WO2016178478A1 - Method of forming transparent electrode having improved transmissivity, and semiconductor device including transparent electrode formed by using same - Google Patents

Method of forming transparent electrode having improved transmissivity, and semiconductor device including transparent electrode formed by using same Download PDF

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WO2016178478A1
WO2016178478A1 PCT/KR2016/002996 KR2016002996W WO2016178478A1 WO 2016178478 A1 WO2016178478 A1 WO 2016178478A1 KR 2016002996 W KR2016002996 W KR 2016002996W WO 2016178478 A1 WO2016178478 A1 WO 2016178478A1
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transparent electrode
ito
metal layer
forming
metal
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PCT/KR2016/002996
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French (fr)
Korean (ko)
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김태근
김민주
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고려대학교 산학협력단
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/02—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/06—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
    • H01B1/08—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances oxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables

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  • the present invention relates to a method for forming a transparent electrode, and more particularly, to a method for forming a transparent electrode with improved transmittance.
  • Structural design of the light receiving device and the light emitting device, and device manufacturing technology play a very important role in improving the performance of the device.
  • there is a method of lowering the driving voltage by increasing the current injection efficiency For the purpose of uniform current distribution and injection, the contact area of the electrode is increased or a transparent conduction electrode (TCE) is used. Methods for making nanopatterns on surfaces for light extraction and absorption are widely used.
  • Transparent electrodes are the core materials of the IT industry that require light transmission and current injection / extraction at the same time. Indium-tin-oxide (ITO) and indium-zinc-oxide (IZO) are mainly used. In addition, transparent electrodes based on polymer transparent electrodes, CNT, Graphene, and silver nanowires have been proposed.
  • the transparency and conductivity of the transparent electrode have a trade-off relationship with each other.
  • the material with a large band-gap has a high transmittance as it can pass light of short wavelengths such as ultraviolet rays, while the electrode is very low in conductivity and does not have ohmic contact with the semiconductor material. It is impossible to use as. With the current technology, it is difficult to realize a transparent electrode exhibiting high electrical conductivity by forming ohmic contacts in the visible region as well as the ultraviolet region.
  • the problem to be solved by the present invention is to provide a method for forming a transparent electrode exhibiting high transmittance to light in the ultraviolet region without deteriorating the electrical characteristics.
  • the transparent electrode forming method for solving the above problems, (a) depositing indium oxide and tin oxide on the substrate to form an ITO (Indium-Tin-Oxide) transparent electrode; (b) depositing a metal belonging to a period lower than indium on the periodic table to form a metal layer on the ITO transparent electrode; And (d) heat treating the substrate on which the metal layer is formed to form a transparent electrode by penetrating the metal into the ITO transparent electrode.
  • ITO Indium-Tin-Oxide
  • the step (b) may form a metal layer composed of a plurality of dot-shaped metal crystals on the ITO transparent electrode.
  • the metal deposited on the ITO transparent electrode may be any one of Al, Ti, Ga, and Ge.
  • the metal layer in the step (b), may be formed to a thickness of 1nm to 5nm.
  • heat treatment may be performed at 450 to 750 degrees in a nitrogen or air atmosphere.
  • the metal of the metal layer formed with the uneven pattern is the ITO.
  • the concave-convex pattern may be formed on the surface of the transparent electrode by penetrating into the transparent electrode.
  • the composition ratio of the metal increases from the surface of the substrate toward the opposite surface of the surface of the ITO transparent electrode in contact with the surface of the substrate, thereby reducing the difference in refractive index with air.
  • a metal layer is formed on a ITO transparent electrode, which is most widely used as a transparent electrode, using a metal having a lower period on the periodic table than indium, and the metals forming the metal layer through heat treatment are transparent to ITO.
  • the transparency of the transparent electrode is extended to the ultraviolet region, and the metal penetrated into the ITO transparent electrode improves the conductivity of the entire transparent electrode.
  • the method for forming a transparent electrode of the present invention improves the transmittance and conductivity of the transparent electrode only by adding a simple metal layer forming process and a heat treatment process to the conventional transparent electrode forming process without adding complicated patterning or etching processes. Can be, there is an advantage that can be applied directly to the current commercially available transparent electrode forming process.
  • FIG. 1 is a flowchart illustrating a method of forming a transparent electrode according to an exemplary embodiment of the present invention.
  • Figure 2 is a graph measuring the composition ratio of each element constituting the ITO transparent electrode and the Al metal layer according to a preferred embodiment of the present invention through the AES analysis method.
  • FIG 3 is a view for explaining a phenomenon that the transmittance is improved in the transparent electrode of the present invention.
  • FIG. 5 is a graph illustrating experiments of I-V characteristics after a metal layer is formed and heat-treated on a general ITO transparent electrode and an ITO transparent electrode according to a preferred embodiment of the present invention.
  • FIG. 6 is a view for explaining a method of forming a transparent electrode according to another embodiment of the present invention.
  • FIG. 1 is a flowchart illustrating a method of forming a transparent electrode according to an exemplary embodiment of the present invention.
  • the preferred embodiment of the present invention exemplarily describes a method of forming a transparent electrode for improving the transmittance and conductivity of the ITO transparent electrode 121 by forming the Al metal layer 123 on the ITO transparent electrode 121.
  • the substrate 110 on which the ITO transparent electrode 121 is to be prepared is prepared, the cleaning operation is performed on the surface of the substrate 110, and the substrate 110.
  • Indium oxide and tin oxide are deposited on the ITO transparent electrode 121.
  • the substrate 110 of the present invention is formed with a light emitting element or a light receiving element, for example, the light emitting element, the substrate 110 of the present invention is an n-GaN, an active layer, and a p-GaN layer on the semiconductor substrate 110 It may be a substrate 110 including a sequentially formed structure.
  • the transparent electrode formed on the substrate 110 is used indium-tin-oxide (ITO) which is most commonly used as a transparent electrode in the light emitting device and the light receiving device, the substrate 110 It was formed by depositing a thickness of about 90nm to 130nm above.
  • ITO indium-tin-oxide
  • the material and thickness of the ITO transparent electrode 121 may be changed according to process conditions and product specifications.
  • the ITO transparent electrode 121 has a thickness of about 110 nm.
  • a thin metal layer 123 is formed on the ITO transparent electrode 121.
  • a metal having a periodic table period lower than Indium among the elements constituting the ITO transparent electrode 121 is used as the metal constituting the metal layer 123.
  • Indium is a 5 period element on the periodic table.
  • As the metal used to form the metal layer 123 of the present invention 2, 3, or 4 periodic metals may be used.
  • Al is a metal layer.
  • metals such as Ti, Ge, Ga, and the like may be used. Since these metals have a larger energy gap than indium, they can penetrate into the transparent electrode and provide a larger energy gap than indium in the heat treatment process described later, thereby improving the transmittance of the transparent electrode.
  • the thickness of the metal layer 123 formed on the ITO transparent electrode 121 is determined according to the thickness of the ITO transparent electrode 121, and penetrates into the ITO transparent electrode 121 during the heat treatment to be described later, but ITO transparent electrode 121 It is preferable to form a thin film so as not to affect the light emitting device or the light receiving device formed on the semiconductor substrate 110 outside of the range.
  • the metal layer 123 may be formed of a thin film having a thickness of 2 to 5 nm with Al, and the ITO transparent electrode 121 layer is formed with a thickness of about 110 nm.
  • the Al metal layer 123 was formed to a thickness of 3 nm.
  • the metal layer 123 which is a thin film, is formed using a sputtering device, but any method may be applied as long as it is a method of forming a metal thin film layer on the ITO transparent electrode 121.
  • the substrate 110, the metal layer 123 is formed on the ITO transparent electrode 121, as shown in Figure 1 (c), the heat treatment is carried out at 450 to 750 degrees in nitrogen or air atmosphere, heat treatment
  • the metal of the metal layer 123 formed on the ITO transparent electrode 121 penetrates into the ITO transparent electrode 121.
