JP2013040394A - Oxide sintered compact target for sputtering and manufacturing method of the same, and forming method of thin film using the target and thin film forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a GTO sputtering target that can control the generation of a nodule and a particle even at continuous sputtering, and can obtain a film with high uniformity of a membrane property, and especially to provide a sputtering target for an FPD.SOLUTION: The oxide sintered compact target for sputtering includes: 1-20 mol% of GaO; and the balance SnOand inevitable impurities, and the oxide sintered compact target for sputtering is characterized in that the relative density is at least 97%, and the bulk resistivity is at most 1,000 Ωcm in the phase observed in the structure of the oxide sintered compact target.

Description

  The present invention relates to a sintered oxide target for sputtering (GTO target) composed of gallium (Ga), tin (Sn), oxygen (O) and inevitable impurities, a method for producing the target, and a method for forming a thin film using the target. And a thin film.

In general, a thin film transistor called TFT (Thin Film Transistor) includes a three-terminal element having a gate terminal, a source terminal, and a drain terminal. In these elements, a semiconductor thin film formed on a substrate is used as a channel layer in which electrons or holes move, a voltage is applied to the gate terminal to control a current flowing in the channel layer, and a current flows between the source terminal and the drain terminal. It has a function of switching current.
At present, the most widely used device is a device using a polycrystalline silicon film or an amorphous silicon film as a channel layer.

However, since a silicon-based material (polycrystalline silicon or amorphous silicon) absorbs in the visible light region, there is a problem that the thin film transistor malfunctions due to generation of carriers due to light incidence. As a preventive measure, a light blocking layer such as metal is provided, but there is a problem that the aperture ratio decreases. Moreover, in order to maintain the screen brightness, it is necessary to increase the brightness of the backlight, and there is a drawback that power consumption increases.

Furthermore, in the production of these silicon-based materials, the amorphous silicon film, which can be produced at a lower temperature than polycrystalline silicon, requires a high temperature of about 200 ° C. or higher. Therefore, at such a temperature, However, since a polymer film having the advantages of low cost, light weight, and flexibility cannot be used as a base material, there is a problem that a range of selection of a substrate material is narrow. Furthermore, the device fabrication process at a high temperature has disadvantages in production such as high energy cost and the time required for heating.

Thus, in recent years, thin film transistors using transparent oxide semiconductors have been developed in place of silicon-based materials. A typical example is an In—Ga—Zn—O-based (IGZO) material. This material has been proposed to be used for a field effect transistor because an amorphous oxide having an electron carrier concentration of less than 10 ¹⁸ / cm ³ can be obtained (see Patent Document 1).
In addition, there are some proposals using this type of oxide using field effect transistors (Patent Literature 2, Patent Literature 3, Patent Literature 4, Patent Literature 5, Patent Literature 6, Patent Literature 7, Patent Literature 8 and (See Patent Document 9).

  In the above Patent Document 1, there is a suggestion that the sputtering method is most suitable for the formation of the amorphous oxide, but in the example where 1 to 12 are present, the film is formed by the pulse laser deposition method (PLD method). Only one example is an example in which radio frequency (RF) sputtering is performed. Also in Patent Documents 2 to 9, only the characteristics of a field effect transistor are disclosed, or only a reactive epitaxial method or a pulsed laser deposition method is shown as a film forming method. There is no one that offers high direct current (DC) sputtering.

This direct current (DC) sputtering requires a target, but an In—Ga—Zn—O-based (IGZO) oxide target is not easy to manufacture.
It is composed of multi-component components, is manufactured by mixing each oxide powder, is affected by the properties and conditions of the powder, the properties of the sintered body differ depending on the sintering conditions, This is because there are many problems such as loss of electrical conductivity due to the sintering conditions and composition of ingredients, and generation of nodules and abnormal discharge during sputtering depending on the nature and state of the target.

For these reasons, a Ga—Sn—O-based (GTO) oxide target with few component systems has been studied. The GTO target is known for a transparent conductive film, and there are Patent Document 10 and Patent Document 11 below.
Patent Document 10 is a SnO ₂ based sintered body in which one addition amount selected from Ga, Bi, Nb, Mn, Fe, Ni, Co, and Ta is 20% by weight or less in terms of oxide, A sintered body having a sintered density of 4.0 g / cm ³ or less is described. Its use is a target for forming a transparent conductive film for a plasma display panel or a touch panel.

In the example of the GTO sintered body, as described in Table 1 of the same document, the sintered density is a fairly low value of 5.07 g / cm ³ , which is not a good target.
In Patent Document 11, although it is a Ga—Sn—O-based (GTO) oxide target, it is an invention in which other oxides such as Zn, Nb, and Al are added. As a comparative example, Ga— An oxide target of Sn-O (GTO) is described.

However, in the comparative example, it is described that measurement cannot be performed in a case where the relative density is as low as 89% or less and the bulk resistance value exceeds 1.8 kΩ, and the GTO target itself has no strong interest. It is described.

WO2005 / 088726A1 JP 2004-103957 A JP 2006-165527 A JP 2006-165528 A JP 2006-165529 A JP 2006-165530 A JP 2006-165532 A JP 2006-173580 A JP 2006-186319 A JP 2000-273622 A WO2010 / 018707

  The present invention is a sputtering oxide sintered compact target made of gallium (Ga), tin (Sn), oxygen (O), and inevitable impurities, and improves the structure of the sintered compact target and becomes a nodule generation source. GTO target that minimizes phase formation, lowers bulk resistance, has high density, can suppress abnormal discharge, and is capable of DC sputtering, a manufacturing method thereof, and a thin film forming method using the target, and It is an object to provide a thin film.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive research, and as a result, have found that it is extremely effective to improve the target structure in the GTO target.

Based on this knowledge, the following invention is proposed.
1) A sputtering oxide sintered compact target composed of 1 to 20 mol% of Ga ₂ O ₃ , the remainder SnO ₂ and unavoidable impurities, wherein the oxide sintered compact target has a relative density of 97% or more, bulk resistance An oxide sintered compact target for sputtering, wherein the rate is 1000 Ωcm or less.
2) The oxide sintered compact target for sputtering according to 1) above, wherein Zr is contained in an amount of 2000 wtppm or less (excluding 0 wtppm).

