WO2012147219A1 - Transparent conductive film and method for forming same - Google Patents

Transparent conductive film and method for forming same Download PDF

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Publication number
WO2012147219A1
WO2012147219A1 PCT/JP2011/069550 JP2011069550W WO2012147219A1 WO 2012147219 A1 WO2012147219 A1 WO 2012147219A1 JP 2011069550 W JP2011069550 W JP 2011069550W WO 2012147219 A1 WO2012147219 A1 WO 2012147219A1
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transparent conductive
conductive film
film
forming
transparent
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PCT/JP2011/069550
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French (fr)
Japanese (ja)
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高橋　大輔
裕士 今田
真佑 前田
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シャープ株式会社
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • H01L31/1884—Manufacture of transparent electrodes, e.g. TCO, ITO

Definitions

  • the present invention relates to a transparent conductive film and a film forming method thereof, and more specifically to a transparent conductive film provided on a transparent substrate of a thin film solar cell and a film forming method thereof.
  • a thin film solar cell is manufactured by forming a transparent conductive film on a transparent substrate and further forming a photoelectric conversion layer or the like thereon.
  • the thin-film solar cell has a demerit that the power generation cost is several times higher than other power sources and the production cost is high. In order to eliminate these disadvantages, it is necessary to increase the photoelectric conversion efficiency and simplify the manufacturing method.
  • Patent Document 1 discloses a method for easily producing the transparent conductive film using a spray pyrolysis method. According to the method of Patent Document 1, a transparent conductive film can be produced without forming an underlayer or a buffer layer on a glass substrate. For this reason, it is not necessary to form the film in two stages, and the film forming method can be simplified.
  • the sheet resistance of the transparent conductive film is 10 ⁇ / ⁇ or less, the light transmittance is 80% or more, and the haze ratio is 7 to 15%. It is extremely difficult to adjust these three characteristics. For example, if the film thickness of the transparent conductive film is increased, the sheet resistance can be lowered, but the light transmittance is also lowered.
  • tin oxide As a material satisfying these characteristics, the use of tin oxide, zinc oxide, indium oxide or the like for the transparent conductive film has been studied.
  • tin oxide is widely used for a transparent conductive film of a thin film solar cell because it is a low-cost and chemically stable material.
  • Patent Document 2 a film forming raw material solution blended so as to obtain desired characteristics is adjusted to a high temperature, and then fluorine-doped tin oxide (FTO) is formed by a spray pyrolysis method.
  • FTO fluorine-doped tin oxide
  • Patent Document 2 since a transparent conductive film is formed by a moving spray mechanism, a transparent conductive film having high crystallinity can be formed in a large area regardless of crystal orientation.
  • Patent Document 2 discloses forming a transparent conductive film regardless of the crystal orientation, but generally there is a correlation between the crystal orientation and the surface shape of the transparent conductive film.
  • Non-patent Document 1 K.Murakami et al.Thin Solid Films 515 (2007) 8632-8636 (Non-patent Document 1), when crystal grains with uniform crystal orientation are combined and enlarged, haze is caused by the effect of surface irregularities. Has been reported to be higher.
  • JP 7-330336 A International Publication No. 2008/117605
  • the transparent conductive film disclosed in Patent Document 2 described above is not sufficient in light transmittance, haze ratio, and sheet resistance, and further improvement in performance is required.
  • the crystallinity of the transparent conductive film is good and the light transmittance is high by bonding the crystal grains at a high substrate temperature. And since the size of the crystal grain of a transparent conductive film becomes large, a haze rate can also be raised.
  • the transparent conductive film formed by the film forming method of Patent Document 2 satisfies desired characteristics in that the light transmittance and haze ratio are high.
  • fluorine evaporates due to the high temperature when forming the transparent conductive film.
  • the carrier density in the transparent conductive film decreases and the sheet resistance increases.
  • the present invention has been made in view of the above situation, and the object of the present invention is to provide a transparent conductive film having a high haze ratio and light transmittance and a low sheet resistance, and the transparent An object is to provide a method for easily forming a conductive film.
  • the method for forming a transparent conductive film of the present invention comprises a step of heating a transparent substrate to 510 ° C. or more, and spraying droplets of a film forming raw material solution onto the transparent substrate, thereby forming a transparent conductive film on the transparent substrate.
  • the step of depositing the transparent conductive film is characterized by depositing the transparent conductive film at a deposition rate of 12 nm / sec or more.
  • the film forming raw material solution preferably contains a tin and fluorine compound.
  • the present invention relates to a transparent conductive film formed by the above film forming method, and in the X-ray diffraction pattern of the transparent conductive film, the diffraction peak intensity of the (301) plane is any crystal plane other than the (301) plane. It is characterized by being larger than the diffraction peak intensity.
  • the average particle diameter of the crystal grains calculated from the half-value width of the diffraction peak intensity on the (301) plane is the diffraction peak intensity on any crystal plane other than the (301) plane. It is preferable that the average particle diameter of the crystal grains calculated from the half width is larger.
  • the transparent conductive film can be formed by a simple process by having the above-described configuration.
  • the transparent conductive film formed by the film forming method described above exhibits excellent performance such as high light transmittance and haze ratio and low sheet resistance.
  • FIG. 1 is a schematic cross-sectional view of a film forming apparatus using the method for forming a transparent conductive film of the present invention.
  • the transparent conductive film forming method of the present invention is typically formed using the film forming apparatus shown in FIG.
  • the film forming apparatus in FIG. 1 includes a film forming raw material solution 1 containing a film forming material, a liquid feed pump 2 for transporting the film forming raw material solution 1, and droplet generation for replacing the film forming raw material solution 1 with liquid droplets 5.
  • a part 6, a transparent substrate 7 for forming a transparent conductive film on the surface, and a heating part 8 for heating the transparent substrate 7 are included.
  • the carrier gas 3 is introduced into the nozzle head 4, and the droplet 5 is sprayed onto the transparent substrate 7 by the carrier gas.
  • the transparent substrate 7 is heated by heating the transparent substrate 7 to 510 ° C. or more, and the droplet 5 of the film forming raw material solution 1 is sprayed on the transparent substrate 7.
  • the step of forming the transparent conductive film is characterized in that the transparent conductive film is formed at a film formation rate of 12 nm / sec or more. By forming a film at such a high film formation rate, a transparent conductive film having a high light transmittance and a high haze ratio and a low sheet resistance can be formed. Below, each said step is demonstrated.
  • the film forming method of the present invention includes a step of heating the transparent substrate 7 to 510 ° C. or higher.
  • the transparent substrate 7 By heating the transparent substrate 7 to such a temperature, the crystallinity of the transparent conductive film is improved during or after film formation even if fluorine is taken into the transparent conductive film during film formation. Therefore, the light transmittance can be improved.
  • the transparent substrate 7 is preferably heated to 510 ° C. or higher, more preferably 530 ° C. or higher.
  • the temperature of the transparent substrate 7 is lower than 510 ° C.
  • the crystallinity of the transparent conductive film is lowered due to the temperature lowered by the sprayed film forming raw material solution, which is not preferable.
  • the upper limit of the heating temperature of the transparent substrate 7 is preferably a temperature lower than 700 ° C.
  • the heating temperature of the transparent substrate exceeds 700 ° C., it is not preferable because droplets made of the film forming raw material solution do not easily reach the surface of the substrate and the film forming rate is lowered.
  • the transparent substrate 7 is disposed on the upper surface of the heating unit 8. In the following, the transparent substrate 7 and the heating unit 8 will be described.
  • any material can be used as the transparent substrate 7 as long as it is a transparent material in the absorption region of the photoelectric conversion layer.
  • a glass substrate, a resin material substrate, or the like can be used.
  • a material exhibiting transparency at the wavelength of the absorption region of the photoelectric conversion layer is preferable, and alkali-free glass is preferably used as such a material.
  • the heating unit 8 is provided to heat the transparent substrate to 510 ° C. or higher.
  • the heating unit 8 can be used without particular limitation as long as it can heat the transparent substrate 7 to a predetermined temperature.
  • Such a heating unit 8 includes a method of heating by direct conduction heat transfer using a hot plate, a method of heating by convection heat transfer using a furnace in which the inside is heated, and a method of heating by radiation heat transfer irradiating an infrared lamp or the like. Any of these heating methods can be used.
  • a transparent substrate is heated by direct conduction heat transfer using a hot plate.
  • a transparent conductive film is formed on the transparent substrate 7 by spraying droplets of the film forming raw material solution 1 on the transparent substrate 7.
  • the transparent conductive film is formed at a film formation rate of 12 nm / sec or more.
  • the upper limit of the film forming rate of the transparent substrate 7 is preferably 30 nm / sec or less, and more preferably 20 nm / sec or less. If a transparent conductive film is formed at a film formation rate exceeding 20 nm / sec, there is a problem that the film quality such as crystal orientation deteriorates due to a decrease in the substrate temperature or the like, which is not preferable.
  • any method can be used as long as the film forming raw material solution 1 is formed into droplets 5 having an average particle diameter of 0.1 ⁇ m to several tens ⁇ m.
  • a spray method, an ultrasonic method, or the like can be used.
  • FIG. 1 shows a spray-type droplet generator 6 that applies a high-pressure gas to the film-forming raw material solution 1 to form fine droplets from a fine slit nozzle.
  • the spray method is preferably a two-fluid spray method in which two fluids, a liquid and a carrier gas, are mixed and a droplet is ejected from the tip of the spray nozzle.
  • the film forming raw material solution becomes droplets through the droplet generation unit immediately before the transparent substrate. For this reason, the film-forming raw material solution is conveyed to the tip of the spray nozzle.
  • the droplet is formed by a high-pressure carrier gas, the droplet and the carrier gas are sprayed onto the transparent substrate.
  • a carrier gas may be used in order to provide directivity in the droplet transport direction.
  • compressed air, N 2 , H 2 , water vapor, O 2 , or a mixture of one or more of these can be used.
  • the spray nozzle is made of, for example, a metal and a resin material.
  • droplets are generated from the transparent substrate 7 by applying ultrasonic waves to the film forming raw material solution 1 from the droplet generator 6 attached to the solution bottle. Since the droplet itself has no kinetic energy, the droplet is transported by a carrier gas.
  • the carrier gas the same gas as that used in the above-described spray method can be used.
  • the ultrasonic vibrator can spray droplets having a relatively uniform average particle diameter, there is an advantage that the droplets hardly aggregate.
  • the liquid feed pump 2 preferably has a function of adjusting the supply amount as well as supplying the film forming raw material solution 1 to the nozzle head 4.
  • the transparent conductive film scans either one or both of the transparent substrate 7 and the droplet generator 6, so that the entire surface of the transparent substrate 7 is scanned.
  • the film is formed.
  • the transparent conductive film may be formed by one droplet generator 6 or may be formed by two or more droplet generators 6.
  • two or more droplet generation units are arranged on the entire upper surface of the transparent substrate and droplets are sprayed, it is not always necessary to scan either the transparent substrate 7 or the droplet generation unit 6.
  • the film-forming raw material solution 1 used in the present invention is obtained by dissolving a film-forming material composed of an organic metal or a metal halide compound of an inorganic material such as zinc, tin, indium, cadmium, or strontium in one or more kinds of solvents. Is.
  • the film forming raw material solution 1 generally dissolves the organometallic or metal halide compound at a concentration of 0.1 to 3 mol / L, but is not limited to this concentration.
  • said film-forming raw material solution 1 it is preferable to contain the compound of tin and a fluorine, and it is more preferable to use the thing containing the organometallic compound containing tin and containing the compound of fluorine as a dopant agent.
  • the fluorine compound contained in the film forming raw material solution include hydrogen fluoride and ammonium fluoride.
  • examples of tin contained in the film forming raw material solution include tin tetrachloride, tin dichloride, dibutyltin diacetate, and tetrabutyltin.
  • water, an organic solvent, or a mixture thereof can be used as the solvent used for the film forming raw material solution.
  • the organic solvent here include methanol, ethanol, acetone, isopropyl alcohol, and the like, but are not limited thereto.
  • the film forming raw material solution may further contain an additive in addition to the solvent and the film forming material.
  • additives include a dopant agent, a surfactant, a pH adjuster, and the like, but it is preferable to use a mixture of two or more of these additives.
  • examples of the dopant agent include materials containing Mg, Ga, Al, Te, Ag, Ge, Cu, Sr, B, Sb, F, As, and the like, and examples of the surfactant include lower organic compounds.
  • examples of the pH adjuster include nitric acid, acetic acid, sulfuric acid, hydrofluoric acid, hydrogen peroxide, butyric acid, hydrochloric acid, and ammonia.
  • the film thickness of the transparent conductive film formed by the above film forming method is in the range of 600 nm to 1200 nm in order to satisfy the specifications of sheet resistance, haze ratio, and transmittance.
  • the diffraction peak intensity on the (301) plane is larger than the diffraction peak intensity on any crystal plane other than the (301) plane.
  • the large peak from the (301) plane suggests that even crystal grains that have sufficiently incorporated fluorine have high crystallinity, and the transparent conductive film that satisfies the specifications of low resistance, light transmittance, and haze ratio It becomes.
  • the average particle diameter of the crystal grains calculated from the half-value width of the diffraction peak intensity of the (301) plane is the diffraction peak of any crystal plane other than the (301) plane. It is preferably larger than the average particle diameter of the crystal grains calculated from the half width of the strength. This suggests that crystal grains sufficiently incorporating fluorine are growing dominantly, and means that the transparent conductive film satisfies the specifications of light transmittance and haze ratio with lower resistance. .
  • Example 1 In this example, first, as the film forming raw material solution 1, the concentration of tin chloride pentahydrate is 0.9 mol / L and the concentration of ammonium fluoride is 0.9 mol / L with respect to 200 mL of water. Dissolved in. Furthermore, 20 mL of 35% hydrochloric acid was mixed as a pH adjuster. On the other hand, a hot plate was used as the heating unit 8, and a transparent substrate 7 made of a glass substrate was set on the hot plate. Then, the temperature of the hot plate was set to 590 ° C., and the transparent substrate 7 was heated until the surface temperature of the transparent substrate 7 reached 513 ° C. The surface temperature of the transparent substrate 7 was measured with a K thermocouple.
  • the film-forming raw material solution 1 was sent to the nozzle head 4 by the liquid feed pump 2, and droplets were generated by a spray method in which the film-forming raw material solution 1 was compressed with high-pressure gas into droplets.
  • a compressed air spray having a flow rate of 200 L / min was flowed in the ejection direction.
  • the conveyance stage was conveyed at the speed
  • a transparent conductive film made of SnO 2 is formed on the glass substrate by spraying droplets of the film forming raw material solution on the glass substrate at a flow rate of 12 mL / min for 75 seconds from the nozzle head 4 toward the transparent substrate 7. Filmed. At this time, the time during which the transparent conductive film was formed on the glass substrate was 60 seconds.
  • Example 2 comparative example 2
  • Example 2 and Example 2 were performed in the same manner as in Example 1 except that the film formation rate was changed by changing the supply rate of the film formation raw material solution.
  • the transparent conductive film of Comparative Example 2 was formed.
  • Example 3 Comparative Example 1
  • Example 3 Comparative Example 1
  • the film formation raw material solution supply rate and the film formation rate were changed, and the film formation stage was kept stationary to form a film for 60 seconds.
  • the transparent conductive films of Example 3 and Comparative Example 1 were formed by the same method as in Example 1.
  • Example 4 With respect to Example 3, as shown in Table 1 below, film formation was performed for 60 seconds by changing the substrate temperature, the film formation raw material solution supply rate, and the film formation rate. Except for these differences, the transparent conductive film of Example 4 was formed by the same method as in Example 3.
  • Comparative Example 3 As shown in Table 1 below, the transparent conductive film of Comparative Example 3 was formed by the same method as Example 1 except that the temperature of the transparent substrate during film formation was changed as shown in Table 1 below. did.
  • Comparative Example 4 Compared to Example 3, as shown in Table 1 below, the transparent conductive film of Comparative Example 4 was formed by the same method as Example 3 except that the temperature of the transparent substrate during film formation was changed. did.
  • the haze ratio (%) and the transmittance (%) of the transparent conductive film prepared in each example and each comparative example were measured with a spectral haze meter (product name: TC-1800H (manufactured by Tokyo Denshoku Co., Ltd.)). .
  • the measurement results are shown in Table 1 below.
  • FIG. 2 is an X-ray diffraction profile when the crystal structure analysis of the transparent conductive film of each example and comparative example is performed. Based on the X-ray diffraction profile shown in FIG. 2, the position of each peak (2 ⁇ B ), the intensity and the full width at half maximum (FWHM), and the crystal grain size t were calculated. The results are shown in Table 2.
  • the crystal grain size t means the crystal size in the film thickness direction, and was calculated based on the following Scherrer equation (1).
  • the (301) plane is the preferential orientation plane.
  • the transparent conductive film of the comparative example has a (200) plane as a preferential orientation plane.
  • the transparent conductive film of each example has a maximum crystal grain size of (301) -oriented crystals, while in Comparative Example 1 ( 200) A plane-oriented crystal has the largest crystal grain size in the film.
  • the transparent conductive films of Examples 1 to 3 have the properties of high haze and transmittance and low sheet resistance.
  • the transparent conductive film of Comparative Example 1 has the properties of high transmittance but low haze ratio and high sheet resistance.
  • a transparent conductive film having a high haze ratio and transmittance and a low sheet resistance can be formed by forming a transparent conductive film at a deposition rate of 12 nm / s or more. became.
  • the reason for this is thought to be that the re-evaporation of fluorine is suppressed by forming the film at a high film formation rate, and the transparent conductive film oriented in the (301) plane is preferentially formed.
  • the transparent conductive film formed by the film forming method of the present invention forms a transparent conductive film having a high light transmittance and a high haze ratio and a low sheet resistance without forming a buffer layer and an underlayer. be able to. For this reason, the transparent conductive film of this invention can be used conveniently as a transparent electrode for thin film solar cells, especially a thin film silicon solar cell.

