JP6468158B2 - ZnO-Ga2O3-based oxide sintered tablet for vapor deposition and method for producing the same - Google Patents

Description

The present invention relates to a ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets for use in producing the transparent conductive film of low resistance by a vacuum deposition method, in particular, high power of the electron beam (EB) or high The present invention relates to a ZnO—Ga ₂ O ₃ based oxide sintered body tablet for vapor deposition that hardly breaks even when irradiated with output plasma and a manufacturing method thereof.

A transparent conductive film used as an electrode material for liquid crystal displays, solar cells, and the like has a low specific resistance. Therefore, an In ₂ O ₃ —SnO ₂ (hereinafter abbreviated as ITO) film or a ZnO—Al ₂ O ₃ system is used. A film (hereinafter abbreviated as AZO) is increasingly used. These transparent conductive films are formed by sputtering on a heated substrate using a sputtering target as a raw material.

By the way, due to the recent trend toward lower costs such as liquid crystal displays and solar cells, the above ITO has a problem in terms of cost because In ₂ O _{3 as} a main component is expensive. In AZO, since the raw material powder is inexpensive, there is no problem in terms of cost, but there is a problem in productivity because the range of optimum film formation conditions for obtaining a low resistance film is narrow.

Therefore, instead of the ITO film or AZO film, a transparent conductive film of ZnO—Ga ₂ O ₃ (hereinafter abbreviated as GZO) having no problem in cost and productivity and having high resistance and low durability. And a ZnO—Ga ₂ O ₃ -based sputtering target for forming this GZO film is drawing attention (see Patent Document 1).

Further, in recent years, film formation by a vacuum evaporation method, which is superior in productivity of a transparent conductive film compared to the above sputtering method, has become the mainstream, and a ZnO-Ga ₂ O ₃ based sintered body (tablet) that can be used for the vacuum evaporation method. Is desired.

However, the ZnO—Ga ₂ O ₃ -based sintered body (tablet) manufactured by applying the ZnO—Ga ₂ O ₃ -based sputtering target was applied to vacuum deposition methods such as electron beam (EB) and ion plating. In this case, if the density of the manufactured ZnO—Ga ₂ O ₃ sintered body (tablet) is too low, when the electron beam or high-power plasma is irradiated, the material evaporates from the surface, and at the same time There was a problem that sintering occurred suddenly and the tablet was damaged by partial shrinkage of the tablet. Conversely, if the density of the manufactured ZnO—Ga ₂ O ₃ sintered body (tablet) is too high, a temperature difference occurs between the surface and the inside of the tablet when irradiated with an electron beam or the like, and due to the difference in thermal expansion. There is a problem that tablet breakage (breakage due to thermal shock) occurs, and an existing ZnO—Ga ₂ O ₃ sintered body (tablet) manufactured by applying a ZnO—Ga ₂ O ₃ based sputtering target is used. It is not enough.

Under such technical background, the present applicant is a tin oxide-based sintered body (tablet) of a different type from the ZnO—Ga ₂ O ₃ system, but has high power from the initial stage of vapor deposition. There has already been proposed a vapor deposition tablet that is not easily damaged during vapor deposition even when irradiated with an electron beam (EB) or high-power plasma (see Patent Document 2).

That is, the vapor deposition tablet described in Patent Document 2 is a vapor deposition tablet composed of a tin oxide-based sintered body containing zinc or the like as a dopant and having a relative density of 50% to 70%. The average particle diameter of the first sintered grains constituting the body and derived from the first raw material powder is D1, and the average particle diameter of the second sintered grains constituting the tin oxide sintered body and derived from the second raw material powder When the diameter is D2, the ratio of the average particle size D2 of the second sintered particles to the average particle size D1 of the first sintered particles [ie (D2 / D1) × 100 (%)] is 4% or more and 14 % Or less, for example, manufactured through the following first to third steps.
(First step) Oxide powder for dopant such as zinc oxide and tin oxide powder are mixed and heat-treated at a calcining temperature of 1300 ° C. or higher and 1600 ° C. or lower, followed by sieving, and an average particle size of 4 μm or more and 20 μm. Obtaining the following calcined first raw material powder;
(Second step) The mixing ratio of the first raw material powder is 50 masses of the uncalcined second raw material powder composed of the dopant oxide powder and the tin oxide powder with respect to the calcined first raw material powder. % And 75% by mass or less, and granulating to obtain a granulated powder,
(Third step) The obtained granulated powder is molded into a molded body, and the molded body is sintered at a temperature of 1100 ° C. or higher and 200 ° C. or lower than the calcining temperature in the first step to obtain zinc or the like. A step of obtaining a sintered body of tin oxide contained as a dopant.

  The tin oxide-based sintered body (tablet) described in Patent Document 2 is difficult to be damaged during vapor deposition even when irradiated with a high-power electron beam (EB) or high-power plasma continuously for a long time. It has become possible to significantly improve the mass productivity of transparent conductive films and the like.

Japanese Patent Laid-Open No. 10-306367 JP 2014-231626 A

Incidentally, in the sintered body (tablets) in accordance patent document 2 applied to manufactured ZnO-Ga ₂ O ₃ oxide sintered procedures described in the tin oxide (tablets), above the previous ZnO- Compared to Ga ₂ O ₃ based sintered body (tablet), it was certainly hard to be damaged even when irradiated with high power electron beam (EB) or high power plasma, but on the other hand, heating of electron beam etc. If the film continues, film formation by vapor deposition becomes unstable, resulting in deterioration of film characteristics over time, or other problems such as partial tablet breakage during vapor deposition have been confirmed.

The present invention has been made paying attention to such problems, and the problem is that ZnO—Ga ₂ O for vapor deposition that enables stable film formation even when heating by an electron beam or the like is continued. _The object is to provide a _three- system oxide sintered tablet and a method for producing the same.

As a result of continuous research conducted by the inventor in order to solve the above problems, ZnO-Ga ₂ O ₃ -based sintered bodies (tablets) manufactured by using the technique described in Patent Document 2 have ZnGa ₂ O. It was confirmed that the high resistance spinel structure compound represented by ₄ was included, and it was found that the presence of the spinel structure compound made stable vapor deposition difficult.

  The present invention has been completed based on such technical findings.

