JPH11297640A - Transparent conductive film and manufacture of the film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent conductive film containing ZnO with high productivity and heat resistance as main components, and a method for manufacturing this. SOLUTION: This is a method for manufacturing a transparent conductive film containing ZnO as main components. In this case, In and three group elements of a long period type periodic table are contained, and In is contained at the rate of 0.5-5 at.% and three group elements other than In are contained at the rate of 0.5-15 at.% to the total sum of Zn and three group elements. Also, the three group elements other than In are one or more kinds of elements selected from a group constituted of Ga, Al, and B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a transparent conductive film and a method for manufacturing the same.

[0002]

2. Description of the Related Art A long-period type periodic table of Al, B, Ga, etc.
Transparent conductive film (hereinafter simply referred to as Zn
The O-based transparent conductive film has an advantage that the material is inexpensive and abundant as compared with an ITO film that is widely used at present. Further, since wet etching can be performed under mild conditions, there is a feature that patterning can be performed without damaging a base or a substrate. For this reason, it is expected as an electrode for various display devices and an electrode for solar cells.

[0003] However, Zn produced by the sputtering method
The O-based transparent conductive film is formed of a residual gas (mainly H ₂
O) Fluctuations in physical properties such as specific resistance are likely to occur depending on the pressure. For this reason, especially when the film is formed at a low substrate temperature of 150 ° C. or less, the characteristics tend to vary from lot to lot. In addition, a film formed in an atmosphere containing a large amount of residual gas easily changes its resistance due to heat and has poor heat resistance. For this reason, Z
The nO-based transparent conductive film has a problem that the evacuation time must be extended in order to remove the residual gas, and the productivity is not improved.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a transparent conductive film containing ZnO as a main component, which is excellent in productivity and heat resistance, and a method for producing the same.

[0005]

According to the present invention, there is provided a semiconductor device comprising ZnO as a main component and containing In and a Group 3 element of a long-periodic periodic table other than In (hereinafter simply referred to as a Group 3 element). A transparent conductive film, characterized by containing 0.5 to 5 at% of In and 0.5 to 15 at% of a group 3 element other than In with respect to the total amount of group III elements, and a method for producing the same. I will provide a.

The transparent conductive film of the present invention contains 0.5 to 5 at% of In with respect to the total of Zn and Group 3 element. If In is less than 0.5 at%, the dependency on residual gas pressure is large, and In
Exceeds 5 at%, the visible light transmittance decreases. The addition of In makes the film less susceptible to the residual gas, provides reproducibility of resistance even when fabricated in an atmosphere with a large amount of residual gas, and improves the heat resistance of the film.

In the transparent conductive film of the present invention, a group 3 element other than In is contained in an amount of 0.5 to 15 at% based on the total amount of Zn and a group 3 element.
contains. If it is less than 0.5 at%, the specific resistance is high and 15 a
If it exceeds t%, the visible light transmittance becomes low. The Group 3 element other than In is preferably at least one element selected from the group consisting of Ga, Al and B. When high conductivity is required, addition of Ga is preferable.

The effect of adding In will be described below.
FIG. 1 shows a Ga-doped ZnO (hereinafter abbreviated as GZO) film and In
Shows the residual gas pressure dependence of the sheet resistance of a GZO (hereinafter abbreviated as GZI) film to which G is added. The GZO film was formed by sputtering a ZnO—Ga ₂ O ₃ sintered target containing 5 atomic% of Ga with respect to the sum of Ga and Zn in an Ar atmosphere. The GZI film is ZnO—Ga ₂ O containing 3 atomic% of Ga and 2 atomic% of In with respect to the total of Ga, In, and Zn.
The ₃ -In ₂ O ₃ sintered target was produced by sputtering in an Ar atmosphere. The sheet resistance of the GZO film greatly changes under the influence of the residual gas.
It is understood that the I film is hardly affected by the residual gas.

The geometric thickness of the transparent conductive film of the present invention (hereinafter simply referred to as the film thickness) is, for example, in the range of 3 to 2000 nm. The film thickness is appropriately determined according to the required sheet resistance. If it is less than 3 nm, conductivity cannot be expected, and if it exceeds 2000 nm, film peeling due to internal stress tends to occur.