Abstract

In this method, a transparent conductive film can be formed with a simple process, said transparent conductive film having excellent characteristics, i.e., high light transmissivity, high haze rate, and low sheet resistance. This method for forming a transparent conductive film is characterized in that the method includes a step of heating a transparent substrate (7) to 510°C or higher, and a step of forming a transparent conductive film on the transparent substrate (7) by spraying liquid droplets (5) of the film-forming raw material solution (1) to the transparent substrate (7), and that in the step of forming the transparent conductive film, the transparent conductive film is formed at a film-forming speed of 12 nm/sec or higher.

Description

透明導電膜およびその成膜方法Transparent conductive film and method for forming the same
　本発明は、透明導電膜およびその成膜方法に関し、より特定的には、薄膜太陽電池の透明基板上に設ける透明導電膜およびその成膜方法に関する。 The present invention relates to a transparent conductive film and a film forming method thereof, and more specifically to a transparent conductive film provided on a transparent substrate of a thin film solar cell and a film forming method thereof.
　近年、エネルギー問題や、環境問題が盛んに取り上げられている。これらの問題の解決策が様々な方面から模索されている。これらの問題の対策の１つとして、太陽光を利用してクリーンなエネルギーを供給し得る太陽電池が注目されている。中でも省資源で作製できる薄膜太陽電池が注目を集めている。 In recent years, energy issues and environmental issues have been highlighted. Solutions to these problems are being sought from various directions. As one of countermeasures against these problems, a solar cell that can supply clean energy using sunlight has attracted attention. In particular, thin-film solar cells that can be manufactured with less resources are attracting attention.
　薄膜太陽電池は、透明基板上に透明導電膜を形成した上で、その上にさらに光電変換層などを形成することによって作製される。しかし、薄膜太陽電池は、他の電源に比して数倍以上も発電コストが高く、しかも生産コストも高いというデメリットがある。これらのデメリットを解消するために、光電変換効率を高めるとともに、製造方法を簡略化する必要がある。 A thin film solar cell is manufactured by forming a transparent conductive film on a transparent substrate and further forming a photoelectric conversion layer or the like thereon. However, the thin-film solar cell has a demerit that the power generation cost is several times higher than other power sources and the production cost is high. In order to eliminate these disadvantages, it is necessary to increase the photoelectric conversion efficiency and simplify the manufacturing method.
　製造方法を簡略化する方法として、たとえば特開平７－３３０３３６号公報（特許文献１）には、スプレー熱分解法を用いて、上記の透明導電膜を簡便に作製する方法が開示されている。特許文献１の方法によれば、ガラス基板上に下地層やバッファ層を形成することなく、透明導電膜を作製することができる。このため、２段階に分けて成膜する必要がなく、成膜方法を簡略化することができる。 As a method for simplifying the production method, for example, Japanese Patent Application Laid-Open No. 7-330336 (Patent Document 1) discloses a method for easily producing the transparent conductive film using a spray pyrolysis method. According to the method of Patent Document 1, a transparent conductive film can be produced without forming an underlayer or a buffer layer on a glass substrate. For this reason, it is not necessary to form the film in two stages, and the film forming method can be simplified.
　ところで、薄膜太陽電池の光電変換効率を高めるためには、上記の透明導電膜のシート抵抗を低くする一方で、光透過率およびヘイズ率を高める必要がある。具体的には、透明導電膜のシート抵抗を１０Ω／□以下とし、光透過率を８０％以上とし、かつヘイズ率を７～１５％とする必要がある。これらの３特性の調整を図るのは極めて難しく、たとえば透明導電膜の膜厚を厚くすると、シート抵抗を下げることはできるが、光透過率も下がってしまう。 By the way, in order to increase the photoelectric conversion efficiency of the thin film solar cell, it is necessary to increase the light transmittance and the haze ratio while reducing the sheet resistance of the transparent conductive film. Specifically, it is necessary that the sheet resistance of the transparent conductive film is 10Ω / □ or less, the light transmittance is 80% or more, and the haze ratio is 7 to 15%. It is extremely difficult to adjust these three characteristics. For example, if the film thickness of the transparent conductive film is increased, the sheet resistance can be lowered, but the light transmittance is also lowered.
　これらの特性を満たす材料として、酸化スズ、酸化亜鉛、酸化インジウムなどを透明導電膜に用いることが検討されている。中でも、酸化スズは、低価格で化学的にも安定性が高い材料であるため、薄膜太陽電池の透明導電膜に多用されている。たとえば国際公開第２００８／１１７６０５号（特許文献２）には、所望の特性が得られるように配合した成膜原料溶液を高温に調整した上で、スプレー熱分解法によってフッ素ドープ酸化スズ（ＦＴＯ）からなる透明導電膜を作製する方法が開示されている。 As a material satisfying these characteristics, the use of tin oxide, zinc oxide, indium oxide or the like for the transparent conductive film has been studied. Among these, tin oxide is widely used for a transparent conductive film of a thin film solar cell because it is a low-cost and chemically stable material. For example, in International Publication No. 2008/117605 (Patent Document 2), a film forming raw material solution blended so as to obtain desired characteristics is adjusted to a high temperature, and then fluorine-doped tin oxide (FTO) is formed by a spray pyrolysis method. A method for producing a transparent conductive film is disclosed.
　特許文献２では、移動噴霧機構によって透明導電膜を成膜するため、結晶配向性に関係なく結晶性が高い透明導電膜を大面積で成膜することができる。ここで、特許文献２は、結晶配向性に関係なく透明導電膜を成膜することを開示しているが、一般的に結晶配向性と透明導電膜の表面形状とは相関関係がある。たとえばK.Murakami　et　al.Thin　Solid　Films　515（2007）8632-8636（非特許文献１）には、結晶配向性が揃った結晶粒同士が結合して巨大化すると、その表面凹凸の影響によってヘイズが高くなることが報告されている。 In Patent Document 2, since a transparent conductive film is formed by a moving spray mechanism, a transparent conductive film having high crystallinity can be formed in a large area regardless of crystal orientation. Here, Patent Document 2 discloses forming a transparent conductive film regardless of the crystal orientation, but generally there is a correlation between the crystal orientation and the surface shape of the transparent conductive film. For example, in K.Murakami et al.Thin Solid Films 515 (2007) 8632-8636 (Non-patent Document 1), when crystal grains with uniform crystal orientation are combined and enlarged, haze is caused by the effect of surface irregularities. Has been reported to be higher.
特開平７－３３０３３６号公報JP 7-330336 A 国際公開第２００８／１１７６０５号International Publication No. 2008/117605
　上記の特許文献２に開示される透明導電膜は、光透過率、ヘイズ率、およびシート抵抗の各特性が十分ではなく、さらなる性能の向上が求められている。その点、非特許文献１では、基板温度を高温にして結晶粒同士を結合させることにより、透明導電膜の結晶性がよく、光透過率が高い。しかも、透明導電膜の結晶粒のサイズが大きくなるため、ヘイズ率を高めることもできる。 The transparent conductive film disclosed in Patent Document 2 described above is not sufficient in light transmittance, haze ratio, and sheet resistance, and further improvement in performance is required. In that respect, in Non-Patent Document 1, the crystallinity of the transparent conductive film is good and the light transmittance is high by bonding the crystal grains at a high substrate temperature. And since the size of the crystal grain of a transparent conductive film becomes large, a haze rate can also be raised.
　したがって、特許文献２の成膜方法によって成膜される透明導電膜は、光透過率およびヘイズ率が高いという点では所望の特性を満たしていた。しかし、その反面、特許文献２では、透明導電膜を成膜するときの温度が高温であることに起因して、フッ素が蒸発してしまう。これにより透明導電膜中のキャリア密度が低下し、シート抵抗が増大してしまうという問題があった。 Therefore, the transparent conductive film formed by the film forming method of Patent Document 2 satisfies desired characteristics in that the light transmittance and haze ratio are high. However, in Patent Document 2, fluorine evaporates due to the high temperature when forming the transparent conductive film. As a result, there is a problem that the carrier density in the transparent conductive film decreases and the sheet resistance increases.
　本発明は、上記のような現状に鑑みてなされたものであり、その目的とするところは、ヘイズ率および光透過率が高く、かつシート抵抗が低い透明導電膜を提供すること、および該透明導電膜を簡便に成膜する方法を提供することにある。 The present invention has been made in view of the above situation, and the object of the present invention is to provide a transparent conductive film having a high haze ratio and light transmittance and a low sheet resistance, and the transparent An object is to provide a method for easily forming a conductive film.