That is, the first invention is
In a ZnO—Ga ₂ O ₃ oxide sintered body tablet for vapor deposition composed of Zn (zinc), Ga (gallium), In (indium) and oxygen (O),
(1) The atomic ratio (%) of Zn, Ga and In satisfies the following formula:
1.75 ≦ Ga / (Zn + Ga + In) × 100 ≦ 3.54
1.25 ≦ In / (Zn + Ga + In) × 100 ≦ 2.54
(2) The sintered density is 2.9 g / cm ³ or more and 4.0 g / cm ³ or less, and the volume resistivity is 70 Ω · cm or less,
(3) The oxide sintered body calcined by an average grain size of the first sintering particle derived from the first raw material powder consisting of zinc oxide powder were appearing on the fracture surface of the tablet is 10μm or 20μm or less, and, the The average grain size of the second sintered grains derived from the second raw material powder composed of uncalcined zinc oxide powder, gallium oxide powder and indium oxide powder appearing on the fracture surface of the sintered oxide tablet is 1 μm or more and 3 μm or less And
(4) The oxide sintered body contains a homologous structure compound represented by ZnO and InGaO ₃ (ZnO) m (m = 1 to 10), and is represented by Ga ₂ O ₃ and ZnGa ₂ O _4. It does not contain a spinel structure compound,
The second invention is
In the deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according to the first invention,
In the homologous structure compound represented by InGaO ₃ (ZnO) m, the above m is 5.

Next, the third invention is:
In the manufacturing method of the first invention or the second evaporation ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according to the invention,
A first step of heat treating the zinc oxide powder at a calcining temperature of 1000 ° C. or higher and 1400 ° C. or lower, followed by sieving to obtain a calcined first raw material powder having an average particle size of 10 μm or more and 50 μm or less;
An uncalcined second raw material powder composed of zinc oxide powder, gallium oxide powder and indium oxide powder having an average particle size of 0.1 μm or more and 1.5 μm or less is compared with the first calcined first raw material powder. Mixing so that the mixing ratio of one raw material powder is 40 wt% or more and 80 wt% or less, and granulating to obtain a granulated powder;
The obtained granulated powder is molded into a molded body, and this molded body is sintered at a temperature of 800 ° C. or higher and 200 ° C. or lower than the calcining temperature in the first step to burn ZnO—Ga ₂ O ₃ oxide. The third step of obtaining the union,
It comprises each process of these.

In addition, the fourth invention is
In the method for producing a ZnO—Ga ₂ O ₃ -based oxide sintered tablet for vapor deposition according to the third invention,
The second raw material powder in the second step contains indium oxide powder in an amount of 2% by weight to 4% by weight and contains gallium oxide powder in an amount of 2% by weight to 4% by weight,
The fifth invention is:
In the method for producing a ZnO—Ga ₂ O ₃ -based oxide sintered tablet for vapor deposition according to the third invention,
In the third step, the rate of temperature increase to a sintering temperature of 800 ° C. or higher is 0.2 ° C./min or more and 1.0 ° C./min or less,
The sixth invention is:
In the method for producing a ZnO—Ga ₂ O ₃ -based oxide sintered tablet for vapor deposition according to the third invention,
The holding time of the sintering temperature in the third step is 15 hours or more and 25 hours or more,
The seventh invention
In the method for producing a ZnO—Ga ₂ O ₃ -based oxide sintered tablet for vapor deposition according to the third invention,
After completion of the sintering process in the third step, the temperature is returned to room temperature, and a reduction process is performed.
The eighth invention
In the method for manufacturing a deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according to the seventh invention,
The reduction treatment is performed by raising the temperature from room temperature to a reduction temperature of 600 ° C. or more and 1000 ° C. or less at a rate of temperature increase of 1 to 10 ° C./min and then holding the inside of the reduction furnace in a vacuum state for 1 to 6 hours. It is characterized by this.

According to the ZnO—Ga ₂ O ₃ based oxide sintered body tablet for vapor deposition according to the present invention,
A first raw material powder comprising a calcined zinc oxide powder having a sintered density of 2.9 g / cm ³ or more and 4.0 g / cm ³ or less (requirement 2) and appearing on the fracture surface of the oxide sintered body tablet. The first sintered grains derived from the first sintered grains have a mean grain size of 10 μm or more and 20 μm or less, and are formed of uncalcined zinc oxide powder, gallium oxide powder and indium oxide powder appearing on the fracture surface of the oxide sintered body tablet . Because the average grain size of the second sintered grains derived from the two raw powders is 1 μm or more and 3 μm or less (Requirement 3), the tablet may be damaged even when irradiated with a high-power electron beam or high-power plasma. It can be avoided.

Further, the atomic ratio (%) of Zn, Ga, and In satisfies the following formula (requirement 1),
1.75 ≦ Ga / (Zn + Ga + In) × 100 ≦ 3.54
1.25 ≦ In / (Zn + Ga + In) × 100 ≦ 2.54
The oxide sintered body constituting the tablet contains a homologous structure compound represented by ZnO and InGaO ₃ (ZnO) m (m = 1 to 10), and is a high-resistance Ga ₂ O ₃ and ZnGa ₂ O ₄ Because it does not contain the represented spinel structure compound (Requirement 4),
Since the volume resistivity is 70 Ω · cm or less (Requirement 2),
Even if heating with an electron beam or the like is continued, stable film formation is possible.

  Accordingly, the deposition tablet can be irradiated with a high-power electron beam or high-power plasma continuously for a long time, so that the mass productivity of a transparent conductive film or the like can be remarkably improved.

SEM (scanning electron microscope) imaging view in fracture surface of the deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according to Example 1. X-ray diffraction chart of the deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according to Example 1. X-ray diffraction chart of the deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets of Comparative Example 1.