  • the metal penetrated into the ITO transparent electrode 121 improves transmittance by expanding the band gap in combination with the components constituting the ITO transparent electrode 121, and does not combine with the components of the ITO transparent electrode 121.
  • the metal atoms serve to provide a donor in the ITO transparent electrode 121, thereby improving the conductivity of the ITO transparent electrode 121 as a whole.
  • FIG. 2 is a graph measuring the composition ratio of each element constituting the ITO transparent electrode 121 and the Al metal layer 123 according to the preferred embodiment of the present invention through an AES analysis method.
  • FIG. 2 is a graph illustrating a composition ratio according to depth when an ITO transparent electrode 121 is formed on a p-GaN layer, and then a metal layer 123 is formed of Al thereon.
  • (b) is a graph measuring the composition ratio before the heat treatment
  • Figure 2 (a) is a graph measuring the composition ratio after the heat treatment. For reference, as the sputtering time of the x-axis of the graph increases, the depth from the surface increases.
  • Al may be present only on the surface of the metal layer 123, and may not be present in the ITO transparent electrode 121.
  • the boundary between the metal layer 123 and the ITO transparent electrode 121 disappears by heat treatment, and the ITO transparent electrode 121 and the metal layer 123 before the heat treatment are formed into one transparent electrode 120 by heat treatment.
  • the composition ratio of Al, which is a metal increases as the composition ratio of Indium decreases toward the surface of the transparent electrode 120, and the Al component, which is a metal, decreases as it enters the transparent electrode 120 from the surface of the transparent electrode 120. It can be seen that the composition ratio of indium increases.
  • FIG. 3 is a view for explaining a phenomenon that the transmittance is improved in the transparent electrode of the present invention.
  • the energy band gap (E g-In-O ) of the conventional ITO transparent electrode 121 is obtained.
  • the energy band gap (E g-In-O-Al ) after Al penetrates) expands, and the amount of light absorbed decreases as the band gap expands, thereby improving transmittance.
  • the present invention changes the bonding structure of the transparent electrode material, thereby extending the band gap as a whole and simultaneously exhibiting an impurity doping effect, thereby simultaneously improving the transmittance and conductivity.
  • the present invention since the composition ratio of each component in the transparent electrode is changed according to the depth from the surface, the refractive index of the transparent electrode also from the surface of the transparent electrode toward the inside of the transparent electrode, or from inside the transparent electrode It will change toward the surface.
  • the refractive index of the ITO transparent electrode 121 is 1.7 to 2.1, and in the case of Al, the refractive index is about 0.4 to 1.7 even when considering the oxide state. Therefore, since the Al component is extremely small inside the transparent electrode away from the surface, the refractive index of the general ITO (1.7 to 2.1) is shown. However, when the Al component increases toward the surface and becomes a quaternary material, the refractive index is 120. The refractive index changes depending on the contribution of the four elements constituting). As described above, the ratio of the Al component increases toward the surface of the transparent electrode 120, which reduces the refractive index of the transparent electrode 120 as a whole. Accordingly, the difference in refractive index with air outside the transparent electrode 120 decreases toward the surface of the transparent electrode 120, thereby reducing the total reflection of light on the surface of the transparent electrode 120.
  • FIG 4 is a graph illustrating the change in transmittance when the Al metal layer 123 is formed on the ITO transparent electrode 121 and the ITO transparent electrode 121.
  • FIG. 4A shows a 110 nm thick ITO transparent electrode 121 and a 110 nm thick ITO transparent electrode 121 having a 3 nm thick Al metal layer 123 formed thereon (ITO / Al transparent electrode).
  • ITO / Al transparent electrode As showing the transmittance of 120, it can be seen that there is almost no change in the transmittance.
  • the graph of FIG. 4B is a transparent layer in which an Al metal layer 123 having a thickness of 3 nm is formed on the 110 nm thick ITO transparent electrode 121 and the 110 nm thick ITO transparent electrode 121 shown in FIG. 4A.
  • Transmittance of the electrode (ITO / Al transparent electrode) 120 after the heat treatment at a temperature of about 550 degrees showing that the transmittance of the ITO / Al transparent electrode 120 after the heat treatment is improved than the ITO transparent electrode 121 You can check.
  • FIG. 5 is a graph illustrating I-V characteristics after the general ITO transparent electrode 121 and the metal layer 123 are formed and heat-treated on the ITO transparent electrode 121 according to a preferred embodiment of the present invention.
  • the metal layer 123 is formed of a metal having a period lower than that of indium on the ITO transparent electrode 121, and heat treatment is performed.
  • the metal is infiltrated into the ITO transparent electrode 121, it can be seen that the transmittance can be greatly improved without deteriorating the electrical characteristics.
  • FIG. 6 is a view for explaining a method of forming a transparent electrode according to another embodiment of the present invention.
  • a flat metal layer 123 is formed on the ITO transparent electrode 121.
  • the metal layer 123 is formed on the ITO transparent electrode 121 in the form of a plurality of dots, thereby exhibiting substantially the same effect as the unevenness formed on the surface of the transparent electrode. .
  • an ITO transparent electrode 121 is formed on a substrate 110 on which a light emitting device or a light receiving device is formed in the same manner as in FIG. 1A (see FIG. 6A).
  • a metal layer 125 is formed by depositing a metal on the ITO transparent electrode 121 using an e-beam deposition apparatus (see FIG. 6B).
  • a metal having a periodic table period lower than Indium such as Al, Ti, Ge, Ga, or the like, may be used.
  • the metal layer 125 is formed of a plurality of dot-shaped metal crystals 125 having a thickness of 3 nm or less using e-beam deposition equipment.
  • the surface in contact with the ITO transparent electrode 121 is flat, and the opposite side is defined as a shape protruding convexly into the surface shape of the water droplets.
  • the metal of the metal layer 123 is heat-treated at 450 to 750 degrees in the same manner as illustrated in FIG. 1C. It penetrates into the ITO transparent electrode 121, and completes a transparent electrode (refer FIG. 6 (c)).
  • the completed transparent electrode 120 since the surface is formed in a dot shape, as a whole, it has the same effect as the irregularities formed on the surface of the transparent electrode 120. Therefore, in the case of the transparent electrode 120 shown in FIG. 6, as described above with reference to FIG. 1, not only an effect in which total reflection is reduced by changing the refractive index by increasing the metal composition ratio on the surface of the transparent electrode 120, Since irregularities are formed on the surface of the transparent electrode 120 to cause diffuse reflection, an effect of reducing total reflection additionally occurs, and thus may exhibit higher light extraction efficiency and light absorption efficiency.
  • the bottom surfaces of the plurality of metal crystals are connected to each other to substantially form a metal layer having a structure in which irregularities are formed on the ITO transparent electrode 121. It may be.

Abstract

The present invention discloses a method of forming a transparent electrode. A method of forming a transparent electrode according to a preferred embodiment of the present invention forms a metal layer on an ITO transparent electrode that is the most widely used type of transparent electrode by using a metal in a period lower than Indium in the periodic table, and permeating metals forming the metal layer through heat treatment into the ITO transparent electrode to expand the effective bandgap, so as to have the effects of expanding the transmissivity of the transparent electrode to the ultraviolet range and, at the same time, improving the conductivity of the overall transparent electrode by virtue of the metals permeated into the ITO transparent electrode. This method of forming a transparent electrode of the present invention can improve the transmissivity and the conductivity of a transparent electrode by only adding a simple process of forming a metal layer and a heat treating process to a conventional process of forming a transparent electrode, without adding a complicated patterning or etching process, so as to have the advantage of being directly applicable to transparent electrode forming processes being commercialized.

Description

투과도가 향상된 투명 전극 형성 방법 및 이를 이용하여 형성된 투명 전극을 포함하는 반도체 소자Method for forming a transparent electrode having improved transmittance and a semiconductor device including the transparent electrode formed using the same
본 발명은 투명 전극 형성 방법에 관한 것으로서, 보다 구체적으로는 투과도가 향상된 투명 전극 형성 방법에 관한 것이다.The present invention relates to a method for forming a transparent electrode, and more particularly, to a method for forming a transparent electrode with improved transmittance.
