CN117280428A - Laminate having function as transparent conductive film, method for producing same, and oxide sputtering target for producing same - Google Patents
Laminate having function as transparent conductive film, method for producing same, and oxide sputtering target for producing same Download PDFInfo
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- CN117280428A CN117280428A CN202280031068.9A CN202280031068A CN117280428A CN 117280428 A CN117280428 A CN 117280428A CN 202280031068 A CN202280031068 A CN 202280031068A CN 117280428 A CN117280428 A CN 117280428A
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- 238000005477 sputtering target Methods 0.000 title claims description 44
- 238000004519 manufacturing process Methods 0.000 title claims description 9
- 238000000137 annealing Methods 0.000 claims abstract description 68
- 238000002834 transmittance Methods 0.000 claims abstract description 56
- 238000010030 laminating Methods 0.000 claims abstract description 13
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 10
- 238000005245 sintering Methods 0.000 claims description 10
- 229910005191 Ga 2 O 3 Inorganic materials 0.000 claims description 8
- 229910052725 zinc Inorganic materials 0.000 claims description 5
- 229910015902 Bi 2 O 3 Inorganic materials 0.000 claims description 2
- 229910052733 gallium Inorganic materials 0.000 claims description 2
- 238000004544 sputter deposition Methods 0.000 description 26
- 239000000203 mixture Substances 0.000 description 22
- 238000000034 method Methods 0.000 description 16
- 239000012298 atmosphere Substances 0.000 description 14
- 239000002356 single layer Substances 0.000 description 13
- 230000000052 comparative effect Effects 0.000 description 11
- 230000000694 effects Effects 0.000 description 10
- 239000000758 substrate Substances 0.000 description 9
- 230000015572 biosynthetic process Effects 0.000 description 8
- 230000007423 decrease Effects 0.000 description 8
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Inorganic materials [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 4
- 229910052718 tin Inorganic materials 0.000 description 4
- 238000002425 crystallisation Methods 0.000 description 3
- 230000008025 crystallization Effects 0.000 description 3
- 229910052738 indium Inorganic materials 0.000 description 3
- 239000000523 sample Substances 0.000 description 3
- 230000003746 surface roughness Effects 0.000 description 3
- 229910018557 Si O Inorganic materials 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 238000005459 micromachining Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910006404 SnO 2 Inorganic materials 0.000 description 1
- 230000005260 alpha ray Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 125000001475 halogen functional group Chemical group 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 1
- AMGQUBHHOARCQH-UHFFFAOYSA-N indium;oxotin Chemical compound [In].[Sn]=O AMGQUBHHOARCQH-UHFFFAOYSA-N 0.000 description 1
- 238000009766 low-temperature sintering Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 238000005240 physical vapour deposition Methods 0.000 description 1
- 238000001028 reflection method Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
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Abstract
The present invention addresses the problem of providing a laminate having a lower resistivity (higher conductivity) and a higher transmittance than conventional ITO films. A laminate obtained by laminating an ITO film and an oxide film, wherein the laminate has a surface resistance of 40 Ω/sq or less, and the laminate has an average visible light transmittance of 90% or more, and the ratio of the film thickness of the ITO film to the film thickness of the oxide film (film thickness of the ITO film/film thickness of the oxide film) is less than 15. A laminate obtained by laminating an ITO film and an oxide film, wherein R2/R1 is 1.0 or less when R1 is the surface resistance of the laminate when atmospheric annealing is performed at 220 ℃ and R2 is the surface resistance of the laminate when atmospheric annealing is performed at 550 ℃.
Description
Technical Field
The present invention relates to a laminate having a function as a transparent conductive film, a method for producing the laminate, and an oxide sputtering target for producing the laminate.
Background
ITO (indium tin oxide) films have characteristics such as low resistivity, high transmittance, and easiness in micromachining, and are excellent in comparison with other transparent conductive films, and therefore are used in a wide range of fields including display electrodes for flat panel displays. Currently, an industrially practical ITO film is often produced by a so-called sputtering film formation method in which a film is formed using an ITO sintered body as a sputtering target, and this is because the film has excellent uniformity over a large area and can be produced with good productivity.
