JP6946770B2 - Composite oxide transparent conductive film and base material with transparent conductive film - Google Patents

Description

The present invention relates to a composite oxide transparent conductive film and a substrate with a transparent conductive film.

In the current elements or electronic devices, especially in displays with touch panels, the element structure is fundamentally changed to make one element with a touch panel inside the display, which makes it possible to make the device lighter and thinner. Attempts are being considered (see, for example, Patent Document 1).

In such a movement, when the current touch panel made of a transparent conductive film is used for the display, there is an opportunity to form a film on a resin base material such as a base material in contact with an organic substance or a base material containing an organic substance. As a result, the process temperature in manufacturing has been restricted to a lower level. A transparent conductive film having low resistance can be formed by using a resin substrate at a process temperature of about 200 ° C. (see, for example, Patent Document 2), but in the above element structure, a temperature at which molecules such as liquid crystal do not decompose. For example, a transparent conductive film capable of achieving low resistance at a temperature of 170 ° C. or lower is required. Furthermore, in recent years, when an organic substrate having relatively poor heat resistance is used, a transparent conductive film capable of lowering resistance at 150 ° C. or lower has been required, and a technique for achieving low resistance at lower temperatures. Demand for

International Patent Publication No. 2013/018625 Pamphlet Japanese Unexamined Patent Publication No. 2012-218163

An object of the present invention is an oxide transparent conductive film capable of achieving low resistance even on a substrate structurally inseparable from an organic substance or an organic substrate in a low temperature process of 150 ° C. or lower, the substrate with the oxide transparent conductive film, and the substrate. The purpose is to provide a method for producing them.

In view of such a situation, as a result of diligent studies, the present inventors have found an oxide transparent conductive film showing low resistance even in a low temperature process, the base material with the oxide transparent conductive film, and a method for producing them.

That is, the present invention
[1] Indium and one or more elements M selected from the elements of Groups 4 to 5 of the periodic table are contained, and when indium is In and hydrogen is H, hydrogen is contained in the following range.
11 at% ≤ H / (In + M + H) ≤ 30 at%
When the wavelength in the wavelength region of 350 nm to 800 nm is λ, the refractive index of the thin film is n, and the extinction coefficient is k, the ^{dielectric parameter D defined by n 2-} k ² is within the range of the following equation. An oxide transparent conductive film characterized by.
2.2 + 0.5568exp (-(λ-350) /31.60)) +
3.5853exp (-(λ-350) /645.72)) ≤ D ≤
3.0 + 0.5568exp (-(λ-350) /31.60)) +
3.5853exp (-(λ-350) /645.72))
[2] The oxide transparent conductive film according to [1], wherein the element M is Hf.
[3] The oxide transparent conductive film according to [1], wherein the elements M are Hf and Ta.
[4] A base material with an oxide transparent conductive film in which the oxide transparent conductive film according to any one of [1] to [3] is laminated on a base material that is structurally inseparable from an organic substance or an organic base material.
[5] A method for producing an oxide transparent conductive film by a sputtering method, in which the degree of vacuum of the film forming chamber when the introduced gas pressure is P (Pa) is 6.0 × 10 ⁻⁵ ≦ P ≦ 7. When 0 × 10 ^-4 Pa, the discharge power is W (W / cm ² ), and the flow rate of the introduced gas is F (sccm).
0.1 ≤ W / (P ² x F) ≤ 0.25
The method for producing an oxide transparent conductive film according to any one of [1] to [3], which comprises forming a film so as to satisfy the above conditions.
It is about.

The details of the present invention will be described below.

The oxide transparent conductive film of the present invention contains indium and one or more elements M selected from the elements of Groups 4 to 5 of the periodic table, and when indium is In and hydrogen is H, hydrogen is contained in the following range. Contains and
11 at% ≤ H / (In + M + H) ≤ 30 at%
When the wavelength in the wavelength region of 350 nm to 800 nm is λ, the refractive index of the thin film is n, and the extinction coefficient is k, the ^{dielectric parameter D defined by n 2-} k ² is within the range of the following equation. It is characterized by.
2.2 + 0.5568exp (-(λ-350) /31.60)) +
3.5853exp (-(λ-350) /645.72)) ≤ D ≤
3.0 + 0.5568exp (-(λ-350) /31.60)) +
3.5853exp (-(λ-350) /645.72))
The region represented by the above equation is plotted with the wavelength (nm) on the horizontal axis as shown in FIG.