1907년 CaO물질이 투명전극으로 제안된 이후 Display 산업이 태동하기까지 투명전극에 대한 관심은 그리 크지 않았다. 그러나 LED, 태양전지, LCD, OLED, 투명 Display, 터치패널 등의 수광소자 및 발광소자 사업이 성장하면서 다양한 투명전극이 많은 관심을 받고 있다. Since CaO was proposed as a transparent electrode in 1907, interest in transparent electrodes was not so great until the display industry began. However, as the light-receiving device and light-emitting device business of LED, solar cell, LCD, OLED, transparent display, and touch panel are growing, various transparent electrodes are attracting much attention.
수광소자 및 발광소자의 구조설계, 소자 제작기술은 소자의 성능 향상에 있어서 매우 중요한 역할을 한다. 이러한 소자의 성능을 향상시키는 방법으로는 전류 주입효율을 높여 구동전압을 낮추는 방법이 있고, 균일한 전류 분산 및 주입을 위해서 전극의 접촉 면적을 넓히거나 투명전극(transparent conduction electrode; TCE)을 사용하거나, 광추출 및 흡수를 위해 표면에 나노 패턴을 만드는 방법들이 널리 사용되고 있다.Structural design of the light receiving device and the light emitting device, and device manufacturing technology play a very important role in improving the performance of the device. In order to improve the performance of the device, there is a method of lowering the driving voltage by increasing the current injection efficiency.For the purpose of uniform current distribution and injection, the contact area of the electrode is increased or a transparent conduction electrode (TCE) is used. Methods for making nanopatterns on surfaces for light extraction and absorption are widely used.
그 중에서 수광 및 발광소자의 효율을 향상시키기 위한 노력으로 TCE의 연구는 가장 중요한 부분을 차지하고 있다. 투명전극은 빛의 투과와 전류의 주입/추출을 동시에 필요로 하는 IT산업의 핵심 재료로 주로 ITO(Indium-tin-oxide), IZO(indium-zinc-oxide; IZO)가 사용되고 있다. 더하여 고분자 투명전극, CNT, Graphene, 은나노와이어 등 기반의 투명전극이 제안되고 있다. Among them, the research of TCE is the most important part in an effort to improve the efficiency of light receiving and light emitting devices. Transparent electrodes are the core materials of the IT industry that require light transmission and current injection / extraction at the same time. Indium-tin-oxide (ITO) and indium-zinc-oxide (IZO) are mainly used. In addition, transparent electrodes based on polymer transparent electrodes, CNT, Graphene, and silver nanowires have been proposed.
그러나 TCE층의 빛의 흡수에 의해 수광소자의 광흡수나 발광소자의 광추출에 어려움이 있다. 효율향상을 위해서는 오믹접촉을 통해 동작전압을 낮추어주거나 생성된 빛을 잘 투과시켜 효율을 높여줄 수 있다. 일반적으로는 투명전극의 투과도와 전도도는 서로 trade-off 관계를 가지고 있다.However, due to the absorption of light in the TCE layer, there is a difficulty in light absorption of the light receiving element or light extraction of the light emitting element. In order to improve the efficiency, it is possible to lower the operating voltage through ohmic contact or improve the efficiency by transmitting the generated light well. In general, the transparency and conductivity of the transparent electrode have a trade-off relationship with each other.
큰 밴드갭(wide band-gap)을 가지는 물질은 자외선 등의 단파장의 빛을 통과 시킬 수 있는 만큼 높은 투과도를 가지는 반면, 전극으로 이용되기에는 전도성이 매우 낮고 반도체 물질과 Ohmic contact 이 이루어지지 않아 전극으로 이용하는 것이 불가능하다. 현재의 기술로는 가시광 영역뿐만 아니라 자외선 영역에서도 높은 투과도를 나타내면서도, Ohmic contact 이 이루어져 높은 전기 전도도를 나타내는 투명 전극을 구현하기에는 어려움이 있다.The material with a large band-gap has a high transmittance as it can pass light of short wavelengths such as ultraviolet rays, while the electrode is very low in conductivity and does not have ohmic contact with the semiconductor material. It is impossible to use as. With the current technology, it is difficult to realize a transparent electrode exhibiting high electrical conductivity by forming ohmic contacts in the visible region as well as the ultraviolet region.
따라서, 가시광 영역부터 UV 영역까지 적용될 수 있는 투명전극을 구현하기 위해서는, 높은 투과도를 지니는 동시에 발광 소자 및 수광 소자와 오믹 접촉 형성이 가능한 투명전극 개발이 필수적이다.Therefore, in order to implement a transparent electrode that can be applied from the visible region to the UV region, it is necessary to develop a transparent electrode having high transmittance and capable of forming ohmic contact with the light emitting element and the light receiving element.
본 발명이 해결하고자 하는 과제는 전기적 특성을 열화시키지 않으면서도 자외선 영역의 빛에 대해서 높은 투과도를 나타내는 투명 전극 형성 방법을 제공하는 것이다.The problem to be solved by the present invention is to provide a method for forming a transparent electrode exhibiting high transmittance to light in the ultraviolet region without deteriorating the electrical characteristics.
상술한 과제를 해결하기 위한 본 발명의 바람직한 실시예에 따른 투명 전극 형성 방법은, (a) 기판위에 인듐 산화물 및 주석 산화물을 증착하여 ITO(Indium-Tin-Oxide) 투명 전극을 형성하는 단계; (b) 상기 ITO 투명 전극 위에, 주기율표상에서 인듐보다 낮은 주기에 속하는 금속을 증착하여 금속층을 형성하는 단계; 및 (d) 상기 금속층이 형성된 기판을 열처리하여, 상기 금속을 ITO 투명 전극 내부로 침투시켜 투명 전극을 형성하는 단계를 포함한다.The transparent electrode forming method according to a preferred embodiment of the present invention for solving the above problems, (a) depositing indium oxide and tin oxide on the substrate to form an ITO (Indium-Tin-Oxide) transparent electrode; (b) depositing a metal belonging to a period lower than indium on the periodic table to form a metal layer on the ITO transparent electrode; And (d) heat treating the substrate on which the metal layer is formed to form a transparent electrode by penetrating the metal into the ITO transparent electrode.
또한, 본 발명의 일 실시예에 따르면, 상기 (b) 단계는, 상기 ITO 투명 전극 위에, 복수의 dot 형태의 금속 결정들로 구성되는 금속층을 형성할 수 있다.In addition, according to an embodiment of the present invention, the step (b) may form a metal layer composed of a plurality of dot-shaped metal crystals on the ITO transparent electrode.
또한, 본 발명의 일 실시예에 따르면, 상기 (b) 단계에서, 상기 ITO 투명 전극 위에 증착되는 금속은 Al, Ti, Ga, 및 Ge 중 어느 하나일 수 있다.In addition, according to an embodiment of the present invention, in step (b), the metal deposited on the ITO transparent electrode may be any one of Al, Ti, Ga, and Ge.
또한, 본 발명의 일 실시예에 따르면, 상기 (b) 단계에서, 상기 금속층은 1nm 내지 5nm의 두께로 형성될 수 있다.In addition, according to an embodiment of the present invention, in the step (b), the metal layer may be formed to a thickness of 1nm to 5nm.
또한, 본 발명의 일 실시예에 따르면, 상기 (d) 단계는, 질소 또는 대기 분위기에서, 450도 내지 750도에서 열처리가 수행될 수 있다.In addition, according to an embodiment of the present invention, in step (d), heat treatment may be performed at 450 to 750 degrees in a nitrogen or air atmosphere.
