JPH0543273A - Transparent electrode - Google Patents

Abstract

PURPOSE:To provide the novel transparent electrode film which is extremely low in electric resistivity, has an extremely high transmittance, and is not impaired in etching characteristics by photolithography and the material for this transparent electrode film. CONSTITUTION:This transparent electrode film consists essentially of indium oxide and contains 1 to 20wt.% tin oxide and 0.05 to 5wt.% zinc oxide. The material for producing the transparent electrode film is a sintered body for vapor deposition of the transparent electrode formed by sintering indium oxide powder contg. 1 to 20wt.% tin oxide powder and 0.05 to 5wt.% zinc oxide powder or the powder for the transparent electrode formed by pulverizing this sintered body or the alloy for vapor deposition of the transparent electrode contg. 60 to 98.5wt.% indium, 1 to 20wt.% tin and 0.1 to 30wt.% zinc.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrode for a liquid crystal display device,
The present invention relates to a novel transparent electrode used for transparent heaters, solar cells, and the like.

[0002]

2. Description of the Related Art The transmittance of visible light is high, and
It is a characteristic of the transparent electrode that it exhibits large electric conductivity.
Conventionally, as a material of the transparent electrode, SnO doped with Sb is used.
₂ there is, but the resistance value is high, because such a difficulty in etching by photolithography, _{an In} 2 _{O 3} containing the SnO ₂ 5 to 10 wt% today (hereinafter referred to as ITO) has become a mainstay .

Demands for transparent electrodes using such materials are increasing day by day, such as electrodes for liquid crystal display devices and transparent heaters used for windows such as automobiles, trains and airplanes.

Among them, the display is an interface between a human being and a computer or other electric device,
It has changed to a larger and more visible one. However, as the display becomes larger, the distance between the transparent electrodes becomes longer, and the resistance value thereof affects 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 flowing at a constant voltage becomes small, and the charging of electric charges becomes slow.

In order to prevent this, it is possible to solve the problem by making the transparent electrode thicker or making it metallic, but on the other hand, there is a drawback that the transparency of light is deteriorated and the function of the transparent electrode is reduced.

[0006] Further, it seems that the need for solar cells that take out electricity from the sun as clean energy will increase more and more in the future, but in this case as well, a lower resistance electrode material is used at a similar cost. Moreover, there is a growing demand for materials that do not deteriorate in transparency.

The mainstream method for producing a transparent electrode thin film is a vapor deposition method on a glass substrate or a plastic substrate in a vacuum, which is called a sputtering method or an EB vapor deposition method. The resistivity changes. Further, the transparent electrode material used in these vapor deposition methods is also a factor in changing the resistivity.

[0008]

DISCLOSURE OF THE INVENTION The inventors of the present invention have developed a novel resin which has a lower resistance, a higher transmittance with respect to visible light and ultraviolet light, and excellent characteristics such as etching characteristics by photolithography and life. As a transparent electrode film and a transparent electrode material for forming the electrode film,
March 26 (reference number P9102-003), March 1991
I applied for a patent on the 1st of the month (reference number P9103-004). The present invention has been found as a novel transparent electrode as a result of further research based on the above invention.

[0009]

Means for Solving the Problems The present invention achieves the object by including indium oxide as a main component as a transparent electrode film, and containing 1 to 20% by weight of tin oxide and 0.05 to 5% by weight of zinc oxide. You can

Further, 1 to 20% by weight of a sintered body for vapor deposition of transparent electrodes or tin oxide powder obtained by sintering indium oxide powder containing 1 to 20% by weight of tin oxide powder and 0.05 to 5% by weight of zinc oxide powder. %, By using a transparent electrode material such as a transparent electrode powder obtained by sintering and crushing indium oxide powder containing 0.05 to 5% by weight of zinc oxide powder,
The above transparent electrode film can be manufactured.