Since the ITO film is crystallized to form a low-resistance transparent film, annealing is performed at about 220 ℃ to about 250 ℃ after the film formation. On the other hand, films of lower resistivity and higher transmittance are desired, and annealing at a temperature of 300 ℃ or higher is also attempted. However, when annealing is performed, the transmittance increases, and on the other hand, the resistivity increases, so that a film having both lower resistivity and higher transmittance cannot be obtained. The applicant has previously proposed a technique capable of forming an ITO film having a low resistance at a low temperature (for example, patent document 1).
Prior art literature
Patent literature
Patent document 1: japanese patent laid-open No. 2020-164930
Disclosure of Invention
Problems to be solved by the invention
The present invention addresses the problem of providing a laminate having a lower resistivity (surface resistance) and a higher transmittance than an ITO film.
Means for solving the problems
As a result of intensive studies to solve the above-described problems, the present inventors have found that, by forming a laminate in which a specific oxide film is laminated on an ITO film, an increase in resistivity (surface resistance) due to annealing can be prevented and high transmittance can be maintained. In view of such insight, the present disclosure provides the following manner.
One embodiment of the present invention is a laminate obtained by laminating an oxide film on an ITO film, wherein the laminate has a surface resistance of 40 Ω/sq or less, an average visible light transmittance of 90% or more, a film thickness of the oxide film is less than 90nm, and a ratio of the film thickness of the ITO film to the film thickness of the oxide film (film thickness of the ITO film/film thickness of the oxide film) is less than 15.
Another aspect of the present invention is a laminate obtained by laminating an ITO film and an oxide film, wherein when R1 is the surface resistance of the laminate when atmospheric annealing is performed at 220 ℃ and R2 is the surface resistance of the laminate when atmospheric annealing is performed at 550 ℃, R2/R1 is 1.0 or less.
In addition, another aspect of the present invention is a laminate obtained by laminating an ITO film and an oxide film, wherein the oxide film contains 0 mol% or more and 69 mol% or less of Zn in terms of ZnO, and contains Ga in terms of Ga 2 O 3 Ga is contained in an amount of 9 to 100 mol% in terms of SiO 2 The oxide film has a thickness of less than 90nm and a ratio of the film thickness of the ITO film to the film thickness of the oxide film (film thickness of the ITO film/film thickness of the oxide film) of less than 15 in terms of Si of 0 mol% or more and less than 60 mol%.
In another aspect of the present invention, there is provided an oxide sputtering target comprising more than 10 mol% and less than 60 mol% of Zn in terms of ZnO, and comprising Ga in terms of Ga 2 O 3 Ga is contained in an amount of 10 to 60 mol% in terms of SiO 2 And 25 mol% or more and less than 50 mol% of Si in terms of Si.
Effects of the invention
The laminate of the present invention has excellent characteristics of low resistivity (surface resistance) and high transmittance compared with an ITO film. Further, by stacking a specific oxide film over an ITO film, a transparent conductive film (stacked body) having good characteristics can be provided easily.
Drawings
Fig. 1 is a composition diagram showing a relationship between the composition of an oxide film (zn—ga-si—o) and the effect of the invention in the laminate according to the present embodiment.
Detailed Description
An ITO film containing indium (In), tin (Sn), and oxygen (O) as main components has characteristics such as low resistivity, high transmittance, and easiness In micromachining, and is therefore excellent In comparison with other transparent conductive films, and is therefore used In a wide range of applications such as flat panel displays. On the other hand, there is a demand for an ITO film having a lower resistivity and a higher transmittance, and attempts have been made to improve characteristics by adding other elements.
Since the ITO film is crystallized to be a low-resistance transparent film, an operation of annealing the film in the atmosphere at about 220 ℃ to about 250 ℃ to crystallize the film is performed. At this time, by annealing at a higher temperature (300 ℃ or higher), the transmittance can be improved, but the resistivity is increased. This is thought to be due to a decrease in carrier concentration of the ITO film at the time of high temperature annealing. Therefore, it is considered that the increase in resistivity can be prevented by laminating an oxide film on the ITO film to suppress the decrease in carrier concentration caused by high-temperature annealing.
As a result of intensive studies, the present inventors have found that, by forming a specific oxide film on an ITO film, a decrease in carrier concentration due to annealing can be suppressed, thereby preventing an increase in resistivity, while maintaining high transmittance. Hereinafter, embodiments of the present invention will be described in detail.