　本発明の透明導電膜の成膜方法は、透明基板を５１０℃以上に加熱するステップと、該透明基板に対し、成膜原料溶液の液滴を噴霧することにより、透明基板上に透明導電膜を成膜するステップとを含み、該透明導電膜を成膜するステップは、１２ｎｍ／ｓｅｃ以上の成膜速度で透明導電膜を成膜することを特徴とする。上記の成膜原料溶液は、スズおよびフッ素の化合物を含むことが好ましい。 The method for forming a transparent conductive film of the present invention comprises a step of heating a transparent substrate to 510 ° C. or more, and spraying droplets of a film forming raw material solution onto the transparent substrate, thereby forming a transparent conductive film on the transparent substrate. The step of depositing the transparent conductive film is characterized by depositing the transparent conductive film at a deposition rate of 12 nm / sec or more. The film forming raw material solution preferably contains a tin and fluorine compound.
　本発明は、上記の成膜方法によって成膜された透明導電膜に関し、該透明導電膜のＸ線回折パターンにおいて、（３０１）面の回折ピーク強度は、（３０１）面以外のいずれの結晶面の回析ピーク強度よりも大きいことを特徴とする。 The present invention relates to a transparent conductive film formed by the above film forming method, and in the X-ray diffraction pattern of the transparent conductive film, the diffraction peak intensity of the (301) plane is any crystal plane other than the (301) plane. It is characterized by being larger than the diffraction peak intensity.
　上記の透明導電膜のＸ線回折パターンにおいて、（３０１）面の回折ピーク強度の半値幅から算出した結晶粒の平均粒子径は、（３０１）面以外のいずれの結晶面の回析ピーク強度の半値幅から算出した結晶粒の平均粒子径よりも大きいことが好ましい。 In the X-ray diffraction pattern of the transparent conductive film, the average particle diameter of the crystal grains calculated from the half-value width of the diffraction peak intensity on the (301) plane is the diffraction peak intensity on any crystal plane other than the (301) plane. It is preferable that the average particle diameter of the crystal grains calculated from the half width is larger.
　本発明は、上記のような構成を有することにより、簡便なプロセスで透明導電膜を成膜することができる。上記の成膜方法で成膜された透明導電膜は、光透過率およびヘイズ率が高く、かつシート抵抗が低いという優れた性能を示す。 In the present invention, the transparent conductive film can be formed by a simple process by having the above-described configuration. The transparent conductive film formed by the film forming method described above exhibits excellent performance such as high light transmittance and haze ratio and low sheet resistance.
本発明の透明導電膜の成膜方法を用いる成膜装置の模式的な断面図である。It is typical sectional drawing of the film-forming apparatus using the film-forming method of the transparent conductive film of this invention. 各実施例および比較例の透明導電膜の結晶構造解析を行なったときのＸ線回折プロファイルである。It is an X-ray diffraction profile when the crystal structure analysis of the transparent conductive film of each Example and a comparative example is performed.
　以下、本発明の透明導電膜の成膜方法について図面を用いて説明する。なお、本発明の図面において、同一の参照符号は、同一部分または相当部分を表わすものである。また、長さ、幅、厚さ、深さなどの寸法関係は図面の明瞭化と簡略化のために適宜に変更されており、実際の寸法関係を表わすものではない。 Hereinafter, a method for forming a transparent conductive film of the present invention will be described with reference to the drawings. In the drawings of the present invention, the same reference numerals represent the same or corresponding parts. In addition, dimensional relationships such as length, width, thickness, and depth are changed as appropriate for clarity and simplification of the drawings, and do not represent actual dimensional relationships.
　＜透明導電膜の成膜方法＞
　図１は、本発明の透明導電膜の成膜方法を用いる成膜装置の模式的な断面図である。本発明の透明導電膜の成膜方法は、典型的には図１に示される成膜装置を用いて成膜する。以下においては、図１の成膜装置を参照しつつ、本発明の透明導電膜の成膜方法を説明する。図１における成膜装置は、成膜材料を含む成膜原料溶液１と、成膜原料溶液１を搬送するための送液ポンプ２と、成膜原料溶液１を液滴５に代える液滴発生部６と、表面上に透明導電膜を成膜するための透明基板７と、透明基板７を加熱する加熱部８とを有する。上記液滴発生部６は、ノズルヘッド４にキャリアガス３が導入され、キャリアガスによって液滴５が透明基板７に噴き付けられる。 <Method for forming transparent conductive film>
FIG. 1 is a schematic cross-sectional view of a film forming apparatus using the method for forming a transparent conductive film of the present invention. The transparent conductive film forming method of the present invention is typically formed using the film forming apparatus shown in FIG. Hereinafter, the film forming method of the transparent conductive film of the present invention will be described with reference to the film forming apparatus of FIG. The film forming apparatus in FIG. 1 includes a film forming raw material solution 1 containing a film forming material, a liquid feed pump 2 for transporting the film forming raw material solution 1, and droplet generation for replacing the film forming raw material solution 1 with liquid droplets 5. A part 6, a transparent substrate 7 for forming a transparent conductive film on the surface, and a heating part 8 for heating the transparent substrate 7 are included. In the droplet generator 6, the carrier gas 3 is introduced into the nozzle head 4, and the droplet 5 is sprayed onto the transparent substrate 7 by the carrier gas.
　本発明の透明導電膜の成膜方法は、透明基板７を５１０℃以上に加熱するステップと、該透明基板７に対し、成膜原料溶液１の液滴５を噴霧することにより、透明基板７上に透明導電膜を成膜するステップとを含む。上記の透明導電膜を成膜するステップは、１２ｎｍ／ｓｅｃ以上の成膜速度で透明導電膜を成膜することを特徴とする。このような高速の成膜レートで成膜することにより、光透過率およびヘイズ率が高く、かつシート抵抗が低い透明導電膜を成膜することができる。以下において、上記各ステップを説明する。 In the method for forming a transparent conductive film of the present invention, the transparent substrate 7 is heated by heating the transparent substrate 7 to 510 ° C. or more, and the droplet 5 of the film forming raw material solution 1 is sprayed on the transparent substrate 7. Forming a transparent conductive film thereon. The step of forming the transparent conductive film is characterized in that the transparent conductive film is formed at a film formation rate of 12 nm / sec or more. By forming a film at such a high film formation rate, a transparent conductive film having a high light transmittance and a high haze ratio and a low sheet resistance can be formed. Below, each said step is demonstrated.
　＜透明基板を加熱するステップ＞
　本発明の成膜方法は、透明基板７を５１０℃以上に加熱するステップを含むことを特徴とする。このような温度に透明基板７を加熱することにより、成膜中に透明導電膜の内部にフッ素が取り込まれても、成膜中または成膜後の冷却過程で透明導電膜の結晶性を向上させるため、光透過率を向上させることができる。 <Step of heating the transparent substrate>
The film forming method of the present invention includes a step of heating the transparent substrate 7 to 510 ° C. or higher. By heating the transparent substrate 7 to such a temperature, the crystallinity of the transparent conductive film is improved during or after film formation even if fluorine is taken into the transparent conductive film during film formation. Therefore, the light transmittance can be improved.
　上記の透明基板７は、５１０℃以上に加熱することが好ましく、より好ましくは５３０℃以上である。透明基板７の温度が５１０℃未満であると、噴霧された成膜原料溶液によって温度が低下することにより透明導電膜の結晶性が低下するため好ましくない。一方、上記の透明基板７の加熱温度の上限は、７００℃より低い温度であることが好ましい。透明基板の加熱温度が７００℃を超えると、成膜原料溶液からなる液滴が基板の表面まで到達しにくくなり、成膜レートが低下することになるため好ましくない。このように透明基板７の温度を調整するために、加熱部８の上面に透明基板７を配置する。以下においては、透明基板７および加熱部８を説明する。 The transparent substrate 7 is preferably heated to 510 ° C. or higher, more preferably 530 ° C. or higher. When the temperature of the transparent substrate 7 is lower than 510 ° C., the crystallinity of the transparent conductive film is lowered due to the temperature lowered by the sprayed film forming raw material solution, which is not preferable. On the other hand, the upper limit of the heating temperature of the transparent substrate 7 is preferably a temperature lower than 700 ° C. When the heating temperature of the transparent substrate exceeds 700 ° C., it is not preferable because droplets made of the film forming raw material solution do not easily reach the surface of the substrate and the film forming rate is lowered. In order to adjust the temperature of the transparent substrate 7 in this way, the transparent substrate 7 is disposed on the upper surface of the heating unit 8. In the following, the transparent substrate 7 and the heating unit 8 will be described.