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

(I) ZnO—Ga ₂ O ₃ oxide sintered body tablet for vapor deposition ZnO—Ga ₂ O ₃ for vapor deposition according to the present invention composed of Zn (zinc), Ga (gallium), In (indium) and oxygen (O) Based oxide sintered tablets
(1) The atomic ratio (%) of Zn, Ga and In satisfies the following formula:
1.75 ≦ Ga / (Zn + Ga + In) × 100 ≦ 3.54
1.25 ≦ In / (Zn + Ga + In) × 100 ≦ 2.54
(2) The sintered density is 2.9 g / cm ³ or more and 4.0 g / cm ³ or less, and the volume resistivity is 70 Ω · cm or less,
(3) The oxide sintered body calcined by an average grain size of the first sintering particle derived from the first raw material powder consisting of zinc oxide powder were appearing on the fracture surface of the tablet is 10μm or 20μm or less, and, the The average grain size of the second sintered grains derived from the second raw material powder composed of uncalcined zinc oxide powder, gallium oxide powder and indium oxide powder appearing on the fracture surface of the sintered oxide tablet is 1 μm or more and 3 μm or less And
(4) The oxide sintered body contains a homologous structure compound represented by ZnO and InGaO ₃ (ZnO) m (m = 1 to 10), and is represented by Ga ₂ O ₃ and ZnGa ₂ O _4. It does not contain a spinel structure compound.

[Homologous structural compounds]
A homologous crystal structure is a crystal structure consisting of a “natural superlattice” structure with a long period of several crystal layers of different materials, and if the crystal period or thickness of each thin film layer is on the order of nanometers, homologous The crystal structure compound can exhibit unique characteristics different from the properties of a single substance or a mixed crystal obtained by uniformly mixing the layers depending on the combination of the chemical composition of each layer and the thickness of the layers.

Examples of the oxide crystal having a homologous crystal structure include an oxide crystal represented by RAO ₃ (MO) m. Here, R is a positive trivalent metal element, and examples thereof include In, Ga, Al, Fe, and B. A is a positive trivalent metal element, and examples thereof include Ga, Al, and Fe. M is a positive divalent metal element, and examples thereof include Zn and Mg. Moreover, m is preferably 1 to 10, more preferably 3 to 7, and further preferably 5.

Then, homologous structure compound contained in the deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according to the present invention is a R is In, the A is Ga, the case M is Zn.

The homologous structural compound represented by InGaO ₃ (ZnO) m (m = 1 to 10) may be a single type or a mixture of two or more types.

  Moreover, the homologous structure compound contained in the target can be confirmed by X-ray diffraction. For example, the X-ray diffraction pattern of the powder obtained by pulverizing the target is a homologous phase crystal structure X-ray diffraction pattern assumed from the composition ratio. This can be confirmed by matching.

  Specifically, it can be confirmed by matching with a crystal structure X-ray diffraction pattern of a homologous phase obtained from a JCPDS (Joint Committee of Powder Diffraction Standards) card or ICSD (The Inorganic Crystal Structure Database).

[Spinel structure compound represented by high resistance Ga ₂ O ₃ and ZnGa ₂ O ₄ ]
The ZnO—Ga ₂ O ₃ oxide sintered body tablet for vapor deposition according to the present invention does not contain a spinel structure compound represented by high resistance Ga ₂ O ₃ and ZnGa ₂ O ₄ as described above (Requirement 4). ).

The ZnO—Ga ₂ O ₃ based oxide sintered body tablet for vapor deposition contains a ZnO phase and a homologous structure compound represented by the above InGaO ₃ (ZnO) m (m = 1 to 10), whereby high resistance Ga spinel structure compound shown by ₂ O ₃ and ZnGa ₂ O ₄ can be prevented from appearing in the oxide-sintered-body tablet, it is possible to prevent the tablet becomes high resistance.

  The spinel structure is described in detail in “Introduction to West Solid Chemistry” (Kodansha Scientific), and has the following structure.

The spinel structure has a composition formula of AB ₂ O ₄ , and can be classified into a normal spinel structure, an inverse spinel structure, and an intermediate structure between the two when classified according to the coordination state of A ions and B ions.

The regular spinel structure has a structure in which A is filled in one-eighth of the tetrahedral gap of the three-dimensional face-centered lattice formed by O ₂ − and B is filled in one-half of the octahedral gap. The reverse spinel structure has a structure in which one-eighth of the tetrahedral gap is filled with B and half of the octahedral gap is filled with A and B.

  The spinel structure is generally cubic, but some are distorted.

The spinel structure compound represented by ZnGa ₂ O ₄ in the tablet can be confirmed by observing the peak of the spinel structure compound by X-ray diffraction measurement.

[Atom ratio of Zn, Ga and In (%)]
In the deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according to the present invention,
The atomic ratio (%) of Zn, Ga, and In must satisfy the following formula (Requirement 1).
1.75 ≦ Ga / (Zn + Ga + In) × 100 ≦ 3.54
1.25 ≦ In / (Zn + Ga + In) × 100 ≦ 2.54
(In, Ga, and Zn indicate the atomic ratio of each element in the tablet.)

When the above formula is not satisfied, a homologous structure compound represented by InGaO ₃ (ZnO) m (m = 1 to 10) is not generated, and due to this, high resistance Ga ₂ O ₃ or ZnGa ₂ O ₄ The spinel structure compound represented is produced | generated, and a tablet becomes high resistance (refer the comparative example 1 and the comparative example 3).

That is, a homologous structure compound represented by a ZnO phase and InGaO ₃ (ZnO) m (m = 1 to 10) by setting each component of zinc oxide, gallium oxide, and indium oxide so as to satisfy the conditions of the above formula. A ZnO—Ga ₂ O ₃ based oxide sintered body containing no spinel structure compound represented by high resistance Ga ₂ O ₃ and ZnGa ₂ O ₄ is fired and has a volume resistivity of 70 Ω · cm or less. A ZnO—Ga ₂ O ₃ -based oxide sintered body tablet for vapor deposition is obtained.

  Furthermore, by adding indium oxide, evaporation of ZnO during sintering can be suppressed and the sintering behavior of the ZnO powder can be improved.

(II) SEM (Scanning Electron Microscope) imaging diagram at the fracture surface of the tablet for vapor deposition The fracture surface of the ZnO-Ga ₂ O ₃ oxide sintered body tablet for vapor deposition obtained by the production method described below is, for example, It has a structure as shown in the SEM imaging diagram of FIG.

  In the SEM imaging diagram of FIG. 1, the “grain 1” grains indicate the first sintered grains derived from the first raw material powder calcined in the following “first step”, and “grain 2”. This granule indicates the second sintered grain derived from the uncalcined second raw material powder mixed in the following “second step”.

