JP3163015B2 - Transparent conductive film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a transparent conductive film and a sintered body used for producing the same.

[0002]

2. Description of the Related Art As a transparent electrode for various display devices and thin-film solar cells, or as a window glass coating material for energy-saving buildings having excellent ultraviolet blocking / infrared reflecting properties expected to be enormous in the future, it has high visible light transmittance and low visible light transmittance. A transparent conductive film having resistance characteristics is indispensable. Currently, the most widely used transparent conductive film is mainly a metal oxide thin film, and a tin oxide SnO ₂ type (F or antimony (Sb)) having high chemical stability is mainly used. ), Indium oxide (In ₂ O ₃ ),
BACKGROUND ART Tin-doped indium oxide [In ₂ O ₃ -SnO ₂ -hereinafter referred to as ITO] having excellent electrical and optical characteristics is known. Recently, the applicants have been developing a transparent conductive film using a new multi-component composite metal oxide such as zinc stannate (ZnSnO ₃ ), In ₄ Sn ₃ O ₁₂ , or Sn-added Zn ₂ In ₂ O _5. Have been. This is because the amount of In, which is an expensive rare metal, is reduced as much as possible without deteriorating the performance of the transparent conductive film or while improving the performance.

[0003]

However, as the amount of Sn contained in the film increases, ordinary etching with an acid gradually becomes difficult, which causes a problem in the patterning process. On the other hand, as the transparent conductive film has been developed for various uses in recent years, the conventional transparent conductive film material has become unable to cope with these. For example, in the application of a transparent pen touch panel for analog input, a low resistivity is not always required as in the past, but rather a uniform and appropriate resistivity over a large area and a high visible light transmittance are required. Further, there is a demand for the provision of a transparent conductive film capable of freely controlling chemical resistance to acids, alkalis, and the like without deteriorating the electrical and optical performance of the film. There was a problem that it could not be adapted to the application.

[0004]

[Means for Solving the Problems] To solve the above problems, a composite metal oxide film containing In, Sn and Zn forms at least one kind of In ₄ Sn ₃ O ₁₂ crystal phase,
The amount of Sn represented by Sn × 100 / (In + Sn) is 40
-60 atomic%, and the amount of Zn represented by Zn × 100 / (In + Zn) is 10-90 atomic%, preferably 30-90 atomic%.
An object of the present invention is to provide a transparent conductive film on which the oxide film containing 70 atomic% is formed. Here, the Zn content is 10% or less,
If it is 0% or more, the features of the present invention cannot be exhibited. The transparent conductive film according to the present invention is made of a conventionally known Sn-added Zn-In.
-O-based oxide [Japanese Patent Application No. Hei 7-91327 or Japanese Unexamined Patent Application Publication No.
318406], and has a feature and a composition region that is completely unexpected. According to the present invention, the conventional amorphous or crystalline Sn-added Zn-I
It is possible to easily control the etching rate by changing the visible light transmittance and the component composition, which cannot be obtained with the n-O or Zn ₂ In ₂ O ₅ oxide transparent conductive film. An object of the present invention is to provide a new transparent conductive film for fully exhibiting the above-mentioned features, and a target material used for manufacturing the film.

Specifically, In ₂ O ₃ —SnO ₂ —ZnO
In the composite metal oxide, the metal component composition includes S
The Sn amount represented by n × 100 / (In + Sn) is 40 to
Z at 60 atomic% and expressed as Zn / (In + Zn)
A mixed powder having an n amount in the range of 10 to 90, preferably 30 to 70 atomic%, or fired as required, or molded and sintered as required, is used as a target,
For example, the object of the present invention can be achieved by forming the composite metal oxide film having the above composition range on a ceramic substrate such as glass or an organic substrate such as plastic by a sputtering method. . In addition, F, which is a Group VII element with respect to Sn in the oxide, is added at an atomic ratio of F / (Sn + F) of 0.1.
Addition in the range of 02 (2%) or less contributes to lowering the resistivity.

The method for producing the transparent conductive film according to the present invention includes not only the above-described method but also a laser ablation method,
Any known film forming method such as a vacuum deposition method, a chemical vapor crystal growth (CVD) method, a sol-gel method, and a molecular beam epitaxial growth method can be used.

[0007]

When forming a film having the above composition range suitable for the purpose of the present invention on the substrate by the known film forming method as described above, intrinsic film due to intrinsic lattice defects such as oxygen vacancies and interstitial atoms. Carriers can be generated by introducing donors and exogenous donors in which a part of group VI elements are substituted with group VII elements. The oxide film according to the present invention is amorphous or
₄ Sn ₃ O ₁₂ , In ₄ Sn ₃ O ₁₂ and In ₂ O ₃ , In ₄ Sn ₃ O
₁₂ and SnO ₂ , In ₄ Sn ₃ O ₁₂ and ZnO, In ₄ Sn ₃ O
₁₂ and Zn ₂ In ₂ O ₅ , or a crystal or microcrystalline material composed of a mixed phase obtained by combining one or more of them, enables high carrier generation by the above-described mechanism, and in addition, the transparent conductive film according to the present invention is Since the desired etching rate can be easily obtained by changing the amount of Zn contained, it is most suitable for various analog input transparent touch panels, transparent low resistance panels, transparent touch switches, and the like. . Hereinafter, the present invention will be described with reference to examples.

