WO2009119962A1 - Boron-doped zinc oxide based transparent conducting film and manufacturing method of thereof - Google Patents

Boron-doped zinc oxide based transparent conducting film and manufacturing method of thereof Download PDF

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Publication number
WO2009119962A1
WO2009119962A1 PCT/KR2008/007343 KR2008007343W WO2009119962A1 WO 2009119962 A1 WO2009119962 A1 WO 2009119962A1 KR 2008007343 W KR2008007343 W KR 2008007343W WO 2009119962 A1 WO2009119962 A1 WO 2009119962A1
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Prior art keywords
boron
transparent conductive
conductive film
zinc oxide
oxide based
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PCT/KR2008/007343
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French (fr)
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Joon Tae Song
Kyu Il Lee
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Sungkyunkwan University Foundation For Corporate Collaboration
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Publication of WO2009119962A1 publication Critical patent/WO2009119962A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/0257—Doping during depositing
    • H01L21/02573—Conductivity type
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • H01L31/1884—Manufacture of transparent electrodes, e.g. TCO, ITO
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/136—Liquid crystal cells structurally associated with a semi-conducting layer or substrate, e.g. cells forming part of an integrated circuit
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H01L21/02551—Group 12/16 materials
    • H01L21/02554—Oxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/28—Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268
    • H01L21/283—Deposition of conductive or insulating materials for electrodes conducting electric current
    • H01L21/285—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation
    • H01L21/28506—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation of conductive layers
    • H01L21/28512—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation of conductive layers on semiconductor bodies comprising elements of Group IV of the Periodic Table
    • H01L21/2855—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation of conductive layers on semiconductor bodies comprising elements of Group IV of the Periodic Table by physical means, e.g. sputtering, evaporation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • H01L31/022466—Electrodes made of transparent conductive layers, e.g. TCO, ITO layers
    • H01L31/022483—Electrodes made of transparent conductive layers, e.g. TCO, ITO layers composed of zinc oxide [ZnO]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02612—Formation types
    • H01L21/02617—Deposition types
    • H01L21/02631—Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01005—Boron [B]