　（透明基板）
　本発明において、透明基板７としては、光電変換層の吸収域において透明な材料であれば、いかなるものをも用いることができ、たとえばガラス基板、樹脂材料基板等を用いることができる。特に光電変換層の吸収領域の波長において透明性を示す材料であることが好ましく、このような材料として無アルカリガラスを用いることが好ましい。 (Transparent substrate)
In the present invention, any material can be used as the transparent substrate 7 as long as it is a transparent material in the absorption region of the photoelectric conversion layer. For example, a glass substrate, a resin material substrate, or the like can be used. In particular, a material exhibiting transparency at the wavelength of the absorption region of the photoelectric conversion layer is preferable, and alkali-free glass is preferably used as such a material.
　（加熱部）
　本発明において、加熱部８は、上記の透明基板を５１０℃以上に加熱するために設けられる。加熱部８は、透明基板７を所定の温度まで加熱することができるものであれば、特に制限なく用いることができる。このような加熱部８は、ホットプレートにより直接伝導伝熱で加熱する方式、内部が加熱された炉による対流伝熱で加熱する方式、赤外ランプ等を照射する放射伝熱で加熱する方式のうちのいずれの加熱方式をも用いることができる。図１においては、ホットプレートによって透明基板を直接伝導伝熱で加熱方式を示している。 (Heating part)
In the present invention, the heating unit 8 is provided to heat the transparent substrate to 510 ° C. or higher. The heating unit 8 can be used without particular limitation as long as it can heat the transparent substrate 7 to a predetermined temperature. Such a heating unit 8 includes a method of heating by direct conduction heat transfer using a hot plate, a method of heating by convection heat transfer using a furnace in which the inside is heated, and a method of heating by radiation heat transfer irradiating an infrared lamp or the like. Any of these heating methods can be used. In FIG. 1, a transparent substrate is heated by direct conduction heat transfer using a hot plate.
　＜透明導電膜を成膜するステップ＞
　上記の透明基板７に対し、成膜原料溶液１の液滴を噴霧することにより、透明基板７上に透明導電膜を成膜する。本ステップでは、１２ｎｍ／ｓｅｃ以上の成膜速度で透明導電膜を成膜することを特徴とする。このような高速の成膜レートで透明導電膜を成膜することにより、ドーパントが再蒸発することなく透明導電膜内に取り込まれ、透明導電膜のシート抵抗を低減させることができる。上記の成膜速度は、１２ｎｍ／ｓｅｃ以上であることが好ましく、より好ましくは１５ｎｍ／ｓｅｃ以上である。一方、上記の透明基板７の成膜速度の上限は、３０ｎｍ／ｓｅｃ以下であることが好ましく、より好ましくは２０ｎｍ／ｓｅｃ以下である。２０ｎｍ／ｓｅｃを超える成膜速度で透明導電膜を成膜すると、基板温度が低下すること等により結晶配向性といった膜質が劣化するという問題があるため好ましくない。 <Step of depositing transparent conductive film>
A transparent conductive film is formed on the transparent substrate 7 by spraying droplets of the film forming raw material solution 1 on the transparent substrate 7. In this step, the transparent conductive film is formed at a film formation rate of 12 nm / sec or more. By forming the transparent conductive film at such a high film formation rate, the dopant is taken into the transparent conductive film without re-evaporation, and the sheet resistance of the transparent conductive film can be reduced. The film formation rate is preferably 12 nm / sec or more, more preferably 15 nm / sec or more. On the other hand, the upper limit of the film forming rate of the transparent substrate 7 is preferably 30 nm / sec or less, and more preferably 20 nm / sec or less. If a transparent conductive film is formed at a film formation rate exceeding 20 nm / sec, there is a problem that the film quality such as crystal orientation deteriorates due to a decrease in the substrate temperature or the like, which is not preferable.
　ここで、成膜原料溶液１から液滴５を形成する方法としては、成膜原料溶液１を０．１μｍ以上数十μｍ以下の平均粒子径の液滴５にするものであれば、どのような方法を用いてもよく、たとえばスプレー方式、超音波方式等を用いることができる。図１においては、成膜原料溶液１に高圧状態のガスを印加して微細スリットノズルから微細液滴にするスプレー方式の液滴発生部６を示している。 Here, as a method of forming the droplets 5 from the film forming raw material solution 1, any method can be used as long as the film forming raw material solution 1 is formed into droplets 5 having an average particle diameter of 0.1 μm to several tens μm. For example, a spray method, an ultrasonic method, or the like can be used. FIG. 1 shows a spray-type droplet generator 6 that applies a high-pressure gas to the film-forming raw material solution 1 to form fine droplets from a fine slit nozzle.
　スプレー方式は、液体およびキャリアガスの２流体を混合して、スプレーノズル先端部から液滴を噴出す２流体スプレー方式を用いることが好ましい。スプレー方式では、成膜原料溶液が透明基板の直前で液滴発生部を通して液滴となる。このため、スプレーノズル先端まで成膜原料溶液が搬送される。このとき液滴は、高圧のキャリアガスによって形成されることから、透明基板には液滴およびキャリアガスが噴き付けられる。 The spray method is preferably a two-fluid spray method in which two fluids, a liquid and a carrier gas, are mixed and a droplet is ejected from the tip of the spray nozzle. In the spray method, the film forming raw material solution becomes droplets through the droplet generation unit immediately before the transparent substrate. For this reason, the film-forming raw material solution is conveyed to the tip of the spray nozzle. At this time, since the droplet is formed by a high-pressure carrier gas, the droplet and the carrier gas are sprayed onto the transparent substrate.
　また、液滴の搬送方向に指向性を持たせるために、キャリアガスを用いてもよい。キャリアガスとしては、圧縮空気、Ｎ2、Ｈ2、水蒸気、Ｏ2、またはこれらの１種以上の混合物を用いることができる。 Further, a carrier gas may be used in order to provide directivity in the droplet transport direction. As the carrier gas, compressed air, N 2 , H 2 , water vapor, O 2 , or a mixture of one or more of these can be used.
　このようなスプレーノズルは、成膜原料溶液の種類やキャリアガス、成膜原料溶液の噴出時の印加圧力に耐え得る材料であれば、いかなる材料をも用いることができる。スプレーノズルは、たとえば金属および樹脂材料によって作製される。 Any material can be used for the spray nozzle as long as it can withstand the type of film forming raw material solution, the carrier gas, and the pressure applied when the film forming raw material solution is ejected. The spray nozzle is made of, for example, a metal and a resin material.
　超音波方式は、溶液ボトルに取り付けられた液滴発生部６から成膜原料溶液１に超音波を印加することによって、透明基板７から液滴を発生させるものである。液滴自体には運動エネルギーがないため、キャリアガスによって液滴を搬送する。キャリアガスとしては、上述のスプレー方式に用いるものと同様のものを用いることができる。 In the ultrasonic method, droplets are generated from the transparent substrate 7 by applying ultrasonic waves to the film forming raw material solution 1 from the droplet generator 6 attached to the solution bottle. Since the droplet itself has no kinetic energy, the droplet is transported by a carrier gas. As the carrier gas, the same gas as that used in the above-described spray method can be used.
　超音波霧化を用いて液滴を発生させる場合、超音波振動子によって液滴を発生させることが好ましい。超音波振動子は、比較的均一な平均粒子径の液滴を噴霧することができるため、液滴同士が凝集しにくくなるという利点がある。 When droplets are generated using ultrasonic atomization, it is preferable to generate droplets using an ultrasonic vibrator. Since the ultrasonic vibrator can spray droplets having a relatively uniform average particle diameter, there is an advantage that the droplets hardly aggregate.
　（送液ポンプ）
　図１に示される成膜装置において、送液ポンプ２は成膜原料溶液１をノズルヘッド４に供給するだけでなく、その供給量を調整する機能を有することが好ましい。 (Feed pump)
In the film forming apparatus shown in FIG. 1, the liquid feed pump 2 preferably has a function of adjusting the supply amount as well as supplying the film forming raw material solution 1 to the nozzle head 4.
　図１における成膜装置を用いて透明導電膜を成膜する場合、透明導電膜は、透明基板７または液滴発生部６のいずれか一方もしくは両方を走査させることによって、透明基板７上の全面に成膜する。透明導電膜は、図１に示されるように、１つの液滴発生部６によって成膜されてもよいし、２以上の液滴発生部６によって成膜されるものであってもよい。２以上の液滴発生部を透明基板の上面の全面に配列して液滴噴霧する場合、必ずしも透明基板７および液滴発生部６のいずれも走査しなくてもよい。 When forming a transparent conductive film using the film forming apparatus in FIG. 1, the transparent conductive film scans either one or both of the transparent substrate 7 and the droplet generator 6, so that the entire surface of the transparent substrate 7 is scanned. The film is formed. As shown in FIG. 1, the transparent conductive film may be formed by one droplet generator 6 or may be formed by two or more droplet generators 6. When two or more droplet generation units are arranged on the entire upper surface of the transparent substrate and droplets are sprayed, it is not always necessary to scan either the transparent substrate 7 or the droplet generation unit 6.
　（成膜原料溶液）
