JP4670877B2 - Zinc oxide based transparent conductive film laminate, transparent conductive substrate and device - Google Patents

Description

  The present invention relates to a zinc oxide-based transparent conductive film laminate containing gallium formed on a substrate by sputtering or ion plating, and in particular, has improved conductivity as compared to conventional zinc oxide-based transparent conductive films. The present invention relates to a zinc oxide-based transparent conductive film laminate, a transparent conductive substrate, and a device such as a solar cell.

  The transparent conductive film has high conductivity and high transmittance in the visible light region, and is used for solar cells, liquid crystal display elements, electrodes of other various light receiving elements, etc., and heat ray reflection for automobile windows and buildings. It is also used as a transparent heating element for various types of anti-fogging for films, antistatic films, frozen showcases, etc. Especially, low resistance transparent conductive films are used for solar cells, liquid crystals, organic electroluminescence, inorganic electroluminescence, etc. It is suitably used for display elements and touch panels.

As the transparent conductive film, tin oxide (SnO ₂ ) -based, zinc oxide (ZnO) -based, and indium oxide (In ₂ O ₃ ) -based thin films are known. (ATO) containing fluorine as a dopant (FTO) containing fluorine as a dopant is used, and zinc oxides containing aluminum as a dopant (AZO) and gallium as a dopant (GZO) are used. . The transparent conductive film most industrially used is the above-mentioned indium oxide type. Among them, indium oxide containing tin (tin) as a dopant is called an ITO (Indium-Tin-Oxide) film, and has a particularly low resistance. Since this film can be easily obtained, it has been widely used so far.

  Further, as an industrial production method for these transparent conductive films, a sputtering method or an ion plating method is often used. These sputtering methods and ion plating methods can easily form a large-area low-resistance film, and when depositing a material with low vapor pressure or when precise film thickness control is required. Since it is an effective method and is very easy to operate, it is most widely used industrially.

  The sputtering method is a film forming method using a sputtering target as a thin film raw material, and the sputtering target is a solid containing a metal element constituting the thin film to be formed, such as metal, metal oxide, metal nitride, metal carbide, etc. In some cases, a single crystal is used. In this method, generally, after the vacuum apparatus is once made into a high vacuum, a rare gas such as argon is introduced, and under a gas pressure of about 10 Pa or less, the substrate is used as an anode and the sputtering target is used as a cathode. In the meantime, glow discharge is generated to generate argon plasma, and argon cations in the plasma are collided with the sputtering target of the cathode, thereby repelling target component particles deposited on the substrate to form a film.

  Sputtering methods are classified according to the generation method of argon plasma. Those using high-frequency plasma are called high-frequency sputtering methods, and those using DC plasma are called DC sputtering methods. In general, the direct current sputtering method is widely used industrially because the film forming speed is higher than that of the high frequency sputtering method, the power supply equipment is inexpensive, and the film forming operation is simple. However, in contrast to the high-frequency sputtering method that can form a film even with an insulating target, the direct current sputtering method must use a conductive target.

  In addition, the film formation rate when using the sputtering method is closely related to the chemical bonding of the target material. The sputtering method uses a phenomenon in which argon cations with kinetic energy collide with the target surface, and the material on the target surface receives energy and is ejected, and the target material has weak interion bonds or interatomic bonds. The probability of jumping out by sputtering increases.

  In addition, in the method of forming the transparent conductive film made of an oxide such as ITO by a sputtering method, a mixed gas of argon and oxygen using an alloy target of an element constituting the film (In-Sn alloy in the case of an ITO film). A method of forming an oxide film by a reactive sputtering method in the inside and argon and oxygen using an oxide sintered body target (In-Sn-O sintered body in the case of an ITO film) of an element constituting the film There is a method in which an oxide film is formed by a reactive sputtering method in the mixed gas. Among these, the method using the above alloy target supplies a large amount of oxygen gas during sputtering, but the film formation rate and film characteristics (specific resistance, transmittance) are extremely dependent on the amount of oxygen gas introduced during film formation. It is difficult to produce a transparent conductive film which is large and has a stable and constant film thickness and desired characteristics. On the other hand, in the method using the oxide sintered compact target, a part of oxygen supplied to the film is supplied by sputtering from the target, and the remaining deficient oxygen amount is supplied as oxygen gas. For this reason, the dependency of the film formation speed and film characteristics (specific resistance, transmittance) on the amount of oxygen gas introduced during film formation is smaller than when using an alloy target, and the film thickness and characteristics are more stable and constant. Since a transparent conductive film can be produced, a method using the above oxide target has been adopted industrially.

  On the other hand, the ion plating method is a method in which a surface of a target material to be a film is locally heated by arc discharge to be sublimated, ionized, and attached to a negatively charged workpiece (substrate material) to form a film. is there. Even with this method, a film having good adhesion at a low temperature can be obtained, a very wide variety of substrate properties and film properties can be selected, and an alloy or a compound film can be formed, which is an environmentally friendly process. Even in the ion plating method, a transparent conductive film having a certain film thickness and characteristics can be stably produced by using an oxide tablet as a target material, similarly to the sputtering method.

  By the way, as described above, indium oxide-based materials such as ITO are widely used industrially for the transparent conductive film used for electrodes of solar cells, liquid crystal display elements, various light receiving elements, and the like. In recent years, non-indium transparent conductive film materials have been demanded because of the high price of indium and the inclusion of toxic components such that the indium element adversely affects the environment and the human body. As the non-indium-based materials, zinc oxide-based materials such as GZO and AZO described above and tin oxide-based materials such as FTO and ATO are known. In particular, zinc oxide-based materials such as GZO and AZO are used as resources. It is abundantly buried and attracts attention as a low-cost material or a material that is friendly to the environment and the human body.

  And the following is mentioned as a prior art regarding a zinc oxide type transparent conductive film material.

Regarding AZO containing aluminum as a dopant, a C-axis oriented AZO transparent conductive film is produced by DC magnetron sputtering using a target in which zinc oxide is the main component and aluminum oxide is mixed in Japanese Patent Laid-Open No. 62-1222011. A method is described. JP-A-2-14959 discloses sputtering made of a zinc oxide sintered body containing an element having a positive trivalent or higher valence having a sintered density of 5 g / cm ³ or more and a specific resistance of 1 Ω · cm or less. Targets are introduced, and the AZO target and In-containing ZnO (IZO) target are described therein. Further, regarding GZO containing gallium as a dopant, JP-A-7-138745 introduces a sputtering target composed of a zinc oxide sintered body containing gallium produced by a hot press sintering method.

And among the above-mentioned non-indium materials such as zinc oxide and tin oxide, the zinc oxide (GZO) material containing gallium as a dopant can realize a transparent conductive film having the lowest resistance.
JP-A-62-122011 JP-A-2-14959 JP-A-7-138745

  Although the GZO material containing gallium as a dopant among the non-indium-based materials exhibits the lowest resistance transparent conductive film, it is still inferior in terms of conductivity as compared with the widely used ITO material. In addition, the film thickness dependence of the conductivity in the GZO film is larger than that of the ITO material. When the film thickness is reduced, the conductivity of the GZO film is remarkably deteriorated, and the difference in conductivity with the ITO film becomes more remarkable. For this reason, it was inadequate for the various devices in which the electroconductivity of a transparent electrode is regarded as important, especially a solar cell. From such a technical background, development of a non-indium transparent conductive film having a lower resistance than that of the prior art, in particular, a ZnO transparent conductive film, has been demanded.