또한, 본 발명의 일 실시예에 따르면, 상기 (b) 단계는, ITO층 표면에 요철 패턴으로 상기 금속층을 형성하고, 상기 (d) 단계가 수행되면, 요철 패턴으로 형성된 금속층의 금속이 상기 ITO 투명 전극으로 침투하여 투명 전극 표면에 요철 패턴이 형성될 수 있다.In addition, according to an embodiment of the present invention, in the step (b), when the metal layer is formed on the surface of the ITO layer with an uneven pattern, and (d) is performed, the metal of the metal layer formed with the uneven pattern is the ITO. The concave-convex pattern may be formed on the surface of the transparent electrode by penetrating into the transparent electrode.
또한, 본 발명의 일 실시예에 따르면, 상기 기판 표면에서, 상기 기판 표면에 접촉하는 ITO 투명 전극의 표면의 반대 표면으로 갈수록 상기 금속의 조성비가 증가하여, 공기와의 굴절율 차이가 감소할 수 있다.In addition, according to an embodiment of the present invention, the composition ratio of the metal increases from the surface of the substrate toward the opposite surface of the surface of the ITO transparent electrode in contact with the surface of the substrate, thereby reducing the difference in refractive index with air. .
[유리한 효과][Favorable effect]
본 발명의 바람직한 실시예에 따른 투명 전극 형성 방법은 투명전극으로 가장 널리 사용되는 ITO 투명 전극 위에 Indium보다 주기율표상의 주기가 낮은 금속을 이용하여 금속층을 형성하고 열처리를 통해서 금속층을 구성하는 금속들을 ITO 투명 전극 내부로 침투시켜 유효 밴드갭을 확장시킴으로써, 투명 전극의 투과도를 자외선 영역으로 확장시킴과 동시에, ITO 투명 전극 내부에 침투한 금속이 전체 투명 전극의 전도도를 향상시키는 효과가 있다. 이러한 본 발명의 투명 전극 형성 방법은 종래의 투명 전극 형성 공정에, 복잡한 패터닝이나 에칭 공정을 추가함 없이, 단순한 금속층을 형성하는 공정과 열처리 공정을 추가하는 것 만으로도 투명 전극의 투과도 및 전도도를 향상시킬 수 있어, 현재 상용화된 투명 전극 형성 공정에 바로 적용이 가능한 장점이 있다.In the method of forming a transparent electrode according to the preferred embodiment of the present invention, a metal layer is formed on a ITO transparent electrode, which is most widely used as a transparent electrode, using a metal having a lower period on the periodic table than indium, and the metals forming the metal layer through heat treatment are transparent to ITO. By penetrating into the electrode to extend the effective bandgap, the transparency of the transparent electrode is extended to the ultraviolet region, and the metal penetrated into the ITO transparent electrode improves the conductivity of the entire transparent electrode. The method for forming a transparent electrode of the present invention improves the transmittance and conductivity of the transparent electrode only by adding a simple metal layer forming process and a heat treatment process to the conventional transparent electrode forming process without adding complicated patterning or etching processes. Can be, there is an advantage that can be applied directly to the current commercially available transparent electrode forming process.
도 1은 본 발명의 바람직한 실시예에 따른 투명 전극 형성 방법을 설명하는 공정도이다.1 is a flowchart illustrating a method of forming a transparent electrode according to an exemplary embodiment of the present invention.
도 2는 본 발명의 바람직한 실시예에 따른 ITO 투명 전극과 Al 금속층을 구성하는 각 원소의 구성비를 AES 분석 방법을 통해서 측정한 그래프이다.Figure 2 is a graph measuring the composition ratio of each element constituting the ITO transparent electrode and the Al metal layer according to a preferred embodiment of the present invention through the AES analysis method.
도 3은 본 발명의 투명 전극에서 투과도가 향상되는 현상을 설명하는 도면이다.3 is a view for explaining a phenomenon that the transmittance is improved in the transparent electrode of the present invention.
도 4는 ITO 투명 전극과 ITO 투명 전극에 Al 금속층을 형성한 경우에 투과도 변화를 설명하는 그래프이다.4 is a graph illustrating the change in transmittance when the Al metal layer is formed on the ITO transparent electrode and the ITO transparent electrode.
도 5는 일반적인 ITO 투명 전극과 본 발명의 바람직한 실시예에 따라서 ITO 투명 전극 위에 금속층이 형성되고 열처리된 후의 I-V 특성을 실험한 그래프를 도시한 도면이다.FIG. 5 is a graph illustrating experiments of I-V characteristics after a metal layer is formed and heat-treated on a general ITO transparent electrode and an ITO transparent electrode according to a preferred embodiment of the present invention.
도 6은 본 발명의 바람직한 다른 실시예에 따른 투명 전극 형성 방법을 설명하는 도면이다.6 is a view for explaining a method of forming a transparent electrode according to another embodiment of the present invention.
이하, 첨부된 도면을 참조하여 본 발명의 바람직한 실시예들을 설명한다.Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
도 1은 본 발명의 바람직한 실시예에 따른 투명 전극 형성 방법을 설명하는 공정도이다. 1 is a flowchart illustrating a method of forming a transparent electrode according to an exemplary embodiment of the present invention.
도 1을 참조하여, 본 발명의 바람직한 실시예에 따른 투명 전극 형성 방법을 설명한다. 단, 본 발명의 바람직한 실시예는 ITO 투명 전극(121) 위에 Al 금속층(123)을 형성하여 ITO 투명 전극(121)의 투과도 및 전도도를 향상시키는 투명 전극 형성 방법을 예시적으로 설명한다.Referring to FIG. 1, a transparent electrode forming method according to a preferred embodiment of the present invention will be described. However, the preferred embodiment of the present invention exemplarily describes a method of forming a transparent electrode for improving the transmittance and conductivity of the ITO transparent electrode 121 by forming the Al metal layer 123 on the ITO transparent electrode 121.
먼저, 도 1의 (a)에 도시된 바와 같이, ITO 투명 전극(121)이 형성될 기판(110)을 준비하고, 기판(110)의 표면에 대해서 세척 작업을 수행한 후, 그 기판(110)위에 인듐 산화물과 주석 산화물을 증착하여 ITO 투명 전극(121)을 형성한다.First, as shown in FIG. 1A, the substrate 110 on which the ITO transparent electrode 121 is to be prepared is prepared, the cleaning operation is performed on the surface of the substrate 110, and the substrate 110. Indium oxide and tin oxide are deposited on the ITO transparent electrode 121.
본 발명의 기판(110)은 발광 소자 또는 수광 소자가 형성된 것으로서, 발광소자를 예를 들면, 본 발명의 기판(110)은 반도체 기판(110) 위에 n-GaN, 활성층, 및 p-GaN층이 순차적으로 형성된 구조를 포함하는 기판(110)일 수 있다.The substrate 110 of the present invention is formed with a light emitting element or a light receiving element, for example, the light emitting element, the substrate 110 of the present invention is an n-GaN, an active layer, and a p-GaN layer on the semiconductor substrate 110 It may be a substrate 110 including a sequentially formed structure.
또한, 본 발명의 바람직한 실시예에서, 기판(110) 위에 형성되는 투명 전극은 발광소자 및 수광소자에서 투명 전극으로 가장 보편적으로 이용되는 ITO(Indium-Tin-Oxide) 가 이용되는데, 기판(110)위에 약 90nm 내지 130nm 의 두께로 증착시켜 형성하였다. ITO 투명 전극(121)의 재질 및 두께는 공정 조건 및 제품 사양에 따라서 변경될 수 있음은 물론이며, 본 발명의 바람직한 실시예는 ITO 투명 전극(121)을 약 110nm 두께로 형성하였다.In addition, in a preferred embodiment of the present invention, the transparent electrode formed on the substrate 110 is used indium-tin-oxide (ITO) which is most commonly used as a transparent electrode in the light emitting device and the light receiving device, the substrate 110 It was formed by depositing a thickness of about 90nm to 130nm above. The material and thickness of the ITO transparent electrode 121 may be changed according to process conditions and product specifications. Of course, in the preferred embodiment of the present invention, the ITO transparent electrode 121 has a thickness of about 110 nm.