  As can be confirmed from the SEM image of FIG. 1, the first sintered grain indicated by “grain 1” is composed of a plurality of grain groups having a grain size larger than that of the second sintered grain. The second sintered grain indicated by “2” is composed of a plurality of particle groups having a particle diameter smaller than that of the first sintered grain, and the first sintered grain and the second sintered grain are present in a properly mixed state. doing. The first sintered grains are composed of large particle groups and the growth of the first sintered grains themselves is suppressed in the “first step” at a temperature of 1000 ° C. to 1400 ° C. This is probably because the first raw material powder having an average particle size of 10 μm or more and 50 μm or less is prepared after heat treatment at the firing temperature. By performing sieving after the above heat treatment, sintering treatment of the following “third step” (however, the sintering temperature is 800 ° C. or higher and 200 ° C. or higher than the calcining temperature of “first step” as described later) When the temperature is set to a low temperature, an effect of dispersing the growth of the first sintered grains is generated, and it is considered that the bonding and the growth of the first sintered grains are suppressed by this effect. In addition, since an appropriate void | hole can be made by making a big difference in the particle size of a 1st sintered grain and a 2nd sintered grain, the effect which disperse | distributes heat also arises.

Then, the deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according to the present invention, the calcined was first sintered grains having an average particle diameter of 10μm or more 20μm derived from the first raw material powder or less, The requirement (requirement 3) is that the average particle size of the second sintered grains derived from the uncalcined second raw material powder is 1 μm or more and 3 μm or less. For this reason, the first raw material powder calcined in the “third step” so as to have the above particle size should not be grown as much as possible. As described above, the sintering temperature in the “third step” is 800 ° C. or higher. It is necessary to set the temperature at 200 ° C. or more lower than the calcining temperature in the “first step”. Ignoring this, sintering at a temperature higher than the calcining temperature in the “first step”, sintering near the calcining temperature, and longer sintering time, the first sintering indicated by “grain 1” The grains grow. While the strength increases due to the growth of the first sintered grains, when a high power electron beam (EB) or high power plasma is applied to the evaporation tablet, there is a temperature difference between the tablet surface and the inside. Since a temperature difference also occurs between the first sintered grains indicated by “grain 1” and the second sintered grains indicated by “grain 2”, cracks occur. Such a tablet for vapor deposition is not suitable for an application in which high-power electron beam (EB) or high-power plasma is irradiated suddenly for mass production.

By the way, using the SEM image of FIG. 1 (SEM image of the fracture surface of the ZnO—Ga ₂ O ₃ oxide sintered body tablet for vapor deposition according to Example 1), the average particle size of the first sintered particles For example, the following method can be used to obtain the average particle size of the second sintered grains.

  First, a plurality of straight lines are drawn from one edge of the SEM image to the other edge at an arbitrary location on the SEM image shown in FIG. Here, it is desirable that the number of straight lines is four or more from the viewpoint of quantitative accuracy, and the straight line drawing method can be a cross-beam shape or a radial shape.

Next, the number n divided by the grain boundary portions of the “first sintered grains” and the “second sintered grains” present on the straight line drawn on the SEM image is measured, and the following formula (1) is obtained. The average particle diameter d is obtained, and the average value is obtained from each average particle diameter d obtained from a plurality of straight lines.
d = L / n / m (1)
[In Formula (1), d is an average particle diameter obtained from one straight line, L is the length of one straight line, n is the number of grain boundaries existing on one straight line, and m is an electron microscope. Show magnification]

(III) The present invention in accordance with the deposition ZnO-Ga ₂ O ₃ system manufacturing method of the oxide-sintered-body tablets "First step: calcination is to obtain a first raw material powder"
After adding water, a dispersing agent, and a binder as needed (the binder is not limited as long as it is a known binder that disappears or vaporizes by heating, and polyvinyl alcohol can be used) in the zinc oxide powder Mix with a stirrer and spray dry using a spray dryer to obtain a mixed powder.

  Next, the obtained mixed powder was heat-treated (sintered) at a calcining temperature of 1000 ° C. or higher and 1400 ° C. or lower, and then sieved to obtain a calcined first powder having an average particle size of 10 μm or more and 50 μm or less. A raw material powder is obtained.

When the calcining temperature is lower than 1000 ° C., there is a disadvantage that the density and dimensional variations of the ZnO—Ga ₂ O ₃ oxide sintered body obtained in the “third process” below increase. On the other hand, when the calcining temperature exceeds 1400 ° C., zinc oxide evaporates, making it difficult to control the composition, and there is a disadvantage that a desired sintered body structure cannot be obtained. Therefore, the calcination temperature needs to be 1000 ° C. or higher and 1400 ° C. or lower.

"Second step: Step of obtaining granulated powder"
Next, an uncalcined second raw material powder composed of zinc oxide powder, gallium oxide powder and indium oxide powder having an average particle size of 0.1 μm or more and 1.5 μm or less was prepared in the above “first step”. After blending so that it may become the following composition with respect to raw material powder, mixing and stirring are performed, and it granulates using a spray dryer etc. and obtains granulated powder.

  Here, about the ratio of the calcined 1st raw material powder and the uncalcined 2nd raw material powder, it mix | blends so that the calcined 1st raw material powder may be 40 to 80 weight% Is preferably blended so as to be 50% to 70% by weight. When the ratio of the first raw material powder that has been calcined is more than 80% by weight, the first raw material powder is quickly settled during slurry preparation, and separated from the uncalcined second raw material powder. Causes compositional deviation at the time of graining. In addition, it becomes difficult to control density shrinkage during sintering in the “third step” described later. Furthermore, since the density is low, the strength is low, which makes it difficult to produce a desired sintered body. Moreover, when the ratio of the calcined first raw material powder is as low as less than 40% by weight, the amount of uncalcined second raw material powder increases, and in the sintering process described later, grain growth is likely to proceed. However, the neck growth between grains is promoted and the strength of the sintered body itself is increased, but on the other hand, a temperature difference tends to occur between the outermost surface and the inside during tablet use, and the tablet breaks due to the difference in thermal expansion. Is likely to occur. Thus, by blending the calcined first raw material powder under the conditions of 40 wt% or more and 80 wt% or less, the shrinkage during sintering can be easily controlled, and a stable strength can be obtained. Thus, a sintered body having a desired density can be obtained.

  In addition, as a method of mixing the calcined first raw material powder and the uncalcined second raw material powder, stirring by a stirrer in which the powder is not easily pulverized during mixing is preferable. Furthermore, at the time of mixing, it is good to add 0.5 to 1 weight% of water, a binder, a dispersing agent, and the stearic acid which functions as a lubrication agent at the time of a metal mold | die press.