　本発明で用いられる成膜原料溶液１は、亜鉛、スズ、インジウム、カドミウム、ストロンチウム等の無機材料の有機金属または金属ハロゲン系化合物からなる成膜材料を１種または２種以上溶媒に溶解させたものである。かかる成膜原料溶液１は、上記有機金属または金属ハロゲン系化合物を、０．１～３ｍｏｌ／Ｌの濃度で溶解させることが一般的であるが、この濃度に限定されない。上記の成膜原料溶液１としては、スズおよびフッ素の化合物を含むことが好ましく、スズを含む有機金属化合物を含み、かつドーパント剤としてフッ素の化合物を含むものを用いることがより好ましい。ここで、成膜原料溶液に含まれるフッ素の化合物としては、フッ化水素、フッ化アンモニウム等を挙げることができる。また、成膜原料溶液に含まれるスズとしては、四塩化スズ、二塩化スズ、ジブチルスズジアセテート、テトラブチルスズを挙げることができる。 (Film forming raw material solution)
The film-forming raw material solution 1 used in the present invention is obtained by dissolving a film-forming material composed of an organic metal or a metal halide compound of an inorganic material such as zinc, tin, indium, cadmium, or strontium in one or more kinds of solvents. Is. The film forming raw material solution 1 generally dissolves the organometallic or metal halide compound at a concentration of 0.1 to 3 mol / L, but is not limited to this concentration. As said film-forming raw material solution 1, it is preferable to contain the compound of tin and a fluorine, and it is more preferable to use the thing containing the organometallic compound containing tin and containing the compound of fluorine as a dopant agent. Here, examples of the fluorine compound contained in the film forming raw material solution include hydrogen fluoride and ammonium fluoride. Examples of tin contained in the film forming raw material solution include tin tetrachloride, tin dichloride, dibutyltin diacetate, and tetrabutyltin.
　また、成膜原料溶液に用いられる溶媒は、水、有機溶剤、またはこれらの混合液を用いることができる。ここでの有機溶剤としては、たとえばメタノール、エタノール、アセトン、イソプロピルアルコール等を挙げることができるが、これらに限定されるものではない。 Further, water, an organic solvent, or a mixture thereof can be used as the solvent used for the film forming raw material solution. Examples of the organic solvent here include methanol, ethanol, acetone, isopropyl alcohol, and the like, but are not limited thereto.
　さらに、成膜原料溶液は、上記の溶媒および成膜材料に加え、さらに添加物を含んでいてもよい。このような添加物としては、ドーパント剤、界面活性剤、ｐＨ調整剤等を挙げることができるが、これらの添加剤の２種以上を混合して用いることが好ましい。 Further, the film forming raw material solution may further contain an additive in addition to the solvent and the film forming material. Examples of such additives include a dopant agent, a surfactant, a pH adjuster, and the like, but it is preferable to use a mixture of two or more of these additives.
　ここで、ドーパント剤としては、Ｍｇ、Ｇａ、Ａｌ、Ｔｅ、Ａｇ、Ｇｅ、Ｃｕ、Ｓｒ、Ｂ、Ｓｂ、Ｆ、Ａｓ等を含む材料を挙げることができ、界面活性剤としては、低級有機化合物等を挙げることができる。ｐＨ調整剤としては、硝酸、酢酸、硫酸、フッ酸、過酸化水素、酪酸、塩酸、アンモニア等を挙げることができる。 Here, examples of the dopant agent include materials containing Mg, Ga, Al, Te, Ag, Ge, Cu, Sr, B, Sb, F, As, and the like, and examples of the surfactant include lower organic compounds. Etc. Examples of the pH adjuster include nitric acid, acetic acid, sulfuric acid, hydrofluoric acid, hydrogen peroxide, butyric acid, hydrochloric acid, and ammonia.
　（透明導電膜）
　上記の成膜方法によって成膜された透明導電膜の膜厚は、シート抵抗、ヘイズ率、透過率の仕様を満たすために、６００ｎｍ以上１２００ｎｍ以下の範囲となる。 (Transparent conductive film)
The film thickness of the transparent conductive film formed by the above film forming method is in the range of 600 nm to 1200 nm in order to satisfy the specifications of sheet resistance, haze ratio, and transmittance.
　このような透明導電膜のＸ線回折パターンにおいて、（３０１）面の回折ピーク強度は、（３０１）面以外のいずれの結晶面の回析ピーク強度よりも大きいことを特徴とする。（３０１）面からのピークが大きいということは、フッ素を十分に取り込んだ結晶粒でも結晶性が高いことを示唆しており、低抵抗化と光透過率およびヘイズ率の仕様を満たす透明導電膜となる。 In the X-ray diffraction pattern of such a transparent conductive film, the diffraction peak intensity on the (301) plane is larger than the diffraction peak intensity on any crystal plane other than the (301) plane. The large peak from the (301) plane suggests that even crystal grains that have sufficiently incorporated fluorine have high crystallinity, and the transparent conductive film that satisfies the specifications of low resistance, light transmittance, and haze ratio It becomes.
　さらに、上記の透明導電膜のＸ線回折パターンにおいて、（３０１）面の回折ピーク強度の半値幅から算出した結晶粒の平均粒子径は、（３０１）面以外のいずれの結晶面の回析ピーク強度の半値幅から算出した結晶粒の平均粒子径よりも大きいことが好ましい。このことは、フッ素を十分に取り込んだ結晶粒が支配的に成長していることを示唆しており、より低抵抗で光透過率およびヘイズ率の仕様を満たす透明導電膜であることを意味する。 Furthermore, in the X-ray diffraction pattern of the transparent conductive film, the average particle diameter of the crystal grains calculated from the half-value width of the diffraction peak intensity of the (301) plane is the diffraction peak of any crystal plane other than the (301) plane. It is preferably larger than the average particle diameter of the crystal grains calculated from the half width of the strength. This suggests that crystal grains sufficiently incorporating fluorine are growing dominantly, and means that the transparent conductive film satisfies the specifications of light transmittance and haze ratio with lower resistance. .
　以下、実施例を挙げて本発明をより詳細に説明するが、本発明はこれらに限定されるものではない。 Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
　（実施例１）
　本実施例では、まず、成膜原料溶液１として、水２００ｍＬに対し、塩化スズ・５水和物の濃度を０．９ｍｏｌ／Ｌとし、フッ化アンモニウムの濃度を０．９ｍｏｌ／Ｌとなるように溶解させた。さらにｐＨ調整剤として３５％塩酸を２０ｍＬ混合した。一方、加熱部８としてはホットプレートを用い、該ホットプレート上に、ガラス基板からなる透明基板７をセットした。そして、ホットプレートの温度を５９０℃に設定し、透明基板７の表面温度が５１３℃となるまで透明基板７を加熱した。なお、透明基板７の表面温度は、Ｋ熱電対によって測定した。 Example 1
In this example, first, as the film forming raw material solution 1, the concentration of tin chloride pentahydrate is 0.9 mol / L and the concentration of ammonium fluoride is 0.9 mol / L with respect to 200 mL of water. Dissolved in. Furthermore, 20 mL of 35% hydrochloric acid was mixed as a pH adjuster. On the other hand, a hot plate was used as the heating unit 8, and a transparent substrate 7 made of a glass substrate was set on the hot plate. Then, the temperature of the hot plate was set to 590 ° C., and the transparent substrate 7 was heated until the surface temperature of the transparent substrate 7 reached 513 ° C. The surface temperature of the transparent substrate 7 was measured with a K thermocouple.
　上記の成膜原料溶液１を送液ポンプ２によってノズルヘッド４に送り出し、高圧気体で圧縮して液滴化するスプレー方式によって液滴を発生させた。ノズルヘッド４からガラス基板に液滴を到着させるために、２００Ｌ／分の流量の圧縮空気スプレーを噴出し方向に流した。そして、ガラス基板およびノズルヘッド４を固定したままで、搬送ステージを３ｍｍ／秒の速度で搬送させた。その後、ノズルヘッド４から透明基板７に向けて、ガラス基板に１２ｍＬ／分の流量で成膜原料溶液の液滴を７５秒間吹きつけることにより、ガラス基板上にＳｎＯ2からなる透明導電膜を成膜した。なお、このときにガラス基板上に透明導電膜が成膜されている時間は６０秒であった。 The film-forming raw material solution 1 was sent to the nozzle head 4 by the liquid feed pump 2, and droplets were generated by a spray method in which the film-forming raw material solution 1 was compressed with high-pressure gas into droplets. In order to cause the droplets to reach the glass substrate from the nozzle head 4, a compressed air spray having a flow rate of 200 L / min was flowed in the ejection direction. And the conveyance stage was conveyed at the speed | rate of 3 mm / sec, with the glass substrate and the nozzle head 4 fixed. Then, a transparent conductive film made of SnO 2 is formed on the glass substrate by spraying droplets of the film forming raw material solution on the glass substrate at a flow rate of 12 mL / min for 75 seconds from the nozzle head 4 toward the transparent substrate 7. Filmed. At this time, the time during which the transparent conductive film was formed on the glass substrate was 60 seconds.
　（実施例２、比較例２）
　実施例１に対し、下記の表１に示すように、成膜原料溶液の供給速度を変更して成膜速度を代えたことが異なる他は、実施例１と同様の方法によって実施例２および比較例２の透明導電膜を成膜した。 (Example 2, comparative example 2)
In contrast to Example 1, as shown in Table 1 below, Example 2 and Example 2 were performed in the same manner as in Example 1 except that the film formation rate was changed by changing the supply rate of the film formation raw material solution. The transparent conductive film of Comparative Example 2 was formed.
　（実施例３、比較例１）
　実施例１に対し、下記の表１に示すように、成膜原料溶液の供給速度および成膜速度を代えるとともに、成膜時のステージを静止させて６０秒間成膜した。これらのことが異なる他は、実施例１と同様の方法によって実施例３および比較例１の透明導電膜を成膜した。 (Example 3, Comparative Example 1)