Further, it is more preferable that the content is within the range of the following formula.
2.2 + 0.5568exp (-(λ-350) /31.60)) +
3.5853exp (-(λ-350) /645.72)) ≤ D ≤
2.6 + 0.5568exp (-(λ-350) /31.60)) +
3.5853exp (-(λ-350) /645.72))
The region represented by the above equation is plotted with the wavelength (nm) on the horizontal axis as shown in FIG.

By setting the dielectric parameter D within the range of the above formula in the wavelength region of 350 nm to 800 nm, a transparent conductive film having high mobility and high transmittance in the near infrared region can be obtained. The dielectric parameter D can be measured using a spectroscopic ellipsometer or the like, and the transparent conductive film used in the actual element is a scanning electron microscope even when the transparent conductive film is embedded in the laminated film. It is also possible to measure by combining structural analysis by (SEM) and a transmission electron microscope (TEM) and spectroscopic ellipsometry.

The thin film contains indium oxide as a main component and contains elements of Groups 4 to 5 (element M) of the periodic table and hydrogen as additional elements. It is also preferable to use two or more kinds of elements as the element M because the electric resistance can be lowered. When two or more kinds of elements are used for the element M, it is more preferable to add a large amount of Group 4 elements.

Further, when the element M is added to indium oxide, when indium is In and the element M is M, the content ratio in atomic ratio is 0.5 at% ≤ M / (In + M). Preferred for lowering. In order to keep the electrical resistance low in the low temperature process, 0.5 at% ≤ M / (In + M) ≤ 3.5 at% is more preferable, and 1 at% ≤ M / (In + M) ≤ 3 at% is further preferable. Most preferably, 2.2 at% ≤ M / (In + M) ≤ 3.0 at%. When group 4 and group 5 elements are used at the same time among these additive elements, the atomic ratio is 0.2 at when indium, group 4 and group 5 elements are set to In, M4 and M5, respectively. % ≤ M4 / (In + M4 + M5) ≤ 3.0 at%, 0.02 at% ≤ M5 / (In + M4 + M5) ≤ 1.3 at%. Further, the ratio of M4 to M5 (M4 / M5) is preferably 1.6 ≦ (M4 / M5) ≦ 3.0.

In the present invention, unavoidable trace amounts of impurities may be mixed.

At this time, the content of hydrogen contained in the membrane must be in the following range: 11 at% ≤ H / (In + M + H) ≤ 30 at%.
The range is preferably as follows:
13 at% ≤ H / (In + M + H) ≤ 24 at%
More preferably, the range is 13 at% ≤ H / (In + M + H) ≤ 22 at%.

The method for controlling the hydrogen content in the membrane is not particularly limited, but the introduction of hydrogen gas into the process gas, the degree of vacuum of the chamber during film formation, the adsorbed water in the substrate and the chamber, etc. It can be used. It is also possible to change the hydrogen content in the film depending on the sputter power, gas pressure, and gas flow rate during film formation.

Further, as the element M selected from the elements of Groups 4 to 5 of the periodic table, at least one type can be selected. It is preferable to use a plurality of types. In particular, it is preferable to select one or more of each of Group 4 elements and Group 5 elements. Most preferably, hafnium is selected from Group 4 elements and tantalum is selected from Group 5 elements. Further, the film of the present invention may contain indium, one or more elements M of the group consisting of elements of Groups 4 to 5 of the periodic table, and hydrogen. However, it is preferably composed of indium and one or more elements M and hydrogen in the group consisting of elements of Groups 4 to 5 of the periodic table, and more preferably indium, tantalum, hafnium and hydrogen.

Further, as the transparent base material in the transparent laminated base material of the present invention, it is preferable to use a transparent base material made of a glass material or a resin material. Examples of the glass material include soda lime glass, Pyrex (registered trademark) glass, non-alkali glass, and quartz glass. The resin substrate includes a polyester resin film such as polyethylene terephthalate (PET), polyethylene naphthalate, or modified polyester, a polyethylene (PE) resin film, a polypropylene (PP) resin film, a polystyrene resin film, or a cyclic olefin resin. Polyethylene resin film such as, polyvinyl chloride, vinyl resin film such as polyvinylidene chloride, polyether ether ketone (PEEK) resin film, polysalphon (PSF) resin film, polyether salphon (PES) resin film, polycarbonate. (PC) resin film, polyamide resin film, polyimide resin film, acrylic resin film, triacetyl cellulose (TAC) resin film and the like can be mentioned. These can be appropriately selected according to the intended use and purpose. Among them, biaxially stretched polyethylene terephthalate film, biaxially stretched polyethylene naphthalate film, polyether sulfone film, or polycarbonate film is preferable from the viewpoint of transparency, heat resistance, ease of handling, strength and cost, and biaxially stretched polyethylene terephthalate. A film or a biaxially stretched polyethylene naphthalate film is more preferable.