  Therefore, as a result of extensive research conducted by the present inventors in order to solve the above problems, the conductivity of the transparent conductive film has been improved by optimizing the film configuration of the zinc oxide-based transparent conductive film containing gallium. The present inventors have found that this can be done and have completed the present invention.

That is, the invention according to claim 1
In a zinc oxide-based transparent conductive film laminate composed of a plurality of zinc oxide-based transparent conductive films having different gallium contents formed on a substrate by a sputtering method or an ion plating method,
The zinc oxide-based transparent conductive film formed on the most substrate side has a gallium content of 5.6 to 10.0% and a film thickness of 20 to 40 nm at an atomic ratio of Ga / (Zn + Ga). The zinc oxide-based thin film layer (1), and the zinc oxide-based thin film layer (1) is formed on the zinc oxide-based thin film layer (1). ) It is characterized by being constituted by a zinc oxide thin film layer (2) having a lower gallium content.

The invention according to claim 2
In the zinc oxide based transparent conductive film laminate according to the invention of claim 1,
The gallium content of the zinc oxide thin film layer (2) formed on the zinc oxide thin film layer (1) is 3.5 to 5.5% in terms of the atomic ratio of Ga / (Zn + Ga). Features
The invention according to claim 3
In the zinc oxide-based transparent conductive film laminate according to the invention of claim 2,
The gallium content of the zinc oxide thin film layer (2) formed on the zinc oxide thin film layer (1) is 4.5 to 5.5% in terms of the atomic ratio of Ga / (Zn + Ga). Features
The invention according to claim 4
In the zinc oxide based transparent conductive film laminate according to the invention of claim 3,
The total thickness of the zinc oxide-based thin film layer (1) and the zinc oxide-based thin film layer (2) is 80 nm or more and less than 400 nm, and the specific resistance is 8.0 × 10 ⁻⁴ Ωcm or less. age,
The invention according to claim 5
In the zinc oxide-based transparent conductive film laminate according to the invention of claim 2,
The zinc oxide-based thin film layer (2) formed on the zinc oxide-based thin film layer (1) has a gallium content of 4.5 to 5.5% in terms of the atomic ratio of Ga / (Zn + Ga). The zinc oxide thin film layer (2-1) and the zinc oxide thin film layer (2-1) are formed on the zinc oxide thin film layer (2-1) and have a gallium content of 3.5-4. It is composed of a zinc oxide thin film layer (2-2) set to 4%,
The invention according to claim 6
In the zinc oxide based transparent conductive film laminate according to the invention of claim 5,
The zinc oxide thin film layer (1) and the zinc oxide thin film layer (2-1) in which the gallium content is set to 4.5 to 5.5% by the atomic ratio of Ga / (Zn + Ga); The total film thickness with the zinc oxide thin film layer (2-2) in which the gallium content is set to 3.5 to 4.4% in terms of the atomic ratio of Ga / (Zn + Ga) is 400 nm or more, and The specific resistance is 3.5 × 10 ⁻⁴ Ωcm or less,
The invention according to claim 7 provides:
In the zinc oxide-based transparent conductive film laminate according to any one of claims 1 to 6,
The substrate temperature during film formation is set to 100 to 500 ° C., and the film is formed by sputtering.

Next, the invention according to claim 8 is:
In transparent conductive substrate,
It is composed of a glass substrate or a resin substrate and the zinc oxide-based transparent conductive film laminate according to any one of claims 1 to 7 formed on the substrate,
The invention according to claim 9 is:
In a device selected from a solar cell, a display device or a light emitting device,
The zinc oxide based transparent conductive film laminate according to any one of claims 1 to 7 is incorporated as a transparent electrode.

According to the zinc oxide-based transparent conductive film laminate of the present invention formed of a plurality of zinc oxide-based transparent conductive films having different gallium contents while being formed on a substrate by a sputtering method or an ion plating method,
The zinc oxide-based transparent conductive film formed on the most substrate side has a gallium content of 5.6 to 10.0% and a film thickness of 20 to 40 nm at an atomic ratio of Ga / (Zn + Ga). The zinc oxide-based thin film layer (1), and the zinc oxide-based thin film layer (1) is formed on the zinc oxide-based thin film layer (1). ) Since it is composed of the zinc oxide thin film layer (2) having a smaller gallium content, the conductivity is improved as compared with the conventional zinc oxide transparent conductive film, and the zinc oxide transparent of the present invention is further improved. Since the conductive film laminate is mainly composed of zinc oxide, it is abundantly embedded as a resource, and has an effect that is friendly to the environment and the human body as a low-cost material.

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

1. Zinc oxide-based transparent conductive film laminate Zinc oxide-based transparent film of the present invention, which is formed on a substrate by sputtering or ion plating, and is composed of a plurality of zinc oxide-based transparent conductive films having different gallium contents As shown in FIG. 1, in the conductive film laminate, the zinc oxide-based transparent conductive film formed on the most substrate side has a gallium content of 5.6 to 10.0 at a Ga / (Zn + Ga) atomic ratio. % And a zinc oxide thin film layer (1) having a film thickness of 20 to 40 nm, and a single or plural zinc oxide films formed on the zinc oxide thin film layer (1) The transparent conductive film is characterized by being composed of a zinc oxide-based thin film layer (2) having a smaller gallium content than the zinc oxide-based thin film layer (1).

  The zinc oxide-based transparent conductive film laminate according to the present invention shown in FIG. 1 is a single-layer zinc oxide thin film having the same composition and the same total film thickness as the zinc oxide-based transparent conductive film laminate. The conductivity is improved as compared with the conventional zinc oxide transparent conductive film shown in FIG. 3 in which the layer (2) is formed on the substrate. This improvement effect can be interpreted as follows.

  First, the inventors investigated the dependence of the gallium content on the specific resistance of a zinc oxide-based transparent conductive film containing gallium, and found that there was an optimal gallium content that exhibited low resistance. It turned out that content changes with film thicknesses. The zinc oxide-based transparent conductive film is an n-type semiconductor, and its conductivity depends on the carrier concentration and mobility, and higher conductivity can be obtained with higher carrier concentration and mobility.

  Here, a zinc oxide-based transparent conductive film formed on a glass substrate or a resin substrate by a sputtering method or an ion plating method has a large crystallinity dependency. That is, the film on the substrate side has poor crystallinity, and the crystallinity of the film becomes better as the distance from the substrate increases. Moreover, when the crystallinity of the film is high, the mobility is high because there are few grain boundaries. Since the zinc oxide-based transparent conductive film is an n-type semiconductor, the carrier concentration increases as the amount of gallium dopant increases, but the mobility decreases due to the influence of ionized impurity scattering as the carrier concentration increases.

