7), 8.2 × 10 ⁻⁴ Ω · cm (Reference) Example 8), 5.0 × 10 ⁻⁴ Ω · cm (Reference Example 9), 7.1 × 10 ⁻⁴ Ω · cm (Reference Example 10), 7.5 × 10 ⁻⁴ Ω · cm (Reference Example 11) ) 5.4 × 10 ⁻⁴ Ω · cm (Reference Example 12), 7.8 × 10 ⁻⁴ Ω · cm (Reference Example 7-2), 6.1 × 10 ⁻⁴ Ω · cm (Reference Example 9) 2) and 7.2 × 10 ⁻⁴ Ω · cm (2 of Reference Example 12).

  Therefore, the transparent conductive film according to Reference Examples 6 to 12, 7 of 2, 9 of 2 and 12 of 2 is excellent not only in the visible region but also in the near infrared region, and requires a visible light transmission. It was confirmed that it is useful not only for device applications such as, but also for solar cell applications that require high transparency in the near infrared region.

[Comparative Example 5]
The conditions were the same as in Example 1 except that the wet milling was performed until the average particle size of the raw material powder became 0.5 μm or less using a ball mill apparatus in which hard ZrO ₂ balls having a particle size of 3.0 mm were introduced. Thus, an oxide sintered body was obtained.

As in Example 1, powder X-ray diffraction measurement of the obtained oxide sintered body was performed. As a result, only the peak of the ZnO phase having a hexagonal wurtzite structure was detected, and the SiO ₂ phase alone or zinc silicate ( No peak attributed to the spinel complex oxide phase of Zn ₂ SiO ₄ ) was detected.

However, when the milled end of the obtained oxide sintered body was thinned by FIB processing and observed with a transmission electron microscope (TEM) mounted on an energy dispersive X-ray fluorescence spectrometer (EDX), the oxide sintered body In this case, the raw material powder was not sufficiently pulverized and mixed to cause agglomeration, or there was a SiO ₂ phase that was not dissolved in the mother phase having a wurtzite structure. In addition, the above ball mill requires 24 hours to pulverize to 0.5 μm or less, and not only the productivity is remarkably low, but also the Zr component that is worn and mixed from the ball during pulverization is detected at 4000 ppm, This manufacturing method cannot be used as a mass production process that requires high productivity and quality.

  Next, the obtained oxide sintered body was processed to have a diameter of 152.4 mm (6 inches) and a thickness of 5 mm to obtain a sputtering target.

  After mounting this sputtering target on a sputtering apparatus (SPF-530K, manufactured by Tokki), after using it for film formation by sputtering under the same conditions as in Example 1, as a result of confirming the state of the target, abnormal discharge occurred. It occurred 10 to 20 times in 10 minutes from the initial stage of the film. Such an oxide sintered body cannot be used in a mass production process that requires high productivity.

Next, when the transmittance and specific resistance value of the film itself obtained in the same manner as in Example 1 were measured and calculated, it was 82% in the visible region and 83% in the near infrared region, and the specific resistance value was 9. It was 8 × 10 ⁻⁴ Ω · cm.

[Comparative Example 6]
An oxide sintered body was obtained under the same conditions as in Example 1 except that ZnO powder having an average particle diameter of 1.3 μm and SiO ₂ powder having an average particle diameter of 1.5 μm were used as raw material powders.

As in Example 1, powder X-ray diffraction measurement of the obtained oxide sintered body was performed. As a result, only the peak of the ZnO phase having a hexagonal wurtzite structure was detected, and the SiO ₂ phase alone or zinc silicate ( No peak attributed to the spinel complex oxide phase of Zn ₂ SiO ₄ ) was detected.

However, when the milled end of the obtained oxide sintered body was thinned by FIB processing and observed with a transmission electron microscope (TEM) mounted on an energy dispersive X-ray fluorescence spectrometer (EDX), the oxide sintered body In Si, the particle size of the raw material powder was large, and Si, which was uniformly dispersed only on a macroscopic scale, was not dissolved in the parent phase having a wurtzite structure, and an SiO ₂ phase was present.

  Next, the obtained oxide sintered body was processed to have a diameter of 152.4 mm (6 inches) and a thickness of 5 mm to obtain a sputtering target.