In the present specification, the ITO film contains an oxide containing In and Sn, and the composition range thereof is not particularly limited, and for example, a film containing tin as SnO can be used 2 50 wt% or less (about 65 mol%) of Sn In terms of the content of Sn and the balance of In and noITO, an impurity that can be avoided.
The first embodiment is a laminate obtained by laminating an oxide film on an ITO film, which has a surface resistance of 40 Ω/sq. or less and an average visible light transmittance of 90% or more. The laminate of the present embodiment has an excellent effect that low resistivity and high transmittance can be achieved compared to an ITO film (single-layer film). The surface resistance is preferably 30 Ω/sq.or less, more preferably 20 Ω/sq.or less. The average visible light transmittance is preferably 93% or more. Since the surface resistance and the transmittance vary depending on the annealing temperature, the laminate of the present embodiment is included as long as the surface resistance and the transmittance are achieved regardless of the annealing temperature at which the laminate is annealed.
In the first embodiment, the film thickness of the oxide film laminated on the ITO is less than 90nm. The film thickness of the oxide film laminated on the ITO is preferably 70nm or less, more preferably 50nm or less. When the film thickness is too thick, the resistivity of the laminate may increase. On the other hand, if the film thickness is too small, the decrease in carrier concentration of the ITO film may not be sufficiently suppressed, and therefore the film thickness of the oxide film is preferably 10nm or more. Since the effect of suppressing the decrease in carrier concentration and the transmittance are affected by the composition of the oxide film, the film thickness can be adjusted in consideration of the composition of the oxide film.
In the first embodiment, the ratio of the film thickness of ITO to the film thickness of the oxide film laminated on ITO (ITO film thickness/oxide film thickness) is less than 15. The ITO film thickness/oxide film thickness is preferably 10 or less. The surface roughness of the ITO film increases due to crystallization, and the thicker the film thickness is, the greater the surface roughness is. This is because, when the film thickness of the oxide film is too small relative to the surface roughness of the ITO film, the decrease in carrier concentration of the ITO film may not be sufficiently suppressed.
The laminate of the second embodiment is a laminate obtained by laminating an ITO film and an oxide film, wherein R2/R1 is 1.0 or less when R1 is the surface resistance of the laminate when atmospheric annealing is performed at 220 ℃ and R2 is the surface resistance of the laminate when atmospheric annealing is performed at 550 ℃. The laminate of the present embodiment has an excellent effect that low resistivity and high transmittance can be achieved compared to an ITO film (single-layer film). Preferably R2/R1 is less than or equal to 0.5. In the case of an ITO single-layer film (film thickness 100 nm), R2/R1 is about 1.53, and the laminate of the present embodiment has an excellent effect of being able to suppress an increase in resistivity even if the annealing temperature is increased.
The laminate of the present embodiment can be used as a transparent conductive film, and in this case, high transmittance is required. The laminate of the present embodiment preferably has a visible light average transmittance of 85% or more when annealed at 220 ℃ in the atmosphere, and preferably has a visible light average transmittance of 90% or more when annealed at 550 ℃ in the atmosphere.
In the laminate of the present embodiment, when the refractive index of the ITO film is n1 and the refractive index of the oxide film is n2, n1 > n2 is preferably satisfied. By stacking an oxide film having a lower refractive index than the ITO film over the ITO film, the reflectance can be reduced and the transmittance can be improved. This can produce a laminate suitable for use as a transparent conductive film.
In the laminate of the present embodiment, the oxide film to be laminated on the ITO film is not particularly limited as long as it is a film that suppresses a decrease in carrier concentration of the ITO film, and is preferably an oxide film containing one or more of Zn, ga, and Si. The ITO film itself may be referred to as an oxide film, but the oxide film in the present specification does not include an ITO film having the same composition as the substrate.
The laminate of the third embodiment is a laminate obtained by laminating an ITO film and an oxide film, wherein the oxide film contains 0 mol% or more and 69 mol% or less of Zn in terms of ZnO, and contains Ga in terms of Ga 2 O 3 Ga is contained in an amount of 9 to 100 mol% in terms of SiO 2 And 0 mol% or more and less than 60 mol% of Si in terms of Si. The laminate of the present embodiment has an excellent effect that low resistivity and high transmittance can be achieved compared to an ITO film (single-layer film).