  And in the case of a zinc oxide thin film having a thin film thickness of 20 to 40 nm on the substrate, it is difficult to form large crystal grains, and the crystallinity is very poor, so the mobility is low. The conductivity of such a low mobility thin film is less dependent on the composition of mobility, and the carrier concentration is more dominant than the mobility, and the carrier concentration is increased by increasing the dopant. Contributes predominantly to conductivity. Therefore, in the case of a zinc oxide thin film having a thin film thickness of 20 to 40 nm formed on the substrate, the gallium content is set to a large value of 5.6 to 10.0% in terms of the atomic ratio of Ga / (Zn + Ga). The made zinc oxide thin film exhibits the highest conductivity.

  On the other hand, as the thickness of the zinc oxide-based thin film formed on the substrate increases, the crystallinity improves, the composition dependence of mobility becomes significant, and the highest conductivity shifts to the lower gallium content side. To do. That is, when the film thickness of the zinc oxide-based thin film exceeds 40 nm and the crystallinity is improved, increasing the amount of dopant and increasing the carrier concentration lowers the mobility due to the influence of the ionized impurity scattering described above. Will worsen. Therefore, if the amount of dopant is large, the conductivity is not high, and there is an optimum amount of dopant that does not have these effects.

  For the reasons described above, the zinc oxide-based transparent conductive film formed on the most substrate side has a gallium content of 5.6 to 10.0% and a film thickness of Ga / (Zn + Ga) atomic ratio. Is made of a zinc oxide thin film layer (1) set to 20 to 40 nm and is formed on the zinc oxide thin film layer (1), the zinc oxide thin film layer ( 1) By comprising the zinc oxide-based thin film layer (2) having a lower gallium content, high conductivity can be exhibited. In this case, the zinc oxide-based thin film layer (2) may be composed of a single layer having a uniform composition or a plurality of layers having different compositions.

Here, the gallium content of the zinc oxide thin film layer (2) according to the present invention is preferably 3.5 to 5.5% in terms of the atomic ratio of Ga / (Zn + Ga), and more preferably Ga / (Zn + Ga). The atomic ratio is 4.5 to 5.5%. In this case, the specific resistance can be 8.0 × 10 ⁻⁴ Ωcm or less under the condition that the total thickness of the zinc oxide-based transparent conductive film laminate is 80 nm or more and less than 400 nm.

When the zinc oxide thin film layer (2) according to the present invention is composed of a plurality of layers having different compositions, the zinc oxide thin film layer (2) formed on the zinc oxide thin film layer (1) 2, the zinc oxide thin film layer (2-1) in which the gallium content is set to 4.5 to 5.5% by the atomic ratio of Ga / (Zn + Ga), and this zinc oxide thin film layer (2-1) and a zinc oxide thin film layer (2-2) in which the gallium content is set to 3.5 to 4.4% by atomic ratio of Ga / (Zn + Ga). It is preferable. In this case, a low resistance film having a specific resistance of 3.5 × 10 ⁻⁴ Ωcm or less can be realized under the condition that the total thickness of the zinc oxide-based transparent conductive film laminate is 400 nm or more.

  Next, the zinc oxide-based transparent conductive film of the present invention is formed by sputtering or ion plating as described above. The sputtering method is used to form a dense thin film with high adhesion to a substrate at high speed and large size. It is industrially advantageous because it can form a film uniformly in area, and the direct current (DC) sputtering method is particularly preferable because the film forming speed is high. In addition, when the substrate temperature during film formation is 100 to 500 ° C., the film thickness dependency of the above-described good conductivity (minimum specific resistance) of the zinc oxide-based thin film becomes significant. When the sputtering film formation is performed at 500 ° C., the effect of the present invention becomes remarkable.

In order to form the zinc oxide-based transparent conductive film according to the present invention by sputtering, it is preferable to use an inert gas such as argon as a sputtering gas and to use direct current (DC) sputtering as described above. Further, the sputtering apparatus can perform sputtering under a pressure condition of 0.1 to 1 Pa, particularly 0.2 to 0.8 Pa, and the target as a raw material for forming the zinc oxide thin film of each layer is the thin film. In order to obtain a highly conductive thin film with good reproducibility, it is effective to use a zinc oxide-based sintered body having substantially the same composition. In the present invention, for example, after evacuating to 5 × 10 ⁻⁵ Pa or less, pure Ar gas is introduced, the gas pressure is set to 0.2 to 0.8 Pa, and 0.55 to 4.7 W / cm ² is charged. Pre-sputtering can be performed by applying DC power density (DC input power / target area) to generate DC plasma. After performing this pre-sputtering for 5 to 30 minutes, it is preferable to perform sputtering after correcting the substrate position if necessary.

Further, the zinc oxide based transparent conductive film according to the present invention can be formed by an ion plating method. The raw material in this case is a sintered body called a tablet (also referred to as a pellet), but is made of a zinc oxide-based oxide sintered body having the same composition as the composition of each layer, as in the case of sputtering. In the ion plating method, when a tablet as an evaporation source is irradiated with heat or the like by an electron beam or arc discharge, the irradiated portion becomes locally high in temperature, and evaporated particles are evaporated and deposited on the substrate. At this time, the evaporated particles are ionized by an electron beam or arc discharge. There are various ionization methods. The high-density plasma-assisted deposition method (HDPE method) using a plasma generator (plasma gun) is suitable for forming a high-quality transparent conductive film. In this method, arc discharge using a plasma gun is used. Arc discharge is maintained between the cathode built in the plasma gun and the crucible (anode) of the evaporation source. Electrons emitted from the cathode are introduced into the crucible by magnetic field deflection, and concentrated and irradiated on the local part of the tablet charged in the crucible. By this electron beam, the evaporated particles are evaporated and deposited on the substrate from the portion where the temperature is locally high. Since the vaporized evaporated particles and the O ₂ gas introduced as a reaction gas are ionized and activated in the plasma, a high-quality thin film having excellent conductivity can be formed.

  Next, the above-mentioned tendency of the zinc oxide-based thin film formed by sputtering or ion plating is not limited to glass substrates and resin substrates, and the same applies to metals, ceramics, and single crystal substrates. Further, the same applies to a substrate on which an amorphous or crystalline oxide thin film or metal thin film other than zinc oxide is formed. If the surface of the substrate on which the zinc oxide-based thin film layer (1) is formed is not covered with a crystalline material having the same crystal structure as that of zinc oxide (wurtzite structure), it can be applied in the same manner and exhibits the above-described effects. .

  The glass substrate includes a quartz substrate, and the resin substrate includes polycarbonate (PC), polyethylene terephthalate (PET), polyethersulfone (PES), polyethylene naphthalate (PEN), polyimide (PI), and the like. However, the substrate is not limited thereto.

2. Transparent conductive substrate The transparent conductive substrate according to the present invention is composed of a glass substrate or a resin substrate and the above-described zinc oxide-based transparent conductive film laminate formed on these substrates and having improved conductivity. . Although the said zinc oxide type transparent conductive film is formed into a film by sputtering method or an ion plating method, it is preferable to form especially at substrate temperatures of 100-500 degreeC by sputtering method. The transparent conductive substrate according to the present invention can be effectively used as a member for solar cells, touch panels, liquid crystal elements, plasma displays, EL elements and the like.