The sintered body for vapor deposition of a transparent electrode is used for producing a transparent electrode thin film, and the powder for a transparent electrode is also used as a thick film paste for producing a transparent electrode thick film. Therefore, the transparent electrode film according to the present invention is applicable not only to a thin film but also to a thick film.

The ITO film is manufactured by the sputtering method using In
It is also carried out by DC sputtering an alloy target of Sn and Sn in an oxygen atmosphere. Similarly, 60 to 98.9% by weight of indium, 1 to 20% by weight of tin, and 0.
The transparent electrode film can also be manufactured by DC sputtering an alloy for vapor deposition of a transparent electrode containing 1 to 20% by weight in an oxygen atmosphere.

[0013]

Example 1 A mixture of powders of 94% by weight of In ₂ O ₃ , 5% by weight of SnO _{2 and} 1% by weight of ZnO was pressure-molded and sintered to prepare a sputtering target. Sputtering was performed using this target to deposit a transparent electrode film on the glass substrate. The film thickness was 1000 Å. This film was etched with a solution obtained by heating a 3% HCl aqueous solution to 60 ° C. to form a pattern, and the transmittance, resistivity, etc. were measured.

As a result, the light transmittance was extremely high at 90% at a wavelength of 550 nanometers, and the electric resistivity was 1.5 × 10 5.
^{It was -4} Ωcm, and it was found that the electrical resistivity was comparable to that of metal. Also, it was revealed that the number of abnormal discharges during sputtering was about one fifth of that of the conventional ITO material, which was extremely efficient. Further, it was found that a good film can be obtained even if the sputtering rate is higher than that of the conventional ITO film. It was also found that the etching characteristics of the film were extremely good.

[0015]

[Example 2] 94 wt% In, 5 wt% Sn, and 1 wt% Zn were heated and melted at about 200 ° C to produce an alloy, which was cast and then processed to prepare a sputtering target of 6 inches φ x 5 t. did. However, Zn used an alloy previously melted in Sn to facilitate the melting of Zn. Sputtering was performed using this target to deposit a transparent electrode film on the glass substrate. The film thickness was 800 Å. At the time of sputtering, argon gas and pure oxygen gas were introduced into the vapor deposition machine. The volume ratio of argon gas to oxygen gas was 8: 2.

After this film was annealed at 300 ° C. for 2 hours in the atmosphere, the transmittance and the resistivity were measured. As a result, it was found that the light transmittance was 90% at a wavelength of 550 nanometers and the electric resistivity was 1.3 × 10 ⁻⁴ Ωcm, which was an extremely excellent film quality.

[0017]

EFFECTS OF THE INVENTION In comparison with the ITO film which has been most widely used as a transparent electrode in the past, the present invention is characterized in that the resistivity is extremely low and the light transmittance is extremely high. Further, there is a feature that the characteristics such as etching characteristics by photolithography and film life are excellent. Further, there is an advantage that the manufacturing process of the transparent electrode material or the transparent electrode film does not need to be changed and the cost is high.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C22C 29/12 7217-4K G02F 1/1343 9018-2K G09F 9/30 339 7926-5G H05B 3 / 03 8715-3K

Claims (4)

[Claims] 1. A transparent electrode film containing indium oxide as a main component and containing 1 to 20% by weight of tin oxide and 0.05 to 5% by weight of zinc oxide. 2. A sintering electrode for vapor deposition of a transparent electrode, comprising indium oxide powder containing 1 to 20% by weight of tin oxide powder and 0.05 to 5% by weight of zinc oxide powder. 3. A powder for a transparent electrode, which is obtained by sintering an indium oxide powder containing 1 to 20% by weight of tin oxide powder and 0.05 to 5% by weight of zinc oxide powder and then pulverizing the powder. 4. An alloy for vapor deposition of transparent electrodes, comprising 60 to 98.9% by weight of indium, 1 to 20% by weight of tin, and 0.1 to 20% by weight of zinc.