The oxide film preferably contains more than 10 mol% and less than 60 mol% Zn in terms of ZnO, and contains Ga 2 O 3 Converted to 10 mol% or moreGa in an amount of 60 mol% or less, and SiO in the amount of 2 And 25 mol% or more and less than 50 mol% of Si in terms of Si.
In the laminate of the present embodiment, the oxide film is preferably amorphous. When the laminate of the present embodiment is annealed, the ITO film is crystallized, but the oxide film to be laminated remains amorphous, and it is considered that the ability to retain the amorphous greatly contributes to suppressing an increase in resistivity.
Hereinafter, a method for manufacturing a laminate according to an embodiment of the present invention will be specifically described. The following is an example, but is not limited to this production method, and other methods can be employed in the production method of the laminate itself. In order to avoid unnecessarily obscuring the disclosed manufacturing method, detailed descriptions of known manufacturing steps and processing operations are omitted.
An ITO sputtering target containing an oxide containing In and Sn, and a Zn-Ga-Si-O sputtering target containing an oxide containing Zn, ga and Si were prepared. First, an ITO sputtering target is mounted in a vacuum chamber of a sputtering apparatus, and film formation is performed on a substrate facing the sputtering target. Then, an oxide film was formed on the ITO film formed on the substrate using a Zn-Ga-Si-O sputtering target. The film thickness of the ITO film and the oxide film can be adjusted by sputtering power and sputtering time.
Since the sputtering method forms a film in vacuum, the metal component constituting the sputtering target does not disappear or other metal components are not mixed in during the film forming process, and the composition of the sputtering target is generally reflected on the composition of the film. In examples and comparative examples described below, the composition of the sputtering target is described for convenience.
The sputtering conditions can be set as follows, for example. The sputtering conditions can be appropriately changed according to the desired film thickness, composition, and the like.
(sputtering conditions)
Sputtering device: C-7500L manufactured by ANELVA Co
Sputtering power: DC 500W-1000W
(for targets that cannot be DC sputtered, the sputtering power is RF500W to 1000W)
Gas pressure: 0.5Pa
Heating a substrate: room temperature
Oxygen concentration: 0%, 1%, 2%
Then, the laminate having the predetermined oxide film formed on the ITO film is taken out from the sputtering apparatus, and then annealed at 200 to 600 ℃ in the atmosphere to crystallize the ITO film. The annealing temperature can be appropriately determined in consideration of desired resistivity, transmittance, heat-resistant temperature of the substrate, and the like. The annealing atmosphere is not limited to the atmosphere, and may be a vacuum or a nitrogen atmosphere. By the above operations, the laminate of the present embodiment can be manufactured.
As a sputtering target for forming the oxide film, a sputtering target having the same composition as that of the oxide film can be used, but film formation by co-sputtering can also be performed using two or more sputtering targets. In the above, a Zn-Ga-Si-O sputtering target is exemplified, zn-Ga-O sputtering target, zn-Si-O sputtering target, ga-Si-O sputtering target, znO sputtering target, ga 2 O 3 Sputtering target, siO 2 Sputtering targets, and the like. Sputtering is a suitable method for forming an oxide film, but other chemical or physical vapor deposition methods may be used.
In addition, the sputtering target for forming an oxide film may contain B 2 O 3 、P 2 O 5 、V 2 O 5 、Sb 2 O 3 、TeO 2 、Tl 2 O 3 、PbO、Bi 2 O 3 、MoO 3 As sintering aid. These sintering aids are low-melting-point oxides, and can produce a dense sintered body (sputtering target) even when the sintering temperature is lowered. The addition amount of the sintering aid is not particularly limited, but is preferably 0.5 wt% or more and 3.0 wt% or less with respect to the basic composition of the oxide film target. This is because, when the addition amount of the sintering aid is less than 0.5 wt%, the effect of adding as the sintering aid is poor, and when the addition amount of the sintering aid is more than 3.0 wt%, there is a possibility that the characteristics of the oxide film are affected. If the addition amount of the sintering aid is 0.5 wt% or more and 3.0 wt% or less, low-temperature sintering can be performed while maintaining good characteristics of the oxide film。
In this specification, the laminate was evaluated for characteristics by the following method.
(surface resistance of film)
For a laminate in which an oxide film is laminated on an ITO film, the surface resistance is measured from the oxide film side.