3) The oxide sintered compact target for sputtering according to 1) or 2) above, wherein the content of Cl as an impurity is 5 wtppm or less.
4) The target according to any one of 1) to 3) above, which is a target for forming a transparent conductive film used for FPD, a thin film transistor semiconductor layer, and a thin film used for a semiconductor buffer layer. Oxide sintered compact target for sputtering.

5) In the phase observed in the structure of the oxide sintered compact target, it has a rectangular compound phase composed of Sn, Ga, and O with an aspect ratio of 3 to 15 in the matrix composed of the SnO ₂ phase. The oxide sintered compact target for sputtering according to any one of 1) to 3) above.
6) The oxide sintered compact target for sputtering according to 5) above, wherein the area ratio of the rectangular compound phase composed of Sn, Ga, and O to the matrix composed of SnO ₂ phase is 30 to 70%. .
7) The oxide sintered body for sputtering according to any one of 1 to 6 above, wherein no coarse particles of Ga ₂ O ₃ having an average particle diameter of 10 μm or more are present in the sintered body target. target.

8) Tin oxide (SnO ₂ ) having a particle size of 1.5 μm or less and a BET specific surface area of 4 to 7 m ² / g and oxidation having a particle size of 3.0 μm or less and a BET specific surface area of 10 to 20 m ² / g Oxide sintering for sputtering characterized by adjusting raw material powder of gallium (Ga ₂ O ₃ ), mixing these powders, further pulverizing them, and sintering them in a temperature range of 1450-1600 ° C Manufacturing method of body target.
9) Sputtering using the oxide sintered compact target as described in 1) to 7) above, and forming a GTO thin film on the substrate.

10) The method for forming a thin film as described in 9) above, wherein the substrate temperature is heated to a temperature of room temperature to 200 ° C. and sputtering is performed to form a GTO thin film having an amorphous structure on the substrate.
11) When sputtering using the oxide sintered compact target described in 1) to 7) above, sputtering is performed by adjusting the oxygen concentration in the sputtering atmosphere gas to 1 to 6%, and the resistivity of the GTO film and / or A method for forming a thin film, comprising controlling the transmittance or refractive index of a GTO film.

12) A thin film obtained by the method for forming a thin film described in 11) above, having a transmittance of 80% or more at 550 nm and 68 to 75% at 400 nm.
13) A thin film obtained by the method for forming a thin film according to 11) above, wherein the refractive index of the thin film is 2.08 or more at 550 nm of visible light.

By the above, in the oxide sintered compact target for sputtering composed of gallium (Ga), tin (Sn), oxygen (O), and inevitable impurities, the structure of the sintered compact target is improved, and the phase that becomes the nodule generation source GTO target capable of minimizing bulk formation, lowering bulk resistance, high density, suppressing abnormal discharge, and capable of DC sputtering, a manufacturing method thereof, and a thin film forming method and thin film using the target It has the outstanding effect that it can provide.

It is a figure which shows the XRD spectrum of a GTO sintered compact. It is a SEM image of a sintered compact at each sintering temperature. It is a figure which shows the oxygen concentration dependence of the resistivity of a GTO film | membrane. It is a figure which shows the oxygen concentration dependence of the transmittance | permeability of a GTO film | membrane. It is a figure which shows the wavelength dependence of the refractive index of a GTO film | membrane. Is an SEM image of coarse particles of _Ga 2 _{O 3} in the sintered body.

The oxide sintered compact target for sputtering of the present invention is an oxide sintered compact target for sputtering composed of ₁ to 20 mol% of Ga ₂ O ₃ , the remainder SnO ₂ and unavoidable impurities.

The problem is that nodules that cause abnormal discharge are generated in the sputtering target having such a component composition. This abnormal discharge causes the generation of foreign matter in the sputtered film and causes the film characteristics to deteriorate. Therefore, it was necessary to investigate the cause of this nodule generation on the GTO target.

The present invention has one goal to obtain a conductive target. For this purpose, it is necessary to lower the bulk resistance value. When the coarse particles of Ga ₂ O ₃ increase, the bulk resistance value tends to increase. In the present invention, a bulk resistance value of 1000 Ω · cm or less can be achieved. This is also a condition that enables DC sputtering, and is one of the major features of the usefulness of the present invention. Furthermore, in order to enable stable sputtering, a higher target density is desirable, and in the present invention, a relative density of 97% or more can be achieved.

The present invention is GTO sintered body target, as shown in Comparative Examples described later, usually in a uniform structure, coarse particles of Ga ₂ O ₃ is present. When the Ga ₂ O ₃ coarse particles have a large raw material particle size, a small BET specific surface area, or insufficient pulverization, the reaction with SnO ₂ around the coarse particles becomes insufficient. Ga ₂ O ₃ coarse particles remain without generating a compound of Ga, Sn, and O (a composite oxide mainly composed of Ga ₄ SnO ₈ ). In the GTO sintered body target, the remaining Ga ₂ O ₃ coarse particles are a big problem.

FIG. 6 shows an SEM image in which the surface of the GTO sintered body in which coarse particles are generated is mirror-polished and the surface is observed with an electron microscope (500 times). As shown in FIG. 6, there are coarse particles of Ga ₂ O ₃ in the center portion, and the periphery thereof has a poor reaction with SnO ₂ and has a structure with many pores.
That is, the periphery of Ga ₂ O ₃ has a rough structure with a low density. When there are many such coarse particles, starting from this, it becomes a cause of nodules, and abnormal discharge is likely to occur.

If many such Ga ₂ O ₃ coarse particles are present in the GTO sintered body, it can be said that the density of the target is lowered as a whole and the bulk resistance value is increased. In other words, it is important to improve the density of the target and reduce the bulk resistance value, which can overcome the problems of the prior art.

The present invention has been made from such a viewpoint, and it is an important requirement that the oxide sintered compact target has a relative density of 97% or more and a bulk resistivity of 1000 Ωcm or less. The oxide sintered compact target has been achieved.
Thus, the adjusted oxide sintered compact target for sputtering can suppress the generation of nodules and can reduce the abnormal discharge starting from the nodules. This is the most effective nodule suppression means.

As will be described later, at the stage of manufacturing an oxide sintered compact target for sputtering, gallium oxide (Ga ₂ O ₃ ) and tin oxide (SnO ₂ ), which are sintering raw materials, are introduced into water and dispersed to form a slurry. However, the slurry is finely pulverized using a wet medium stirring mill (bead mill or the like). In this step, zirconium oxide (ZrO ₂ ) beads are often used. However, if the amount of Zr mixed is 2000 wtppm or less, there is no particular problem with the oxide sintered compact target for GTO sputtering.

