JPH04277408A - Transparent electrode - Google Patents

Abstract

PURPOSE:To provide a new transparent electrode film whose electric resistivity is extremely low, and light transmissivity is extremely high, and in which etching property is not damaged upon photolithography and a material used for it. CONSTITUTION:A transparent electrode film comprises indium oxide as a matrix, 1 to 20weight% of tin oxide, and 0.05 to 5weight% of titanium oxide. A material used for producing said transparent electrode film such as a sintered body for vacuum evaporating the transparent electrode by sintering indium oxide powder which contains 1 to 20weight% of tin oxide, and 0.05 to 5weight% of titanium oxide; or pulverunt body for the transparent electrode, obtained by pulverizing the sintered body; or an alloy, for vacuum evaporating the transparent electrode, which contains 60 to 98.9weight% of indium, 1 to 20weight% of tin, and 0.1 to 20weight% of titanium.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to electrodes for liquid crystal display elements,
This invention relates to a new transparent electrode used in transparent heaters, solar cells, etc.

0002

[Prior Art] High transmittance for visible light, and
A characteristic of transparent electrodes is that they exhibit high electrical conductivity. Conventionally, the material for transparent electrodes is SnO doped with Sb.
However, due to its high resistance and difficulty in etching with photolithography, SO2 is
~10% by weight of In2O3 (hereinafter referred to as ITO)
is the mainstay.

Demand for transparent electrodes using such materials is increasing day by day, including electrodes for liquid crystal display elements and transparent heaters used in windows of automobiles, trains, airplanes, and the like.

[0004] Among these, displays are an interface between computers and other electrical equipment and humans, so
It has become larger and more visible. However, as displays have become larger, the distance between the transparent electrodes has become longer, and the resistance value has come to affect the response speed of the display. The delay in response speed is due to the fact that when the resistance value of the electrode is high, the current that flows at a constant voltage becomes small, and the charging of electric charge becomes slow.

[0005] This can be prevented by making the transparent electrode thicker or made of metal, but on the other hand, it has the disadvantage that the light transmittance becomes poor and the function of the transparent electrode is reduced.

[0006] Furthermore, it is thought that the need for solar cells that extract electricity from the sun as clean energy will increase more and more in the future, but in this case as well, it is possible to use electrode materials with lower resistance at the same cost. Moreover, it is increasingly being sought after as a material that does not deteriorate in permeability.

The mainstream method for manufacturing transparent electrode thin films is the sputtering method or EB evaporation method, which is a method of vapor deposition on glass substrates or plastic substrates in a vacuum. Resistivity changes. Furthermore, the transparent electrode materials used in these vapor deposition methods are also a factor in changing the resistivity.

[0008]

[Problems to be Solved by the Invention] The present invention provides a novel method that has lower resistance, higher transmittance to visible light and ultraviolet light, and excellent physical properties such as photolithographic etching characteristics and life span. The present invention aims to provide a transparent electrode film and a transparent electrode material for forming the electrode film.

[0009]

[Means for Solving the Problems] The present invention uses indium oxide as a matrix as a transparent electrode film, and tin oxide 1 to 1.
The purpose can be achieved by including 20% by weight and 0.05 to 5% by weight of titanium oxide.

[0010] Also, a sintered body for transparent electrode deposition, which is obtained by sintering indium oxide powder containing 1 to 20% by weight of tin oxide powder and 0.05 to 5% by weight of titanium oxide powder, or 1 to 20% by weight of tin oxide powder. %, titanium oxide powder to 0.
The above-mentioned transparent electrode film can be manufactured by using a transparent electrode material such as a transparent electrode powder obtained by sintering and pulverizing indium oxide powder containing 05 to 5% by weight.

[0011] The sintered body for transparent electrode deposition is used for manufacturing transparent electrode thin films, and the transparent electrode powder is also used for manufacturing thick transparent electrode films in the form of paste for thick films. Therefore, the transparent electrode film of the present invention is applicable not only to thin films but also to thick films.

[0012] In the production of an ITO film by sputtering, In
It has also been carried out by DC sputtering an alloy target of and Sn in an oxygen atmosphere. Similarly, by DC sputtering an alloy for transparent electrode deposition containing 60 to 98.9% by weight of indium, 1 to 20% by weight of tin, and 0.1 to 20% by weight of titanium in an oxygen atmosphere, the above transparent electrode can be formed. Membranes can be manufactured.

[0013]

[Example 1] In2O392% by weight, SnO25% by weight
A mixture of powders containing 20.5% by weight of TiO was press-molded and sintered to prepare a sputtering target. A transparent electrode film was deposited on a glass substrate by sputtering using this target. The film thickness was 1400 angstroms. This film was etched with a 3% HCl aqueous solution heated to 60° C. to form a pattern, and transmittance, resistivity, etc. were measured.

As a result, the light transmittance is extremely high at 92% at a wavelength of 550 nanometers, and the electrical resistivity is 1×10-4.
Ωcm, and it was found that the electrical resistivity was comparable to that of metal. It was also revealed that the number of abnormal discharges during sputtering was about one-fifth less than that of conventional ITO materials, indicating that it is extremely efficient. moreover,
It was found that a good film could be obtained even if the sputtering speed was higher than that of the conventional 1TO film. It was also found that the etching properties of the film were extremely good.

[0015]

[Example 2] In 94.5% by weight, Sn 5% by weight, Ti
An alloy was prepared by heating and melting 0.1% by weight at about 250°C, which was then cast and processed to create a sputtering target with a size of 6 inches φ x 5 tons. However, Ti is Sn
The melting of the Ti was facilitated by using an alloy that had been pre-melted in the molten metal. A transparent electrode film was deposited on a glass substrate by sputtering using this target. Film thickness is 100
It was 0 angstrom. During sputtering, argon gas and pure oxygen gas were introduced into the vapor deposition machine. The ratio of argon gas to oxygen gas was 8:2 by volume.

After this film was annealed in the atmosphere at 300° C. for 2 hours, transmittance, resistivity, etc. were measured. As a result, it was found that the light transmittance was 93% at a wavelength of 550 nanometers, and the electrical resistivity was 1.2×10 −4 Ωcm, indicating extremely excellent film quality.

[0017]

Effects of the Invention The present invention is characterized by extremely low resistivity and extremely high light transmittance compared to ITO films, which have conventionally been most widely used as transparent electrodes. Additionally, it has excellent physical properties such as photolithographic etching characteristics and film life. moreover,
It does not require any change in the transparent electrode material or the manufacturing process of the transparent electrode film, and has the advantage of being highly economical.

Claims (4)

[Claims] [Claim 1] Indium oxide is used as a matrix,
Tin oxide 1-20% by weight, titanium oxide 0.05-5%
A transparent electrode film characterized in that it contains % by weight. 2. A sintered body for transparent electrode deposition, characterized in that indium oxide powder containing 1 to 20% by weight of tin oxide powder and 0.05 to 5% by weight of titanium oxide powder is sintered. 3. A powder for a transparent electrode, characterized in that indium oxide powder containing 1 to 20% by weight of tin oxide powder and 0.05 to 5% by weight of titanium oxide powder is sintered and then pulverized. 4. An alloy for transparent electrode deposition, comprising 60 to 98.9% by weight of indium, 1 to 20% by weight of tin, and 0.1 to 20% by weight of titanium.