ITO 투명 전극(121)이 형성된 후, 도 1의 (b)에 도시된 바와 같이, ITO 투명 전극(121) 위에 박막의 금속층(123)을 형성한다. 이 때, 금속층(123)을 구성하는 금속으로는 ITO 투명 전극(121)을 구성하는 원소 중 Indium 보다 주기율표상 주기가 낮은 금속이 이용된다.After the ITO transparent electrode 121 is formed, as shown in FIG. 1B, a thin metal layer 123 is formed on the ITO transparent electrode 121. At this time, as the metal constituting the metal layer 123, a metal having a periodic table period lower than Indium among the elements constituting the ITO transparent electrode 121 is used.
참고로, Indium은 주기율표상 5주기 원소로서, 본 발명의 금속층(123)을 형성하는데 이용되는 금속으로는 2, 3, 4 주기 금속이 이용될 수 있는데, 본 발명의 바람직한 실시예에서는 Al을 금속층(123)을 형성하는 금속으로 이용하였으나, Ti, Ge, Ga 등의 금속들이 이용될 수도 있다. 이러한 금속들은 원자의 에너지 갭이 Indium 보다 일반적으로 크기 때문에, 후술하는 열처리 공정에서 투명 전극 내부로 침투하여 Indium 보다 큰 에너지 갭을 제공 할 수 있어, 투명 전극의 투과도를 향상시킬 수 있다.For reference, Indium is a 5 period element on the periodic table. As the metal used to form the metal layer 123 of the present invention, 2, 3, or 4 periodic metals may be used. In a preferred embodiment of the present invention, Al is a metal layer. Although used as a metal for forming 123, metals such as Ti, Ge, Ga, and the like may be used. Since these metals have a larger energy gap than indium, they can penetrate into the transparent electrode and provide a larger energy gap than indium in the heat treatment process described later, thereby improving the transmittance of the transparent electrode.
ITO 투명 전극(121) 위에 형성되는 금속층(123)의 두께는 ITO 투명 전극(121)의 두께에 따라서 결정되며, 후술하는 열처리 과정에서 ITO 투명 전극(121) 내부로 침투하되, ITO 투명 전극(121)의 범위를 벗어나서 반도체 기판(110)위에 형성된 발광 소자 또는 수광 소자에 영향을 미치지 않도록 박막으로 형성되는 것이 바람직하다. The thickness of the metal layer 123 formed on the ITO transparent electrode 121 is determined according to the thickness of the ITO transparent electrode 121, and penetrates into the ITO transparent electrode 121 during the heat treatment to be described later, but ITO transparent electrode 121 It is preferable to form a thin film so as not to affect the light emitting device or the light receiving device formed on the semiconductor substrate 110 outside of the range.
도 1에 도시된 본 발명의 바람직한 실시예에서, 금속층(123)은 Al 으로 2~5nm의 두께의 얇은 박막으로 형성될 수 있고, ITO 투명 전극(121)층이 약 110nm의 두께로 형성된 경우에 Al 금속층(123)은 3nm의 두께로 형성되었다. 본 발명의 바람직한 실시예에서, 박막인 금속층(123)은 스퍼터 장비를 이용하여 형성되었으나, ITO 투명 전극(121) 위에 금속 박막층을 형성할 수 있는 방법이라면 모두 적용이 가능하다.In the preferred embodiment of the present invention shown in FIG. 1, the metal layer 123 may be formed of a thin film having a thickness of 2 to 5 nm with Al, and the ITO transparent electrode 121 layer is formed with a thickness of about 110 nm. The Al metal layer 123 was formed to a thickness of 3 nm. In a preferred embodiment of the present invention, the metal layer 123, which is a thin film, is formed using a sputtering device, but any method may be applied as long as it is a method of forming a metal thin film layer on the ITO transparent electrode 121.
한편, ITO 투명 전극(121)위에 금속층(123)이 형성된 기판(110)은, 도 1의 (c)에 도시된 바와 같이, 질소 또는 대기 분위기에서 450도 내지 750도에서 열처리가 수행되고, 열처리 과정에서 ITO 투명 전극(121) 위에 형성된 금속층(123)의 금속이 ITO 투명 전극(121) 내부로 침투한다. ITO 투명 전극(121) 내부로 침투한 금속은 ITO 투명 전극(121)을 구성하는 성분들과 결합하여 밴드갭을 확장시킴으로써 투과도를 향상시키고, ITO 투명 전극(121)의 구성 성분들과 결합하지 않은 금속 원자들은 ITO 투명 전극(121) 내부에 도너를 제공하는 역할을 수행함으로써, ITO 투명 전극(121) 전체적으로 전도도를 향상시키는 효과를 나타낸다.On the other hand, the substrate 110, the metal layer 123 is formed on the ITO transparent electrode 121, as shown in Figure 1 (c), the heat treatment is carried out at 450 to 750 degrees in nitrogen or air atmosphere, heat treatment In the process, the metal of the metal layer 123 formed on the ITO transparent electrode 121 penetrates into the ITO transparent electrode 121. The metal penetrated into the ITO transparent electrode 121 improves transmittance by expanding the band gap in combination with the components constituting the ITO transparent electrode 121, and does not combine with the components of the ITO transparent electrode 121. The metal atoms serve to provide a donor in the ITO transparent electrode 121, thereby improving the conductivity of the ITO transparent electrode 121 as a whole.
도 2는 본 발명의 바람직한 실시예에 따른 ITO 투명 전극(121)과 Al 금속층(123)을 구성하는 각 원소의 구성비를 AES 분석 방법을 통해서 측정한 그래프이다.2 is a graph measuring the composition ratio of each element constituting the ITO transparent electrode 121 and the Al metal layer 123 according to the preferred embodiment of the present invention through an AES analysis method.
도 2에 도시된 그래프는, p-GaN층 위에 ITO 투명 전극(121)을 형성한 후, 그 위에 Al으로 금속층(123)을 형성한 경우에, 깊이에 따른 조성비를 측정한 것으로서, 도 2의 (b)는 열처리를 수행하기 전의 조성비를 측정한 그래프이고, 도 2의 (a)는 열처리를 수행한 후의 조성비를 측정한 그래프이다. 참고로, 그래프의 x축의 sputtering time 이 증가할수록 표면으로부터의 깊이가 증가함을 의미한다.2 is a graph illustrating a composition ratio according to depth when an ITO transparent electrode 121 is formed on a p-GaN layer, and then a metal layer 123 is formed of Al thereon. (b) is a graph measuring the composition ratio before the heat treatment, Figure 2 (a) is a graph measuring the composition ratio after the heat treatment. For reference, as the sputtering time of the x-axis of the graph increases, the depth from the surface increases.
도 2의 (b)를 참조하면, 열처리 이전에, Al은 금속층(123)의 표면에만 존재하고, ITO 투명 전극(121) 내부에는 존재하지 않음을 알 수 있다. Referring to FIG. 2B, before the heat treatment, Al may be present only on the surface of the metal layer 123, and may not be present in the ITO transparent electrode 121.
그러나, 열처리가 수행되면, 도 2의 (a)에 도시된 바와 같이, 금속층(123)의 표면에서 Al의 조성비가 급격히 낮아진 반면, ITO 투명 전극(121) 내부에는 Al이 침투하여, 도 2의 (b)에서는 Al이 거의 검출되지 않았던 깊이에서, 상당한 조성비의 Al이 검출됨을 확인할 수 있고, Al의 조성비는 표면으로부터 깊이 들어갈수록 점차 감소함을 알 수 있다.However, when the heat treatment is performed, as shown in (a) of FIG. 2, while the composition ratio of Al is sharply lowered on the surface of the metal layer 123, Al penetrates into the ITO transparent electrode 121 and thus, FIG. In (b), it can be seen that Al of a considerable composition ratio is detected at a depth at which Al is hardly detected, and it can be seen that the composition ratio of Al gradually decreases as it goes deeper from the surface.