"Third process: Molding process by forming granulated powder into a compact"
Next, the granulated powder obtained in the “second step” is molded into a molded body. The granulated powder is molded by a mold press. Under the present circumstances, since shrinkage | contraction by sintering is controlled by the setting conditions of the mixing ratio of the calcined 1st raw material powder and the sintering temperature of a post process, the dimension of a tablet is substantially determined at the time of this shaping | molding. As described above, when the ratio of the first raw material powder that has been calcined is large, dimensional control becomes difficult, and the same is true even when the ratio is small. And the mixing ratio of the calcined first raw material powder needs to be 40 wt% or more and 80 wt% or less as described above, and is preferably 50 wt% to 70 wt%.

"Third Step: sintering step of sintering the shaped body to obtain a ZnO-Ga ₂ O ₃ type oxide-sintered body"
Next, the atmosphere during sintering of the molded body may be any of oxygen, air, and vacuum, but is most preferable because it can be inexpensively sintered in air.

First, the obtained molded body was placed in a sintering furnace, and oxygen was introduced into the sintering furnace at a rate of 100 L (liter) / minute per 1 m ^{3 of} the furnace volume, and the oxygen concentration in the sintering atmosphere was adjusted. 30% or more (volume ratio) is set so that the oxygen concentration is higher than that in the atmosphere (oxygen amount 21%), and heating (debinding) is performed at 200 to 800 ° C. for 20 hours or more.

  Thereafter, the sintering temperature is set to 800 ° C. or higher and 200 ° C. or lower than the calcining temperature in the first step. If the temperature is lower than 800 ° C., the sintered body is not sufficiently sintered, so that the strength of the obtained sintered body is low, and cracks and chips occur during handling of the sintered body. Furthermore, since the shrinkage at the time of sintering is not completed, the variation in density and size also increases.

If the sintering temperature is 800 ° C. or higher and 200 ° C. or lower than the calcining temperature in the first step, a sintered body having a sintered density of 2.9 g / cm ³ or more and 4.0 g / cm ³ or less is obtained. can get. However, if the sintering temperature is too close to the calcination temperature, cracks will occur during irradiation with a high power beam even if the sintering density is within the range of 2.9 g / cm ^{3 to} 4.0 g / cm ³ . For this reason, the sintering temperature needs to be 800 ° C. or higher and 200 ° C. or lower than the calcining temperature in the first step.

The sintering is preferably performed for 15 to 25 hours, but the most preferable time is 17 to 23 hours. Within this range, it is possible to obtain a high-quality ZnO—Ga ₂ O ₃ oxide sintered body tablet for vapor deposition while realizing a reduction in sintering time (reduction in power consumption) and high productivity. it can.

Then, the deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according to the present invention, for example, can be used in cylindrical tablet or pellet height 5~60mm diameter 10~50mm is there.

“Reduction treatment after the third step of sintering”
In order to promote the oxygen deficiency of ZnO and further reduce the volume resistivity, it is preferable to perform a reduction treatment on the ZnO—Ga ₂ O ₃ based oxide sintered body after the sintering treatment.

  The reduction treatment is performed by, for example, a method of performing normal pressure while introducing a non-oxidizing gas such as nitrogen, argon, carbon dioxide, or helium, and preferably heating at 600 to 1000 ° C. in a vacuum atmosphere of 2 Pa or less. it can.

  Next, an example of performing the reduction process in a vacuum atmosphere will be described.

  After the sintering process of the third step is completed, the exhaust gas is evacuated to a vacuum atmosphere of 2 Pa or less at room temperature, and then the temperature is increased from room temperature to a reduction temperature of 600 to 1000 ° C. at a rate of 1 to 10 ° C./min. The reduction temperature is maintained for 1 to 6 hours.

  When the reduction temperature is less than 600 ° C., the reducing action in a vacuum atmosphere is reduced. On the other hand, when the temperature exceeds 1000 ° C., the evaporation of ZnO is activated and the composition is likely to shift, and the life of the furnace material and the heater is shortened and the productivity is easily deteriorated. On the other hand, if the cooling rate is less than 1 ° C./min, crystal grain growth of the sintered body becomes remarkable. On the other hand, if it exceeds 10 ° C./minute, the uniformity of the temperature in the reducing furnace is lowered, and the amount of expansion / contraction in the sintered body varies. Moreover, when the vacuum atmosphere exceeds 2 Pa, the reducing action is reduced. Furthermore, when the holding time is less than 1 hour, it is difficult to further reduce the volume resistivity. On the other hand, when the time exceeds 6 hours, the crystal grains grow significantly in the sintered body, and the pores become coarse and consequently the maximum pore diameter increases.

  Examples of the present invention will be specifically described below.

[Example 1]
To zinc oxide powder having an average particle size of 0.6 μm, 60% by weight of water, 0.5% by weight of a dispersant (polycarboxylic acid ammonium salt) and 1.0% by weight of a binder (PVA) are added. After mixing with a stirrer, a pre-calcined powder was prepared using a spray dryer. Then, after calcining at 1200 ° C. for 20 hours in the air, sieving was performed to obtain calcined powder (calcined first raw material powder) having an average particle size of 30 μm.

  Next, an uncalcined powder (non-calcined second raw material) having an average particle size of 1.0 μm, which is mixed with zinc oxide powder so that gallium oxide is 3% by weight and indium oxide is 3% by weight. Is mixed with the calcined powder (calcined first raw material powder) so that the mixing ratio of the calcined powder is 60% by weight, and 1.0% by weight of the binder and 0% are mixed. After adding 0.5% by weight of the dispersant and 0.5% by weight of stearic acid (lubricant) and stirring for 18 hours or more with a stirrer, granulated powder was obtained using a spray dryer.

  Next, the obtained granulated powder was molded at a pressure of 90 kN using a uniaxial press to obtain a molded body having a diameter of 30.7 mm and a height of 40.7 mm, and then the molded body was sintered. .

  In the sintering process, the temperature was raised from room temperature to 1000 ° C. over 58 hours, and the sintering was performed at 1000 ° C. for 20 hours.