  After mounting this sputtering target on a sputtering apparatus (SPF-530K, manufactured by Tokki), after using it for film formation by sputtering under the same conditions as in Example 1, as a result of confirming the state of the target, abnormal discharge occurred. It occurred 20 to 30 times in 10 minutes from the initial stage of the film. Such an oxide sintered body cannot be used in a mass production process that requires high productivity.

Next, the transmittance and specific resistance value of the film itself obtained in the same manner as in Example 1 were measured and calculated to be 85% in the visible region and 85% in the near infrared region. It was 2 × 10 ⁻³ Ω · cm.

[Example 13]
ZnO powder and SiO ₂ powder having an average particle size of 1.0 μm or less were used as raw material powders, and weighed so that the Si / (Zn + Si) atomic ratio was 3.0 atomic%.

Next, 60 wt% each of ZnO powder and SiO ₂ powder, pure water, and an organic dispersant were mixed so as to form a slurry having a raw material powder concentration of 60 wt%, and a slurry was prepared in a mixing tank.

  The obtained slurry was sprayed and dried with a spray dryer (Okawara Koki Co., Ltd., ODL-20 type) to obtain a mixed powder having a particle size of 300 μm or less.

  The obtained mixed powder is heated in an atmospheric pressure firing furnace at a temperature range of 700 to 900 ° C. at a rate of temperature increase of 5 ° C./min, and the rate of temperature increase in a temperature range other than 700 to 900 ° C. Was calcined for 20 hours at a maximum firing temperature of 1200 ° C. and pulverized after firing to obtain a calcined powder of 300 μm or less.

Next, the obtained calcined powder, the remaining weighed ZnO powder and SiO ₂ powder are mixed with pure water, an organic binder, and a dispersant so as to form a slurry having a raw material powder concentration of 70 wt%. Then, a slurry was prepared in a mixing tank, and sprayed and dried with a spray dryer device to obtain a granulated powder having a particle size of 300 μm.

  And the obtained granulated powder was press-molded in a mold (manufactured by Sansho Industry Co., Ltd., a wave molding press) to obtain 200 cylindrical molded bodies having a diameter of 30 mm and a height of 40 mm.

  The obtained compact is heated in a temperature range of 700 to 900 ° C. at a rate of temperature increase of 5 ° C./min in an atmospheric pressure firing furnace, and the temperature is raised in a temperature range other than 700 to 900 ° C. The oxide sintered body was obtained by firing at a rate of 3 ° C./min and a maximum firing temperature of 1000 ° C. for 20 hours.

As in Example 1, when the powder X-ray diffraction measurement of the obtained oxide sintered body was performed, only the peak of the ZnO phase having a hexagonal wurtzite structure was detected in all 200 sintered bodies, No peaks due to the SiO ₂ phase alone or the spinel complex oxide phase of zinc silicate (Zn ₂ SiO ₄ ) were detected.

Further, the end material of the obtained oxide sintered body was sliced by FIB processing and observed with a transmission electron microscope (TEM) mounted on an energy dispersive X-ray fluorescence spectrometer (EDX). As a result, it was confirmed by electron beam diffraction that the obtained oxide sintered body did not have a single SiO ₂ phase in the parent phase having a wurtzite structure.

Next, using the obtained sintered body as a vapor deposition tablet, film formation was performed by an ion plating method. For the film formation, a reactive plasma vapor deposition apparatus capable of high density plasma assisted vapor deposition (HDPE method) was used. Specifically, the distance between the evaporation source and the substrate is 0.6 m, the discharge current of the plasma gun is 100 A, the Ar flow rate is 30 sccm, and the O ₂ flow rate is 10 sccm. While being supplied, film formation was performed without heating to form a transparent conductive film having a thickness of 200 nm. As a result, stable film formation was possible in all the tablets for vapor deposition, and there was no chipping or cracking during automatic transportation, and stable film formation was possible.

Further, the transmittance and specific resistance value of the film itself obtained in the same manner as in Example 1 were measured and calculated. As a result, it was 90% in the visible region and 92% in the near infrared region, and the specific resistance value was 7.9. × 10 ⁻⁴ Ω · cm.