The mode is as follows: constant current application mode
The device comprises: resistivity measuring instrument sigma-5+ manufactured by NPS company
The method comprises the following steps: direct current four-probe method
In the case of high resistance (above 100kΩ/sq.)
The mode is as follows: constant voltage application mode
The device comprises: hiresta UX, a high resistivity meter manufactured by Mitsubishi chemical analysis technology Co., ltd
The method comprises the following steps: MCC-A method (JIS K6911)
Annular electrode probe: URS
Measurement voltage: 1V to 1000V
(regarding transmittance of film)
For a laminate in which an oxide film is laminated on an ITO film, the transmittance is measured from the oxide film side.
Average transmittance of visible light
The device comprises: spectrophotometer UV-2450, UV-2600 manufactured by SHIMADZU Co
Reference is made to: non-film forming glass substrate (eagleXG)
Measurement wavelength: 380nm to 780nm
Step size: 5nm of
(concerning film thickness)
The device comprises: stylus type film height difference meter Dektak XT manufactured by BRUKER corporation
(refractive index of film)
The device comprises: spectrophotometer UV-2450 manufactured by SHIMADZU Co
The method comprises the following steps: calculated from the transmittance and the front and back reflection rates
(regarding the carrier concentration, carrier mobility of the film)
For a laminate in which an oxide film is laminated on an ITO film, the carrier concentration and carrier mobility are measured from the oxide film side.
Principle of: hall measurement
The device comprises: lake Shore 8400 type
(regarding the crystallinity and amorphism of the film)
In the X-ray diffraction spectrum, when a clear diffraction peak due to the film material is confirmed, the crystalline film is judged, and when no clear diffraction peak is observed and only the halo pattern is observed, the amorphous film is judged.
Principle of: x-ray diffraction method
The device comprises: ultimaIV manufactured by Physics Co., ltd
Vacuum tube: cu-K alpha ray
Tube voltage: 40kV (kilovolt)
Tube current: 30mA
The measuring method comprises the following steps: 2 theta-theta reflection method
Measurement range: 20-90 DEG
Scanning speed: 8 DEG/min
Sampling interval: 0.02 degree
Measuring a sample: the film surface of a single-layer film having a film thickness of 300nm or more was measured.
Examples
Hereinafter, description will be made based on examples and comparative examples. The present embodiment is merely an example, and is not limited to this example. That is, the present invention is limited only by the claims, and various modifications other than the embodiments included in the present invention are included.
(reference example)
Will be composed of In 2 O 3 :90 wt.% (83 mol%) SnO 2 : an ITO sintered body sputtering target consisting of 10 wt% (17 mol%) was mounted in a sputtering apparatus, and sputtering was performed under the above conditions, whereby an ITO film having a film thickness of 100nm was formed on a substrate. Then, annealing was performed in the atmosphere at different temperatures of 220 ℃ and 550 ℃ for 30 minutes. For the ITO film obtained in the above manner, the surface resistance and the average transmittance of visible light were measured. The results are shown in Table 1. The term "as-depo" in the table means that the film was formedThe annealed film was not subsequently performed.
As is clear from table 1, in the ITO film, crystallization occurred when annealing was performed at 220 ℃, and the surface resistance was rapidly lowered, but when annealing was performed at 550 ℃, the surface resistance was raised. For ITO films, R2/R1 is greater than 1.0, and the surface resistance increases in the case of high temperature annealing (550 ℃) compared to low temperature annealing (220 ℃). On the other hand, when the annealing temperature is set to 550 ℃, the transmittance is increased to 90% or more.
Example 1
A sputtering target comprising a Zn-Ga-Si-O sintered body is mounted in a sputtering apparatus, sputtering is performed under the above-mentioned conditions, an oxide film (Zn-Ga-Si-O) having a film thickness of 20nm was laminated on an ITO film (film thickness of 100 nm) produced under the same conditions as in the reference example. The composition (in terms of oxide) of the sputtering target was ZnO: ga 2 O 3 ：SiO 2 =40: 20:40 (mol%). Then, annealing was performed in the atmosphere at different temperatures of 220 ℃ and 550 ℃ for 30 minutes. For the laminate obtained in the above manner, the surface resistance and the average transmittance of visible light were measured. The results are shown in Table 1.