Further, the sintered oxide tablet after sintering was heated in a vacuum state from room temperature to 800 ° C. over 2.4 hours, and held at 800 ° C. for 3 hours for reduction. to obtain a deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according.

In addition, a part of end part in the obtained ZnO—Ga ₂ O ₃ oxide sintered compact tablet for vapor deposition according to Example 1 was cut to obtain an SEM (scanning electron microscope) imaging diagram at the fracture surface. . This imaging diagram is shown in FIG. Moreover, the sintered density of the ZnO—Ga ₂ O ₃ based oxide sintered body tablet for vapor deposition according to Example 1 was 3.35 g / cm ³ , and the volume resistivity was 50 Ω · cm. These results are shown in Table 2.

Furthermore, the X-ray diffraction of the deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according to Example 1, represented by _{InGaO 3 (ZnO) 5 (InGaZn} 5 O 8) phase during the tablet A homologous structural compound was detected, and a spinel structural compound represented by a high-resistance Ga ₂ O ₃ phase and a ZnGa ₂ O ₄ phase was not detected. The results are shown in Table 2 and the X-ray diffraction chart is shown in FIG.

Then, with respect to deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according to Example 1 was obtained, high power (acceleration voltage 15kV, output 24 kW) with the aim of production it was suddenly irradiated with an electron beam The crack of the tablet was not confirmed, and the crack of the ZnO—Ga ₂ O ₃ oxide sintered body tablet for vapor deposition during vapor deposition was not confirmed.

[Example 2]
The ZnO—Ga ₂ O ₃ -based oxidation for vapor deposition according to Example 2 is performed in the same manner as in Example 1 except that the average particle diameter of the calcined first raw material powder is 15 μm (30 μm in Example 1). A sintered product tablet was obtained.

The above-mentioned “sintering density” of the obtained ZnO—Ga ₂ O ₃ -based oxide sintered body tablet for vapor deposition according to Example 2 was 3.35 g / cm ³ and “volume resistivity” was 55 Ω · cm. .

  These results are shown in Table 2.

Further, from the X-ray diffraction of the deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according to Example 2, during the tablet, represented by _{InGaO 3 (ZnO) 5 (InGaZn} 5 O 8) phase And a spinel structure compound represented by a high resistance Ga ₂ O ₃ phase and a ZnGa ₂ O ₄ phase was not detected. Further, as in Example 1, a high power (acceleration voltage 15 kV, output 24 kW) electron beam was suddenly irradiated, but cracking of the ZnO—Ga ₂ O ₃ oxide sintered compact tablet for vapor deposition immediately after irradiation and during vapor deposition. Was not confirmed. These results are also shown in Table 2.

[Examples 3 to 9]
Set to “weight% (mixing ratio)” and “atom ratio (%)” of the raw material powder shown in Table 1, and “average particle diameter (μm) of the first raw material powder” and “second” shown in Table 1 Except for the point of “average particle diameter of raw material powder (μm)”, a ZnO—Ga ₂ O ₃ based oxide sintered body tablet for vapor deposition according to Examples 3 to 9 was obtained in the same manner as in Example 1.

“Sintering density” and “volume resistivity” of the obtained ZnO—Ga ₂ O ₃ -based oxide sintered body tablets for vapor deposition according to Examples 3 to 9 were values shown in Table 2.

Further, from the X-ray diffraction of the deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according to Example 3-9, during each tablet, in _{InGaO 3 (ZnO) 5 (InGaZn} 5 O 8) phase The represented homologous structural compound was detected, and the spinel structural compound represented by the high-resistance Ga ₂ O ₃ phase and ZnGa ₂ O ₄ phase was not detected. Further, as in Example 1, a high power (acceleration voltage 15 kV, output 24 kW) electron beam was suddenly irradiated, but cracking of each tablet was not confirmed immediately after irradiation or during vapor deposition. These results are also shown in Table 2.

[Comparative Example 1]
Except for the point that the atomic ratio (%) of In was set to “0.63” (see Table 1) and was set outside the range of “1.25 ≦ In / (Zn + Ga + In) × 100 ≦ 2.54”. In the same manner as in Example 1, a ZnO—Ga ₂ O ₃ based oxide sintered body tablet for vapor deposition according to Comparative Example 1 was obtained.

The “sintered density” of the obtained ZnO—Ga ₂ O ₃ -based oxide sintered body tablet for vapor deposition according to Comparative Example 1 was 3.35 g / cm ³ , and “volume resistivity” was 80 Ω · cm.

Moreover, from the X-ray diffraction of the ZnO—Ga ₂ O ₃ oxide sintered body tablet for vapor deposition according to Comparative Example 1, the InGaZn ₅ O ₈ phase was not detected in the tablet, and the high-resistance ZnGa ₂ O ₄ phase was detected. As a result, a spinel structure compound represented by the following formula was detected, and a high-resistance Ga ₂ O ₃ phase was not detected. The results are shown in Table 2 and an X-ray diffraction chart is shown in FIG.

In addition, as described in the main phase column in Table 2, “ZnO (In is a solid solution)”, the atomic ratio (%) of In is “1.25 ≦ In / (Zn + Ga + In) × 100 ≦ 2. Since the decimal value “0.63” which is out of the range of “54” is set, the homologous structure compound represented by the (InGaZn ₅ O ₈ ) phase is not generated, and In is dissolved in the ZnO phase. As a result, a spinel structure compound represented by a high-resistance ZnGa ₂ O ₄ phase was detected, and the “volume resistivity” of the tablet was as high as 80 Ω · cm. When irradiated with an electron beam under the same conditions, it is confirmed that the ZnO—Ga ₂ O ₃ oxide sintered tablet for vapor deposition is cracked during vapor deposition.

[Comparative Example 2]
Except for the point that the atomic percentage (%) of Ga was set to “0.88” (see Table 1) and was set outside the range of “1.75 ≦ Ga / (Zn + Ga + In) × 100 ≦ 3.54”. In the same manner as in Example 1, a ZnO—Ga ₂ O ₃ -based oxide sintered body tablet for vapor deposition according to Comparative Example 2 was obtained.

The “sintered density” of the obtained ZnO—Ga ₂ O ₃ -based oxide sintered body tablet for vapor deposition according to Comparative Example 2 was 3.36 g / cm ³ , and “volume resistivity” was 86 Ω · cm.