[Examples 14 and 15, Comparative Examples 7 and 8]
The oxide firing was performed under the same conditions as in Example 13 except that the firing temperature was 1400 ° C. (Example 14), 900 ° C. (Example 15), 1500 ° C. (Comparative Example 7), and 700 ° C. (Comparative Example 8). A ligature was obtained.

As in Example 1, powder X-ray diffraction measurement was performed on the obtained oxide sintered body. As a result, only the peak of the ZnO phase having a hexagonal wurtzite structure was detected in all the sintered bodies. _No peaks due to the _two- phase simple substance or the spinel-type complex oxide phase of zinc silicate (Zn ₂ SiO ₄ ) were detected.

Further, the end material of the obtained oxide sintered body was sliced by FIB processing and observed with a transmission electron microscope (TEM) mounted on an energy dispersive X-ray fluorescence spectrometer (EDX). As a result, the oxide sintered bodies obtained in Examples 14 and 15 and Comparative Example 8 do not have a single SiO ₂ phase in the parent phase having a wurtzite structure, also from electron diffraction. Was confirmed. However, in Comparative Example 7, because the firing temperature was too high, a region with a high Si concentration was formed inside the crystal grain adjacent to the grain boundary, and an SiO ₂ phase was present.

The obtained sintered body was used as a tablet for vapor deposition, and vapor deposition was performed by irradiating an electron beam while continuously supplying it into a vacuum vapor deposition apparatus. As a result, although stable film formation was possible in the vapor deposition tablets of Examples 14 and 15, in Comparative Example 7, the film was formed due to insufficient resistance to thermal shock due to charging to the SiO ₂ phase or oversintering. Tablet breakage, abnormal discharge, and splash phenomenon occurred. In addition, in the sintered body of Comparative Example 8, cracks occurred during automatic transportation and film formation due to insufficient sintering. These oxide sintered bodies according to Comparative Examples 7 and 8 cannot be used in mass production processes that require high productivity.

  Next, when the transmittance and specific resistance value of the film itself obtained in the same manner as in Example 1 were measured and calculated, 90% (Example 14), 90% (Example 15), and 86% in the visible region. (Comparative Example 7), 88% (Comparative Example 8) 93% (Example 14), 91% (Example 15), 88% (Comparative Example 7), 89% (Comparative Example 8) in the near infrared region )Met.

The specific resistance values are 8.2 × 10 ⁻⁴ Ω · cm (Example 14), 8.0 × 10 ⁻⁴ Ω · cm (Example 15), and 8.9 × 10 ⁻⁴ Ω · cm (Example 14). Comparative Example 7) and 8.7 × 10 ⁻⁴ Ω · cm (Comparative Example 8).

  It is considered that the transparent conductive films obtained in Comparative Examples 7 and 8 had an adverse effect on the transmittance due to the instability of film formation, and such transparent conductive films are applied as transparent electrode films that require high permeability. It was confirmed that it was not possible.

[Comparative Example 9]
A hard ZrO ₂ ball having a particle diameter of 3.0 mm is prepared by using ZnO powder and SiO ₂ powder having an average particle diameter of 0.4 μm as raw material powders, and having a Si / (Zn + Si) atomic ratio of 4.0 atomic%. Was used to dry-grind until the average particle size of the raw material powder became 0.3 μm or less to obtain granulated powder.

Next, the obtained granulated powder was fired at 15 MPa (150 kg / cm ² ) and 1000 ° C. with a vacuum hot press to obtain an oxide sintered body. At this time, the heating rate was 3 ° C./min.

As in Example 1, powder X-ray diffraction measurement was performed on the obtained oxide sintered body. As a result, a ZnO phase having a hexagonal wurtzite structure and a spinel-type composite of zinc silicate (Zn ₂ SiO ₄ ) were obtained. A peak due to the oxide phase was detected.

Moreover, as a result of slicing the end material of the obtained oxide sintered body by FIB processing and observing with a transmission electron microscope (TEM) mounted on an energy dispersive X-ray fluorescence spectrometer (EDX), the oxide sintered body The material powder was not sufficiently pulverized and mixed to cause agglomeration, or Si that was uniformly dispersed only on a macroscopic scale was not dissolved in the mother phase having a wurtzite structure. _Two phases were present.