또한, 도 2의 (b)를 참조하면, Indium 및 ITO를 구성하는 다른 성분 역시 열처리에 의해서 금속층(123)으로 확산되어, 금속층(123) 표면에서 그 성분들이 검출되며, 특히 Indium의 경우에는 금속층(123) 표면에서 약 20%의 성분이 검출되고, 금속층 표면으로부터의 깊이가 깊어질수록 그 성분비가 점차 증가하여, Al의 성분비가 거의 0에 도달하는 깊이에서 원래 ITO에서 차지하던 성분비로 회복됨을 알 수 있다.In addition, referring to FIG. 2B, other components constituting Indium and ITO are also diffused into the metal layer 123 by heat treatment, so that the components are detected on the surface of the metal layer 123, in particular, in the case of Indium. (123) About 20% of the component was detected on the surface, and as the depth from the metal layer surface became deeper, the component ratio gradually increased, recovering to the component ratio originally occupied by ITO at a depth where Al component ratio reached almost zero. Able to know.
따라서, 열처리에 의해서 금속층(123)과 ITO 투명 전극(121)의 경계는 사라지고, 열처리전의 ITO 투명 전극(121)과 금속층(123)이 열처리에 의해서 하나의 투명 전극(120)으로 형성되고, 다만, 투명 전극(120)의 표면으로 갈수록 Indium의 조성비가 감소하는 대신에 금속인 Al의 조성비가 증가하고, 투명 전극(120) 표면에서 투명 전극(120) 내부로 들어갈수록 금속인 Al 성분은 감소하고 Indium 의 조성비가 증가함을 알 수 있다.Therefore, the boundary between the metal layer 123 and the ITO transparent electrode 121 disappears by heat treatment, and the ITO transparent electrode 121 and the metal layer 123 before the heat treatment are formed into one transparent electrode 120 by heat treatment. The composition ratio of Al, which is a metal, increases as the composition ratio of Indium decreases toward the surface of the transparent electrode 120, and the Al component, which is a metal, decreases as it enters the transparent electrode 120 from the surface of the transparent electrode 120. It can be seen that the composition ratio of indium increases.
도 3은 본 발명의 투명 전극에서 투과도가 향상되는 현상을 설명하는 도면이다. 도 3을 참조하면, 금속층(123)을 형성하는 Al의 오비탈 구조로 인하여 ITO 투명 전극(121)에 Al을 침투시키면, 종래의 ITO 투명 전극(121)의 에너지 밴드 갭(Eg-In-O)보다 Al이 침투된 후의 에너지 밴드 갭(Eg-In-O-Al)이 확장되는 현상이 발생하고, 밴드갭이 확장됨에 따라서 흡수되는 광량이 줄어 투과도가 향상된다. 3 is a view for explaining a phenomenon that the transmittance is improved in the transparent electrode of the present invention. Referring to FIG. 3, when Al is infiltrated into the ITO transparent electrode 121 due to the orbital structure of Al forming the metal layer 123, the energy band gap (E g-In-O ) of the conventional ITO transparent electrode 121 is obtained. The energy band gap (E g-In-O-Al ) after Al penetrates) expands, and the amount of light absorbed decreases as the band gap expands, thereby improving transmittance.
일반적으로 밴드갭이 넓어지면 투과도는 향상되고 전도도는 감소한다고 알려져 있으나, 본 발명의 경우, 열처리 과정중에 Indium을 대체하여 산소 원자와 결합한 Al이 전체적인 밴드갭을 향상시키면서도 산소 원자와 결합하지 않은 Al이 결정 사이 사이를 불순물 형식으로 침투하여 전도도를 향상시킨다. 결과적으로, 본 발명은 투명 전극 물질의 결합 구조를 변화시킴으로써, 전체적으로 밴드갭을 확장시킴과 동시에 불순물 도핑 효과를 나타내고, 이에 따라서 투과도 및 전도도가 동시에 향상된다.In general, when the bandgap is wider, the permeability is improved and the conductivity is decreased. However, in the present invention, Al bonded to the oxygen atom by replacing Indium during the heat treatment process improves the overall bandgap while Al is not bonded to the oxygen atom. It penetrates between the crystals in the form of impurities to improve conductivity. As a result, the present invention changes the bonding structure of the transparent electrode material, thereby extending the band gap as a whole and simultaneously exhibiting an impurity doping effect, thereby simultaneously improving the transmittance and conductivity.
또한, 본 발명은 상술한 바와 같이, 투명 전극 내에서 각 성분의 조성비가 표면으로부터의 깊이에 따라서 변화하게 되므로, 투명 전극의 굴절율 역시 투명 전극의 표면으로부터 투명 전극 내부로 갈수록, 또는 투명전극 내부로부터 표면으로 갈수록 변화하게 된다.In addition, the present invention, as described above, since the composition ratio of each component in the transparent electrode is changed according to the depth from the surface, the refractive index of the transparent electrode also from the surface of the transparent electrode toward the inside of the transparent electrode, or from inside the transparent electrode It will change toward the surface.
일반적으로 ITO 투명 전극(121)의 굴절율은 1.7 ~ 2.1이고, Al의 경우는 산화물 상태를 고려해도 0.4 ~ 1.7 정도이다. 따라서, 표면으로부터 멀어진 투명 전극 내부에는 Al 성분이 극히 적으므로 일반적인 ITO 의 굴절율(1.7 ~ 2.1)을 나타내지만, 표면으로 갈수록 Al 성분이 증가하여 4원계 물질이 되었을때의 굴절률은, 투명 전극(120)을 구성하는 4가지 원소들이 기여하는 정도에 따라서 굴절률에 변화가 생긴다. 전술한 바와 같이, 투명 전극(120)의 표면으로 갈수록 Al 성분의 비율이 높아지고, 이는 투명 전극(120)의 굴절률을 표면으로 갈수록 전체적으로 감소시킨다. 따라서, 투명 전극(120)의 표면으로 갈수록 투명 전극(120) 외부의 공기와의 굴절률 차이가 감소하여, 투명 전극(120) 표면에서의 광의 전반사를 감소시키는 효과가 나타난다.In general, the refractive index of the ITO transparent electrode 121 is 1.7 to 2.1, and in the case of Al, the refractive index is about 0.4 to 1.7 even when considering the oxide state. Therefore, since the Al component is extremely small inside the transparent electrode away from the surface, the refractive index of the general ITO (1.7 to 2.1) is shown. However, when the Al component increases toward the surface and becomes a quaternary material, the refractive index is 120. The refractive index changes depending on the contribution of the four elements constituting). As described above, the ratio of the Al component increases toward the surface of the transparent electrode 120, which reduces the refractive index of the transparent electrode 120 as a whole. Accordingly, the difference in refractive index with air outside the transparent electrode 120 decreases toward the surface of the transparent electrode 120, thereby reducing the total reflection of light on the surface of the transparent electrode 120.
도 4는 ITO 투명 전극(121)과 ITO 투명 전극(121)에 Al 금속층(123)을 형성한 경우에 투과도 변화를 설명하는 그래프이다.4 is a graph illustrating the change in transmittance when the Al metal layer 123 is formed on the ITO transparent electrode 121 and the ITO transparent electrode 121.
도 4의 (a) 그래프는, 110nm 두께의 ITO 투명 전극(121)과, 110nm 두께의 ITO 투명 전극(121)에 3nm 두께의 Al 금속층(123)을 형성한 투명 전극(ITO/Al 투명 전극)(120)의 투과도를 도시한 것으로서, 투과도에 거의 변화가 없음을 알 수 있다.4A shows a 110 nm thick ITO transparent electrode 121 and a 110 nm thick ITO transparent electrode 121 having a 3 nm thick Al metal layer 123 formed thereon (ITO / Al transparent electrode). As showing the transmittance of 120, it can be seen that there is almost no change in the transmittance.