Moreover, since the phenomenon that the density does not increase occurs when the content of Cl as an impurity exceeds 5 wtppm, it should be particularly noted as an impurity, and the content of Cl must be 5 wtppm or less.
The sputtering oxide sintered compact target described above is particularly effective as a target for forming a transparent conductive film used for FPD, a thin film transistor semiconductor layer, and a thin film used for a semiconductor buffer layer.

The oxide sintered compact target for GTO sputtering of the present invention capable of achieving a relative density of the oxide sintered compact target of 97% or more and a bulk resistivity of 1000 Ωcm or less has a specific structure. FIG. 1 is a diagram showing a phase contained by XRD, but in a GTO sintered body sintered at a certain temperature or higher (1500 ° C. in FIG. 1), an oxide of SnO ₂ phase and Ga ₄ SnO ₈ as a matrix Although a phase peak is observed, the oxide phase peak of Ga ₄ SnO ₈ is not observed at 1400 ° C. In FIG. 1, the portion surrounded by a circle in the 1500 ° C. spectrum is the peak of the oxide phase of Ga ₄ SnO ₈ .

In this case, in addition to the oxide phase of Ga ₄ SnO ₈ , there are a few other oxide phases, but a compound phase composed of Sn, Ga, and O (including Ga ₄ SnO ₈ as the main component) is included. Complex oxide phase). The presence of this phase greatly affects the improvement of relative density and the reduction of bulk resistivity.

FIG. 2 is an SEM image in which the surface of a sintered GTO sintered body is mirror-polished at 1400 ° C., 1450 ° C., 1500 ° C., and 1550 ° C., and the surface is observed with an electron microscope (2000 times). . In FIG. 2, the slightly darker color is a compound phase composed of Sn, Ga and O. As is apparent from this figure, a unique tissue can be observed.

In sintering at 1400 ° C, the oxide sintered compact target of the present invention has a relative density of 97% or more and a bulk resistivity of 1000 Ωcm or less, but at 1450 ° C, 1500 ° C and 1550 ° C, The sintered GTO sintered body can achieve this condition. 2 is correlated with the relative density and bulk resistivity of the target.

That is, in the phase observed in the structure of the oxide sintered body target, a compound phase composed of Sn, Ga, and O (a composite oxide phase mainly composed of Ga ₄ SnO ₈ ) in a matrix composed of SnO ₂ phase. However, when this phase is observed, it is a rectangular phase having an aspect ratio of 3 to 15. The shape of this phase is that the surface of the GTO sintered body is a mirror-polished surface, but it is considered that the sintered body target has a shape of a rectangular parallelepiped, a columnar body, a rod-shaped body, or the like. This is a compound phase composed of Sn, Ga and O (a composite oxide phase mainly composed of Ga ₄ SnO ₈ ), and it can be seen that the shape becomes larger as the sintering becomes higher.

This is a compound phase composed of Sn, Ga and O (a composite oxide phase mainly composed of Ga ₄ SnO ₈ ), and it can be seen that the shape becomes larger as the sintering becomes higher.
The area ratio of the rectangular compound phase composed of Sn, Ga, and O (composite oxide phase mainly composed of Ga ₄ SnO ₈ ) with respect to the matrix composed of the SnO ₂ phase is about 30 to 70%. These are considered to affect the improvement of the relative density of the GTO oxide sintered compact target of the present invention and the reduction of the bulk resistivity.

In the production of an oxide sintered compact target for sputtering, tin oxide (SnO ₂ ) having a particle size of 1.5 μm or less and a BET specific surface area of 4 to 7 m ² / g and a particle size of 3.0 μm or less, a BET ratio A raw material powder of gallium oxide (Ga ₂ O ₃ ) having a surface area of 10 to 20 m ² / g is prepared, these powders are mixed, further pulverized, and then sintered in a temperature range of 1450 to 1600 ° C. .
Adjustment of raw material powder and limitation of numerical values, if the respective conditions are not satisfied, may cause a decrease in the density of the sintered body, increase the existence probability of coarse particles in the sintered body, and cause arcing during sputtering, etc. This is because it adversely affects the properties of the sintered body.

A GTO thin film can be formed on a substrate by sputtering using the oxide sintered compact target. In this case, a GTO thin film having an amorphous structure can be formed on the substrate by heating the substrate to a temperature of room temperature to 200 ° C. for sputtering. Further, when sputtering using an oxide sintered compact target, sputtering is performed by adjusting the oxygen concentration in the sputtering atmosphere gas to 1 to 6%, and the resistivity of the GTO film and / or the transmittance or refractive index of the GTO film. Can be controlled.

  FIG. 3 shows the relationship between the resistivity of the sputtered film and the oxygen concentration. This is the case of room temperature film formation (Ts = RT) and substrate heating film formation (Ts = 200 ° C.), and the resistivity can be controlled to about 100 times by adjusting the oxygen concentration. As shown in FIG. 3, the oxygen concentration is 0.350 Ω · cm at 1%, 0.094 Ω · cm at 2%, 0.025 Ω · cm at 4%, and 0.037 Ω · cm at 6%. When the film is formed by heating the substrate, the resistance of the sputtering film can be further increased.

FIG. 4 shows the relationship between the wavelength of visible light and the transmittance of the sputtered film. In the case of room temperature film formation and 200 ° C. substrate heating film formation, the introduction of oxygen during film formation improves the transmittance on the low wavelength side.
FIG. 5 shows the relationship between the wavelength of visible light and the refractive index of the sputtered film. In this case, the refractive index of the GTO film is shown when the film formation is performed at room temperature and the oxygen concentration is 4%. Thus, the resistivity of the GTO film and / or the transmittance or refractive index of the GTO film can be controlled by the amount of oxygen during sputtering. The amount of oxygen is adjusted in the range of 1 to 6%. The transmittance of the GTO thin film of the present invention can achieve 80% or more at 550 nm and 68 to 75% at 400 nm, and the refractive index of the thin film can achieve 2.08 or more at 550 nm of visible light.

The present invention has one goal to obtain a conductive target. For this purpose, it is necessary to lower the bulk resistance value. When the coarse particles of Ga ₂ O ₃ increase, the bulk resistance value tends to increase. In the present invention, a bulk resistance value of 1000 Ω · cm or less can be achieved. This is also a condition that enables DC sputtering, and is one of the major features of the usefulness of the present invention. Furthermore, in order to enable stable sputtering, a higher target density is desirable. In the present invention, a relative density of 97% or more can be achieved.