  Next, the obtained oxide sintered body was processed to have a diameter of 152.4 mm (6 inches) and a thickness of 5 mm to obtain a sputtering target.

  After mounting this sputtering target on a sputtering apparatus (SPF-530K, manufactured by Tokki), after using it for film formation by sputtering under the same conditions as in Example 1, as a result of confirming the state of the target, abnormal discharge occurred. It occurred 10 to 20 times in 10 minutes from the initial stage of the film. Such an oxide sintered body cannot be used in a mass production process that requires high productivity.

Next, when the transmittance and specific resistance value of the film itself obtained in the same manner as in Example 1 were measured and calculated, it was 82% in the visible region and 79% in the near infrared region, and the specific resistance value was 7. It was 0 × 10 ⁻⁴ Ω · cm.

[Reference Comparative Example 10]
ZnO powder, SiO ₂ powder, and Al ₂ O ₃ powder having an average particle size of 0.1 μm are used as raw material powders, the Si / (Zn + Si) atomic ratio is 1.1 atomic%, and the Al / (Zn + Si + Al) atomic ratio is 3 The mixture was prepared at a ratio of 0.5 atomic%, mixed with pure water, an organic binder, and a dispersant, mixed so that the raw material powder concentration was 60 wt%, and a slurry was prepared in a mixing tank.

Next, granulated powder was obtained under the same conditions as in Example 1 except that wet grinding was performed for 18 hours using a ball mill apparatus in which hard ZrO ₂ balls having a particle diameter of 3.0 mm were introduced.

The obtained granulated powder was molded by applying a pressure of 294 MPa (3 ton / cm ² ) with a cold isostatic press, and the resulting molded body of about 200 mmφ was heated at the maximum firing temperature in an atmospheric pressure firing furnace. The oxide sintered body was obtained by firing at 1300 ° C. for 5 hours in the air. At this time, the temperature rising rate was 1 ° C./min from room temperature to 800 ° C., and 3 ° C./min from 800 to 1300 ° C.

As in Example 1, powder X-ray diffraction measurement of the obtained oxide sintered body was performed. As a result, a ZnO phase having a hexagonal wurtzite structure and a spinel-type composite oxidation of zinc silicate (Zn ₂ SiO ₄ ) were obtained. A peak due to the physical phase was detected.

Moreover, as a result of slicing the end material of the obtained oxide sintered body by FIB processing and observing with a transmission electron microscope (TEM) mounted on an energy dispersive X-ray fluorescence spectrometer (EDX), the oxide sintered body The material powder was not sufficiently pulverized and mixed to cause agglomeration, or Si that was uniformly dispersed only on a macroscopic scale was not dissolved in the mother phase having a wurtzite structure. _Two phases existed.

  Next, the obtained oxide sintered body was processed to have a diameter of 152.4 mm (6 inches) and a thickness of 5 mm to obtain a sputtering target.

  After mounting this sputtering target on a sputtering apparatus (SPF-530K, manufactured by Tokki), after using it for film formation by sputtering under the same conditions as in Example 1, as a result of confirming the state of the target, abnormal discharge occurred. It occurred 3 times in 10 minutes from the initial stage of the film. Although abnormal discharge is suppressed in such an oxide sintered body, abnormal discharge cannot be completely eliminated, and it cannot be used in mass production processes that require high productivity because it leads to deterioration in yield. .

Further, the transmittance and specific resistance value of the film itself obtained in the same manner as in Example 1 were measured and calculated. As a result, it was 82% in the visible region and 75% in the near infrared region, and the specific resistance value was 8.0. × 10 ⁻⁴ Ω · cm.

[Reference Comparative Example 11]
ZnO powder, SiO ₂ powder and Ga ₂ O ₃ powder having an average particle size of 0.1 μm are used as raw material powder, Si / (Zn + Si) atomic ratio is 0.85 atomic%, and Ga / (Zn + Si + Ga) atomic ratio is 4. The mixture was prepared at a ratio of 0.0 atomic%, mixed with pure water, an organic binder, and a dispersant, mixed so that the raw material powder concentration was 60 wt%, and a slurry was prepared in a mixing tank.