The oxide transparent conductive film of the present invention has a resistivity of 3.0 × 10 ^-4 Ω · cm or less even at a low process temperature of 150 ° C. or less, and is a crystalline thin film. Even if a film is formed on a base material that is structurally inseparable from an organic substance or an organic base material, it exhibits suitable properties.

Next, the method for producing the oxide transparent conductive film of the present invention will be described.

In the manufacturing method of the present invention, it is necessary to adjust the flow rate of the introduced gas in addition to the discharge power and the introduced gas pressure. This is because even if the discharge power and the introduced gas pressure are the same, if the introduced gas flow rate is different, the state of the plasma changes and the movement of the sputtered particles of the deposited film changes, which affects the film quality.

That is, the vacuum of the film-forming chamber when the discharge power per unit area with respect to the sputtering target during film-forming by sputtering is W (W / cm ² ) and the introduction gas pressure in the chamber during film-forming is P (Pa). When the degree is 6.0 × 10 ^-5 ≦ P ≦ 7.0 × 10 ^-4 Pa and the introduced gas flow rate at this time is F (sccm),
0.1 ≤ W / (P ² x F) ≤ 0.25
It is characterized by. In particular, it is preferable that 0.1 ≦ W / (P ² × F) ≦ 0.15.

The sputtering target to be used is not particularly limited, but it is preferable to use a sputtering target having the above-mentioned composition (including indium and one or more elements selected from the elements of Groups 4 to 5 of the periodic table). Specifically, it is preferable that the target contains indium oxide as a main component and contains an element of Group 4 to 5 (element M) of the periodic table as an additive element. When two or more kinds of elements are used for the element M, Group 4 It is more preferable to add a large amount of elements.

Further, when element M is added to indium oxide as a target, when indium is In and element M is M, the content ratio in atomic ratio is 0.5 at% ≤ M / (In + M). It is preferable to reduce the electrical resistance of the obtained thin film. In order to keep the electrical resistance low in the low temperature process, 0.5 at% ≤ M / (In + M) ≤ 3.5 at% is more preferable, and 1 at% ≤ M / (In + M) ≤ 3 at% is further preferable. Most preferably, 2.2 at% ≤ M / (In + M) ≤ 3.0 at%. When group 4 and group 5 elements are used at the same time among these additive elements, the atomic ratio is 0.2 at when indium, group 4 and group 5 elements are set to In, M4 and M5, respectively. % ≤ M4 / (In + M4 + M5) ≤ 3.0 at%, 0.02 at% ≤ M5 / (In + M4 + M5) ≤ 1.3 at%. Further, the ratio of M4 to M5 (M4 / M5) is preferably 1.6 ≦ (M4 / M5) ≦ 3.0.

In the target used in the production method of the present invention, unavoidable trace amounts of impurities may be mixed.

Further, as the element M selected from the elements of Groups 4 to 5 of the periodic table, at least one type can be selected. It is preferable to use a plurality of types. In particular, it is preferable to select one or more of each of Group 4 elements and Group 5 elements. Most preferably, hafnium is selected from Group 4 elements and tantalum is selected from Group 5 elements. Further, the target may include indium and one or more elements M in the group consisting of elements of Groups 4 to 5 of the periodic table. However, it is preferably composed of indium and one or more elements M in the group consisting of elements of Groups 4 to 5 of the periodic table, and more preferably indium, tantalum and hafnium.

As the sputtering method, a DC sputtering method, an RF sputtering method, an AC sputtering method, a DC magnetron sputtering method, an RF magnetron sputtering method, an ion beam sputtering method and the like can be appropriately selected. The DC magnetron sputtering method and the RF magnetron sputtering method are preferable because they can form a film at high speed.

As the introduction gas during sputtering, an inert gas such as argon gas is usually used. If necessary, oxygen gas, nitrogen gas, hydrogen gas and the like may be used.

The present invention relates to an oxide transparent conductive film capable of achieving low resistance even in a low temperature process, can be suitably used for a display element, a detection element, a photoelectric conversion element, and the like, and has excellent characteristics. It becomes a device.

The range of the dielectric parameter D in claim 1 of the present application is shown. The values of the dielectric parameters D of Examples 1 to 4 are shown. The values of the dielectric parameters D of Examples 5 to 8 are shown. The values of the dielectric parameters D of Examples 9 to 12 are shown. The values of the dielectric parameters D of Comparative Examples 1 to 6 are shown.