A representative example of the manufacturing process of the oxide sintered body according to the present invention is as follows. As raw materials, gallium oxide (Ga ₂ O ₃ ) and tin oxide (SnO ₂ ) can be used. In order to avoid an adverse effect on electrical characteristics due to impurities, it is desirable to use a raw material having a purity of 4N or higher. Each raw material powder is weighed so as to have a desired composition ratio. As described above, impurities inevitably contained in these are included.

Next, mixing and grinding are performed. If pulverization is insufficient, each component will segregate in the manufactured target, and there will be a high-resistivity region and a low-resistivity region. Therefore, sufficient mixing and pulverization are necessary. Gallium oxide (Ga ₂ O ₃ ) and tin oxide (SnO ₂ ) are added to water and dispersed to form a slurry. The slurry is finely pulverized using a wet medium stirring mill (bead mill or the like).

  Next, the finely pulverized slurry is dried with a hot air dryer at 100 to 150 ° C. for 5 to 48 hours, and sieved with a sieve having an opening of 250 μm to collect powder. The specific surface area of each powder is measured before and after pulverization. 125 g of a PVA aqueous solution (PVA solid content 3%) is mixed with 1000 g of GTO powder, and sieved with a sieve having an opening of 500 μm.

Next, a mold having a diameter of 210 mm is filled with 1000 g of powder and pressed at a surface pressure of 400 to 1000 kgf · cm ² to obtain a molded body. Then, sintering is performed at a predetermined temperature (holding time 5 to 24 hours, in an oxygen atmosphere) to obtain a sintered body. When the target is manufactured, the oxide sintered body obtained as described above is processed into a target of, for example, 152.4φ × 5 tmm by performing cylindrical grinding on the outer periphery and surface grinding on the surface side. Further, for example, an indium alloy or the like is bonded to a copper backing plate as a bonding metal to obtain a sputtering target.

  Hereinafter, description will be made based on Examples and Comparative Examples. In addition, a present Example is an example to the last, and is not restrict | limited at all by this example. In other words, the present invention is limited only by the scope of the claims, and includes various modifications other than the examples included in the present invention.

(Overview of Examples and Comparative Examples)
The properties of the raw material powder used in the examples and comparative examples are as follows. Raw material powder is pulverized with an attritor and φ3mm zirconia beads are used.
Ga ₂ O ₃ raw material: average particle size 2.60 μm, specific surface area 11.60 m ² / g
SnO ₂ raw material: average particle diameter of 1.25 μm, specific surface area of 5.46 m ² / g

For these raw materials, the GTO is prepared in a molar ratio such as Ga ₂ O ₃ : SnO ₂ = 10: 90, and the raw material combination and manufacturing conditions (pulverization, sintering temperature) are changed, A target was prepared and various tests were performed. Details thereof are shown in Examples and Comparative Examples.
The blending ratio (10:90) is a typical GTO target. In order to prevent the generation of nodules in the target of the present invention, the mixing ratio of GTO is not particularly problematic, but Ga ₂ O ₃ is composed of 1 to 20 mol%, the remainder SnO ₂ and unavoidable impurities. The raw materials were prepared and carried out.

In the following examples and comparative examples, various measurements and evaluations are required, and the conditions are shown below.
(Measurement of particle size)
The particle diameter was measured using a laser diffraction / scattering particle size measuring apparatus (Microtrac MT3000, manufactured by Nikkiso Co., Ltd.) after ultrasonic dispersion for 1 minute using ethanol as a dispersion medium. In the present invention, the particle diameter (or average particle diameter) refers to the median diameter (volume basis, also expressed as D50).
(Measurement of specific surface area)
The BET specific surface area was measured with an automatic surface area meter beta soap (manufactured by Nikkiso Co., Ltd., MODEL-4200). The BET specific surface area referred to here is a measurement result using the BET method (one-point method).
(Measurement of bulk resistance)
For the measurement of the bulk resistance, a resistivity measuring device (manufactured by NP Corp., Σ-5 +) using a DC four-point probe method was used.

(Image analysis and tissue evaluation)
About the test piece of the produced target, it grind | polished to the mirror surface with the grinder. And about this test piece, the acceleration voltage 15 (kV) of an electron gun, irradiation current about 2.0 * 10 < ^-8 > (A) by FE-EPMA (the JEOL Co., Ltd. make, JXA-8500F electron probe microanalyzer). The structure was observed under the conditions of
The observed structure photograph (SEM image) was measured for the aspect ratio of the compound phase of Ga, Sn, and O with image processing software. The image processing software used was analySIS ver.5 (manufactured by Soft Imaging System GmbH). The aspect ratio represents the size in the major axis direction / the size in the minor axis direction as seen in the SEM image.

(Sputtering conditions)
About the test piece of the produced target, it sputtered on sputtering conditions shown in Table 1, and generation | occurrence | production of the nodule was observed visually.
As the sputtering apparatus, φ8 ”sputtering apparatus is used, back pressure: 0.1 mPa, target size: φ8” × 5 mmt, gas pressure: 0.5 Pa, sputtering gas: Ar + O ₂ gas, DC power (density): 735 W (2 3 W / cm ² ), glass substrate: (150 mmSq.), Film thickness: ˜55 nm, substrate temperature during film formation: no heating, 200 ° C. heating.

Example 1
In Example 1, a powder having an average particle diameter of 2.60 μm and a specific surface area of 11.60 m ² / g is used as the Ga ₂ O ₃ raw material, and an average particle diameter of 1.25 μm and a specific surface area of 5.5 are used as the SnO ₂ raw material. A powder of 46 m ² / g was used. The raw materials were prepared so that these powders had a molar ratio of Ga ₂ O ₃ : SnO ₂ = 10: 90. Next, these powders were mixed and pulverized. The average particle size after pulverization was 0.84 μm, and the specific surface area was 7.55 m ² / g.

In addition, powder mixing, pulverization, sintering, and target production were carried out under the conditions shown in the above paragraphs [0047] and [0048]. Here, the main conditions are described. Various measurements and evaluations were performed by the methods described in the above paragraphs [0049] and [0050]. The chlorine (Cl) content was less than 1 wtppm, and the zirconium (Zr) content was 680 wtppm, both of which were not problematic levels.