Next, granulated powder was obtained under the same conditions as in Example 1 except that wet grinding was performed for 18 hours using a ball mill apparatus in which hard ZrO ₂ balls having a particle diameter of 3.0 mm were introduced.

Next, the obtained granulated powder was molded by applying a pressure of 294 MPa (3 ton / cm ² ) with a cold isostatic press, and the resulting molded body of about 200 mmφ was the highest in an atmospheric pressure firing furnace. The firing temperature was set to 1300 ° C. and fired in the air for 5 hours to obtain an oxide sintered body. At this time, the temperature rising rate was 1 ° C./min from room temperature to 800 ° C., and 3 ° C./min from 800 to 1300 ° C.

As in Example 1, powder X-ray diffraction measurement was performed on the obtained oxide sintered body. As a result, a ZnO phase having a hexagonal wurtzite structure and a spinel-type composite of zinc silicate (Zn ₂ SiO ₄ ) were obtained. A peak due to the oxide phase was detected.

Moreover, as a result of slicing the end material of the obtained oxide sintered body by FIB processing and observing with a transmission electron microscope (TEM) mounted on an energy dispersive X-ray fluorescence spectrometer (EDX), the oxide sintered body The material powder was not sufficiently pulverized and mixed to cause agglomeration, or Si that was uniformly dispersed only on a macroscopic scale was not dissolved in the mother phase having a wurtzite structure. _Two phases existed.

  Next, the obtained oxide sintered body was processed to have a diameter of 152.4 mm (6 inches) and a thickness of 5 mm to obtain a sputtering target.

  After mounting this sputtering target on a sputtering apparatus (SPF-530K, manufactured by Tokki), after using it for film formation by sputtering under the same conditions as in Example 1, as a result of confirming the state of the target, abnormal discharge occurred. It occurred 3 times in 10 minutes from the initial stage of the film. Although abnormal discharge is suppressed in oxide sintered bodies such as these, abnormal discharge cannot be completely eliminated, and it is used because it leads to yield deterioration in mass production processes that require high productivity. I can't.

Further, the transmittance and specific resistance value of the film itself obtained in the same manner as in Example 1 were measured and calculated. As a result, it was 82% in the visible region and 76% in the near infrared region, and the specific resistance value was 7.5. × 10 ⁻⁴ Ω · cm.

[Reference Comparative Example 12]
ZnO powder, SiO ₂ powder, and Al ₂ O ₃ powder having an average particle size of 0.1 μm are used as raw material powder, and the Si / (Zn + Si) atomic ratio is 0.7 atomic%, and the Al / (Zn + Si + Al) atomic ratio is 4. The mixture was prepared at a ratio of 0.7 atomic%, mixed with pure water, an organic binder, and a dispersant, mixed so that the raw material powder concentration became 60 wt%, and a slurry was prepared in a mixing tank.

Next, granulated powder was obtained under the same conditions as in Example 1 except that wet grinding was performed for 18 hours using a ball mill apparatus in which hard ZrO ₂ balls having a particle diameter of 3.0 mm were put.

The obtained granulated powder was molded by applying a pressure of 98 MPa (1 ton / cm ² ) with a cold isostatic press, and the resulting molded body of about 200 mmφ was subjected to a maximum firing temperature in an atmospheric pressure firing furnace. The oxide sintered body was obtained by firing at 1500 ° C. for 5 hours in the air. At this time, the temperature rising rate was 1 ° C./min from room temperature to 1000 ° C., and 3 ° C./min from 1000 to 1500 ° C.

As in Example 1, powder X-ray diffraction measurement was performed on the obtained oxide sintered body. As a result, a ZnO phase having a hexagonal wurtzite structure and a spinel-type composite of zinc silicate (Zn ₂ SiO ₄ ) were obtained. A peak due to the oxide phase was detected.

Moreover, as a result of slicing the end material of the obtained oxide sintered body by FIB processing and observing with a transmission electron microscope (TEM) mounted on an energy dispersive X-ray fluorescence spectrometer (EDX), the oxide sintered body The material powder is not sufficiently pulverized and mixed, and is agglomerated, and the firing temperature is too high, or a region with a high Si concentration is formed inside the crystal particles adjacent to the grain boundary, and there is an SiO ₂ phase. It was.