As shown in table 1, when annealing is performed at 220 ℃ for the laminate, the ITO film is crystallized, and the resistivity is drastically reduced. On the other hand, unlike the ITO film (single-layer film), when annealing is performed at 550 ℃. R2/R1 was significantly lower than 1.0, and it was found that the surface resistance was significantly reduced by high temperature annealing (550 ℃ C.). When the annealing temperature is set to 550 ℃, the transmittance is increased to 90% or more. By forming a laminate in which an ITO film and an oxide film are laminated in this manner, low resistivity and high transmittance which cannot be obtained by the conventional ITO film can be achieved.
Examples 2 to 23
An oxide film (Zn-Ga-Si-O) having a film thickness of 20nm was laminated on the ITO film (film thickness of 100 nm) in the same manner as in example 1. In each example, the composition of the sputtering target (in terms of oxide) and the oxygen concentration at the time of film formation were adjusted as shown in table 1. In examples 22 and 23, 1.0 wt% of B was added to the sputtering target 2 O 3 As sintering aid. However, the method is thatThereafter, annealing was performed in the atmosphere at different temperatures of 220 ℃ and 550 ℃ for 30 minutes. For the laminate obtained in the above manner, the surface resistance and the average transmittance of visible light were measured. The results are shown in Table 1.
As shown in table 1, when annealing is performed at a certain temperature or higher, the ITO film is crystallized, and the surface resistance is drastically reduced. On the other hand, unlike the ITO film (single-layer film), when annealing is performed at 550 ℃, the surface resistance decreases. R2/R1 was significantly lower than 1.0, and it was found that the surface resistance was significantly reduced by high temperature annealing (550 ℃ C.). When the annealing temperature is set to 550 ℃, the transmittance is increased to 90% or more. In addition, in all the laminated bodies, the oxide film remains amorphous. By forming a laminate in which an ITO film and an oxide film are laminated in this manner, low resistivity and high transmittance which cannot be obtained by an ITO film (single-layer film) can be achieved.
Comparative examples 1 to 4
An oxide film (Zn-Ga-Si-O) having a film thickness of 20nm was laminated on the ITO film (film thickness of 100 nm) in the same manner as in example 1. In each comparative example, the composition of the sputtering target (in terms of oxide) and the oxygen concentration at the time of film formation were adjusted as shown in table 1. Then, annealing was performed in the atmosphere at different temperatures of 220 ℃ and 550 ℃ for 30 minutes. The surface resistance and the average transmittance of visible light were measured for the laminate obtained in the above manner. The results are shown in Table 1.
As shown in table 1, when annealing is performed at 220 ℃ on the laminate, the ITO film is crystallized, and the surface resistance is drastically reduced. On the other hand, when annealing is performed at 550 ℃, the surface resistance increases. In the comparative examples, R2/R1 was larger than 1.0, and it was found that the surface resistance was increased in the case of high-temperature annealing (550 ℃) compared with low-temperature annealing (220 ℃). On the other hand, when annealing is performed at 550 ℃, the transmittance is increased to 90% or more.
Fig. 1 shows a composition diagram showing the relationship between the composition of the sputtering targets (corresponding to the composition of the oxide film) and the effect of the present invention (low resistance and high transmittance) in examples 1 to 21 and comparative examples 1 to 4.
Examples 24 to 25
The sputtering targets containing the oxide sintered bodies of table 2 were mounted in a sputtering apparatus, sputtering was performed under the above conditions, and an oxide film having a film thickness of 20nm was laminated on an ITO film (film thickness of 100 nm) produced under the same conditions as in the reference example. At this time, the composition of the sputtering target (in terms of oxide) was changed as shown in table 2. Then, the temperature was changed and annealing was performed in the atmosphere for 30 minutes. The surface resistance and the average transmittance of visible light were measured for the laminate obtained in the above manner. The results are shown in Table 2. The term "as-depo" in the table means a film that was not annealed after film formation.
As shown in table 2, when annealing is performed at 220 ℃ for the laminate, crystallization of the ITO film occurs, and the resistivity is drastically reduced. On the other hand, unlike the ITO film (single-layer film), when annealing is performed at 550 ℃. R2/R1 was significantly lower than 1.0, and it was found that the surface resistance was significantly reduced by high temperature annealing (550 ℃ C.). When the annealing temperature is set to 550 ℃, the transmittance is increased to 90% or more. In addition, in all the laminated bodies, the oxide film remains amorphous. By thus forming a laminate in which an ITO film and an oxide film are laminated, low resistance and high transmittance which cannot be obtained by an ITO film (single-layer film) can be achieved.