Sintering was performed at 1500 ° C. As a result, the relative density was as high as 98.5%, the bulk resistance value was 17.1 Ω · cm, and it had a low bulk resistance value capable of DC sputtering. A representative example of the SEM image of the tissue is shown in FIG. The average aspect ratio of the rectangular compound phase composed of Sn, Ga, and O (a composite oxide phase mainly composed of Ga ₄ SnO ₈ ) was 9. Further, coarse particles having an average particle diameter of more than 10 [mu] m _Ga 2 _{O 3} were not present.

Next, as a result of performing DC sputtering under the above-mentioned conditions (paragraph [0051]), the number of nodules was 54, which was 1/4 or less compared to a comparative example described later. The number of arcing during sputtering was 201, which was less than the comparative example described later. The results are shown in Table 2.

(Example 2)
In Example 2, a powder having an average particle size of 2.60 μm and a specific surface area of 11.60 m ² / g was used as the Ga ₂ O ₃ raw material, and an average particle size of 1.25 μm and a specific surface area of 5.5 were used as the SnO ₂ raw material. A powder of 46 m ² / g was used. The raw materials were prepared so that these powders had a molar ratio of Ga ₂ O ₃ : SnO ₂ = 10: 90. Next, these powders were mixed and pulverized. The average particle size after pulverization was 0.84 μm, and the specific surface area was 7.55 m ² / g.

In addition, powder mixing, pulverization, sintering, and target production were carried out under the conditions shown in the above paragraphs [0047] and [0048]. Here, the main conditions are described. Various measurements and evaluations were performed by the methods described in the above paragraphs [0049] and [0050]. The chlorine (Cl) content was less than 1 wtppm, and the zirconium (Zr) content was 680 wtppm, both of which were not problematic levels.

Sintering was performed at 1450 ° C. As a result, the relative density was as high as 98.1%, the bulk resistance value was 850 Ω · cm, and the bulk resistance value was low enough to enable DC sputtering. A representative example of the SEM image of the tissue is shown in FIG. The average aspect ratio of the rectangular compound phase composed of Sn, Ga, and O (a composite oxide phase mainly composed of Ga ₄ SnO ₈ ) was 4. Further, coarse particles having an average particle diameter of more than 10 [mu] m _Ga 2 _{O 3} were not present.

Next, as a result of performing DC sputtering on the said conditions (paragraph [0051]), the number of nodules was 314, and was 1/2 or less compared with the comparative example mentioned later. The number of arcing during sputtering was 314, which was less than the comparative example described later. The above results are similarly shown in Table 2.

(Example 3)
In Example 3, a powder having an average particle size of 2.60 μm and a specific surface area of 11.60 m ² / g is used as the Ga ₂ O ₃ raw material, and an average particle size of 1.25 μm and a specific surface area of 5.5 are used as the SnO ₂ raw material. A powder of 46 m ² / g was used. The raw materials were prepared so that these powders had a molar ratio of Ga ₂ O ₃ : SnO ₂ = 10: 90. Next, these powders were mixed and pulverized. The average particle size after pulverization was 0.84 μm, and the specific surface area was 7.55 m ² / g.

In addition, powder mixing, pulverization, sintering, and target production were carried out under the conditions shown in the above paragraphs [0047] and [0048]. Here, the main conditions are described. Various measurements and evaluations were performed by the methods described in the above paragraphs [0049] and [0050]. The chlorine (Cl) content was less than 1 wtppm, and the zirconium (Zr) content was 710 wtppm, both of which were not problematic levels.

Sintering was performed at 1550 ° C. As a result, the relative density was as high as 98.0%, the bulk resistance value was 9.2 Ω · cm, and it had a low bulk resistance value capable of DC sputtering. A representative example of the SEM image of the tissue is shown in FIG. The average aspect ratio of the rectangular compound phase composed of Sn, Ga, and O (a composite oxide phase mainly composed of Ga ₄ SnO ₈ ) was 11. Further, coarse particles having an average particle diameter of more than 10 [mu] m _Ga 2 _{O 3} were not present.

Next, as a result of performing DC sputtering under the above-mentioned conditions (paragraph [0051]), the number of nodules was 60, which was 1/4 or less as compared with a comparative example described later. The number of arcing during sputtering was 233 times, which was smaller than the comparative example described later. The above results are similarly shown in Table 2.

Example 4
In Example 4, a powder having an average particle size of 2.60 μm and a specific surface area of 11.60 m ² / g was used as the Ga ₂ O ₃ raw material, and an average particle size of 1.25 μm and a specific surface area of 5.5 were used as the SnO ₂ raw material. A powder of 46 m ² / g was used. The raw materials were prepared so that these powders had a molar ratio of Ga ₂ O ₃ : SnO ₂ = 10: 90. Next, these powders were mixed and pulverized. The average particle size after pulverization was 0.84 μm, and the specific surface area was 7.55 m ² / g.

In addition, powder mixing, pulverization, sintering, and target production were performed under the conditions shown in paragraphs [0047] and [0048] above. Here, the main conditions are described. Various measurements and evaluations were performed by the methods described in the above paragraphs [0049] and [0050]. The chlorine (Cl) content was less than 1 wtppm, and the zirconium (Zr) content was 680 wtppm, both of which were not problematic levels.

Sintering was performed at 1580 ° C. As a result, the relative density was as high as 97.9%, the bulk resistance value was 4.5 Ω · cm, and the bulk resistance value was low enough to enable DC sputtering. From the SEM image of the structure, the average aspect ratio of the compound phase composed of rectangular Sn, Ga, and O (a composite oxide phase mainly composed of Ga ₄ SnO ₈ ) was 13. Further, coarse particles having an average particle diameter of more than 10 [mu] m _Ga 2 _{O 3} were not present.

Next, as a result of performing DC sputtering on the said conditions (paragraph [0051]), the number of nodules was 71, and was about 1/4 compared with the comparative example mentioned later. The number of arcing during sputtering was 251 times, which was less than the comparative example described later. The above results are similarly shown in Table 2.

(Example 5)
In Example 5, a powder having an average particle size of 2.60 μm and a specific surface area of 11.60 m ² / g was used as the Ga ₂ O ₃ raw material, and an average particle size of 1.25 μm and a specific surface area of 5.5 were used as the SnO ₂ raw material. A powder of 46 m ² / g was used. The raw materials were prepared so that these powders had a molar ratio of Ga ₂ O ₃ : SnO ₂ = 5: 95. Next, these powders were mixed and pulverized. The average particle size after pulverization was 0.77 μm and the specific surface area was 7.25 m ² / g.