  Next, the obtained oxide sintered body was processed to have a diameter of 152.4 mm (6 inches) and a thickness of 5 mm to obtain a sputtering target.

  After mounting this sputtering target on a sputtering apparatus (SPF-530K, manufactured by Tokki), after using it for film formation by sputtering under the same conditions as in Example 1, as a result of confirming the state of the target, abnormal discharge occurred. It occurred 3 times in 10 minutes from the initial stage of the film. Although abnormal discharge is suppressed in such an oxide sintered body, abnormal discharge cannot be completely eliminated, and it cannot be used in mass production processes that require high productivity because it leads to deterioration in yield. . Moreover, in this target manufacturing conditions, the firing temperature is too high at 1500 ° C., the crystal grains are coarsened, the sintered body strength is low, and cracks occur in 4 of 20 sheets during processing.

Further, the transmittance and specific resistance value of the film itself obtained in the same manner as in Example 1 were measured and calculated. As a result, it was 85% in the visible region and 76% in the near infrared region, and the specific resistance value was 5.0. × 10 ⁻⁴ Ω · cm.

[Reference Comparative Example 13]
The raw material powder is ZnO powder having an average particle size of 1.0 μm or less, SiO ₂ powder, and Al ₂ O ₃ powder. The Si / (Zn + Si) atomic ratio is 6.8 atomic%, and the Al / (Zn + Si + Al) atomic ratio is The mixture was prepared at a ratio of 3.1 atomic%, and pulverization was not performed, and only dry mixing was performed to obtain granulated powder.

Next, an oxide sintered body was obtained under the same conditions as in Example 1 except that wet grinding was performed for 18 hours using a ball mill apparatus in which hard ZrO ₂ balls having a particle diameter of 3.0 mm were placed. It was.

The obtained granulated powder was molded by applying a pressure of 98 MPa (1 ton / cm ² ) with a cold isostatic press, and the resulting molded body of about 200 mmφ was subjected to a maximum firing temperature in an atmospheric pressure firing furnace. The oxide sintered body was obtained by firing at 1400 ° C. for 20 hours in the air. At this time, the heating rate was 3 ° C./min.

As in Example 1, powder X-ray diffraction measurement was performed on the obtained oxide sintered body. As a result, a ZnO phase having a hexagonal wurtzite structure and a spinel-type composite of zinc silicate (Zn ₂ SiO ₄ ) were obtained. A peak due to the oxide phase was detected.

Moreover, as a result of slicing the end material of the obtained oxide sintered body by FIB processing and observing with a transmission electron microscope (TEM) mounted on an energy dispersive X-ray fluorescence spectrometer (EDX), the oxide sintered body The material powder was not sufficiently pulverized and mixed to cause agglomeration, or Si that was uniformly dispersed only on a macroscopic scale was not dissolved in the mother phase having a wurtzite structure. _Two phases existed.

  Next, the obtained oxide sintered body was processed to have a diameter of 152.4 mm (6 inches) and a thickness of 5 mm to obtain a sputtering target.

  After mounting this sputtering target on a sputtering apparatus (SPF-530K, manufactured by Tokki), after using it for film formation by sputtering under the same conditions as in Example 1, as a result of confirming the state of the target, abnormal discharge occurred. It occurred 10 to 20 times in 10 minutes from the initial stage of the film. Such an oxide sintered body cannot be used in a mass production process that requires high productivity.

Further, the transmittance and specific resistance value of the film itself obtained in the same manner as in Example 1 were measured and calculated to be 79% in the visible range and 77% in the near infrared range, and the specific resistance value was 4.3. × 10 ⁻³ Ω · cm.

[Comparative Example 14]
ZnO powder having an average particle size of 1.0 μm or less and SiO ₂ powder are used as raw material powders, and the Si / (Zn + Si) atomic ratio is prepared at a ratio of 5.0 atomic%. Using a ball mill apparatus in which hard ZrO ₂ balls of 3.0 mm were introduced, mixing and drying were carried out for 20 hours to obtain a mixture.