도 4의 (b) 그래프는 도 4의 (a)에 도시된 110nm 두께의 ITO 투명 전극(121)과, 110nm 두께의 ITO 투명 전극(121)에 3nm 두께의 Al 금속층(123)을 형성한 투명 전극(ITO/Al 투명 전극)(120)을 약 550 도의 온도에서 열처리를 수행한 후의 투과도를 도시하는 것으로서, 열처리 이후 ITO/Al 투명 전극(120)의 투과도가 ITO 투명 전극(121)보다 향상됨을 확인 할 수 있다. 특히 ITO/Al 투명 전극(120)의 경우, 열처리 이후에 근자외선 영역인 365 ~ 385 nm에서 90% 이상의 투과도를 나타내는 것을 확인할 수 있어, 투과도가 크게 향상되었음을 알 수 있다.The graph of FIG. 4B is a transparent layer in which an Al metal layer 123 having a thickness of 3 nm is formed on the 110 nm thick ITO transparent electrode 121 and the 110 nm thick ITO transparent electrode 121 shown in FIG. 4A. Transmittance of the electrode (ITO / Al transparent electrode) 120 after the heat treatment at a temperature of about 550 degrees, showing that the transmittance of the ITO / Al transparent electrode 120 after the heat treatment is improved than the ITO transparent electrode 121 You can check. In particular, in the case of the ITO / Al transparent electrode 120, it can be seen that after the heat treatment exhibits a transmittance of 90% or more in the near ultraviolet region 365 ~ 385 nm, it can be seen that the transmittance is greatly improved.
도 5는 일반적인 ITO 투명 전극(121)과 본 발명의 바람직한 실시예에 따라서 ITO 투명 전극(121) 위에 금속층(123)이 형성되고 열처리된 후의 I-V 특성을 실험한 그래프를 도시한 도면이다.FIG. 5 is a graph illustrating I-V characteristics after the general ITO transparent electrode 121 and the metal layer 123 are formed and heat-treated on the ITO transparent electrode 121 according to a preferred embodiment of the present invention.
도 5를 참조하면, ITO 투명 전극(121)만을 110nm 두께로 형성한 경우와, 110nm 두께의 ITO 투명 전극(121) 위에 3nm의 Al 금속층(123)을 형성한 후 열처리를 수행한 경우(ITO(110nm)/Al(3nm))의 전기적 특성은 실질적으로 차이가 없음을 알 수 있다.Referring to FIG. 5, when only the ITO transparent electrode 121 is formed to have a thickness of 110 nm, and when the Al metal layer 123 of 3 nm is formed on the ITO transparent electrode 121 having a thickness of 110 nm, heat treatment is performed (ITO ( It can be seen that the electrical properties of 110 nm) / Al (3 nm)) are substantially different.
따라서, 도 4 및 도 5에 도시된 실험 결과를 종합해보면, 본 발명의 바람직한 실시예에 따라서 ITO 투명 전극(121) 위에 Indium 보다 주기가 낮은 금속으로 금속층(123) 박막을 형성하고, 열처리를 수행하여 금속을 ITO 투명 전극(121) 내부로 침투시키는 경우, 전기적 특성을 열화시키지 않고 투과도를 크게 향상시킬 수 있음을 알 수 있다.4 and 5, according to a preferred embodiment of the present invention, the metal layer 123 is formed of a metal having a period lower than that of indium on the ITO transparent electrode 121, and heat treatment is performed. Thus, when the metal is infiltrated into the ITO transparent electrode 121, it can be seen that the transmittance can be greatly improved without deteriorating the electrical characteristics.
도 6은 본 발명의 바람직한 다른 실시예에 따른 투명 전극 형성 방법을 설명하는 도면이다.6 is a view for explaining a method of forming a transparent electrode according to another embodiment of the present invention.
도 1을 참조하여 설명한 본 발명의 투명 전극 형성 방법은, ITO 투명 전극(121) 위에 평탄한 금속층(123)을 형성하였다. 그러나, 도 6에 도시된 실시예의 경우, ITO 투명 전극(121) 위에, 금속층(123)이 복수의 dot 형태로 형성되도록 함으로써, 투명 전극 표면에 요철을 형성한 것과 실질적으로 동일한 효과를 나타낼 수 있다.In the method for forming a transparent electrode of the present invention described with reference to FIG. 1, a flat metal layer 123 is formed on the ITO transparent electrode 121. However, in the embodiment illustrated in FIG. 6, the metal layer 123 is formed on the ITO transparent electrode 121 in the form of a plurality of dots, thereby exhibiting substantially the same effect as the unevenness formed on the surface of the transparent electrode. .
도 6을 참조하면, 먼저, 도 1(a)와 동일한 방식으로 발광소자 또는 수광소자가 형성된 기판(110)위에 ITO 투명 전극(121)을 형성 한다(도 6 (a) 참조).Referring to FIG. 6, first, an ITO transparent electrode 121 is formed on a substrate 110 on which a light emitting device or a light receiving device is formed in the same manner as in FIG. 1A (see FIG. 6A).
그 후, e-beam 증착 장비를 이용하여 ITO 투명 전극(121) 위에 금속을 증착하여 금속층(125)을 형성한다(도 6의 (b) 참조). 이 때, ITO 투명 전극(121) 위에 증착되는 금속은 상술한 바와 같이, Al, Ti, Ge, Ga 등과 같이, Indium 보다 주기율표상 주기가 낮은 금속이 이용될 수 있다.Thereafter, a metal layer 125 is formed by depositing a metal on the ITO transparent electrode 121 using an e-beam deposition apparatus (see FIG. 6B). In this case, as the metal deposited on the ITO transparent electrode 121, a metal having a periodic table period lower than Indium, such as Al, Ti, Ge, Ga, or the like, may be used.
또한, e-beam 증착 장비를 이용하여 금속을 증착하면, 처음에는 금속 결정들이 dot 형태로 ITO 투명 전극(121) 위에 형성되다가 금속 결정들이 더 커지면 인접한 결정들과 연결되어 박막이 형성된다. 따라서, ITO 투명 전극(121) 위에 형성되는 금속의 두께는 금속의 재질에 따라서 박막으로 형성되지 않고 dot 형태를 유지할 정도의 두께로 형성되어야 한다. 본 발명의 바람직한 실시예에서는, Al을 e-beam 증착 장비를 이용하여 3nm 이하 두께의 복수의 dot 형태의 금속 결정(125)들로 금속층(125)을 형성하였다. 본 발명에서 dot 형태는 도면 부호 125 가 지시하는 바와 같이, ITO 투명 전극(121)과 접하는 표면은 평탄하고, 그 반대편을 물방울의 표면 형상으로 볼록하게 돌출된 형상으로 정의한다.In addition, when the metal is deposited using an e-beam deposition apparatus, metal crystals are initially formed on the ITO transparent electrode 121 in a dot form, and when the metal crystals become larger, the thin films are connected to adjacent crystals. Therefore, the thickness of the metal formed on the ITO transparent electrode 121 should not be formed into a thin film depending on the material of the metal, but should be formed to a thickness sufficient to maintain a dot shape. In a preferred embodiment of the present invention, the metal layer 125 is formed of a plurality of dot-shaped metal crystals 125 having a thickness of 3 nm or less using e-beam deposition equipment. In the present invention, as indicated by the reference numeral 125, the surface in contact with the ITO transparent electrode 121 is flat, and the opposite side is defined as a shape protruding convexly into the surface shape of the water droplets.
복수의 dot 형태의 금속 결정들로 구성되는 금속층(125)이 형성된 후, 도 1의 (c)에 도시된 바와 동일한 방식으로, 450도 내지 750도에서 열처리를 수행하여 금속층(123)의 금속을 ITO 투명 전극(121) 내부로 침투시켜 투명 전극을 완성한다(도 6의 (c) 참조). After the metal layer 125 formed of a plurality of dot-shaped metal crystals is formed, the metal of the metal layer 123 is heat-treated at 450 to 750 degrees in the same manner as illustrated in FIG. 1C. It penetrates into the ITO transparent electrode 121, and completes a transparent electrode (refer FIG. 6 (c)).