3. Devices such as solar cells A solar cell as a device according to the present invention is a photoelectric conversion element in which the zinc oxide-based transparent conductive film laminate is incorporated as a transparent electrode. The structure of the solar cell element is not particularly limited, and examples thereof include a PN junction type and a PIN junction type.

  As the PN junction type solar cell element, for example, a monocrystalline or polycrystalline silicon substrate having a thickness of about 0.2 to 0.5 mm and a size of about 180 mm square can be used. A PN junction is formed in which the P layer containing a large amount of P-type impurities contacts the N layer containing a large amount of N-type impurities such as phosphorus. A transparent substrate such as a glass plate, a resin plate, or a resin film is also used instead of the silicon substrate. In the present invention, a transparent substrate is preferable. In that case, after forming the zinc oxide based transparent conductive film laminate on the substrate as an electrode, amorphous or polycrystalline silicon is laminated. Amorphous silicon is a PIN junction in which an insulating layer (I layer) is interposed between PN junctions.

  In any type of solar cell element, a bus bar electrode and a finger electrode are formed on the light receiving surface side and the back surface side by a screen printing method using a silver paste, respectively, and these electrode surfaces have protection and connection tabs. In order to facilitate the mounting, the entire surface is solder coated. When the solar cell element is a silicon substrate, a transparent protective material such as a glass plate, a resin plate, or a resin film is provided on the light receiving surface side.

  The thickness of the zinc oxide-based transparent conductive film laminate incorporated in the solar cell is not particularly limited, and is preferably 500 to 1500 nm, particularly preferably 800 to 1300 nm, although it depends on the composition of the material. The zinc oxide-based transparent conductive film laminate according to the present invention has low resistance and high transmittance of sunlight including from 350 nm ultraviolet rays to 2500 nm infrared rays, so that the light energy of sunlight can be converted to electrical energy very effectively. Can be converted.

  The zinc oxide-based transparent conductive film laminate according to the present invention is applied as a transparent electrode of a touch panel, a flat panel display (LCD, PDP, EL, etc.) and a light emitting device (LED, LD, etc.) in addition to a solar battery. Can do.

EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is naturally not limited to the technical content of these Examples.
[Examples 1 to 5]
A zinc oxide-based transparent conductive film laminate having the laminated structure shown in FIG. 1 was produced by the direct current sputtering method according to the following procedures and conditions. The sputtering target, which is a raw material for forming the thin film, has a circular shape with a diameter of 152 mm. The zinc oxide thin film layer (1) and the zinc oxide thin film layer (2) have the same composition [Ga / Each film was individually formed using a gallium-containing zinc oxide-based sintered body target with a (Zn + Ga) atomic ratio] to prepare a zinc oxide-based transparent conductive film multilayer body having a multilayer structure shown in FIG.

  First, a sputtering target having a different composition corresponding to the composition of the zinc oxide-based thin film layer (1) and the zinc oxide-based thin film layer (2) on the cathode for a non-magnetic material target of a DC magnetron sputtering apparatus equipped with a DC power source. Attached. An alkali-free glass substrate (Corning # 7059) was used as the substrate, and the distance between the target and the substrate was fixed to 60 mm.

Then, after evacuating to 5 × 10 ⁻⁵ Pa or less, pure Ar gas was introduced, the gas pressure was set to 0.3 Pa, DC power was applied to generate 200 W, and pre-sputtering was performed. After sufficient pre-sputtering, the substrate was placed stationary immediately above the center (non-erosion part) of the sputtering target, and DC sputtering film formation was performed at a substrate temperature of 200 ° C. Each zinc oxide-based thin film obtained under these conditions was confirmed by quantitative analysis by ICP emission spectrometry of the thin film obtained to be almost the same as the target composition [Ga / (Zn + Ga) atomic ratio]. . The film thickness of each layer is controlled by the film formation time based on the film formation rate measured in advance, and the substrate is sequentially moved immediately above the sputtering target having a different composition, so that the zinc oxide-based thin film layer (1) and the zinc oxide are moved. The system thin film layer (2) was sequentially formed by a predetermined film thickness to obtain a zinc oxide based transparent conductive film laminate according to Examples 1 to 5 having a laminated structure shown in FIG.

  And evaluation of the obtained zinc oxide type transparent conductive film laminated body concerning each Example was implemented as follows.

  First, the total film thickness of the zinc oxide-based transparent conductive film laminate according to each example was measured with a surface roughness meter manufactured by Tencor. The specific resistance of the zinc oxide-based transparent conductive film laminate was calculated from the product of the surface resistance measured by the four probe method and the total film thickness. The optical properties of the zinc oxide-based transparent conductive film laminate were measured with a spectrophotometer made by Hitachi, Ltd., and the generated phase of the zinc oxide-based transparent conductive film laminate was X-ray diffraction measurement made by PANalytical. Identified by instrument.

  As a result of the evaluation, the zinc oxide-based transparent conductive film laminate according to each example has a film thickness of 20 to 40 nm and an atomic ratio of Ga / (Zn + Ga) with a gallium content of 5.6 to 10.0%. A transparent conductive film laminate having a total film thickness of 80 nm in which a certain zinc oxide thin film layer (1) and a zinc oxide thin film layer (2) having a gallium content less than the zinc oxide thin film layer (1) are sequentially formed. It was confirmed to be a body.

  In addition, each gallium content and film thickness of the zinc oxide-based thin film layer (1) and the zinc oxide-based thin film layer (2) of the zinc oxide-based transparent conductive film laminate according to Examples 1 to 5, and each zinc oxide-based film The total film thickness and specific resistance of the transparent conductive film laminate are shown in Table 1 below.

［比較例１〜６］
基板の種類や成膜条件は実施例１〜５と同様にして、図３に示す単層膜構造の比較例１〜４に係る酸化亜鉛系透明導電膜を作製した。

[Comparative Examples 1-6]
The type of substrate and film forming conditions were the same as in Examples 1 to 5, and zinc oxide-based transparent conductive films according to Comparative Examples 1 to 4 having a single-layer film structure shown in FIG.

  That is, the zinc oxide thin film layer (1) in Examples 1 to 5 is not included, the zinc oxide thin film layer having a Ga / (Zn + Ga) atomic ratio of 5.1% and a thickness of 80 nm. A zinc oxide-based transparent conductive film according to Comparative Example 1 having the single-layer film structure shown in FIG. 3 configured in (2) was prepared, and in the same manner as Comparative Example 1, the atomic ratio of Ga / (Zn + Ga) was A zinc oxide-based transparent conductive film according to Comparative Example 2 composed of a zinc oxide-based thin film layer (2) having a gallium content of 5.9% and a film thickness of 80 nm, and gallium in an atomic ratio of Ga / (Zn + Ga) A zinc oxide-based transparent conductive film according to Comparative Example 3 composed of a zinc oxide-based thin film layer (2) having a content of 7.3% and a film thickness of 80 nm, and containing gallium in an atomic ratio of Ga / (Zn + Ga) A zinc oxide thin film layer (2) having an amount of 10.0% and a film thickness of 80 nm. It made a comparative Example 4 zinc oxide transparent conductive film according to a were produced.