  This mixed powder was calcined in the atmosphere for 2 hours in an atmospheric pressure firing furnace at a rate of temperature increase of 3 ° C./min and a maximum calcining temperature of 1300 ° C. to obtain a calcined powder. About this calcined powder, ball mill treatment is performed in the same manner as described above, and this calcined powder and ZnO powder similar to the above are prepared at a ratio where the Si / (Zn + Si) atomic number ratio is 3.0 atomic%, The mixed powder was obtained by mixing and drying with a ball mill for 20 hours.

Next, after adding polyvinyl alcohol to the obtained granulated powder to obtain a granulated powder, the granulated powder was molded by applying a pressure of 98 MPa (1 ton / cm ² ) with a uniaxial pressure molding machine, Further, it was molded by applying a pressure of 294 MPa (3 ton / cm ² ) with a cold isostatic press to obtain a molded body of about 200 mmφ. The obtained molded body was degreased at 600 ° C. in the air for 1 hour in an atmospheric pressure firing furnace, and then fired in the air at a maximum firing temperature of 1400 ° C. for 2 hours to obtain an oxide sintered body. At this time, the heating rate was 3 ° C./min.

As in Example 1, powder X-ray diffraction measurement was performed on the obtained oxide sintered body. As a result, a ZnO phase having a hexagonal wurtzite structure and a spinel-type composite of zinc silicate (Zn ₂ SiO ₄ ) were obtained. A peak due to the oxide phase was detected.

Moreover, as a result of slicing the end material of the obtained oxide sintered body by FIB processing and observing with a transmission electron microscope (TEM) mounted on an energy dispersive X-ray fluorescence spectrometer (EDX), the oxide sintered body The material powder was not sufficiently pulverized and mixed to cause agglomeration, or Si that was uniformly dispersed only on a macroscopic scale was not dissolved in the mother phase having a wurtzite structure. _Two phases existed.

  Next, the obtained oxide sintered body was processed to have a diameter of 152.4 mm (6 inches) and a thickness of 5 mm to obtain a sputtering target.

  After mounting this sputtering target on a sputtering apparatus (SPF-530K, manufactured by Tokki), after using it for film formation by sputtering under the same conditions as in Example 1, as a result of confirming the state of the target, abnormal discharge occurred. It occurred 20 to 30 times in 10 minutes from the initial stage of the film. Such an oxide sintered body cannot be used in a mass production process that requires high productivity.

Further, the transmittance and specific resistance value of the film itself obtained in the same manner as in Example 1 were measured and calculated to be 80% in the visible range and 78% in the near infrared range, and the specific resistance value was 9.5. × 10 ⁻⁴ Ω · cm.

[Reference Comparative Example 15]
ZnO powder, SiO ₂ powder, Al ₂ O ₃ powder, and MgO powder having an average particle diameter of 5.0 μm have an Si / (Zn + Si) atomic ratio of 0.5 atomic% and (Al + Mg) / (Zn + Si + Al + Mg) atomic numbers, respectively. Weighing and preparation were performed so that the ratio was 5.1 atomic%.

Next, after mixing the ZnO powder and the Al ₂ O ₃ powder, calcining in an atmospheric pressure firing furnace at a rate of temperature increase of 3 ° C./min and a maximum temperature of 1000 ° C. (1) was obtained.

On the other hand, the SiO ₂ powder and MgO powder were calcined at 1000 ° C. in the same manner as in the production of AZO powder to obtain calcined powder (2).

Next, the calcined powders (1) and (2) are further mixed and re-calcined, and then the re-calcined powder is charged with a hard ZrO ₂ ball having a particle size of 3.0 mm. And pulverized until the average particle size became 1.0 μm or less.

The obtained granulated powder was press-molded by applying a pressure of 49 MPa (500 kg / cm ² ), and the resulting molded body of about 200 mmφ was placed in an oxygen atmosphere at a maximum firing temperature of 1400 ° C. in an atmospheric pressure firing furnace. Was fired for 5 hours to obtain an oxide sintered body. At this time, the heating rate was 3 ° C./min.

As in Example 1, powder X-ray diffraction measurement was performed on the obtained oxide sintered body. As a result, a ZnO phase having a hexagonal wurtzite structure and a spinel-type composite of zinc silicate (Zn ₂ SiO ₄ ) were obtained. A peak due to the oxide phase was detected.