In addition, powder mixing, pulverization, sintering, and target production were carried out under the conditions shown in the above paragraphs [0047] and [0048]. Here, the main conditions are described. Various measurements and evaluations were performed by the methods described in the above paragraphs [0049] and [0050]. The chlorine (Cl) content was less than 1 wtppm, and the zirconium (Zr) content was 1220 wtppm, both of which were not problematic levels.

Sintering was performed at 1500 ° C. As a result, the relative density was as high as 98.3%, the bulk resistance value was 20.3 Ω · cm, and it had a low bulk resistance value capable of DC sputtering. From the SEM image of the structure, the average aspect ratio of the compound phase composed of rectangular Sn, Ga, and O (a composite oxide phase mainly composed of Ga ₄ SnO ₈ ) was 5. Further, coarse particles having an average particle diameter of more than 10 [mu] m _Ga 2 _{O 3} were not present.

Next, as a result of performing DC sputtering on the said conditions (paragraph [0051]), the number of nodules was 51 and was 1/4 or less compared with the comparative example mentioned later. The number of arcing during sputtering was 209, which was less than the comparative example described later. The above results are similarly shown in Table 2.

(Example 6)
In Example 6, a powder having an average particle size of 2.60 μm and a specific surface area of 11.60 m ² / g was used as the Ga ₂ O ₃ raw material, and an average particle size of 1.25 μm and a specific surface area of 5.5 were used as the SnO ₂ raw material. A powder of 46 m ² / g was used. The raw materials were prepared so that these powders had a molar ratio of Ga ₂ O ₃ : SnO ₂ = 20: 80. Next, these powders were mixed and pulverized. The average particle size after pulverization was 0.92 μm and the specific surface area was 7.95 m ² / g.

In addition, powder mixing, pulverization, sintering, and target production were carried out under the conditions shown in the above paragraphs [0047] and [0048]. Here, the main conditions are described. Various measurements and evaluations were performed by the methods described in the above paragraphs [0049] and [0050]. The chlorine (Cl) content was less than 1 wtppm, and the zirconium (Zr) content was 530 wtppm, both of which were not problematic levels.

Sintering was performed at 1500 ° C. As a result, the relative density was as high as 97.8%, the bulk resistance value was 940 Ω · cm, and it had a low bulk resistance value capable of DC sputtering. The average aspect ratio of the compound phase (composite oxide phase mainly composed of Ga ₄ SnO ₈ ) composed of rectangular Sn, Ga, and O from the SEM image of the structure was 10. Further, coarse particles having an average particle diameter of more than 10 [mu] m _Ga 2 _{O 3} were not present.

Next, as a result of performing DC sputtering on the said conditions (paragraph [0051]), the number of nodules was 86 pieces, and was about 1/3 compared with the comparative example mentioned later. The number of arcing during sputtering was 274, which was less than the comparative example described later. The above results are similarly shown in Table 2.

(Comparative Example 1)
In Comparative Example 1, powder having an average particle size of 2.60 μm and a specific surface area of 11.60 m ² / g was used as the Ga ₂ O ₃ raw material, and an average particle size of 1.25 μm and a specific surface area of 5.5 were used as the SnO ₂ raw material. A powder of 46 m ² / g was used. The raw materials were prepared so that these powders had a molar ratio of Ga ₂ O ₃ : SnO ₂ = 10: 90. Next, these powders were mixed and pulverized. The average particle size after pulverization was 0.84 μm, and the specific surface area was 7.55 m ² / g.

In addition, powder mixing, pulverization, sintering, and target production were carried out under the conditions shown in the above paragraphs [0047] and [0048]. Here, the main conditions are described. Various measurements and evaluations were performed by the methods described in the above paragraphs [0049] and [0050]. The chlorine (Cl) content was less than 1 wtppm, and the zirconium (Zr) content was 680 wtppm, both of which were not problematic levels.

Sintering was performed at 1400 ° C. As a result, the relative density decreased to 96.5%, and the bulk resistance value could not be measured. DC sputtering was also impossible. The average aspect ratio of the compound phase (composite oxide phase mainly composed of Ga ₄ SnO ₈ ) composed of rectangular Sn, Ga, and O from the SEM image of the structure was 2. In addition, a large number of pores and coarse particles of Ga ₂ O _{3 having} an average particle diameter of 10 μm or more were found in the sintered body. Sputtering is not performed.

These bad results of the GTO sintered body are thought to be due to the low sintering temperature, which caused unreacted Ga ₂ O ₃ coarse particles with an average particle size of 10 μm or more, resulting in a decrease in density. It is done. The above results are similarly shown in Table 2.

(Comparative Example 2)
In Comparative Example 2, a powder having an average particle size of 2.60 μm and a specific surface area of 11.60 m ² / g is used as the Ga ₂ O ₃ raw material, and an average particle size of 2.64 μm and a specific surface area of 3.60 μm are used as the SnO ₂ raw material. A powder of 67 m ² / g was used. The raw materials were prepared so that these powders had a molar ratio of Ga ₂ O ₃ : SnO ₂ = 10: 90. Next, these powders were mixed and pulverized. The average particle size after pulverization was 1.32 μm, and the specific surface area was 5.57 m ² / g.

In addition, powder mixing, pulverization, sintering, and target production were carried out under the conditions shown in the above paragraphs [0047] and [0048]. Here, the main conditions are described. Various measurements and evaluations were performed by the methods described in the above paragraphs [0049] and [0050]. The chlorine (Cl) content was less than 1 wtppm, and the zirconium (Zr) content was 1510 wtppm, both of which were not problematic levels.

Sintering was performed at 1500 ° C. As a result, the relative density was reduced to 95.4%, and the bulk resistance value was 53.8 Ω · cm. DC sputtering was possible. From the SEM image of the structure, the average aspect ratio of the compound phase composed of rectangular Sn, Ga, and O (a composite oxide phase mainly composed of Ga ₄ SnO ₈ ) was 9. Moreover, since the average particle diameter of SnO ₂ was large in the sintered body, the reactivity of SnO ₂ and Ga ₂ O ₃ was poor, and coarse particles of Ga ₂ O ₃ with an average particle diameter of 10 μm or more were scattered.