Comparative examples 5 to 10
Various sputtering targets including oxide sintered bodies were mounted in a sputtering apparatus, sputtering was performed under the above conditions, and an oxide film having a film thickness of 20nm was laminated on an ITO film (film thickness of 100 nm) produced under the same conditions as in the reference example. At this time, the composition of the sputtering target (in terms of oxide) was changed as shown in table 2. Then, the temperature was changed and annealing was performed in the atmosphere for 30 minutes. The surface resistance and the average transmittance of visible light were measured for the laminate obtained in the above manner. The results are shown in Table 2.
As shown in table 2, when annealing was performed at 220 ℃ for the laminate, the ITO film crystallized, and the surface resistance was drastically reduced. On the other hand, when annealing is performed at 550 ℃, the surface resistance increases. In the comparative examples, R2/R1 was larger than 1.0, and it was found that the surface resistance was increased in the case of high-temperature annealing (550 ℃) compared with low-temperature annealing (220 ℃). On the other hand, when the annealing temperature is set to 550 ℃, the transmittance is increased to 90% or more.
Examples 26 to 34
A sputtering target containing a Zn-Ga-Si sintered body was mounted in a sputtering apparatus, sputtering was performed under the above conditions, and an oxide film was laminated on an ITO film produced under the same conditions as in the reference example. At this time, in each embodiment, the film thickness of the ITO film and the film thickness of the oxide film are changed. The composition (in terms of oxide) of the sputtering target was ZnO: ga 2 O 3 ：SiO 2 =40: 20:40 (mol%).
Then, the temperature was changed and annealing was performed in the atmosphere for 30 minutes. The surface resistance and the average transmittance of visible light were measured for the laminate obtained in the above manner. The results are shown in Table 3. The term "as-depo" in the table means a film that was not annealed after film formation.
As shown in table 3, when annealing was performed at 220 ℃ for the laminate, the ITO film crystallized, and the surface resistance was drastically reduced. On the other hand, unlike the ITO film (single-layer film), when annealing is performed at 550 ℃. R2/R1 was significantly lower than 1.0, and it was found that the resistivity was significantly lowered by high temperature annealing (550 ℃ C.). When the annealing temperature is set to 550 ℃, the transmittance is increased to 90% or more. In addition, in all the laminated bodies, the oxide film remains amorphous. By thus forming a laminate in which an ITO film and an oxide film are laminated, low resistance and high transmittance which cannot be obtained by an ITO film (single-layer film) can be achieved.
Comparative examples 11 to 12
Mounting a sputtering target comprising a Zn-Ga-Si sintered bodyIn the sputtering apparatus, sputtering was performed under the above conditions, and an oxide film was laminated on the ITO film produced under the same conditions as in the reference example. At this time, in each comparative example, the film thickness of the ITO film and the film thickness of the oxide film were changed. The composition (in terms of oxide) of the sputtering target was ZnO: ga 2 O 3 ：SiO 2 =40: 20:40 (mol%).
Then, the temperature was changed and annealing was performed in the atmosphere for 30 minutes. The surface resistance and the average transmittance of visible light were measured for the laminate obtained in the above manner. The results are shown in Table 3.
As shown in table 3, when annealing was performed at 220 ℃ for the laminate, the ITO film crystallized, and the surface resistance was drastically reduced. On the other hand, when annealing is performed at 550 ℃, the surface resistance increases. In the comparative examples, R2/R1 was larger than 1.0, and it was found that the surface resistance was increased in the case of high-temperature annealing (550 ℃) compared with low-temperature annealing (220 ℃). On the other hand, when the annealing temperature is set to 550 ℃, the transmittance is increased to 90% or more.
Industrial applicability
The laminate of the present invention can obtain excellent characteristics of low resistance and high transmittance compared with an ITO film (single-layer film). In addition, the present invention has the following excellent effects: by laminating the transparent conductive film on the ITO film, a transparent conductive film (laminate) having good characteristics can be easily provided. The laminate of the present invention is useful as a transparent conductive film in devices (flat panel displays, micro LEDs, etc.) using a glass substrate or a Si substrate that can be annealed at high temperatures.