Moreover, as a result of slicing the end material of the obtained oxide sintered body by FIB processing and observing with a transmission electron microscope (TEM) mounted on an energy dispersive X-ray fluorescence spectrometer (EDX), the oxide sintered body In Si, the particle size of the raw material powder was large, and Si, which was uniformly dispersed only on a macroscopic scale, was not dissolved in the parent phase having a wurtzite structure, and an SiO ₂ phase was present.

  Next, the obtained oxide sintered body was processed to have a diameter of 152.4 mm (6 inches) and a thickness of 5 mm to obtain a sputtering target.

  After mounting this sputtering target on a sputtering apparatus (SPF-530K, manufactured by Tokki), after using it for film formation by sputtering under the same conditions as in Example 1, as a result of confirming the state of the target, abnormal discharge occurred. It occurred 20 to 30 times in 10 minutes from the initial stage of the film. Such an oxide sintered body cannot be used in a mass production process that requires high productivity.

Further, the transmittance and specific resistance value of the film itself obtained in the same manner as in Example 1 were measured and calculated to be 88% in the visible region and 89% in the near infrared region, and the specific resistance value was 9.0. × 10 ⁻⁴ Ω · cm.

  According to the Zn—Si—O-based oxide sintered body of the present invention, abnormal discharge or the like is suppressed when used for a sputtering target, and the splash phenomenon is suppressed when used for a deposition tablet. Therefore, it has the industrial applicability utilized as a film-forming material of the transparent conductive film used for a display, a touch panel, the electrode of a solar cell, etc.

Claims (8)

In a Zn—Si—O-based oxide sintered body containing zinc oxide as a main component and containing no additional elements other than Si,
The oxide sintered body is produced at a firing temperature of 900 to 1400 ° C. while raising the temperature range of 700 to 900 ° C. at a temperature rising rate of 5 ° C./min or more , and
The Si content is 0.1 to 10 atomic% in terms of Si / (Zn + Si) atomic ratio,
Si element is dissolved in the wurtzite zinc oxide phase,
Two detection methods by X-ray diffraction of sintered powder using CuKα rays and electron diffraction of sintered flakes using a transmission electron microscope, with SiO ₂ phase and zinc silicate (Zn ₂ SiO ₄ ) A Zn-Si-O-based oxide sintered body characterized in that a certain spinel type complex oxide phase is not detected.   A sputtering target obtained by processing the Zn—Si—O-based oxide sintered body according to claim 1.   A vapor deposition tablet comprising the Zn—Si—O-based oxide sintered body according to claim 1. In the manufacturing method of the Zn-Si-O type oxide sintered compact according to claim 1,
A first step of drying and granulating a slurry obtained by mixing ZnO powder and SiO ₂ powder with pure water, an organic binder, and a dispersing agent;
A second step of pressure-molding the obtained granulated powder to obtain a molded body,
While having the third step of firing the obtained molded body to obtain a sintered body,
The third step of obtaining the sintered body is a step of raising the temperature range of 700 to 900 ° C. at a rate of temperature rise of 5 ° C./min or more, and the molded body at 900 to 1400 ° C. in a firing furnace. The manufacturing method of the Zn-Si-O type oxide sintered compact characterized by including the process of baking.   5. The Zn—Si—O-based oxidation according to claim 4, wherein in the third step, the temperature range from 900 ° C. to the sintering temperature is increased at a rate of temperature increase of 3 ° C./min or less. A method for manufacturing a sintered body. In the first step, ZnO powder and SiO ₂ powder, calcined powder obtained by mixing and calcining ZnO powder and SiO ₂ powder, and pure water, an organic binder, and a dispersant are raw material ZnO powder. The Zn—Si—O according to claim 4, wherein the slurry is obtained by mixing so that the total concentration of SiO ₂ powder and calcined powder is 50 to 80 wt% and mixing and stirring for 10 hours or more. A method for producing an oxide-based sintered body. Zn-SiO type oxide-sintered according ZnO powder and then calcined under the conditions of SiO ₂ powder were mixed 900 ° C. to 1400 ° C. to claim 6, characterized in that to obtain the calcined powder Body manufacturing method. The method for producing a Zn-Si-O-based oxide sintered body according to any one of claims 4 to 7, wherein ZnO powder having an average particle diameter of 1.0 µm or less and SiO ₂ powder are used.