  Moreover, it is a zinc oxide type transparent conductive film laminated body of the laminated structure shown in FIG. 1, Comprising: The film thickness conditions of the zinc oxide type thin film layer (1) in Examples 1-5 are set out of the "20-40 nm" range. The zinc oxide-based transparent conductive film laminates according to Comparative Examples 5 to 6 were produced in the same manner as in Examples 1 to 5.

  That is, the zinc oxide-based transparent conductive film laminate according to Comparative Example 5 has a zinc oxide-based thin film layer (1) having a film thickness of 10 nm and a Ga / (Zn + Ga) atomic ratio of gallium content of 7.3%. And a zinc oxide-based thin film layer (2) having a gallium content less than that of the zinc oxide-based thin film layer (1). The transparent transparent conductive film laminate includes a zinc oxide thin film layer (1) having a film thickness of 50 nm and an atomic ratio of Ga / (Zn + Ga) of gallium content of 7.3%, and a gallium content of zinc oxide. A zinc oxide-based thin film layer (2) fewer than the thin film layer (1) is sequentially formed to form a laminate having a total thickness of 80 nm.

  The film configurations and characteristic evaluation results of Comparative Examples 1 to 6 are shown in Table 1 above.

  In addition, about the film thickness of the zinc oxide type transparent conductive film which concerns on Comparative Examples 1-4 and the total film thickness of the zinc oxide type transparent conductive film laminated body which concerns on Comparative Examples 5-6, it controls by the film-forming speed | rate and film-forming time. The total target film thickness of each layer was matched. Moreover, when the production | generation phase of each zinc oxide type transparent conductive film was identified by the X-ray diffraction measurement mentioned above, all were comprised only by the zinc oxide phase which has a hexagonal wurtzite structure. The diffraction peak of the zinc oxide phase having the hexagonal wurtzite structure was only observed due to c-plane (002) reflection, and was a c-axis oriented thin film.

  Moreover, the average transmittance | permeability of the visible region (wavelength 380-780 nm) of the zinc oxide type transparent conductive film concerning Comparative Examples 1-4 and the zinc oxide type transparent conductive film laminated body concerning Examples 1-5 and Comparative Examples 5-6. Was 80% or more including the substrate, and sufficient characteristics were obtained in both visible transparency.

However, paying attention to the specific resistance shown in Table 1, in the zinc oxide-based transparent conductive film laminates according to Examples 1 to 5, although they are 710 μΩcm (Example 1) to 790 μΩcm (Examples 3 and 5), On the other hand, in the zinc oxide-based transparent conductive film according to Comparative Examples 1 to 4 and Comparative Examples 5 to 6 in the zinc oxide-based transparent conductive film laminate, it is 848 μΩcm (Comparative Example 5) to 2532 μΩcm (Comparative Example 4). It is confirmed that the conductivity of the zinc oxide-based transparent conductive film laminate according to each example is improved as compared with the above.
[Example 6, Comparative Examples 7-8]
In the same manner as in Examples 1 to 5, a zinc oxide thin film layer (1) having a film thickness of 30 nm and a Ga / (Zn + Ga) atomic ratio of gallium content of 7.3%, and a film thickness of 170 nm In addition, a zinc oxide-based transparent conductive film according to Example 6 having a total film thickness of 200 nm on which zinc oxide-based thin film layers (2) each having a Ga / (Zn + Ga) atomic ratio and a gallium content of 5.5% were sequentially formed. A film laminate was prepared.

  Moreover, by the method similar to Comparative Examples 1-4, the said zinc oxide type thin film layer (1) in Examples 1-5 is not included, but gallium content is 5.5% by the atomic ratio of Ga / (Zn + Ga). A zinc oxide-based transparent conductive film according to Comparative Example 7 having a single-layer film structure shown in FIG. 3 composed of a zinc oxide-based thin film layer (2) having a film thickness of 200 nm was prepared. The zinc oxide thin film layer (1) does not include the zinc oxide thin film layer (2) having a Ga / (Zn + Ga) atomic ratio of gallium content of 7.3% and a film thickness of 200 nm. A zinc oxide-based transparent conductive film according to Comparative Example 8 having a single-layer film structure shown in FIG. 3 was produced.

  And the film | membrane structure of Example 6 and Comparative Examples 7-8 and the result of characteristic evaluation are shown in the said Table 1, respectively.

  About the film thickness of the zinc oxide type transparent conductive film which concerns on Comparative Examples 7-8, and the total film thickness of the zinc oxide type transparent conductive film laminated body which concerns on Example 6, it controls by the film-forming speed | rate and film-forming time, and the target of each layer The total film thickness was matched. Moreover, when the production | generation phase of each zinc oxide type transparent conductive film was identified by the X-ray diffraction measurement mentioned above, all were comprised only by the zinc oxide phase which has a hexagonal wurtzite structure. The diffraction peak of the zinc oxide phase having the hexagonal wurtzite structure was only observed due to c-plane (002) reflection, and was a c-axis oriented thin film. Moreover, the average transmittance | permeability of visible region (wavelength 380-780 nm) of the zinc oxide type transparent conductive film which concerns on Comparative Examples 7-8 and the zinc oxide type transparent conductive film laminated body which concerns on Example 6 is 80% or more including a board | substrate. Thus, sufficient characteristics were obtained with visible transparency.

However, when focusing on the specific resistance shown in Table 1, in the zinc oxide-based transparent conductive film laminate according to Example 6, it is 575 μΩcm, whereas in the zinc oxide-based transparent conductive film according to Comparative Examples 7-8, Is 650 μΩcm (Comparative Example 7) to 950 μΩcm (Comparative Example 8), and it is confirmed that the conductivity of the zinc oxide-based transparent conductive film laminate according to Example 6 is improved as compared with the comparative example.
[Example 7, Comparative Examples 9 to 10]
In the same manner as in Example 6, a zinc oxide thin film layer (1) having a film thickness of 30 nm and a Ga / (Zn + Ga) atomic ratio of gallium content of 7.3%, a film thickness of 350 nm and Ga Zinc oxide-based transparent conductive film laminate according to Example 7 having a total film thickness of 380 nm, on which the zinc oxide-based thin film layer (2) having a gallium content of 4.5% in the atomic ratio of / (Zn + Ga) was sequentially formed The body was made.

  Further, by the same method as in Comparative Examples 7 to 8, the zinc oxide thin film layer (1) in Example 6 was not included, the gallium content was 4.5% and the film thickness was Ga / (Zn + Ga) atomic ratio. A zinc oxide-based transparent conductive film according to Comparative Example 9 having a single-layer film structure shown in FIG. 3 composed of a zinc oxide-based thin film layer (2) having a thickness of 380 nm is prepared. Similarly, the zinc oxide-based thin film layer ( 1), and a single layer film structure shown in FIG. 3 composed of a zinc oxide thin film layer (2) having a Ga / (Zn + Ga) atomic ratio of gallium content of 7.3% and a film thickness of 380 nm A zinc oxide-based transparent conductive film according to Comparative Example 10 was prepared.