Next, as a result of performing DC sputtering under the above conditions (paragraph [0051]), the number of nodules was 244, which was significantly increased compared to the example. The number of arcing during sputtering was 689 times, which was also greatly increased compared to the example. These bad results of the GTO sintered body are considered to be caused by the SnO ₂ raw material powder having a large average particle size of 2.64 μm and a specific surface area of 3.67 m ² / g of the same powder. The above results are similarly shown in Table 2.

(Comparative Example 3)
In Comparative Example 3, a powder having an average particle size of 3.50 μm and a specific surface area of 7.43 m ² / g was used as the Ga ₂ O ₃ raw material, and an average particle size of 1.25 μm and a specific surface area of 5.3 were used as the SnO ₂ raw material. A powder of 46 m ² / g was used. The raw materials were prepared so that these powders had a molar ratio of Ga ₂ O ₃ : SnO ₂ = 10: 90. Next, these powders were mixed and pulverized. The average particle size after pulverization was 1.08 μm, and the specific surface area was 7.12 m ² / g.

In addition, powder mixing, pulverization, sintering, and target production were carried out under the conditions shown in the above paragraphs [0047] and [0048]. Here, the main conditions are described. Various measurements and evaluations were performed by the methods described in the above paragraphs [0049] and [0050]. The chlorine (Cl) content was less than 1 wtppm, and the zirconium (Zr) content was 860 wtppm, both of which were not problematic levels.

Sintering was performed at 1500 ° C. As a result, the relative density was reduced to 94.3%, and the bulk resistance value was 70.7 Ω · cm. DC sputtering was possible. From the SEM image of the structure, the average aspect ratio of the compound phase composed of rectangular Sn, Ga, and O (a composite oxide phase mainly composed of Ga ₄ SnO ₈ ) was 8. Further, many coarse particles of Ga ₂ O ₃ having an average particle diameter of 10 μm or more were observed in the sintered body.

Next, as a result of performing DC sputtering under the above conditions (paragraph [0051]), the number of nodules was significantly increased to 390 compared to the example. The number of arcing during sputtering was 871, which was also greatly increased compared to the example. These bad results of the GTO sintered body are as follows: the average particle size of Ga ₂ O ₃ raw powder is as large as 3.50 μm, the specific surface area of the same powder is as small as 7.43 m ² / g, and as shown in FIG. The cause is considered to be the presence of coarse particles of Ga ₂ O _{3 having} an average particle size of 10 μm or more. The above results are similarly shown in Table 2.

(Comparative Example 4)
In this comparative example 4, a powder having an average particle diameter of 2.60 μm and a specific surface area of 11.60 m ² / g is used as the Ga ₂ O ₃ raw material, and an average particle diameter of 1.25 μm and a specific surface area of 5.5 are used as the SnO ₂ raw material. A powder of 46 m ² / g was used. The raw materials were prepared so that these powders had a molar ratio of Ga ₂ O ₃ : SnO ₂ = 30: 70. Next, these powders were mixed and pulverized. The average particle size after pulverization was 1.11 μm, and the specific surface area was 8.31 m ² / g.

In addition, powder mixing, pulverization, sintering, and target production were performed under the conditions shown in paragraphs [0047] and [0048] above. Here, the main conditions are described. Various measurements and evaluations were performed by the methods described in the above paragraphs [0049] and [0050]. The chlorine (Cl) content was less than 1 wtppm, and the zirconium (Zr) content was 420 wtppm, both of which were not problematic levels.

Sintering was performed at 1500 ° C. As a result, the relative density was reduced to 93.0%, and the bulk resistance value was not measurable. DC sputtering was not possible. The average aspect ratio of the compound phase (composite oxide phase mainly composed of Ga ₄ SnO ₈ ) composed of rectangular Sn, Ga, and O from the SEM image of the structure was 10. Further, many coarse particles of Ga ₂ O ₃ having an average particle diameter of 10 μm or more were observed in the sintered body.

These bad results of the GTO sintered body have a large amount of Ga ₂ O ₃ raw material powder mixed. As a result, there are many coarse particles of Ga ₂ O ₃ having an average particle size of 10 μm or more as shown in FIG. It is thought that it was present. The above results are similarly shown in Table 2.

(Comparative Example 5)
In this comparative example 5, a powder having an average particle diameter of 2.60 μm and a specific surface area of 11.60 m ² / g is used as the Ga ₂ O ₃ raw material, and an average particle diameter of 1.25 μm and a specific surface area of 5.5 are used as the SnO ₂ raw material. A powder of 46 m ² / g was used. The raw materials were prepared so that these powders had a molar ratio of Ga ₂ O ₃ : SnO ₂ = 90: 10. Next, these powders were mixed and pulverized. The average particle size after pulverization was 1.59 μm, and the specific surface area was 12.03 m ² / g.

In addition, powder mixing, pulverization, sintering, and target production were carried out under the conditions shown in the above paragraphs [0047] and [0048]. Here, the main conditions are described. Various measurements and evaluations were performed by the methods described in the above paragraphs [0049] and [0050]. The chlorine (Cl) content was less than 1 wtppm, and the zirconium (Zr) content was 200 wtppm, both of which were not problematic levels.

Sintering was performed at 1500 ° C. As a result, the density decreased to a relative density of 93.5%, and the bulk resistance value could not be measured. DC sputtering was not possible. From the SEM image of the structure, the average aspect ratio of the compound phase composed of rectangular Sn, Ga, and O (a composite oxide phase mainly composed of Ga ₄ SnO ₈ ) was 12. Further, many coarse particles of Ga ₂ O ₃ having an average particle diameter of 10 μm or more were observed in the sintered body.

These bad results of the GTO sintered body are the same as in Example 4 because the amount of the Ga ₂ O ₃ raw material powder is large, and as a result, the Ga ₂ O having an average particle diameter of 10 μm or more as shown in FIG. _This is probably because a large number of coarse particles ₃ were present. The above results are similarly shown in Table 2.

(Comparative Example 6)
In Comparative Example 6, a powder having an average particle size of 2.60 μm and a specific surface area of 11.60 m ² / g was used as the Ga ₂ O ₃ raw material, and an average particle size of 1.25 μm and a specific surface area of 5.5 were used as the SnO ₂ raw material. A powder of 46 m ² / g was used. The raw materials were prepared so that these powders had a molar ratio of Ga ₂ O ₃ : SnO ₂ = 10: 90. Next, these powders were mixed and pulverized. The average particle size after pulverization was 0.84 μm, and the specific surface area was 7.55 m ² / g.