In contrast to Example 1, as shown in Table 1 below, the film formation raw material solution supply rate and the film formation rate were changed, and the film formation stage was kept stationary to form a film for 60 seconds. Except for these differences, the transparent conductive films of Example 3 and Comparative Example 1 were formed by the same method as in Example 1.
　（実施例４）
　実施例３に対し、下記の表１に示すように、基板温度、成膜原料溶液の供給速度および成膜速度を代えて６０秒間成膜した。これらのことが異なる他は、実施例３と同様の方法によって実施例４の透明導電膜を成膜した。 Example 4
With respect to Example 3, as shown in Table 1 below, film formation was performed for 60 seconds by changing the substrate temperature, the film formation raw material solution supply rate, and the film formation rate. Except for these differences, the transparent conductive film of Example 4 was formed by the same method as in Example 3.
　（比較例３）
　実施例１に対し、下記の表１に示すように、成膜時の透明基板の温度を代えたことが異なる他は、実施例１と同様の方法によって比較例３の透明導電膜を成膜した。 (Comparative Example 3)
As shown in Table 1 below, the transparent conductive film of Comparative Example 3 was formed by the same method as Example 1 except that the temperature of the transparent substrate during film formation was changed as shown in Table 1 below. did.
　（比較例４）
　実施例３に対し、下記の表１に示すように、成膜時の透明基板の温度を代えたことが異なる他は、実施例３と同様の方法によって比較例４の透明導電膜を成膜した。 (Comparative Example 4)
Compared to Example 3, as shown in Table 1 below, the transparent conductive film of Comparative Example 4 was formed by the same method as Example 3 except that the temperature of the transparent substrate during film formation was changed. did.
　＜評価結果＞
　各実施例および各比較例で作製した透明導電膜の膜厚を触針式表面形状測定器（製品名：ＤＥＫＴＡＫ（株式会社アルバック製））によって測定したところ、下記の表１に示される結果となった。ここで測定した膜厚を成膜時間で除することにより、成膜速度を算出した。また、透明導電膜のシート抵抗（Ω／□）を低抵抗率計（製品名：ロレスターＧＰ（三菱化学アナリテック株式会社製））によって測定した。さらに、各実施例および各比較例で作製した透明導電膜のヘイズ率（％）および透過率（％）を分光ヘイズメーター（製品名：ＴＣ－１８００Ｈ（有限会社東京電色製））によって測定した。これらの測定結果を以下の表１に示す。 <Evaluation results>
When the film thickness of the transparent conductive film produced in each example and each comparative example was measured with a stylus type surface shape measuring instrument (product name: DEKTAK (manufactured by ULVAC, Inc.)), the results shown in Table 1 below were obtained. became. The film formation rate was calculated by dividing the film thickness measured here by the film formation time. Further, the sheet resistance (Ω / □) of the transparent conductive film was measured with a low resistivity meter (product name: Lorester GP (manufactured by Mitsubishi Chemical Analytech Co., Ltd.)). Furthermore, the haze ratio (%) and the transmittance (%) of the transparent conductive film prepared in each example and each comparative example were measured with a spectral haze meter (product name: TC-1800H (manufactured by Tokyo Denshoku Co., Ltd.)). . The measurement results are shown in Table 1 below.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　さらに、各実施例および比較例の透明導電膜に対し、Ｃｕ－Ｋα（λ＝０．１５４ｎｍ）を線源に用いてＸ線回折による結晶構造解析をθ－２θ法にて行なった。そのＸ線回折プロファイルを図２に示す。図２は、各実施例および比較例の透明導電膜の結晶構造解析を行なったときのＸ線回折プロファイルである。図２に示されるＸ線回折プロファイルに基づいて、各ピークの位置（２θB）、強度およびその強度の半値幅（ＦＷＨＭ）、ならびに結晶粒のサイズｔを算出した。その結果を表２に示す。 Further, for the transparent conductive films of the examples and comparative examples, crystal structure analysis by X-ray diffraction was performed by the θ-2θ method using Cu—Kα (λ = 0.154 nm) as a radiation source. The X-ray diffraction profile is shown in FIG. FIG. 2 is an X-ray diffraction profile when the crystal structure analysis of the transparent conductive film of each example and comparative example is performed. Based on the X-ray diffraction profile shown in FIG. 2, the position of each peak (2θ B ), the intensity and the full width at half maximum (FWHM), and the crystal grain size t were calculated. The results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　なお、結晶粒のサイズｔは、膜厚方向の結晶サイズを意味するものであり、以下のScherrerの式（１）に基づいて算出した。 The crystal grain size t means the crystal size in the film thickness direction, and was calculated based on the following Scherrer equation (1).
　　　　ｔ＝０．９λ／ＢｃｏｓθB　　・・・（１）
　なお、上記式（１）中の各記号はそれぞれ、ｔ：結晶サイズ（ｎｍ）、λ：線源波長（ｎｍ）、Ｂ：半値幅（ラジアン）、θB：ピーク位置２θB×１／２（ｄｅｇ）を示す。 t = 0.9λ / B cos θ B (1)
Each symbol in the above formula (1) is t: crystal size (nm), λ: source wavelength (nm), B: half width (radian), θ B : peak position 2θ B × 1/2. (Deg).
　＜考察＞
　図２に示されるＸ線回析プロファイルから明らかなように、各実施例の透明導電膜は、（３０１）面が優先配向面となっている。一方、比較例の透明導電膜は（２００）面が優先配向面となっている。また、表２に示される結果から明らかなように、各実施例の透明導電膜は、（３０１）面配向した結晶が最大の結晶粒径となっているのに対し、比較例１においては（２００）面配向した結晶が膜中で最大の結晶粒径となっている。 <Discussion>
As is clear from the X-ray diffraction profile shown in FIG. 2, in the transparent conductive film of each example, the (301) plane is the preferential orientation plane. On the other hand, the transparent conductive film of the comparative example has a (200) plane as a preferential orientation plane. Further, as is clear from the results shown in Table 2, the transparent conductive film of each example has a maximum crystal grain size of (301) -oriented crystals, while in Comparative Example 1 ( 200) A plane-oriented crystal has the largest crystal grain size in the film.
　表１に示される結果から明らかなように、実施例１～３の透明導電膜は、ヘイズ率および透過率が高く、かつシート抵抗が低いという性質を示す。これに対し、比較例１の透明導電膜は、透過率は高いが、ヘイズ率が低く、またシート抵抗が高いという性質を示す。 As is clear from the results shown in Table 1, the transparent conductive films of Examples 1 to 3 have the properties of high haze and transmittance and low sheet resistance. On the other hand, the transparent conductive film of Comparative Example 1 has the properties of high transmittance but low haze ratio and high sheet resistance.
　以上の結果から、１２ｎｍ／ｓ以上の成膜速度で透明導電膜を成膜することにより、ヘイズ率および透過率が高く、かつシート抵抗が低い透明導電膜を成膜することができることが明らかとなった。この理由は、高速の成膜速度で成膜することによってフッ素の再蒸発を抑制し、（３０１）面に配向した透明導電膜を優先して形成したことによるものと考えられる。 From the above results, it is clear that a transparent conductive film having a high haze ratio and transmittance and a low sheet resistance can be formed by forming a transparent conductive film at a deposition rate of 12 nm / s or more. became. The reason for this is thought to be that the re-evaporation of fluorine is suppressed by forming the film at a high film formation rate, and the transparent conductive film oriented in the (301) plane is preferentially formed.
　以上のように本発明の実施の形態および実施例について説明を行なったが、上述の各実施の形態および実施例の構成を適宜組み合わせることも当初から予定している。 Although the embodiments and examples of the present invention have been described above, it is also planned from the beginning to appropriately combine the configurations of the above-described embodiments and examples.
　今回開示された実施の形態および実施例はすべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は上記した説明ではなくて請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 It should be considered that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
　本発明の成膜方法によって成膜される透明導電膜は、バッファ層および下地層を成膜しなくても、光透過率およびヘイズ率が高く、かつシート抵抗が低い透明導電膜を成膜することができる。このため、本発明の透明導電膜は、薄膜太陽電池、特に薄膜シリコン太陽電池用の透明電極として好適に使用することができる。 The transparent conductive film formed by the film forming method of the present invention forms a transparent conductive film having a high light transmittance and a high haze ratio and a low sheet resistance without forming a buffer layer and an underlayer. be able to. For this reason, the transparent conductive film of this invention can be used conveniently as a transparent electrode for thin film solar cells, especially a thin film silicon solar cell.
　１　成膜原料溶液、２　送液ポンプ、３　キャリアガス、４　ノズルヘッド、５　液滴、６　液滴発生部、７　透明基板、８　加熱部。 1 film forming raw material solution, 2 liquid feed pump, 3 carrier gas, 4 nozzle head, 5 droplets, 6 droplet generation unit, 7 transparent substrate, 8 heating unit.