이렇게 완성된 투명 전극(120)의 경우에는, 그 표면이 dot 형태로 형성되므로, 전체적으로 보면, 투명 전극(120) 표면에 요철이 형성된 것과 동일한 효과를 나타낸다. 따라서, 도 6에 도시된 투명 전극(120)의 경우에는, 도 1을 참조하여 상술한 바와 같이, 투명 전극(120) 표면에서 금속의 조성비가 높아져 굴절율이 변화함으로써 전반사가 감소하는 효과뿐만 아니라, 투명 전극(120) 표면에 요철이 형성되어 난반사가 일어남으로써 전반사가 감소되는 효과가 추가적으로 발생하므로, 보다 높은 광 추출 효율 및 광 흡수 효율을 나타낼 수 있다.In the case of the completed transparent electrode 120, since the surface is formed in a dot shape, as a whole, it has the same effect as the irregularities formed on the surface of the transparent electrode 120. Therefore, in the case of the transparent electrode 120 shown in FIG. 6, as described above with reference to FIG. 1, not only an effect in which total reflection is reduced by changing the refractive index by increasing the metal composition ratio on the surface of the transparent electrode 120, Since irregularities are formed on the surface of the transparent electrode 120 to cause diffuse reflection, an effect of reducing total reflection additionally occurs, and thus may exhibit higher light extraction efficiency and light absorption efficiency.
또한, 도 6에서는 복수의 금속 결정들(125)이 서로 분리된 것으로 도시되었으나, 복수의 금속 결정들의 바닥면이 서로 연결되어 실질적으로 ITO 투명 전극(121) 위에 요철이 형성된 구조로 금속층이 형성될 수도 있다.In addition, although the plurality of metal crystals 125 are illustrated as being separated from each other in FIG. 6, the bottom surfaces of the plurality of metal crystals are connected to each other to substantially form a metal layer having a structure in which irregularities are formed on the ITO transparent electrode 121. It may be.
이제까지 본 발명에 대하여 그 바람직한 실시예들을 중심으로 살펴보았다. 본 발명이 속하는 기술 분야에서 통상의 지식을 가진 자는 본 발명이 본 발명의 본질적인 특성에서 벗어나지 않는 범위에서 변형된 형태로 구현될 수 있음을 이해할 수 있을 것이다. 그러므로 개시된 실시예들은 한정적인 관점이 아니라 설명적인 관점에서 고려되어야 한다. 본 발명의 범위는 전술한 설명이 아니라 특허청구범위에 나타나 있으며, 그와 동등한 범위 내에 있는 모든 차이점은 본 발명에 포함된 것으로 해석되어야 할 것이다.So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

Claims (8)

  1. (a) 기판위에 인듐 산화물 및 주석 산화물을 증착하여 ITO(Indium-Tin-Oxide) 투명 전극을 형성하는 단계;(a) depositing indium oxide and tin oxide on the substrate to form an indium-tin-oxide (ITO) transparent electrode;
    (b) 상기 ITO 투명 전극 위에, 주기율표상에서 인듐보다 낮은 주기에 속하는 금속을 증착하여 금속층을 형성하는 단계; 및 (b) depositing a metal belonging to a period lower than indium on the periodic table to form a metal layer on the ITO transparent electrode; And
    (d) 상기 금속층이 형성된 기판을 열처리하여, 상기 금속을 ITO 투명 전극 내부로 침투시켜 투명 전극을 형성하는 단계를 포함하는 것을 특징으로 하는 투명 전극 형성 방법.(d) heat-treating the substrate on which the metal layer is formed, thereby penetrating the metal into the ITO transparent electrode to form a transparent electrode.
  2. 제 1 항에 있어서, 상기 (b) 단계는 The method of claim 1, wherein step (b)
    상기 ITO 투명 전극 위에, 복수의 dot 형태의 금속 결정들로 구성되는 금속층을 형성하는 것을 특징으로 하는 투명 전극 형성 방법.And forming a metal layer composed of a plurality of dot-shaped metal crystals on the ITO transparent electrode.
  3. 제 1 항에 있어서, 상기 (b) 단계에서,The method of claim 1, wherein in step (b),
    상기 ITO 투명 전극 위에 증착되는 금속은 Al, Ti, Ga, 및 Ge 중 어느 하나인 것을 특징으로 하는 투명 전극 형성 방법.The metal deposited on the ITO transparent electrode is any one of Al, Ti, Ga, and Ge.
  4. 제 1 항에 있어서, 상기 (b) 단계에서, The method of claim 1, wherein in step (b),
    상기 금속층은 1nm 내지 5nm의 두께로 형성되는 것을 특징으로 하는 투명 전극 형성 방법.The metal layer is a transparent electrode forming method, characterized in that formed in a thickness of 1nm to 5nm.
  5. 제 1 항에 있어서, 상기 (d) 단계는The method of claim 1, wherein step (d)
    질소 또는 대기 분위기에서 450도 내지 750도에서 열처리가 수행되는 것을 특징으로 하는 투명 전극 형성 방법.A transparent electrode forming method, characterized in that the heat treatment is carried out at 450 to 750 degrees in nitrogen or an atmosphere.
  6. 제 1 항에 있어서, The method of claim 1,
    상기 (b) 단계는, ITO층 표면에 요철 패턴으로 상기 금속층을 형성하고, In the step (b), the metal layer is formed on the surface of the ITO layer by an uneven pattern,
    상기 (d) 단계가 수행되면, 요철 패턴으로 형성된 금속층의 금속이 상기 ITO 투명 전극으로 침투하여 투명 전극 표면에 요철 패턴이 형성되는 것을 특징으로 하는 투명 전극 형성 방법.When the step (d) is performed, the metal of the metal layer formed by the uneven pattern penetrates into the ITO transparent electrode to form an uneven pattern on the surface of the transparent electrode.
  7. 제 1 항에 있어서,The method of claim 1,
    상기 기판 표면에서, 상기 기판 표면에 접촉하는 ITO 투명 전극의 표면의 반대 표면으로 갈수록 상기 금속의 조성비가 증가하여, 공기와의 굴절율 차이가 감소하는 것을 특징으로 하는 투명 전극 형성 방법.And the composition ratio of the metal increases from the substrate surface toward the opposite surface of the surface of the ITO transparent electrode in contact with the substrate surface, thereby reducing the difference in refractive index with air.
  8. 제 1 항의 투명 전극 형성 방법에 의해서 형성된 투명 전극을 포함하는 반도체 소자.A semiconductor device comprising a transparent electrode formed by the method for forming a transparent electrode of claim 1.
PCT/KR2016/002996 2015-05-06 2016-03-24 Method of forming transparent electrode having improved transmissivity, and semiconductor device including transparent electrode formed by using same WO2016178478A1 (en)

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US20080014346A1 (en) * 2006-07-12 2008-01-17 Tsinghua University Method of synthesizing single-wall carbon nanotubes
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KR20120119342A (en) * 2011-04-21 2012-10-31 삼성코닝정밀소재 주식회사 Method of manufacturing zno based transparent conductive oxide and zno based transparent conductive oxide by the method
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* Cited by examiner, † Cited by third party
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KR100311926B1 (en) * 1998-09-17 2001-12-17 진 장 Silicide transparent electrode and manufacturing method
US20080014346A1 (en) * 2006-07-12 2008-01-17 Tsinghua University Method of synthesizing single-wall carbon nanotubes
KR20110132858A (en) * 2010-06-03 2011-12-09 주식회사 마프로 Electrochromic films using sol-gel coating solutions dispersed of tungsten oxide nano particle and process thereof
KR20120119342A (en) * 2011-04-21 2012-10-31 삼성코닝정밀소재 주식회사 Method of manufacturing zno based transparent conductive oxide and zno based transparent conductive oxide by the method
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