Claims (14)
1. A laminate obtained by laminating an ITO film and an oxide film, characterized in that,
the surface resistance of the laminate is 40 Ω/sq or less, the visible light average transmittance of the laminate is 90% or more, the film thickness of the oxide film is less than 90nm, and the ratio of the film thickness of the ITO film to the film thickness of the oxide film (film thickness of the ITO film/film thickness of the oxide film) is less than 15.
2. A laminate obtained by laminating an ITO film and an oxide film, characterized in that,
when the surface resistance of the laminate obtained by subjecting the laminate to atmospheric annealing at 220 ℃ is R1 and the surface resistance of the laminate obtained by subjecting the laminate to atmospheric annealing at 550 ℃ is R2, R2/R1 is not more than 1.0.
3. The laminate of claim 2, wherein the ratio R2/R1 of the surface resistance R2 to the surface resistance R1 is 0.5 or less.
4. The laminate according to any one of claims 1 to 3, wherein the laminate has a visible light average transmittance of 85% or more when subjected to atmospheric annealing at 220 ℃.
5. The laminate according to any one of claims 1 to 3, wherein the laminate has a visible light average transmittance of 90% or more when subjected to atmospheric annealing at 550 ℃.
6. The laminate according to any one of claims 1 to 5, wherein n1 > n2 when the refractive index of the ITO film is n1 and the refractive index of the oxide film is n2.
7. The laminate according to any one of claims 1 to 6, wherein the oxide film contains one or more of Zn, ga, and Si.
8. A laminate obtained by laminating an ITO film and an oxide film, characterized in that,
the oxide film contains ZnO or more0 mol% to less than 69 mol% Zn, and Ga 2 O 3 Ga is contained in an amount of 9 to 100 mol% in terms of SiO 2 The oxide film has a thickness of less than 90nm and a ratio of the film thickness of the ITO film to the film thickness of the oxide film (film thickness of the ITO film/film thickness of the oxide film) of less than 15 in terms of Si of 0 mol% or more and less than 60 mol%.
9. The laminate according to claim 8, wherein the oxide film contains more than 10 mol% and less than 60 mol% of Zn in terms of ZnO, and contains Ga 2 O 3 Ga is contained in an amount of 10 to 60 mol% in terms of SiO 2 And 25 mol% or more and less than 50 mol% of Si in terms of Si.
10. The laminate according to any one of claims 1 to 9, wherein the oxide film is an amorphous film.
11. A method for producing a laminate according to any one of claims 1 to 10, wherein an oxide film is laminated on an ITO film, and the obtained laminate is annealed at a temperature of 200 ℃ or higher.
12. An oxide sputtering target for producing the laminate according to any one of claims 1 to 10, wherein the oxide sputtering target contains 0 mol% or more and 69 mol% or less of Zn in terms of ZnO, and contains Ga in terms of Ga 2 O 3 Ga is contained in an amount of 9 to 100 mol% in terms of SiO 2 And 0 mol% or more and less than 60 mol% of Si in terms of Si.
13. The oxide sputtering target according to claim 12, wherein the oxide sputtering target contains more than 10 mol% and less than 60 mol% of Zn in terms of ZnO, and contains Ga 2 O 3 Converted to 10 mol%Ga in an amount of 60 mol% or less based on SiO 2 And 25 mol% or more and less than 50 mol% of Si in terms of Si.
14. The oxide sputter target of claim 12 or 13, further comprising B 2 O 3 、P 2 O 5 、V 2 O 5 、Sb 2 O 3 、TeO 2 、Tl 2 O 3 、PbO、Bi 2 O 3 、MoO 3 Any one or more of these are used as sintering aids.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
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| JP2021-074650 | 2021-04-27 | ||
| JP2022-014394 | 2022-02-01 | ||
| JP2022014394A JP7257562B2 (en) | 2021-04-27 | 2022-02-01 | LAMINATED FUNCTION AS TRANSPARENT CONDUCTIVE FILM, METHOD FOR MANUFACTURING SAME, AND OXIDE SPUTTERING TARGET FOR MANUFACTURING SAME LAMINATED PRODUCT |
| PCT/JP2022/018417 WO2022230754A1 (en) | 2021-04-27 | 2022-04-21 | Layered body having function as transparent electroconductive film and method for producing same, and oxide sputtering target for said layered body production |
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| CN117280428A true CN117280428A (en) | 2023-12-22 |
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