Claims (4)

  1. 　透明基板（７）を５１０℃以上に加熱するステップと、
    　前記透明基板（７）に対し、成膜原料溶液（１）の液滴（５）を噴霧することにより、前記透明基板（７）上に透明導電膜を成膜するステップとを含み、
    　前記透明導電膜を成膜するステップは、１２ｎｍ／ｓｅｃ以上の成膜速度で透明導電膜を成膜する、透明導電膜の成膜方法。     Heating the transparent substrate (7) to 510 ° C. or higher;
    Forming a transparent conductive film on the transparent substrate (7) by spraying droplets (5) of the film forming raw material solution (1) on the transparent substrate (7),
    The step of forming the transparent conductive film is a method of forming a transparent conductive film, wherein the transparent conductive film is formed at a film formation rate of 12 nm / sec or more.
  2. 　前記成膜原料溶液（１）は、スズおよびフッ素の化合物を含む、請求項１に記載の透明導電膜の成膜方法。 The method for forming a transparent conductive film according to claim 1, wherein the film forming raw material solution (1) contains a compound of tin and fluorine.
  3. 　請求項１または２に記載の成膜方法によって成膜された透明導電膜であって、
    　前記透明導電膜のＸ線回折パターンにおいて、（３０１）面の回折ピーク強度は、（３０１）面以外のいずれの結晶面の回析ピーク強度よりも大きい、透明導電膜。     A transparent conductive film formed by the film forming method according to claim 1 or 2,
    The X-ray diffraction pattern of the transparent conductive film, wherein the (301) plane has a diffraction peak intensity greater than the diffraction peak intensity of any crystal plane other than the (301) plane.
  4. 　前記透明導電膜のＸ線回折パターンにおいて、（３０１）面の回折ピーク強度の半値幅から算出した結晶粒の平均粒子径は、（３０１）面以外のいずれの結晶面の回析ピーク強度の半値幅から算出した結晶粒の平均粒子径よりも大きい、請求項３に記載の透明導電膜。 In the X-ray diffraction pattern of the transparent conductive film, the average particle diameter calculated from the half-value width of the diffraction peak intensity on the (301) plane is half the diffraction peak intensity on any crystal plane other than the (301) plane. The transparent conductive film of Claim 3 which is larger than the average particle diameter of the crystal grain calculated from the value range.
PCT/JP2011/069550 2011-04-25 2011-08-30 Transparent conductive film and method for forming same WO2012147219A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020080275A (en) * 2018-11-14 2020-05-28 トヨタ自動車株式会社 Method for manufacturing fuel cell separator