The present invention will be specifically described with reference to the following examples, but the present invention is not limited thereto. The evaluation method is as follows.

(1) Film formation of transparent oxide conductive film A sintered body having a desired composition was prepared and used as a sputtering target having a diameter of 4 inches to prepare a transparent oxide conductive film having a desired composition. Detailed film forming conditions are shown below.

An oxide transparent conductive film was formed under the following sputtering conditions and evaluated.

(Sputtering conditions)
・ Equipment: DC magnetron sputtering equipment (manufactured by ULVAC, Inc.)
-Magnetic field strength: 1000 Gauss (directly above the target, horizontal component)
・ Distance between target substrates: 90 mm
-Substrate temperature: Room temperature (about 25 ° C)
-Type of introduced gas: Argon + oxygen (oxygen / (argon + oxygen) = 0.005 (volume ratio))
-Substrate used: PET film (Toyobo A4100) Thickness 125 μm
(Post-treatment conditions after film formation)
The oxide transparent conductive film formed on the substrate was heat-treated in the air for 60 minutes at the temperatures shown in Table 1.

The composition, crystallinity, and electrical resistance of the film were measured by the following methods.

(composition)
It was quantified by an ICP-MS (inductively coupled plasma mass spectrometry) apparatus.

(crystalline)
The crystallinity of the transparent conductive film was identified by an X-ray diffraction test. The measurement conditions are as follows.
・ X-ray source: CuKα
・ Power: 40kV, 40mA
-Scanning speed: 1 ° / min As a result of analyzing the obtained diffraction pattern, the one in which (222) was observed was judged to be a crystal film, and the one in which no diffraction peak was observed was judged to be amorphous.

(Resistivity)
The resistivity of the thin film was measured using HL5500 (manufactured by Japan Bio-Rad Laboratories).

Examples 1-8, Comparative Examples 1-6
For the film formation of the oxide transparent conductive film, a sintered body containing indium oxide as a main component, which is obtained by adding an additive element to a DC magnetron sputtering device (manufactured by ULVAC, Inc.) so as to have the film composition shown in Table 1, is a sputtering target. Used as.

^{After that, the discharge power W (W / cm 2} ), the introduced gas pressure P (Pa), the introduced gas flow rate F (sccm), and the degree of vacuum of the film forming chamber so as to meet the conditions shown in Table 1 at room temperature without heating. Was adjusted to deposit a transparent conductive film on the substrate.

The deposited film was heated from room temperature at a heating rate of 50 ° C./min and air-annealed at 140 ° C. for 60 minutes to confirm the presence or absence of crystallization. The results are shown in Tables 1 and 2.

Examples 9-12
A transparent conductive film is deposited on the substrate under the conditions shown in Table 1 using a sputtering target having the film composition shown in Table 1 in the same manner as in Examples 1 to 8 and Comparative Examples 1 to 6 except for the conditions for atmospheric annealing. I let you. The deposited film is heated from room temperature at a temperature rise rate of 50 ° C./min, and atmospheric annealing is performed at the temperatures shown in Table 1 for 60 minutes in Examples 9 to 11 and 5 minutes in Example 12, and the presence or absence of crystallization is checked. The confirmed results are shown in Tables 1 and 2.

Claims (3)

Indium, consists element M Hf and Ta, indium In, hydrogen is taken as H, are contained in the following ranges hydrogen,
11 at% ≤ H / (In + M + H) ≤ 30 at%
When the wavelength in the wavelength region of 350 nm to 800 nm is λ, the refractive index of the thin film is n, and the extinction coefficient is k, the ^{dielectric parameter D defined by n 2-} k ² is within the range of the following equation. An oxide transparent conductive film characterized by.
2.2 + 0.5568exp (-(λ-350) /31.60)) +
3.5853exp (-(λ-350) /645.72)) ≤ D ≤
3.0 + 0.5568exp (-(λ-350) /31.60)) +
3.5853exp (-(λ-350) /645.72)) A base material with an oxide transparent conductive film in which the oxide transparent conductive film according to claim 1 is laminated on a base material that is structurally inseparable from an organic substance or an organic base material. A method for producing an oxide transparent conductive film by a sputtering method, in which the degree of vacuum of the film forming chamber when the introduced gas pressure is P (Pa) is 6.0 × 10 ⁻⁵ ≦ P ≦ 7.0 × 10. ^{When -4} Pa, the discharge power is W (W / cm ² ), and the flow rate of the introduced gas is F (sccm),
0.1 ≤ W / (P ² x F) ≤ 0.25
Method of manufacturing an oxide transparent conductive film according to claim 1, characterized in that the film formation to meet.

Images