  And the film | membrane structure of Example 7 and Comparative Examples 9-10 and the result of characteristic evaluation are shown in the said Table 1, respectively.

  About the film thickness of the zinc oxide-type transparent conductive film which concerns on Comparative Examples 9-10 and the total film thickness of the zinc oxide-type transparent conductive film laminated body which concerns on Example 7, it controls by the film-forming speed | rate and film-forming time, and the target of each layer The total film thickness was matched. Moreover, when the production | generation phase of each zinc oxide type transparent conductive film was identified by the X-ray diffraction measurement mentioned above, all were comprised only by the zinc oxide phase which has a hexagonal wurtzite structure. The diffraction peak of the zinc oxide phase having the hexagonal wurtzite structure was only observed due to c-plane (002) reflection, and was a c-axis oriented thin film. Moreover, the average transmittance | permeability of visible region (wavelength 380-780 nm) of the zinc oxide type transparent conductive film which concerns on Comparative Examples 9-10 and the zinc oxide type transparent conductive film laminated body which concerns on Example 7 is 80% or more including a board | substrate. Thus, sufficient characteristics were obtained with visible transparency.

However, when focusing on the specific resistance shown in Table 1, in the zinc oxide-based transparent conductive film laminate according to Example 7, it is 310 μΩcm, whereas in the zinc oxide-based transparent conductive film according to Comparative Examples 9-10, Is 410 μΩcm (Comparative Example 9) to 540 μΩcm (Comparative Example 10), and it is confirmed that the conductivity of the zinc oxide-based transparent conductive film laminate according to Example 7 is improved as compared with the comparative example.
[Examples 8 to 11 and Comparative Examples 11 to 14]
In the same manner as in Example 7, a zinc oxide thin film layer (1) having a film thickness of 30 nm and a Ga / (Zn + Ga) atomic ratio of gallium content of 7.3%, a film thickness of 350 nm and Ga Zinc oxide-based transparent conductive film laminate according to Example 8 having a total film thickness of 380 nm, on which a zinc oxide-based thin film layer (2) having a gallium content of 3.5% with an atomic ratio of / (Zn + Ga) was sequentially formed The body was made.

  Similarly, the zinc oxide according to Example 9 which is the same as Example 8 except that the gallium content of the zinc oxide thin film layer (2) is 3.8% in terms of the atomic ratio of Ga / (Zn + Ga). A transparent transparent conductive film laminate was manufactured, and the same operation as in Example 8 except that the gallium content of the zinc oxide thin film layer (2) was 5.1% at an atomic ratio of Ga / (Zn + Ga) A zinc oxide-based transparent conductive film laminate according to Example 10 was prepared, and the gallium content of the zinc oxide-based thin film layer (2) was 5.5% at an atomic ratio of Ga / (Zn + Ga). A zinc oxide-based transparent conductive film laminate according to Example 11 that was the same as Example 8 was prepared.

  Further, by the same method as in Comparative Examples 9 to 10, the zinc oxide thin film layer (1) in Example 8 was not included, and the gallium content was 3.5% in terms of the atomic ratio of Ga / (Zn + Ga). A zinc oxide-based transparent conductive film according to Comparative Example 11 having a single-layer film structure shown in FIG. 3 composed of a zinc oxide-based thin film layer (2) having a film thickness of 380 nm was produced.

  Similarly, the zinc oxide according to the comparative example 12 which is the same as the comparative example 11 except that the gallium content of the zinc oxide thin film layer (2) is 3.8% in the atomic ratio of Ga / (Zn + Ga). Comparative Example 13 which is the same as Comparative Example 11 except that a GaN-based transparent conductive film is prepared and the gallium content of the zinc oxide-based thin film layer (2) is 5.1% in the atomic ratio of Ga / (Zn + Ga). Comparative Example 11 except that the zinc oxide-based transparent conductive film according to the present invention was prepared, and the gallium content of the zinc oxide-based thin film layer (2) was 5.5% in terms of the atomic ratio of Ga / (Zn + Ga). A zinc oxide-based transparent conductive film according to Comparative Example 14 that is identical to the above was prepared.

  And the film | membrane structure of Examples 8-11 and Comparative Examples 11-14 and the result of characteristic evaluation are shown in the said Table 1, respectively.

  Focusing on the specific resistance shown in Table 1 above, Example 8 (510 μΩcm) and Comparative Example 11 in which the gallium content of the zinc oxide thin film layer (2) is the same at the atomic ratio of Ga / (Zn + Ga) By comparing Example 9 (480 μΩcm), Example 9 (480 μΩcm), Comparative Example 12 (550 μΩcm), Example 10 (280 μΩcm), Comparative Example 13 (380 μΩcm), Example 11 (350 μΩcm), and Comparative Example 14 (450 μΩcm) The zinc oxide thin film layer (1) having a thickness of 30 nm between the zinc oxide thin film layer (2) and the substrate and a Ga / (Zn + Ga) atomic ratio of 7.3%. The conductivity of the zinc oxide-based transparent conductive film laminates according to Examples 8 to 11 interposing the zinc oxide-based transparent conductive film according to Comparative Examples 11 to 14 having no zinc oxide-based thin film layer (1). It is confirmed to be good.

Furthermore, Example 7 (4.5%, 310 μΩcm), in which only the gallium content of the zinc oxide thin film layer (2) is different in the atomic ratio of Ga / (Zn + Ga), in the atomic ratio of Ga / (Zn + Ga) Example 8 (3.5%, 510 μΩcm), Example 9 (3.8%, 480 μΩcm), Example 10 (5.1%, 280 μΩcm) differing only in the gallium content of the zinc oxide-based thin film layer (2) ) And Example 11 (5.5%, 350 μΩcm), when the gallium content of the zinc oxide thin film layer (2) is set to “4.5 to 5.5%” (Example 7) Examples 10 and 11) were also confirmed to exhibit particularly high conductivity.
[Examples 12 to 16, Comparative Examples 15 to 18]
The zinc oxide thin film layer (2) formed on the zinc oxide thin film layer (1) under the same conditions and method as in Example 1 has a Ga / (Zn + Ga) atomic ratio and a gallium content of 4 Zinc oxide thin film layer (2-1) set to 0.5 to 5.5%, and an atomic ratio of Ga / (Zn + Ga) formed on the zinc oxide thin film layer (2-1). Zinc oxide based transparent conductors according to Examples 12 to 16 of the laminated structure shown in FIG. 2 composed of the zinc oxide thin film layer (2-2) having a gallium content set to 3.5 to 4.4%. A film laminate was prepared.