[0008]

Example 1 A metal component composition, that is, In, Sn, Zn was prepared using In ₂ O ₃ , SnO ₂ and ZnO raw material powder.
Of the mixed powder prepared so as to be 15, 50, and 35 at% respectively in an argon (Ar) gas at 1000 ° C. for 5 hours, and then packed in a stainless steel dish having a diameter of 80 mm to produce a powder target for sputtering. did. Ar + 4% oxygen (O ₂ ) was used as a sputtering gas. The sputtering gas pressure was set to 0.2 Pa, and sputtering was performed on a glass substrate at room temperature held in parallel with the target surface with a DC input power of 40 W to produce a film having a thickness of about 300 nm. As a result of immersing the film in 1 mol of dilute hydrochloric acid, as shown in FIG.
Zn / (In + Zn) source corresponding to the above composition

FIG. 1 shows that an etching rate of about 180 nm / min was obtained at a child ratio of 70%. In this case, the addition amount of Sn to In was fixed at 50 atomic%. On the other hand, In, Sn, and Zn prepared to have a film thickness of 20 nm,
In the film consisting of 5, 50 at%, the addition amount of Zn to In which obtains the same etching rate as the thick film described above was about 55 at%. The average visible light transmittance of the films having any thickness was 90% or more. Further, both films had a sheet resistance of about 1 kΩ / □. Further, as a result of analyzing the produced films by x-ray diffraction, all the films were microcrystalline or amorphous. . When the film was formed on a polyethylene terephthalate (PET) film or a PET film formed on a hard polycarbonate plate as a substrate, almost the same results as described above were obtained. Further, when the substrate temperature is 30
When the film was formed at a temperature of about 0 ° C.,
It was found from the result of X-ray diffraction measurement that the n ₄ Sn ₃ O ₁₂ crystal phase was contained although it was weak.

[0009]

Embodiment 2 Sputterer used in Embodiment 1
Using a high frequency magnetron sputtering method
On a glass substrate heated to 0 ° C., a composite metal oxide film having a thickness of about 25 nm and made of 20, 50, and 30 atomic% of In, Sn, and Zn, respectively, was formed as a metal component composition. The obtained etching rate is up to 500 nm / min.
Reached. Other electrical and optical characteristics were almost the same as in Example 1. Incidentally, with respect to Sn, with SnF _2, F
Of the film obtained by adding 2 atomic% of
00 Ω / □, which was considerably lower than the result of Example 1. X-ray diffraction measurement revealed that the film was a mixed phase of In ₄ Sn ₃ O ₁₂ and In ₂ O ₃ . However, when the film was formed at a substrate temperature of room temperature, almost no crystalline phase was observed and the film was amorphous.

[0010]

Example 3 A composite metal oxide film having a thickness of 320 nm was formed by a laser ablation method using a sintered pellet having the same composition as the sputter target used in Example 1. When the composition of the obtained film was analyzed by an electron microprobe analyzer (EPMA), it was found that the composition was almost the same as the target composition.
The electrical / optical characteristics and etching characteristics were the same as in Example 1.

[0011]

Embodiment 4 By atmospheric pressure CVD, indium acetylacetonate was used as the In material and Sn was used as the Sn material.
Using acetate, Zn acetylacetonate as a Zn raw material, and H ₂ O as an oxygen raw material, all raw materials were charged into a heated stainless steel container, and the raw material gas was set in a quartz reactor together with a carrier gas through a stainless steel pipe. A composite metal oxide film having the same metal component composition as that of Example 2 was supplied to the glass substrate heated to ° C., and was formed on the glass substrate. The raw material temperatures were 85 ° C., 150 ° C., and 73 ° C., respectively, and the carrier gas flow rates were 500 CCM, 20 CCM, and 2.6 ×, respectively.
It was 10 ⁻³ mol / min. The prepared film has a thickness of 33
0 nm and the etching rate was 320 nm / min. The resistivity was 2.6 × 10 ⁻³ Ωcm, and the average visible light transmittance was 88% or more. When the film was analyzed by X-ray diffraction, In ₄ Sn ₃ O ₁₂ was detected although it was weak.

The transparent conductive film according to the present invention is not limited to the above-described embodiment, and it goes without saying that various known film forming methods can be used.

According to the present invention, a high visible light transmittance which cannot be obtained by the conventional amorphous or crystalline Sn-added Zn-In-O or Zn ₂ In ₂ O ₅ oxide transparent conductive film, Sn
The remarkable effect that the etching rate of the composite metal oxide film can be easily controlled by changing the atomic ratio of Zn to In in the -Zn-O system was obtained. Since the desired etching rate can be easily obtained by changing the amount of Zn contained in this way, it is most suitable for use in various analog input transparent touch panels, transparent low resistance panels, transparent touch switches, and the like. is there.

[Brief description of the drawings]

FIG. 1 shows the dependence of the etching rate on the film thickness with respect to the atomic ratio of Zn / (In + Zn).

[Explanation of symbols]

1 ... thickness 20nm 2 ... thickness 300nm

Continuation of the front page (58) Fields investigated (Int. Cl. ⁷ , DB name) H01B 5/14 H01B 13/00 H01B 1/00-1/24 C01G 15/00 C01G 19/00 CA (STN)

Claims (1)

(57) [Claims] 1. Indium (In), Tin (S)
n) and a transparent conductive film formed by forming a composite metal oxide film composed of zinc (Zn), wherein the composite metal oxide film contains at least one kind of In4Sn3O12.