In order to improve the mechanical durability and the chemical durability, an overcoat such as an oxide film or a nitride film may be applied. In addition, an undercoat of silicon oxide, silicon nitride, or the like may be applied for the purpose of preventing the adverse effect of alkali ion diffusion from the substrate or improving the adhesion to the substrate.

The transparent conductive film of the present invention can be produced, for example, by a sputtering method using a target containing ZnO as a main component and containing In and a Group 3 element of the long-period periodic table other than In. As a sputtering method, any of a high frequency (RF) sputtering method and a direct current (DC) sputtering method can be used. It is preferable to use the DC sputtering method from the viewpoint of productivity. The composition of the transparent conductive film of the present invention substantially matches the composition of the target used.

As the sputtering method, for example, 1)
Sputtering in an Ar atmosphere using an oxide sintered body target or in an Ar atmosphere containing a small amount of an oxidizing gas, 2) Sputtering in a mixed atmosphere of an oxidizing gas and Ar gas using a metal target, etc. There is. In consideration of production stability, it is preferable to produce the former method 1). Oxidizing gases include O ₂ and C
O ₂ or the like can be used.

[0013]

EXAMPLES Transparent conductive films having the compositions shown in Examples 1 to 7 of Table 1 were formed on a glass substrate by DC sputtering. The amounts of In, Ga, and Al in Table 1 are ratios with respect to the sum of Zn and Group 3 elements. Each of the films of Examples 1 to 7 uses a sintered oxide target having the same composition as the target transparent conductive film, and has a power density of 1 in an atmosphere of a residual gas pressure of 5 × 10 ⁻⁶ Torr and an Ar gas of ⁶ mm Torr. .1W / c
The film was formed under the conditions of m ² . The thickness was 200 nm. AZO in the table is ZnO to which Al and In are added, and IZO is ZnO to which In is added.

For each film, the visible light transmittance (T
Table 1 shows the results of measurement of _v ), sheet resistance (R _s ), resistance fluctuation between batches, and resistance change rate by a heat resistance test (100 ° C., 3 days). In addition, the resistance fluctuation between batches shows the variation from the average value in the case of forming and measuring five times. The other data is the average value of the film formed five times. Compared with the GZO film (Example 4), the GZI film (Examples 1 and 2) to which In is added in an amount of 1 to 2% has a small variation in resistance between batches and a change in resistance due to a heat resistance test, and has good reproducibility and heat resistance. .
The AZI film to which In is added at 2% has good reproducibility and heat resistance similarly to the GZI film. On the other hand, when the In content was as small as 0.1% (Example 6) and as large as 7% (Example 7), both reproducibility and heat resistance were poor. In particular, as the amount of In added increases, the visible light transmittance decreases. In addition, an IZO film containing neither Ga nor Al not only has poor reproducibility and heat resistance, but also has high sheet resistance and low visible light transmittance (Example 5).

[0015]

[Table 1]

[0016]

The transparent conductive film of the present invention has excellent resistance reproducibility and high productivity even when manufactured in an atmosphere having a large amount of residual gas. That is, the evacuation time can be reduced, and a significant improvement in productivity can be expected. Further, it has excellent heat resistance, and is preferably used for an electrode for a display device, an electrode for a solar cell, a transparent heating element for an anti-fog glass, a heat ray shielding film, an electromagnetic wave shielding film, and the like.

[Brief description of the drawings]

FIG. 1 is a graph showing the dependency of the sheet resistance of a GZO film and a GZI film on the residual gas pressure.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H05K 9/00 H01L 21/203 S // H01L 21/203 21/88 M

Claims (3)

[Claims] The present invention comprises ZnO as a main component, and contains In and a Group 3 element of the long-periodic periodic table other than In, and the content of In is 0.5 to 5 atm with respect to the total of Zn and the Group 3 element. %, And a Group 3 element other than In at a ratio of 0.5 to 15 at%. 2. The transparent conductive film according to claim 1, wherein said Group 3 element other than In is at least one element selected from the group consisting of Ga, Al and B. 3. A sputtering method using a target containing ZnO as a main component and containing In and a Group 3 element of a long-periodic periodic table other than In, and using ZnO as a main component by sputtering.
And a Group 3 element of the periodic table other than In,
In is 0.5 to 0.5 with respect to the total of Zn and the group 3 element.
5 at%, and group 3 element other than In is 0.5 to 15 at
%. A method for producing a transparent conductive film, comprising forming a transparent conductive film containing at a ratio of 0.1%.