  That is, a zinc oxide thin film layer (1) having a film thickness of 30 nm and a Ga / (Zn + Ga) atomic ratio of gallium content of 7.3%, and a film thickness of 150 nm and Ga / (Zn + Ga) atomic number Zinc oxide-based thin film layer (2-1) having a gallium content of 5.1% and an oxide having a film thickness of 280 nm and an atomic ratio of Ga / (Zn + Ga) having a gallium content of 4.0% A zinc oxide-based transparent conductive film laminate according to Example 12 having a total film thickness of 460 nm on which the zinc-based thin film layer (2-2) was sequentially formed was produced.

  Similarly, a zinc oxide-based thin film layer (1) having a film thickness of 30 nm and a Ga / (Zn + Ga) atomic ratio of gallium content of 7.3%, and a film thickness of 150 nm and Ga / (Zn + Ga) atoms A zinc oxide thin film layer (2-1) having a gallium content of 5.1% by number ratio and a gallium content of 3.5% by an atomic ratio of 280 nm and Ga / (Zn + Ga). A zinc oxide-based transparent conductive film laminate according to Example 13 having a total film thickness of 460 nm on which the zinc oxide-based thin film layer (2-2) was sequentially formed, with a film thickness of 30 nm and an atomic ratio of Ga / (Zn + Ga) A zinc oxide thin film layer (1) having a gallium content of 7.3% and a zinc oxide thin film layer having a film thickness of 150 nm and a Ga / (Zn + Ga) atomic ratio of 5.1% gallium content (2-1), the film thickness is 280 nm, and Ga / (Zn + G Zinc oxide-based transparent conductive film laminate according to Example 14 having a total film thickness of 460 nm, in which the zinc oxide-based thin film layer (2-2) having a gallium content of 4.4% in terms of the atomic ratio is sequentially formed A zinc oxide thin film layer (1) having a film thickness of 30 nm and a Ga / (Zn + Ga) atomic ratio of 7.3%, and a film thickness of 150 nm and Ga / (Zn + Ga) atomic ratio Zinc oxide thin film layer (2-1) having a gallium content of 4.5% and zinc oxide having a film thickness of 280 nm and a Ga / (Zn + Ga) atomic ratio of 4.0% gallium. A zinc oxide-based transparent conductive film laminate according to Example 15 having a total film thickness of 460 nm and a film thickness of 30 nm and an atomic ratio of Ga / (Zn + Ga) A zinc oxide thin film layer (1) having a gallium content of 7.3%; A zinc oxide thin film layer (2-1) having a film thickness of 150 nm and an atomic ratio of Ga / (Zn + Ga) and a gallium content of 5.5%, and a film thickness of 280 nm and the number of atoms of Ga / (Zn + Ga) A zinc oxide-based transparent conductive film laminate according to Example 16 having a total film thickness of 460 nm in which a zinc oxide-based thin film layer (2-2) having a gallium content of 4.0% was sequentially formed was prepared. .

  Moreover, by the method similar to Comparative Examples 11-14, the zinc oxide type thin film layer (1) and the zinc oxide type thin film layer (2-1) in Example 12 are not included, and the atomic ratio is Ga / (Zn + Ga). A zinc oxide-based transparent conductive film according to Comparative Example 15 having a single-layer film structure shown in FIG. 3 composed of a zinc oxide-based thin film layer (2-2) having a gallium content of 3.5% and a film thickness of 460 nm was produced. did.

  Similarly, according to Comparative Example 16, which is the same as Comparative Example 15 except that the gallium content of the zinc oxide thin film layer (2-2) is 4.0% in terms of the atomic ratio of Ga / (Zn + Ga). A zinc oxide-based transparent conductive film was prepared, and was the same as Comparative Example 15 except that the gallium content of the zinc oxide-based thin film layer (2-2) was 4.4% at an atomic ratio of Ga / (Zn + Ga). The zinc oxide type transparent conductive film which concerns on a certain comparative example 17 is produced, and the gallium content of a zinc oxide type thin film layer (2-2) is 5.1% by atomic number ratio of Ga / (Zn + Ga). A zinc oxide-based transparent conductive film according to Comparative Example 18 which was the same as Comparative Example 15 was prepared.

  And the film | membrane structure of Examples 12-16 and Comparative Examples 15-18 and the result of characteristic evaluation are shown in the following Table 2, respectively.

上記表２に示された比抵抗に着目すると、実施例１２〜１６に係る酸化亜鉛系透明導電膜積層体においては２９５μΩｃｍ（実施例１２）〜３２０μΩｃｍ（実施例１４）であるのに対し、比較例１５〜１８に係る酸化亜鉛系透明導電膜においては３５２μΩｃｍ（比較例１６）〜５２０μΩｃｍ（比較例１８）であり、比較例に較べて各実施例に係る酸化亜鉛系透明導電膜積層体の導電性が改善されていることが確認される。
［実施例１７、比較例１９〜２１］
実施例１２と同様の条件並びに方法により、膜厚が４０ｎｍかつＧａ／（Ｚｎ＋Ｇａ）の原子数比でガリウム含有量が７．３％である酸化亜鉛系薄膜層（１）と、膜厚が３４０ｎｍかつＧａ／（Ｚｎ＋Ｇａ）の原子数比でガリウム含有量が５．１％である酸化亜鉛系薄膜層（２−１）と、膜厚が７００ｎｍかつＧａ／（Ｚｎ＋Ｇａ）の原子数比でガリウム含有量が４．０％である酸化亜鉛系薄膜層（２−２）が順次成膜された総膜厚１０８０ｎｍの実施例１７に係る酸化亜鉛系透明導電膜積層体を作製した。

Focusing on the specific resistance shown in Table 2 above, the zinc oxide-based transparent conductive film laminates according to Examples 12 to 16 have a comparison of 295 μΩcm (Example 12) to 320 μΩcm (Example 14). In the zinc oxide-based transparent conductive film according to Examples 15 to 18, they are 352 μΩcm (Comparative Example 16) to 520 μΩcm (Comparative Example 18), and the conductivity of the zinc oxide-based transparent conductive film laminate according to each example as compared with Comparative Examples. It is confirmed that the sex is improved.
[Example 17, Comparative Examples 19 to 21]
A zinc oxide thin film layer (1) having a film thickness of 40 nm and a Ga / (Zn + Ga) atomic ratio of gallium content of 7.3% and a film thickness of 340 nm under the same conditions and method as in Example 12. And the zinc oxide thin film layer (2-1) whose Ga / (Zn + Ga) atomic ratio is 5.1% and the gallium content is 5.1%, and the film thickness is 700 nm and Ga / (Zn + Ga) atomic ratio contains gallium. A zinc oxide-based transparent conductive film laminate according to Example 17 having a total film thickness of 1080 nm on which the zinc oxide-based thin film layer (2-2) having an amount of 4.0% was sequentially formed was produced.

  Moreover, by the method similar to Comparative Examples 15-18, the zinc oxide type thin film layer (1) and the zinc oxide type thin film layer (2-1) in Example 17 are not included, and the atomic ratio of Ga / (Zn + Ga) is used. A zinc oxide-based transparent conductive film according to Comparative Example 19 having a single-layer film structure shown in FIG. 3 composed of a zinc oxide-based thin film layer (2-2) having a gallium content of 4.0% and a film thickness of 1080 nm is prepared. did.