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7280751B2 (en) * 2019-06-05 2023-05-24 東芝三菱電機産業システム株式会社 Deposition method

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5945926A (en) * 1982-09-08 1984-03-15 Nippon Sheet Glass Co Ltd Formation of film of tin oxide on substrate
JP2000044238A (en) * 1998-07-22 2000-02-15 Matsushita Battery Industrial Co Ltd Production of tin dioxide film and solar cell
JP2002146536A (en) * 2000-11-08 2002-05-22 Japan Science & Technology Corp Low-temperature deposition method for thin film of tin oxide
JP2007290958A (en) * 2006-03-31 2007-11-08 Dainippon Printing Co Ltd Manufacturing method of metal oxide film

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5945926A (en) * 1982-09-08 1984-03-15 Nippon Sheet Glass Co Ltd Formation of film of tin oxide on substrate
JP2000044238A (en) * 1998-07-22 2000-02-15 Matsushita Battery Industrial Co Ltd Production of tin dioxide film and solar cell
JP2002146536A (en) * 2000-11-08 2002-05-22 Japan Science & Technology Corp Low-temperature deposition method for thin film of tin oxide
JP2007290958A (en) * 2006-03-31 2007-11-08 Dainippon Printing Co Ltd Manufacturing method of metal oxide film

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
SOLIMAN ET AL.: "Effect of fluorine doping and spraying technique on the properties of tin oxide films", RENEWABLE ENERGY, vol. 23, 2001, pages 463 - 470 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020080275A (en) * 2018-11-14 2020-05-28 トヨタ自動車株式会社 Method for manufacturing fuel cell separator
JP7031564B2 (en) 2018-11-14 2022-03-08 トヨタ自動車株式会社 Manufacturing method of separator for fuel cell

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