Definitions

  • the present invention relates to a transparent conductive film formed on a substrate and a method of manufacturing the same, and, more particularly, to a boron-additional doped zinc oxide based transparent conductive film.
  • a transparent conductive film having light transmission properties has been used as a photosensitive device for transparent electrodes for solar cells, displays such as LCDs, PDPs and the like, photoelectric cells, image pickup tubes, and the like.
  • a solar cell is a typical silicon semiconductor.
  • a technology for manufacturing a solar cell has been developed while emphasizing the improvement of reliability and energy conversion efficiency and the reduction of production costs. Since the production cost of solar cells is about 40% of the installation cost of a solar photovoltaic power generation system, a technology of decreasing the production cost of the solar cell is a key technology of solar photovoltaic power generation.
  • a novel low-price and high-efficiency solar cell In order to accelerate the spread and use of solar photovoltaic power generation, it is required to develop a novel low-price and high-efficiency solar cell and a method of manufacturing the same.
  • a thin film solar cell is the most proper type of the low-price and high-efficiency solar cell. Therefore, such a thin film solar cell, which has low production cost, high efficiency and high stability, has attracted considerable attention as a most promising solar cell in the future.
  • TCO transparent conductive film
  • ITO has more excellent electrical and optical properties than other raw materials and is easily wet-etched on a large area substrate at low cost, currently, it is chiefly used as a transparent electrode of a transparent conductive film.
  • indium (In) is expensive, and its chemical resistance to plasma is low. Therefore, research on materials replacing the ITO is required.
  • a first object of the present invention is to improve the electrical and optical properties of a zinc oxide based transparent conductive film by additional doping the film with boron (B) to such a degree that indium (In) is replaced.
  • a second object of the present invention is to improve the structural stability of a zinc oxide based transparent conductive film by additional doping the film with boron (B).
  • a third object of the present invention is to provide the optimal amount of boron (B) added.
  • an aspect of the present invention provides a method of manufacturing a boron- additional doped zinc oxide based transparent conductive film on a substrate, including: additional doping an aluminum(Al)-doped ZnO target or a gallium(Ga)-doped ZnO target with boron (B) to form a transparent conductive film (Sl); and depositing the transparent conductive film on a substrate (S2).
  • the transparent conductive film in step 1 (Sl), may include 1 - 3 wt% of (aluminum + boron) or (gallium + boron). In this case, an amount of the boron may be 0.1 - 1 wt%.
  • the transparent conductive film may be deposited on the substrate through a sputtering process.
  • Another aspect of the present invention provides a boron- additional doped zinc oxide based transparent conductive film, including: a substrate; and a transparent conductive film formed on the substrate, wherein the conductive transparent film is formed by additional doping an aluminum(Al)-doped ZnO target or a gallium(Ga)-doped ZnO target with boron (B).
  • the substrate may be a rigid substrate or a flexible substrate.
  • an amount of (aluminum + boron) or (gallium + boron) doped may be 1 ⁇ 3 wt%. In this case, an amount of the boron may be 0.1 ⁇ 1 wt%.
  • At least one electrode layer may be disposed between the substrate and the transparent conductive film.
  • the electrode layer may be a metal layer, and the metal layer may be made of transparent conductive oxide.
  • the boron-additional doped zinc oxide based transparent conductive film according to the present invention is advantageous in that its electrical and optical properties are realized to such a degree that it replaces ITO.
  • the boron- additional doped zinc oxide based transparent conductive film according to the present invention is advantageous in that it exhibits good properties when it is used in a flexible substrate.
  • the method of manufacturing the boron- additional doped zinc oxide based transparent conductive film according to the present invention is advantageous in that the structural stability of a thin film is improved.
  • FIG. 1 is a graph showing XRD spectra of AZO and AZOB transparent conductive films
  • FIGS. 2A and 2E are photographs showing SEM images of AZO and AZOB transparent conductive films
  • FIG. 3 is a graph showing transmittances of AZO and AZOB transparent conductive films
  • FIG. 4 is a graph showing crystal characteristics of an AZOB thin film based on boron (B) content.
  • FIGS. 5A to 5D are schematic sectional views showing transparent conductive films according to a conventional technology and embodiments of the present invention.
  • a transparent conductive film is used as a transparent electrode of thin film displays, such as solar cells, liquid crystal displays and the like. Such a transparent electrode must have high optical transmittance, low electrical resistance and high chemical stability.
  • the present invention is characterized in that an AZO or GZO thin film doped with boron (B), which is a zinc compound based thin film, is formed on a silicon substrate, a glass substrate or a plastic substrate, so that its structural stability is improved, thereby improving chemical stability, increasing optical transmittance and decreasing electrical resistance.
  • B boron