Moreover, from the X-ray diffraction of the ZnO—Ga ₂ O ₃ based oxide sintered body tablet for vapor deposition according to Comparative Example 2, the InGaZn ₅ O ₈ phase was not detected in the tablet, and the high resistance ZnGa ₂ O ₄ phase was detected. As a result, the spinel structure compound represented by the formula and the Ga ₂ O ₃ phase were not detected.

By the way, as described in “ZnO (In, Ga is a solid solution)” in the main phase column in Table 2, the atomic ratio (%) of Ga is “1.75 ≦ Ga / (Zn + Ga + In) × 100 ≦ It is set to a decimal value “0.88” which is out of the range of 3.54 ”, and since the Ga component in the oxide sintered body is extremely small, a high resistance Ga ₂ O ₃ phase and ZnGa ₂ O ₄ phase The spinel structure compound represented by the above formula and the homologous structure compound represented by the (InGaZn ₅ O ₈ ) phase are not produced, and In and Ga are in a solid solution state in the ZnO phase. Even when In and Ga are dissolved in a large amount in the ZnO phase, the “volume resistivity” of the tablet is as high as 86 Ω · cm. As a result, when an electron beam is irradiated under the same conditions as in Example 1. It is confirmed that cracking of the ZnO—Ga ₂ O ₃ -based oxide sintered body tablet for vapor deposition occurs during vapor deposition.

[Comparative Example 3]
Except for the point that the atomic percentage (%) of Ga was set to “5.31” (see Table 1) and was set outside the range of “1.75 ≦ Ga / (Zn + Ga + In) × 100 ≦ 3.54”. In the same manner as in Example 1, a ZnO—Ga ₂ O ₃ -based oxide sintered body tablet for vapor deposition according to Comparative Example 3 was obtained.

The “sintered density” of the obtained ZnO—Ga ₂ O ₃ -based oxide sintered body tablet for vapor deposition according to Comparative Example 3 was 3.35 g / cm ³ , and “volume resistivity” was 89 Ω · cm.

Moreover, from the X-ray diffraction of the ZnO—Ga ₂ O ₃ based oxide sintered body tablet for vapor deposition according to Comparative Example 3, the InGaZn ₅ O ₈ phase was not detected in the tablet, and the high-resistance ZnGa ₂ O ₄ phase was detected. As a result, a spinel structure compound represented by the formula and a Ga ₂ O ₃ phase were detected.

In addition, as described in the main phase column in Table 2, “ZnO (In solid solution)”, the Ga atom number ratio (%) is “1.75 ≦ Ga / (Zn + Ga + In) × 100 ≦ 3. Since the large value “5.31” which is out of the range of “54” is set, the homologous structure compound represented by the (InGaZn ₅ O ₈ ) phase is not generated, and In is dissolved in the ZnO phase. As a result, the spinel structure compound represented by the high-resistance ZnGa ₂ O ₄ phase and the Ga ₂ O ₃ phase are detected, and the “volume resistivity” of the tablet is as high as 89 Ω · cm. Therefore, when irradiated with electron beams under the same conditions as in example 1, to produce a crack of the deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets during deposition is confirmed.

[Comparative Example 4]
Except for the point that the average particle size of the calcined and sieved first raw material powder was set to “5 μm” (see Table 1) and was set outside the range of “10 μm to 50 μm”, the same as in Example 1 to obtain a deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets of Comparative example 4.

The “sintered density” of the obtained ZnO—Ga ₂ O ₃ -based oxide sintered body tablet for vapor deposition according to Comparative Example 4 was 3.36 g / cm ³ , and “volume resistivity” was 56 Ω · cm.

Also, it expressed from the X-ray diffraction of the deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets of Comparative Example 4, in _{InGaO 3 (ZnO) 5 (InGaZn} 5 O 8) phase during the tablet A homologous structural compound was detected, and a spinel structural compound represented by a high-resistance Ga ₂ O ₃ phase and a ZnGa ₂ O ₄ phase was not detected. The results are shown in Table 2.

However, since the average particle size of the first raw material powder is set to a decimal value “5 μm” which is outside the range of “10 μm or more and 50 μm or less”, the average crystal particle size derived from the first raw material powder of the tablet is When the requirement of “10 μm or more and 20 μm or less” is not satisfied. As a result, when the electron beam is irradiated under the same conditions as in Example 1, the ZnO—Ga ₂ O ₃ based oxide sintering for vapor deposition according to Comparative Example 4 is performed during vapor deposition. It is confirmed that the body tablet is cracked (see Table 2).

[Comparative Example 5]
Except that the calcined and sieved first raw material powder has an average particle size of “70 μm” (see Table 1) and is set outside the range of “10 μm or more and 50 μm or less”, the same as in Example 1. to obtain a deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets of Comparative example 5.

The “sintering density” of the obtained ZnO—Ga ₂ O ₃ -based oxide sintered body tablet for vapor deposition according to Comparative Example 5 was 3.35 g / cm ³ and “volume resistivity” was 53 Ω · cm.

Also, it expressed from the X-ray diffraction of the deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets of Comparative Example 5, in _{InGaO 3 (ZnO) 5 (InGaZn} 5 O 8) phase during the tablet A homologous structural compound was detected, and a spinel structural compound represented by a high-resistance Ga ₂ O ₃ phase and a ZnGa ₂ O ₄ phase was not detected. The results are shown in Table 2.

However, since the average particle size of the first raw material powder is set to a large value “70 μm” that is outside the range of “10 μm or more and 50 μm or less”, the average crystal particle size derived from the first raw material powder of the tablet is When the requirement of “10 μm or more and 20 μm or less” is not satisfied. As a result, when the electron beam is irradiated under the same conditions as in Example 1, the ZnO—Ga ₂ O ₃ based oxide sintering for vapor deposition according to Comparative Example 5 is performed during vapor deposition. It is confirmed that the body tablet is cracked (see Table 2).

[Comparative Example 6]
Comparative Example as in Example 1 except that the average particle size of the second raw material powder was set to “0.05 μm” (see Table 1) and was set outside the range of “0.1 μm to 1.5 μm”. A ZnO—Ga ₂ O ₃ oxide sintered body tablet for vapor deposition according to 6 was obtained.

The “sintering density” of the obtained ZnO—Ga ₂ O ₃ -based oxide sintered body tablet for vapor deposition according to Comparative Example 6 was 3.35 g / cm ³ , and “volume resistivity” was 58 Ω · cm.