  Similarly, according to Comparative Example 20, which is the same as Comparative Example 19 except that the gallium content of the zinc oxide-based thin film layer (2-2) is 5.1% at the atomic ratio of Ga / (Zn + Ga). A zinc oxide-based transparent conductive film was prepared, and the same as Comparative Example 19 except that the gallium content of the zinc oxide-based thin film layer (2-2) was 7.3% at an atomic ratio of Ga / (Zn + Ga). A zinc oxide-based transparent conductive film according to a comparative example 21 was produced.

  And the film | membrane structure of Example 17 and Comparative Examples 19-21 and the result of characteristic evaluation are shown in the said Table 2, respectively.

Focusing on the specific resistance shown in Table 2 above, the zinc oxide-based transparent conductive film laminate according to Example 17 is 210 μΩcm, whereas the total film thickness is the same as that of Comparative Examples 19-21. It is 279 μΩcm (Comparative Example 19) to 750 μΩcm (Comparative Example 21) in the system transparent conductive film, and it is confirmed that the conductivity of the zinc oxide based transparent conductive film laminate according to the example is improved as compared with the comparative example. Is done.
[Example 18, comparative example 22]
Performed in the same manner as in Examples 1 to 17 except that the temperature (200 ° C.) of the substrate [non-alkali glass substrate (Corning # 7059)] during film formation was changed to 100 ° C., 300 ° C., and 500 ° C. A zinc oxide-based transparent conductive film laminate group according to Example 18 was produced.

  Further, the zinc oxide-based transparent conductive film according to Comparative Example 22 was performed in the same manner as Comparative Examples 1 to 21 except that the temperature (200 ° C.) during film formation was changed to 100 ° C., 300 ° C., and 500 ° C. Groups were made.

And when it investigated paying attention to the specific resistance of the zinc oxide type transparent conductive film laminated body group which concerns on obtained Example 18, and the zinc oxide type transparent conductive film group which concerns on the comparative example 22, Examples 1-17 and comparison It was confirmed that the same tendency as Examples 1-21 was shown.
[Example 19, comparative example 23]
The type of the above substrate [non-alkali glass substrate (Corning # 7059)] was changed to a PC (polycarbonate) substrate and a PET (polyethylene terephthalate) substrate on which a 20 nm-thickness silicon oxide film was formed. A zinc oxide-based transparent conductive film laminate group according to Example 19 was produced in the same manner as in Examples 1 to 17 except that the substrate temperature at that time was changed to 100 ° C.

  Similarly, the type of substrate [non-alkali glass substrate (Corning # 7059)] is changed to a PC (polycarbonate) substrate, a PET (polyethylene terephthalate) substrate on which a 20 nm-thickness silicon oxide film is formed, and A zinc oxide-based transparent conductive film group according to Comparative Example 23 was produced in the same manner as Comparative Examples 1 to 21 except that the substrate temperature during film formation was changed to 100 ° C.

  And when it investigated paying attention to the specific resistance of the zinc oxide type transparent conductive film laminated body group which concerns on obtained Example 19, and the zinc oxide type transparent conductive film group which concerns on the comparative example 23, Example 1-17 and comparison It was confirmed that the same tendency as Examples 1-21 was shown.

  The zinc oxide-based transparent conductive film laminate according to the present invention has improved conductivity as compared with the conventional zinc oxide-based transparent conductive film, and is therefore applied to solar cells, liquid crystal display elements, electrodes of various light receiving elements, and the like. Has industrial applicability.

BRIEF DESCRIPTION OF THE DRAWINGS Structure explanatory drawing of the zinc oxide type transparent conductive film laminated body based on this invention formed on the board | substrate. Structure explanatory drawing of the zinc oxide type transparent conductive film laminated body which concerns on the modification of this invention. Structure explanatory drawing of the zinc oxide type transparent conductive film which concerns on the comparative example formed on the board | substrate.

Claims (9)

In a zinc oxide-based transparent conductive film laminate composed of a plurality of zinc oxide-based transparent conductive films having different gallium contents formed on a substrate by a sputtering method or an ion plating method,
The zinc oxide-based transparent conductive film formed on the most substrate side has a gallium content of 5.6 to 10.0% and a film thickness of 20 to 40 nm at an atomic ratio of Ga / (Zn + Ga). The zinc oxide-based thin film layer (1), and the zinc oxide-based thin film layer (1) is formed on the zinc oxide-based thin film layer (1). ) A zinc oxide-based transparent conductive film laminate comprising a zinc oxide-based thin film layer (2) having a lower gallium content.   The gallium content of the zinc oxide thin film layer (2) formed on the zinc oxide thin film layer (1) is 3.5 to 5.5% in terms of the atomic ratio of Ga / (Zn + Ga). The zinc oxide-based transparent conductive film laminate according to claim 1.   The gallium content of the zinc oxide thin film layer (2) formed on the zinc oxide thin film layer (1) is 4.5 to 5.5% in terms of the atomic ratio of Ga / (Zn + Ga). The zinc oxide-based transparent conductive film laminate according to claim 2. The total thickness of the zinc oxide-based thin film layer (1) and the zinc oxide-based thin film layer (2) is 80 nm or more and less than 400 nm, and the specific resistance is 8.0 × 10 ⁻⁴ Ωcm or less. The zinc oxide-based transparent conductive film laminate according to claim 3.   The zinc oxide-based thin film layer (2) formed on the zinc oxide-based thin film layer (1) has a gallium content of 4.5 to 5.5% in terms of the atomic ratio of Ga / (Zn + Ga). The zinc oxide thin film layer (2-1) and the zinc oxide thin film layer (2-1) are formed on the zinc oxide thin film layer (2-1), and the gallium content is 3.5 to 4.4 in terms of the atomic ratio of Ga / (Zn + Ga). It is comprised with the zinc oxide type thin film layer (2-2) set to 4%, The zinc oxide type transparent conductive film laminated body of Claim 2 characterized by the above-mentioned. The zinc oxide thin film layer (1) and the zinc oxide thin film layer (2-1) in which the gallium content is set to 4.5 to 5.5% by the atomic ratio of Ga / (Zn + Ga); The total film thickness with the zinc oxide thin film layer (2-2) in which the gallium content is set to 3.5 to 4.4% in terms of the atomic ratio of Ga / (Zn + Ga) is 400 nm or more, and 6. The zinc oxide-based transparent conductive film laminate according to claim 5, wherein the specific resistance is 3.5 × 10 ⁻⁴ Ωcm or less .   The zinc oxide based transparent conductive film laminate according to any one of claims 1 to 6, wherein the substrate temperature during film formation is set to 100 to 500 ° C and the film is formed by sputtering. A transparent conductive substrate comprising a glass substrate or a resin substrate and the zinc oxide-based transparent conductive film laminate according to any one of claims 1 to 7 formed on the substrate. A device selected from a solar cell, a display device, or a light-emitting device, wherein the zinc oxide-based transparent conductive film laminate according to any one of claims 1 to 7 is incorporated as a transparent electrode.

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