  • a method of manufacturing a transparent conductive film according to the present invention includes: additional doping an aluminum(Al)-doped ZnO target or a gallium(Ga)-doped ZnO target with boron (B) to form a transparent conductive film (Sl); and depositing the transparent conductive film on a substrate (S2).
  • a zinc oxide based transparent conductive film has a hexagonal wurzite crystal structure. Therefore, when aluminum (Al) or gallium (Ga) is added thereto, it is located at vacancies existing in zinc oxide crystal, and thus replaces zinc (Zn).
  • this boron- additional doped zinc oxide-based transparent conductive film is not easily oxidized compared to other transparent conductive films when it is exposed to the air. The reason for this is that this transparent conductive film is electrically and structurally stable, and thus it is not easily bonded with oxygen even when it is exposed to the air. Further, this transparent conductive film has improved durability, by which it is not easily dissolved in various solvents used to manufacture a solar cell compared to a conventional AZO thin film.
  • the transparent conductive film include 1 - 3 wt% of (aluminum + boron) or (gallium + boron). That is, it is preferred that the total amount of the added III group elements be 1 ⁇ 3 wt%.
  • the amount of aluminum (Al) or gallium (Ga) added is 1 — 3 wt%.
  • boron (B) is additionally added is different from the related art in which only aluminum (Al) or gallium (Ga) is added, the present invention follows the related art from the point of view of maintenance of the total amount of Group III elements.
  • step 1 (Sl) it is preferred that the amount of the added boron (B) be 0.1 ⁇
  • step 2 (S2) it is preferred that sputtering be used as the deposition method.
  • FIG. 1 is a graph showing XRD spectra of AZO and AZOB transparent conductive films.
  • a flexible substrate is made of polycarbonate (PC), and a rigid substrate is made of glass.
  • voids are formed near about 34 degrees.
  • an AZOB transparent conductive film is more easily crystallized than an AZO transparent conductive film, and that the AZOB or AZO transparent conductive film is more easily crystallized on a flexible substrate than on a rigid substrate. From these results, it can be seen that the crystallization of the AZOB or AZO transparent conductive film can be further accelerated by the addition of boron (B).
  • B boron
  • FIGS. 2A and 2E are photographs showing SEM images and a cross-sectional image of AZO and AZOB transparent conductive films.
  • FIGS. 2A and 2E also show the influence according to the kind of substrate as well as the presence of boron (B). From FIGS. 2A and 2E, it can be seen that a transparent conductive film deposited on a flexible substrate is denser than a transparent conductive film deposited on a rigid substrate.
  • FIG. 3 is a graph showing transmittances of AZO and AZOB transparent conductive films. From FIG. 3, it can be seen that the average transmittance of the AZO and AZOB transparent conductive films is about 80% at a visible region (400 ⁇ 700 nm).
  • FIG. 4 is a graph showing crystal characteristics of an AZOB thin film based on boron (B) content, and the following Table 1 shows specific resistance characteristics of the AZOB thin film depending on the addition of boron (B).
  • FIG. 4 and Table 1 show the crystal characteristics and specific resistance characteristics of a pure AZO thin film (boron (B) content: 0%) to AZO thin films manufactured by increasing the additional doping concentration of the pure AZO thin film by 0.2 wt%. From FIG. 4 and Table 1, it can be seen that an AZO thin film having a boron content of 0.2 wt% exhibits higher crystallinity than a pure AZO thin film, and that the crystallinity and electrical properties values are decreased with the increase of boron (B) content, and thus the state of the AZO thin film becomes good.
  • boron (B) content 0%
  • step 1 in the method of manufacturing a transparent conductive film according to the present invention, in step 1 (Sl), it is preferred that the minimum amount of boron (B) be 0.1 wt% and the maximum amount thereof be 1.0 wt%.
  • the minimum amount of boron (B) is 0.1 wt%.
  • a boron-additional doped zinc oxide based transparent conductive film according to the present invention includes a substrate 10, and a transparent conductive film 21 formed on the substrate 10.
  • the conductive transparent film is formed by additional doping an aluminum(Al)-doped ZnO target or a gallium(Ga)-doped ZnO target with boron (B).
  • the substrate 10 of the transparent conductive film according to the present invention may be a rigid substrate or a flexible substrate.
  • the amount of (aluminum + boron) or (gallium + boron) doped in the transparent conductive film according to the present invention be 1 ⁇ 3 wt%.
  • the amount of boron be 0.1 ⁇ 1 wt%.
  • FIG. 5A shows a conventional transparent conductive film. As shown in FIG. 5A, an
  • ITO thin film 20 is formed between a substrate 10 and a solar cell/ a light-emitting device 30.
  • FIG. 5B shows a transparent conductive film according to an embodiment of the present invention. As shown in FIG. 5B, an AZOB or GZOB thin film is formed between a substrate 10 and a solar cell/ a light-emitting device 30.
  • FIG. 5C shows a transparent conductive film according to another embodiment of the present invention.
  • an electrode layer 22 may be disposed between a substrate 10 and a transparent conductive film 21.
  • FIG. 5D shows a transparent conductive film according to still another embodiment of the present invention.
  • different electrode layers 22 and 23 may be disposed between a substrate 10 and a transparent conductive film 21.
  • the electrode layer may be a metal layer, and the metal layer may be made of transparent conductive oxide.