In addition, powder mixing, pulverization, sintering, and target production were carried out under the conditions shown in the above paragraphs [0047] and [0048]. Here, the main conditions are described. Various measurements and evaluations were performed by the methods described in the above paragraphs [0049] and [0050]. The content of chlorine (Cl) was as large as 8 wtppm. On the other hand, the content of zirconium (Zr) was 680 wtppm, which was not a problematic level.

Sintering was performed at 1500 ° C. As a result, the density decreased to a relative density of 94.8%, and the bulk resistance value was not measurable. DC sputtering was not possible. From the SEM image of the structure, the average aspect ratio of the rectangular compound phase composed of Sn, Ga, and O (a composite oxide phase mainly composed of Ga ₄ SnO ₈ ) was 7. In addition, many pores existed in the sintered body.

These bad results of the GTO sintered body are that a large amount of Cl is mixed in the raw material powder as 8 wtppm, and Cl evaporates during the sintering and becomes a pore, resulting in a low density sintered body. Is considered to be the cause. The above results are similarly shown in Table 2.

(Comparative Example 7)
In Comparative Example 7, a powder having an average particle size of 2.60 μm and a specific surface area of 11.60 m ² / g was used as the Ga ₂ O ₃ raw material, and an average particle size of 1.25 μm and a specific surface area of 5.5 were used as the SnO ₂ raw material. A powder of 46 m ² / g was used. The raw materials were prepared so that these powders had a molar ratio of Ga ₂ O ₃ : SnO ₂ = 10: 90. Next, these powders were mixed and pulverized. The average particle size after pulverization was 0.55 μm and the specific surface area was 8.85 m ² / g.

In addition, powder mixing, pulverization, sintering, and target production were carried out under the conditions shown in the above paragraphs [0047] and [0048]. Here, the main conditions are described. Various measurements and evaluations were performed by the methods described in the above paragraphs [0049] and [0050]. The content of chlorine (Cl) was less than 1 wtppm, which was not a particularly problematic level. However, the content of zirconium (Zr) was a large amount of 2500 wtppm.

Sintering was performed at 1500 ° C. As a result, the relative density was 97.5%, the bulk resistance value was 60.8 Ω · cm, and it had a low bulk resistance value enabling DC sputtering. From the SEM image of the structure, the average aspect ratio of the compound phase composed of rectangular Sn, Ga, and O (a composite oxide phase mainly composed of Ga ₄ SnO ₈ ) was 9.

Next, as a result of performing DC sputtering under the above conditions (paragraph [0051]), the number of nodules was 250, which was greatly increased as compared with the example. The number of arcing during sputtering was 759 times, which was also greatly increased compared to the example. These bad results of the GTO sintered body are thought to be due to arcing during sputtering because Zr contamination from ZrO ₂ beads, which are media used in grinding, is as high as 2500 wtppm. The above results are similarly shown in Table 2.

The present invention is a sputtering oxide sintered compact target made of gallium (Ga), tin (Sn), oxygen (O), and inevitable impurities, and improves the structure of the sintered compact target and becomes a nodule generation source. GTO target that minimizes phase formation, lowers bulk resistance, has high density, can suppress abnormal discharge, and is capable of DC sputtering, a manufacturing method thereof, and a thin film forming method using the target, and It has the effect of providing a thin film. Since this Ga-Sn-O-based (GTO) material has good quality, it has high industrial utility value, and as a GTO target, a thin film such as a transparent conductive film used for FPD, a semiconductor layer of a thin film transistor, a semiconductor buffer layer, etc. Since it is useful as a sputtering target for formation and an amorphous oxide is obtained, it can also be used for a field effect transistor.

Claims (12)

It is an oxide sintered compact target for sputtering composed of 1 to 20 mol% of Ga ₂ O ₃ , the remainder SnO ₂ and inevitable impurities, and the relative density of the oxide sintered compact target is 97% or more, and the bulk resistivity is The oxide sintered compact target for sputtering characterized by being 1000 Ωcm or less.   The oxide sintered compact target for sputtering according to claim 1, wherein Zr is contained in an amount of 2000 wtppm or less (excluding 0 wtppm).   The content of Cl as an impurity is 5 wtppm or less, and the oxide sintered compact target for sputtering according to claim 1 or 2. The oxidation for sputtering according to any one of claims 1 to 3, which is a target for forming a transparent conductive film used for FPD, a semiconductor layer of a thin film transistor, and a thin film used for a buffer layer of a semiconductor. Sintered object target. The phase observed in the structure of the oxide sintered compact target has a rectangular compound phase composed of Sn, Ga, and O having an aspect ratio of 3 to 15 in a matrix composed of SnO ₂ phase. The oxide sintered compact target for sputtering as described in any one of Claims 1-3. 6. The oxide sintered compact target for sputtering according to claim 5, wherein the area ratio of the compound phase composed of rectangular Sn, Ga and O to the matrix composed of SnO ₂ phase is 30 to 70%. In the sintered body target, the sputtering oxide sintered compact target according to any one of claims 1 to 6, an average particle diameter is characterized by the absence of coarse particles of 10μm or more Ga ₂ O ₃ . Particle size 1.5μm or less, the tin oxide has a BET specific surface area of 4~7m _² / g (SnO ²⁾ and the particle size of 3.0μm or less, gallium oxide has a BET specific surface area of 10 to 20 m ² / g ( The raw material powder of Ga ₂ O ₃ ) is prepared, these powders are mixed, pulverized, and then sintered in a temperature range of 1450 to 1600 ° C. Manufacturing method.   Sputtering using the oxide sintered compact target of Claims 1-7, and forming a GTO thin film on a board | substrate, The formation method of the thin film characterized by the above-mentioned.   The method of forming a thin film according to claim 9, wherein the substrate temperature is heated to a temperature of room temperature to 200 ° C and sputtering is performed to form an amorphous structure GTO thin film on the substrate. When sputtering using the oxide sintered compact target according to claim 1, sputtering is performed by adjusting the oxygen concentration in the sputtering atmosphere gas to 1 to 6%, and the resistivity of the GTO film and / or the GTO film A method for forming a thin film, wherein the transmittance or refractive index is controlled.   A thin film obtained by the method for forming a thin film according to claim 11.