JPS5934654B2 - Manufacturing method of transparent conductive film - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a transparent conductive film.

Currently, transparent conductive films formed on transparent substrates such as glass and plastic are being used in many fields, not only in electronic engineering fields such as electro-optical elements and heating elements, but also as drip-proof or anti-fog glass. .

Conventionally, various methods have been proposed as methods for obtaining the above-mentioned transparent conductive film.

Specifically, a method of spraying an aqueous solution of tin halide onto a heated glass plate, a method of forming a thin film by vapor depositing tin oxide, a method of vapor depositing titanium and then performing forced oxidation to obtain a titanium oxide film with an appropriate resistance value. Examples include a method of vapor depositing gold to obtain a gold vapor-deposited thin film, and a method of vapor depositing indium oxide to obtain a thin film.

However, it is difficult to obtain a uniform conductive film using methods such as spraying, and even in vacuum deposition, the materials are expensive, the vapor pressure is low, the deposition conditions are unstable, and the process is complicated. It has been difficult to achieve uniformity in both transparency and conductivity with good reproducibility.

Further, since the reflectance of a gold conductive film having good conductivity is too high, it is insufficient as a transparent conductive film unless antireflection treatment is further applied. In addition, materials that have been forcibly oxidized, such as titanium oxide, have various practical drawbacks, such as a tendency for conductivity to become somewhat unstable. The present inventors kept these difficulties in mind and, as a result of intensive research, reduced Ξ molybdenum oxide to conductive molybdenum pentoxide by the reducing action of silicon oxide during the vapor deposition process, thereby forming conductive molybdenum-acid. I
By forming a silicon oxide-based transparent conductive film, a transparent conductive film with high transparency and stable conductivity can be easily produced, and the ratio of molybdenum trioxide to silicon oxide can be reduced. It was discovered that a transparent conductive film having an arbitrary conductivity can be easily obtained by changing the conductivity, and the present invention was completed based on this knowledge.

That is, the gist of the present invention is to simultaneously deposit molybdenum trioxide and silicon oxide on a substrate, and simultaneously reduce the molybdenum trioxide to molybdenum pentoxide by the reducing action of silicon oxide, thereby forming a conductive molybdenum oxide-silicon oxide system. A method for producing a transparent conductive film characterized by forming a transparent conductive film.

Hereinafter, the present invention will be explained in detail.

Molybdenum trioxide and silicon oxide are mixed and deposited from the same vapor deposition source (5), or each is vaporized simultaneously from separate vapor deposition sources to form a vapor deposited film on the substrate soil, and simultaneously with the vapor deposition, the reducing action of silicon oxide is applied. Molybdenum trioxide is reduced to molybdenum pentoxide to form a transparent conductive film based on conductive molybdenum oxide and silicon monoxide.

In the manufacturing method of the present invention, various materials such as glass, plastic, ceramic cloth, and paper can be used as the substrate.

Next, in the production method of the present invention, silicon oxide is a compound of silicon and oxygen, and the ratio of silicon to oxygen can be up to 0 to 2.

In the present invention, it is sufficient that the silicon oxide as a whole has reducibility before forming the transparent conductive film, so a mixture of various silicon and oxygen ratios may be used. However, it can be said that it is preferable for the ratio of silicon to oxygen to be constant from the viewpoint of adjusting the electrical conductivity. Next, in the production method of the present invention, as a vapor deposition method, resistance heating, electron beam heating, induction heating, thermal radiation heating, vacuum heating vapor deposition, sputtering, etc. can be applied. According to the production method of the present invention, molybdenum trioxide is reduced by silicon oxide and converted to molybdenum pentoxide, but some of the molybdenum trioxide may contain intermediate compounds of pentavalent and hexavalent oxides of molybdenum. Conceivable.

In the case of the production method of the present invention, regardless of whether the vapor deposition sources are the same or different, molybdenum trioxide has a higher vapor pressure than silicon oxide, so molybdenum trioxide is vapor-deposited first and exists in large quantities near the substrate, and near the surface. is almost exclusively silicon oxide.

For this reason, it is possible to insulate the surface layer by increasing the amount of oxidation oxide and to impart conductivity to the surface layer in the same process. According to this method, as described above, in the vapor deposition layer, molybdenum oxide is present in the vicinity of the substrate, and since the surface is almost only silicon oxide, the silicon oxide acts as a protective film and has good stability. According to the production method of the present invention,
By varying the ratio between the amount of molybdenum trioxide and the amount of silicon oxide deposited, the conductivity of the deposited layer can be adjusted.

Further, the film thickness is about 500 to 5000 mm. The transparent conductive film obtained by the production method of the present invention has high transparency, exhibits stable conductivity, and has little reflected light.

Further, the surface can be coated with silicon oxide at the manufacturing stage. In this case, silicon oxide acts as a protective layer, so that a transparent conductive film with very stable conductivity and high strength can be obtained. Silicon oxide and molybdenum trioxide, which are the materials used to manufacture the transparent conductive film according to the manufacturing method of the present invention, are both inexpensive and easily available. It is easy to deposit, and a uniform layer can be obtained.

In addition, according to the production method of the present invention, vapor deposition can be carried out while the substrate is at room temperature.
For example, transparent conductive films can be formed on materials such as plastics. The transparent conductive film obtained by the production method of the present invention, which has many excellent features as described above, can be applied to a wide range of fields such as electro-optical elements, heating elements, and drip-proof and anti-fog glass. As detailed above, according to the manufacturing method of the present invention, a transparent conductive film with high transparency, stable conductivity, little reflected light, and uniform layer thickness can be produced using easily available materials. Not only can it be easily formed, but also a transparent conductive film of arbitrary conductivity can be obtained.

Further, according to the manufacturing method of the present invention, since the substrate can be deposited at room temperature, a transparent conductive film can be formed even on a substrate that cannot withstand high temperatures. Next, an example is shown,
Further, the present invention will be specifically explained.

Example 1 Crucible type thermal radiation heating evaporation device (2×10-3T0rr1
200'C) Molybdenum trioxide and silicon oxide were mixed at a weight ratio of 1:10, placed in a crucible, and deposited on a glass plate, resulting in a surface resistance of 700Ω at a film thickness of 100A, and 1MΩ at a film thickness of 1000λ after continued evaporation. A molybdenum oxide silicon monoxide-based transparent conductive film with a low value near the substrate was obtained.

Example 2 In boat-type resistance heating evaporation (2×10-3T0rr), molybdenum trioxide alone and SiO alone were placed in two boats at a weight ratio of 1:100, respectively, and evaporated. It showed a surface resistance value of 1KΩ after deposition and 200MΩ after deposition by 1000 people.

Transparency was excellent and there was little reflection.

Claims (1)

[Claims] 1. Molybdenum trioxide and silicon oxide are simultaneously vapor-deposited on a substrate, and at the same time as the vapor deposition, molybdenum trioxide is reduced to molybdenum pentoxide by the reduction action of silicon oxide, forming a conductive molybdenum oxide-silicon oxide based transparent conductive film. A transparent conductive manufacturing method characterized by: