KR20180000181A - Multilayer transparent electrode and method for manufacturing thereof - Google Patents

Abstract

The present invention relates to a multilayer transparent electrode with excellent transparency and electrical characteristics, and a manufacturing method thereof. The multilayer transparent electrode comprises: a lower oxide layer (10); a metal layer (20) formed on the lower oxide layer (10); and an upper oxide layer (30) formed on the metal layer (20).

Description

TECHNICAL FIELD [0001] The present invention relates to a multi-layer transparent electrode,

The present invention relates to a multilayer transparent electrode and a manufacturing method thereof.

The transparent electrode usually has a transparency of at least 80% and a sheet resistance of 500 Ω / sq. And has been used extensively in electric and electronic fields such as LCD front electrodes, OLED electrodes, displays, touch screens, solar cells, and optoelectronic devices.

Indium tin oxide (ITO) has been widely used as a transparent electrode material at present, as disclosed in the following patent documents. ITO, which is a transparent conductive oxide, is used by mixing a small amount of tin oxide with indium oxide. When the content of tin oxide is 5 to 10 wt%, the transparent electrode is most favorable. Therefore, a composition containing 10 wt% of tin oxide is used have. In addition to ITO, other conductive oxides such as SnO ₂ and ZnO have also been developed and used. However, they have poor electrical and optical properties compared to ITO, and some are used as touch panels or low-grade transparent electrode materials requiring high resistance. I can not replace it.

Due to such high light transmittance and conductivity, there are some fatal problems with ITO transparent electrodes which can not be easily replaced with other materials. And a representative one of them is difficult to apply to a flexible electronic device. Since ITO, which is an inorganic material, lacks ductility due to its characteristics, cracks are generated at the time of bending, and such cracks result in an increase in resistance. In addition, since the ITO transparent electrode is crystallized on the glass substrate and a heat treatment process at a high temperature is inevitable, a flexible polymer substrate susceptible to heat can not be used. Further, since indium itself, which is a material of ITO, is a rare metal, there is a fear of depletion of resources and an increase in manufacturing cost is expected due to an increase in price every year.

Accordingly, there is an urgent need for a solution to the problem of the conventional ITO transparent electrode.

KR 10-1620870 B1

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior art described above. One aspect of the present invention is to replace the conventional expensive ITO transparent electrode and to be applicable to a flexible substrate, Layer structure in which an oxide layer, a metal layer, and an upper oxide layer are sequentially laminated on the oxide layer to improve the transmittance of the oxide layer / metal layer / oxide layer.

Another aspect of the present invention is to provide a method of manufacturing a transparent electrode having a multilayer structure, which oxidizes an alloy layer in an oxygen atmosphere or an air atmosphere to thereby have excellent transparency and electrical characteristics.

A multilayer transparent electrode according to an embodiment of the present invention includes a lower oxide layer; A metal layer formed on the lower oxide layer on; And a top oxide layer formed on the metal layer.

In the multilayered transparent electrode according to the embodiment of the present invention, the lower oxide layer may be formed of Ti, Ga, Al, Ge, As, Cu, Mn, Zr, Nb, Ru, Hf, Zn, Ag, In, Re, Cr, Ni, Mo, V, W, Mg, Si, Sn and Ta is oxidized.

In the multilayer transparent electrode according to the embodiment of the present invention, the lower oxide layer is formed by oxidizing an alloy containing tungsten (W) and titanium (Ti).

Further, in the multilayer transparent electrode according to the embodiment of the present invention, the alloy contains 45 to 55 wt% of the tungsten and 45 to 55 wt% of the titanium based on the total weight.

In the multilayered transparent electrode according to the embodiment of the present invention, the thickness of the lower oxide layer is 1 to 100 nm.

In the multilayered transparent electrode according to the embodiment of the present invention, the thickness of the metal layer is 1 to 30 nm.

Further, in the multilayer transparent electrode according to the embodiment of the present invention, the lower oxide layer is formed on a flexible substrate.

In the multilayered transparent electrode according to the embodiment of the present invention, the metal layer is made of any one or any one of Ag, Au, Ti, Ni, Mo, Cu, and Al.

In the multilayered transparent electrode according to the embodiment of the present invention, the upper oxide layer may be formed of TiO, ZnO, NiO, MoO, VO, WO, MgO, Si- In-O, Cu-In-O, Ta-O, Hf-O, Nb-O, Zr-O, Cu-O, In- In-O, Ge-In-O, Si-In-O, Sn-In-O, Mn-In-O, In-O, In-O-Cl, In-OF, W-In-O, Ta-In-O, Hf- Zn-In-O, Sr-VO, Ca-VO, and Ga-Sn-Zn-In-O.

Meanwhile, a method of manufacturing a multilayer transparent electrode according to an embodiment of the present invention includes the steps of: (a) forming a lower oxide layer on a substrate; (b) forming a metal layer on the lower oxide layer; And (c) forming a top oxide layer on the metal layer.

In the method for manufacturing a multilayered transparent electrode according to an embodiment of the present invention, the step (a) may include a step of forming a transparent electrode having a composition of Ti, Ga, Al, Ge, As, Cu, Mn, Zr, Nb, Ru, Hf, The base layer is formed of an alloy of any one or any one of Fe, Ag, In, Re, Cr, Ni, Mo, V, W, Mg, Si, Sn, and Ta, Oxidizes the layer.

In the method of manufacturing a multilayer transparent electrode according to an embodiment of the present invention, the step (a) may include forming a base layer with an alloy containing tungsten (W) and titanium (Ti) To oxidize the base layer.

Further, in the method for manufacturing a multilayer transparent electrode according to an embodiment of the present invention, the alloy contains 45 to 55 wt% of the tungsten and 45 to 55 wt% of the titanium based on the total weight.

Further, in the method for manufacturing a multilayer transparent electrode according to an embodiment of the present invention, the thickness of the lower oxide layer is 1 to 100 nm.

Further, in the method for manufacturing a multilayer transparent electrode according to an embodiment of the present invention, the thickness of the metal layer is 1 to 30 nm.

In the method of manufacturing a multilayer transparent electrode according to an embodiment of the present invention, the substrate is a flexible substrate.

In the method for fabricating a multilayer transparent electrode according to an embodiment of the present invention, the metal layer may include at least one of Ag, Au, Ti, Ni, Mo, Cu, and Al.

In the method for manufacturing a multilayer transparent electrode according to an embodiment of the present invention, the upper oxide layer may be formed of TiO, ZnO, NiO, MoO, VO, WO, MgO, In-O, Zn-In-O, Cu-In-O, Ta-O, Hf-O, Nb-O, Zr-O, Cu- In-O, B-In-O, Ge-In-O, Si-In-O, Sn-In-O, Mn- In-O, V-In-O, In-O-Cl, In-OF, W-In-O, Ta- At least one of Ga-Zn-In-O, Sr-VO, Ca-VO, and Ga-Sn-Zn-In-O.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to that, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor may properly define the concept of the term in order to best explain its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

According to the present invention, in a transparent electrode having a multilayer structure of an oxide layer / metal layer / oxide layer, the lower oxide layer is formed of an alloy containing tungsten and titanium, thereby remarkably improving the transmittance and sheet resistance. . This means that the material of the oxide layer can be applied in various ways depending on the degree of the alloy, which means that the electrical and optical properties can be changed according to the application.

In addition, according to the present invention, ohmic contact is formed on the surface of a semiconductor in contact with an oxidizing electrode, and since it has a high transmittance and a low sheet resistance value, the current spreading efficiency is increased in the entire surface of the light emitting layer, Device can be implemented.

1 is a cross-sectional view of a multilayer transparent electrode according to an embodiment of the present invention.
2 is a flowchart of a method of manufacturing a multilayer transparent electrode according to an embodiment of the present invention.
FIGS. 3A to 4 are graphs showing the transmittance of the multilayer transparent electrode according to the embodiment of the present invention.
5 to 6 are graphs showing electrical characteristics of a multilayer transparent electrode according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The objectives, specific advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings. Also, the terms "first "," second ", and the like are used to distinguish one element from another element, and the element is not limited thereto. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the present invention, detailed description of related arts which may unnecessarily obscure the gist of the present invention will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a multilayer transparent electrode according to an embodiment of the present invention.

1, a multilayered transparent electrode according to an embodiment of the present invention includes a lower oxide layer 10, a metal layer 20 formed on the lower oxide layer 10, (Not shown).

The multilayer transparent electrode according to the present embodiment relates to a transparent electrode which is applied to various electronic fields, and includes a lower oxide layer 10, a metal layer 20, and a top oxide layer 30.

The transparent electrode usually has a transparency of at least 80% and a sheet resistance of 500 Ω / sq. And has been used extensively in electric and electronic fields such as LCD front electrodes, OLED electrodes, displays, touch screens, solar cells, and optoelectronic devices.

Indium tin oxide (ITO) has been widely used as an electrode material until now. However, cracking occurs when the material is bent due to insufficient ductility, and a high temperature heat treatment process is performed on the glass substrate 40 It is inevitable that it can not be used for the flexible polymer substrate 40 that is susceptible to heat, so that it is difficult to apply it to a flexible electronic device.

Furthermore, since Indium itself, which is a material of ITO, is a rare metal, there is a fear of resource depletion, and the price rises every year, which causes a problem that the manufacturing cost is continuously increased.

As a method for improving the problem of the conventional ITO transparent electrode, a multilayer transparent electrode according to this embodiment has been devised.

The multilayer transparent electrode according to this embodiment has a structure in which the lower oxide layer 10, the metal layer 20, and the upper oxide layer 30 are sequentially arranged. That is, the oxide layers 10 and 30 are disposed on the upper and lower portions of the metal layer 20 with the metal layer 20 interposed therebetween, and the lower oxide layer 10 / the metal layer 20 / the upper oxide layer 30 Layer structure.

The lower oxide layer 10 is formed by oxidizing a single metal or an alloy of the metal. For example, Ti, Ga, Al, Ge, As, Cu, Mn, Zr, Nb, Ru, Hf, Zn, Sr, Ba, Fe, Ag, In, Re, Cr, Any one or any one of Mg, Si, Sn, and Ta is oxidized to form the lower oxide layer 10.

As an example, the lower oxide layer 10 may be formed by oxidation of an alloy containing tungsten (W) and titanium (Ti), wherein tungsten and titanium comprise 45 to 55 wt% tungsten based on the total weight of the alloy, , The titanium is contained in an amount of 45 to 55 wt%, and the sum thereof may be 100 wt%. That is, the lower oxide layer 10 can be formed of an alloy made only of tungsten and titanium.

Specifically, the lower oxide layer 10 is formed on a substrate 40. The substrate 40 is coated with a single metal, an alloy of the metal, or tungsten and a titanium alloy to form a base layer 40 And oxidizing the base layer in an oxygen atmosphere or an air atmosphere.

At this time, the thickness of the lower oxide layer 10 affects the transmittance, and 1 to 100 nm is suitable for ensuring the optimum transmittance. The thickness of the lower oxide layer 10, the metal layer 20, and the upper oxide layer 30 may be variously selected in consideration of the material and thickness of the lower oxide layer 10 and the conditions of use.

The metal layer 20 formed on the lower oxide layer 10 may be composed of any one of Ag, Au, Ti, Ni, Mo, Cu, and Al, or an alloy thereof. The thickness of the metal layer 20, like the lower oxide layer 10, is also influenced by the transmittance and is optimized to a thickness of 1 to 30 nm. At this time, if the thickness is changed, the wavelength range of the light that is overtransmitted by 80% or more also varies. Thus, the thickness of the metal layer 20 can be selectively determined in consideration of the wavelength of light in the above range. However, the thickness of the metal layer 20 is not necessarily limited to the above-described range, and may be varied depending on the material, the lower and upper oxide layers 10 and 30, and the like.

The upper oxide layer 30 is a layer formed on the metal layer 20. The upper oxide layer 30 may be formed of a metal such as TiO, ZnO, NiO, MoO, VO, WO, MgO, Si- In-O, Cu-In-O, Mo-In-O, Hf-O, Nb-O, Zr-O, Cu-O, In- In-O, Ge-In-O, Si-In-O, Sn-In-O, Mn-In-O, In-O, In-O-Cl, In-OF, W-In-O, Ta-In-O, Hf- In-O, Sr-VO, Ca-VO, and Ga-Sn-Zn-In-O. In this case, the optimum thickness of the upper oxide layer 30 for securing a high transmittance may be 1 to 100 nm, which may be determined in consideration of the relationship with the lower oxide layer 10 and the metal layer 20.

The multilayer transparent electrode according to the present invention having the structure of the lower oxide layer 10 / metal layer 20 / upper oxide layer 30 formed in this way can be applied to various electronic devices. In the light emitting device (LED), particularly a GaN- It can greatly contribute to improvement of dignity and efficiency.

The most important issue for improving the performance of a light emitting device is an ohmic contact which determines a current injection and a current spreading efficiency. If the ohmic contact characteristics of the device are not good, the contact resistance between the electrode and the semiconductor becomes large. As a result, the carrier injection efficiency is lowered and the heat loss at the interface is increased, The efficiency is reduced. A variety of techniques for ohmic contact technology have been studied. The most typical technique is to deposit a material having a specific work function on the GaN by vapor deposition and heat treatment, and then heat-treat the material to have a work function similar to that of p-type or n-type GaN To form an alloy to lower the Schottky barrier.

In the multilayered transparent electrode according to the present invention, the metal and the alloy having such a specific work function are oxidized to form a transparent lower oxide layer 10, and an acceptor and a donor (GaN) and N vacancies (donors) to induce tunneling of holes and electrons, and to lower the Schottky barrier, thereby greatly reducing the contact resistivity.

In addition, the structure of the oxide layer 10 / metal layer 20 / oxide layer 30 is realized, and the material selection is various with high transmittance and low sheet resistance, and a specific work function There is an advantage to match. Therefore, it is possible to easily manufacture a high-quality element, and to easily satisfy electrical and optical characteristics, morphology, bendability, corrosion resistance, and the like.

A multilayer transparent electrode according to the present invention may be formed on a substrate 40 wherein the substrate 40 supporting the metal layer 20 and the lower and upper oxide layers 10 and 30 is a rigid substrate Or a flexible flexible substrate. Unlike the conventional ITO transparent electrode, the process for manufacturing the multilayer transparent electrode according to the present invention can be applied to a flexible substrate susceptible to heat because a high-temperature heat treatment process is unnecessary.

In the case of using a flexible substrate, there is an advantage that a flexible electronic device can be realized and an electronic device can be mass-produced in a short time by a roll-to-roll process or the like. At this time, the substrate 40 may be a polymer substrate, for example, a polyether sulfone (PES), a polyethylene terephthalate (PET), a polycarbonate (PC), a polyimide (PI), or a polyethylene naphthalate Or more than one. However, the material of the polymer substrate is not limited thereto.

Further, the substrate 40 is not necessarily limited to the flexible substrate, and therefore, the substrate 40 may be manufactured using glass, silicon (Si), or the like.

Hereinafter, a method for manufacturing a transparent electrode according to the present invention will be described.

2 is a flowchart of a method of manufacturing a multilayer transparent electrode according to an embodiment of the present invention.

As shown in FIG. 2, a method of manufacturing a multilayer transparent electrode according to an embodiment of the present invention includes the steps of (a) forming a lower oxide layer on a substrate on (S100), (b) (S200); And (c) forming a top oxide layer on the metal layer (S300).

In the step of forming the lower oxide layer (S100), Ti, Ga, Al, Ge, As, Cu, Mn, Zr, Nb, Ru, Hf, Zn, Sr, Ba, Fe, (W) and titanium (Ti) may be formed by forming a base layer with any one or any one of Cr, Ni, Mo, V, W, Mg, Si, The base layer is formed of an alloy, and then the base layer is oxidized in an oxygen atmosphere or an air atmosphere to form a lower oxide layer. At this time, a heat treatment step such as RTA heat treatment, laser heat treatment, and the like may be further performed.

When an alloy containing tungsten (W) and titanium (Ti) is used as a base layer, an alloy containing 45 to 55 wt% of tungsten and 45 to 55 wt% of titanium to total 100 wt% can be used .

At this time, the thickness of the lower oxide layer laminated on the substrate is 1 to 100 nm, which may be determined in consideration of other factors. Here, the substrate may be a rigid substrate, but not limited thereto, and a flexible substrate may be used.

When the lower oxide layer is formed, a metal layer is formed (S200). At this time, the metal layer is made of any one or any one of Ag, Au, Ti, Ni, Mo, Cu, and Al, nm is preferable. However, the thickness is not necessarily limited thereto.

After the metal layer is formed, an upper oxide layer is formed (S300). Wherein the upper oxide layer is selected from the group consisting of TiO, ZnO, NiO, MoO, VO, WO, MgO, SiO, SnO, TaO, HfO, NbO, Zr In-O, Cu-O, In-O, Al-O, Ni-In-O, Zn-In-O, Cu- , Sn-In-O, Mn-In-O, Mg-In-O, Ga-In-O, Al-In-O, B-In- In-O, W-In-O, Ta-In-O, Hf-In-O, Re-In-O, Mg-Sn-O, Ga- Ga-Sn-Zn-In-O, with a thickness of 1 to 100 nm. However, the thickness is not necessarily limited thereto.

The multilayer transparent electrode produced by the above-described production method has excellent transparency and electrical characteristics, which will be described in detail below.

FIGS. 3A to 4 are graphs showing the transmittance of a multilayer transparent electrode according to an embodiment of the present invention, and FIGS. 5 to 6 are graphs showing electrical characteristics of a multilayer transparent electrode according to an embodiment of the present invention.

In Figure 3a, TiO ₂ were measured for a single metal as tungsten and titanium alloys each transmission of, in the case of tungsten and its alloys, eoteuna indicate a transmission of about 20% before the oxidation, the further transmission rate than TiO ₂ single metal after oxidation Respectively. It can be seen from FIG. 3b that the oxidation is good even though the permeability of various metals is examined.

In FIG. 4, the transmittance was measured while the thickness of the lower oxide layer was fixed and the thickness of the upper oxide layer was increased from 20 nm to 10 nm. As a result, the transmittance was 80% or more in any case. Also, it has been confirmed that the wavelength of the light at the maximum transmittance varies with the thickness of the upper oxide layer, and it can be utilized as an element for securing the optimum transmittance at the time of designing.

In FIGS. 5 to 6, the electrical characteristics according to the thickness of the upper oxide layer were measured. The sheet resistance at all thicknesses was 5 Ohm / sq. And showed very good electrical characteristics.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the same is by way of illustration and example only and is not to be construed as limiting the present invention. It is obvious that the modification or improvement is possible.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

10: lower oxide layer 20: metal layer
30: upper oxide layer 40: substrate

Claims (18)

A lower oxide layer;
A metal layer formed on the lower oxide layer on; And
An upper oxide layer formed on the metal layer;
And a transparent electrode.
The method according to claim 1,
The lower oxide layer may include at least one of Ti, Ga, Al, Ge, As, Cu, Mn, Zr, Nb, Ru, Hf, Zn, Sr, Ba, Fe, Ag, In, Re, Cr, , Mg, Si, Sn, and Ta is oxidized to form a multilayered transparent electrode.
The method according to claim 1,
Wherein the lower oxide layer is formed by oxidation of an alloy containing tungsten (W) and titanium (Ti).
The method of claim 3,
Wherein the alloy contains 45 to 55 wt% of the tungsten, and 45 to 55 wt% of the titanium based on the total weight.
The method according to claim 1,
Wherein the thickness of the lower oxide layer is 1 to 100 nm.
The method according to claim 1,
Wherein the thickness of the metal layer is 1 to 30 nm.
The method according to claim 1,
Wherein the lower oxide layer is formed on a flexible substrate.
The method according to claim 1,
Wherein the metal layer is made of any one or combination of Ag, Au, Ti, Ni, Mo, Cu, and Al.
The method according to claim 1,
The upper oxide layer may include at least one of TiO, ZnO, NiO, MoO, VO, WO, MgO, SiO, SnO, TaO, HfO, NbO, Zr In-O, Cu-O, In-O, Al-O, Ni-In-O, Zn-In-O, Cu- , Sn-In-O, Mn-In-O, Mg-In-O, Ga-In-O, Al-In-O, B-In- In-O, W-In-O, Ta-In-O, Hf-In-O, Re-In-O, Mg-Sn-O, Ga- Ga-Sn-Zn-In-O.
(a) forming a lower oxide layer on a substrate;
(b) forming a metal layer on the lower oxide layer; And
(c) forming a top oxide layer on the metal layer;
Wherein the transparent electrode is formed of a transparent conductive material.
The method of claim 10,
The step (a)
Ti, Ga, Al, Ge, As, Cu, Mn, Zr, Nb, Ru, Hf, Zn, Sr, Ba, Fe, Ag, In, Re, Cr, Ni, Mo, V, Sn, and Ta or an alloy of any one of them to form a base layer,
And oxidizing the base layer in an oxygen atmosphere or an air atmosphere.
The method of claim 10,
The step (a)
A base layer is formed of an alloy containing tungsten (W) and titanium (Ti)
And oxidizing the base layer in an oxygen atmosphere or an air atmosphere.
The method of claim 12,
Wherein the alloy contains 45 to 55 wt% of the tungsten and 45 to 55 wt% of the titanium based on the total weight.
The method of claim 10,
Wherein the thickness of the lower oxide layer is 1 to 100 nm.
The method of claim 10,
Wherein the thickness of the metal layer is 1 to 30 nm.
The method of claim 10,
Wherein the substrate is a flexible substrate.
The method of claim 10,
Wherein the metal layer comprises at least one of Ag, Au, Ti, Ni, Mo, Cu, and Al.
The method of claim 10,
The upper oxide layer may include at least one of TiO, ZnO, NiO, MoO, VO, WO, MgO, SiO, SnO, TaO, HfO, NbO, Zr In-O, Cu-O, In-O, Al-O, Ni-In-O, Zn-In-O, Cu- , Sn-In-O, Mn-In-O, Mg-In-O, Ga-In-O, Al-In-O, B-In- In-O, W-In-O, Ta-In-O, Hf-In-O, Re-In-O, Mg-Sn-O, Ga- Ga-Sn-Zn-In-O. ≪ / RTI >

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