Also, it expressed from the X-ray diffraction of the deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets of Comparative Example 6, in _{InGaO 3 (ZnO) 5 (InGaZn} 5 O 8) phase during the tablet A homologous structural compound was detected, and a spinel structural compound represented by a high-resistance Ga ₂ O ₃ phase and a ZnGa ₂ O ₄ phase was not detected. The results are shown in Table 2.

However, since the average particle size of the second raw material powder is set to a decimal value “0.05 μm” that is outside the range of “0.1 μm or more and 1.5 μm or less”, it is derived from the second raw material powder of the tablet. As a result, when the electron beam under the same conditions as in Example 1 is irradiated, ZnO—Ga ₂ O for vapor deposition according to Comparative Example 6 is deposited during the vapor deposition. It is confirmed that the ₃ system oxide sintered tablet is cracked (see Table 2).

[Comparative Example 7]
Comparative Example as in Example 1 except that the average particle diameter of the second raw material powder was set to “2.0 μm” (see Table 1) and was set outside the range of “0.1 μm to 1.5 μm”. A ZnO—Ga ₂ O ₃ -based oxide sintered body tablet for vapor deposition according to 7 was obtained.

The “sintered density” of the obtained ZnO—Ga ₂ O ₃ -based oxide sintered body tablet for vapor deposition according to Comparative Example 7 was 3.35 g / cm ³ and “volume resistivity” was 55 Ω · cm.

Also, expressed from the X-ray diffraction of the deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according to Comparative Example 7, in _{InGaO 3 (ZnO) 5 (InGaZn} 5 O 8) phase during the tablet A homologous structural compound was detected, and a spinel structural compound represented by a high-resistance Ga ₂ O ₃ phase and a ZnGa ₂ O ₄ phase was not detected. The results are shown in Table 2.

However, since the average particle size of the second raw material powder is set to a large value “2.0 μm” that is outside the range of “0.1 μm or more and 1.5 μm or less”, it is derived from the second raw material powder of the tablet. As a result, when the electron beam under the same conditions as in Example 1 is irradiated, ZnO—Ga ₂ O for vapor deposition according to Comparative Example 7 is deposited during the vapor deposition. It is confirmed that the ₃ system oxide sintered tablet is cracked (see Table 2).

  According to the sintered sintered tablet for vapor deposition according to the present invention, since it is difficult to be damaged even when continuously irradiated with a high-power electron beam or high-power plasma, stable film formation for a long time is possible. It has industrial applicability to be used as a sintered compact tablet for vapor deposition when producing transparent conductive films for electrode materials such as displays and solar cells.

Claims (8)

In a ZnO—Ga ₂ O ₃ oxide sintered body tablet for vapor deposition composed of Zn (zinc), Ga (gallium), In (indium) and oxygen (O),
(1) The atomic ratio (%) of Zn, Ga and In satisfies the following formula:
1.75 ≦ Ga / (Zn + Ga + In) × 100 ≦ 3.54
1.25 ≦ In / (Zn + Ga + In) × 100 ≦ 2.54
(2) The sintered density is 2.9 g / cm ³ or more and 4.0 g / cm ³ or less, and the volume resistivity is 70 Ω · cm or less,
(3) The oxide sintered body calcined by an average grain size of the first sintering particle derived from the first raw material powder consisting of zinc oxide powder were appearing on the fracture surface of the tablet is 10μm or 20μm or less, and, the The average grain size of the second sintered grains derived from the second raw material powder composed of uncalcined zinc oxide powder, gallium oxide powder and indium oxide powder appearing on the fracture surface of the sintered oxide tablet is 1 μm or more and 3 μm or less And
(4) The oxide sintered body contains a homologous structure compound represented by ZnO and InGaO ₃ (ZnO) m (m = 1 to 10), and is represented by Ga ₂ O ₃ and ZnGa ₂ O _4. No spinel structure compounds,
A ZnO—Ga ₂ O ₃ -based oxide sintered body tablet for vapor deposition characterized by the following. InGaO ₃ (ZnO) deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets of claim 1, wherein said m of homologous structure compound represented by m is 5. In the method for manufacturing a deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according to claim 1 or 2,
A first step of heat treating the zinc oxide powder at a calcining temperature of 1000 ° C. or higher and 1400 ° C. or lower, followed by sieving to obtain a calcined first raw material powder having an average particle size of 10 μm or more and 50 μm or less;
An uncalcined second raw material powder composed of zinc oxide powder, gallium oxide powder and indium oxide powder having an average particle size of 0.1 μm or more and 1.5 μm or less is compared with the first calcined first raw material powder. Mixing so that the mixing ratio of one raw material powder is 40 wt% or more and 80 wt% or less, and granulating to obtain a granulated powder;
The obtained granulated powder is molded into a molded body, and this molded body is sintered at a temperature of 800 ° C. or higher and 200 ° C. or lower than the calcining temperature in the first step to burn ZnO—Ga ₂ O ₃ oxide. The third step of obtaining the union,
Deposition ZnO-Ga ₂ O ₃ type oxide-sintered body production method of the tablet, characterized by comprising the steps of. The second raw material powder in the second step contains 2 wt% or more and 4 wt% or less of indium oxide powder, and contains 2 wt% or more and 4 wt% or less of gallium oxide powder. method for manufacturing a deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets described. 4. The ZnO—Ga for vapor deposition according to claim 3, wherein a temperature rising rate to a sintering temperature of 800 ° C. or higher in the third step is 0.2 ° C./min to 1.0 ° C./min. ₂ O ₃ type oxide-sintered body production method of the tablet. Method for manufacturing a deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according to claim 3, wherein the retention time of the sintering temperature in the third step is 15 hours or more 25 hours or more. After sintering process of the third step is completed, returning to room temperature, the manufacturing method of the deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets according to claim 3, characterized in that the reduction treatment . The reduction treatment is performed by raising the temperature from room temperature to a reduction temperature of 600 ° C. or more and 1000 ° C. or less at a rate of temperature increase of 1 to 10 ° C./min and then holding the inside of the reduction furnace in a vacuum state for 1 to 6 hours. method for manufacturing a deposition ZnO-Ga ₂ O ₃ type oxide-sintered-body tablets of claim 7, characterized in that.