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Abstract

Disclosed herein is a method of manufacturing a boron- additional doped zinc oxide based transparent conductive film on a substrate, including: additional doping an aluminum(Al)-doped ZnO target or a gallium(Ga)-doped ZnO target with boron (B) to form a transparent conductive film (Sl); and depositing the transparent conductive film on a substrate (S2). The boron- additional doped zinc oxide based transparent conductive film manufactured using the method is advantageous in that its electrical and optical properties are realized to such a degree that it replaces ITO. In particular, the boron-additional doped zinc oxide based transparent conductive film is advantageous in that it exhibits good properties when it is used in a flexible substrate. Moreover, the method of manufacturing the boron- additional doped zinc oxide based transparent conductive film is advantageous in that the structural stability of a thin film is improv ed.

Description

Description
BORON-DOPED ZINC OXIDE BASED TRANSPARENT CONDUCTING FILM AND MANUFACTURING METHOD OF
THEREOF
Technical Field
[1] The present invention relates to a transparent conductive film formed on a substrate and a method of manufacturing the same, and, more particularly, to a boron-additional doped zinc oxide based transparent conductive film. Background Art
[2] A transparent conductive film having light transmission properties has been used as a photosensitive device for transparent electrodes for solar cells, displays such as LCDs, PDPs and the like, photoelectric cells, image pickup tubes, and the like.
[3] Here, a solar cell is a typical silicon semiconductor. A technology for manufacturing a solar cell has been developed while emphasizing the improvement of reliability and energy conversion efficiency and the reduction of production costs. Since the production cost of solar cells is about 40% of the installation cost of a solar photovoltaic power generation system, a technology of decreasing the production cost of the solar cell is a key technology of solar photovoltaic power generation. In order to accelerate the spread and use of solar photovoltaic power generation, it is required to develop a novel low-price and high-efficiency solar cell and a method of manufacturing the same. It is recognized that a thin film solar cell is the most proper type of the low-price and high-efficiency solar cell. Therefore, such a thin film solar cell, which has low production cost, high efficiency and high stability, has attracted considerable attention as a most promising solar cell in the future.
[4] As a raw material of a transparent conductive film (TCO) used in the thin film solar cell, tin(Sn)-doped In O (ITO: Indium Tin Oxide), antimony(Sb)-doped SnO (ATO: Antimony Tin Oxide), fluorine(F)-doped SnO (FTO: Fluorine Tin Oxide), aluminum(Al)-doped ZnO (AZO: Aluminum Zinc Oxide) or the like is experimentally or commercially used.
[5] Here, since ITO has more excellent electrical and optical properties than other raw materials and is easily wet-etched on a large area substrate at low cost, currently, it is chiefly used as a transparent electrode of a transparent conductive film. However, in the case of ITO, indium (In) is expensive, and its chemical resistance to plasma is low. Therefore, research on materials replacing the ITO is required.
[6] Further, research on materials which can be applied to a flexible substrate as well as a rigid substrate is also required. [7] Hence, a SnO -based transparent conductive film and a ZnO-based transparent conductive film are actively researched and developed because they are cheaper than an ITO film. These films exhibit specific resistance 1-2 orders of magnitude higher than that of the ITO film when they are not doped. However, a SnO -based transparent conductive film doped with Sb or F, or a ZnO-based transparent conductive film doped with Al exhibits a low specific resistance of 10 or less. Disclosure of Invention Technical Problem
[8] Accordingly, the present invention has been made to solve the above problems, and a first object of the present invention is to improve the electrical and optical properties of a zinc oxide based transparent conductive film by additional doping the film with boron (B) to such a degree that indium (In) is replaced.
[9] A second object of the present invention is to improve the structural stability of a zinc oxide based transparent conductive film by additional doping the film with boron (B).
[10] A third object of the present invention is to provide the optimal amount of boron (B) added. Technical Solution
[11] In order to accomplish the above objects, an aspect of the present invention provides a method of manufacturing a boron- additional doped zinc oxide based transparent conductive film on a substrate, including: additional doping an aluminum(Al)-doped ZnO target or a gallium(Ga)-doped ZnO target with boron (B) to form a transparent conductive film (Sl); and depositing the transparent conductive film on a substrate (S2).
[12] In the method, in step 1 (Sl), the transparent conductive film may include 1 - 3 wt% of (aluminum + boron) or (gallium + boron). In this case, an amount of the boron may be 0.1 - 1 wt%.
[13] In the method, in step 2 (S2), the transparent conductive film may be deposited on the substrate through a sputtering process.
[14] Another aspect of the present invention provides a boron- additional doped zinc oxide based transparent conductive film, including: a substrate; and a transparent conductive film formed on the substrate, wherein the conductive transparent film is formed by additional doping an aluminum(Al)-doped ZnO target or a gallium(Ga)-doped ZnO target with boron (B).
[15] In the boron- additional doped zinc oxide based transparent conductive film, the substrate may be a rigid substrate or a flexible substrate.
[16] In the boron- additional doped zinc oxide based transparent conductive film, an amount of (aluminum + boron) or (gallium + boron) doped may be 1 ~ 3 wt%. In this case, an amount of the boron may be 0.1 ~ 1 wt%.
[17] In the boron- additional doped zinc oxide based transparent conductive film, at least one electrode layer may be disposed between the substrate and the transparent conductive film. In this case, the electrode layer may be a metal layer, and the metal layer may be made of transparent conductive oxide.
Advantageous Effects
[18] The boron-additional doped zinc oxide based transparent conductive film according to the present invention is advantageous in that its electrical and optical properties are realized to such a degree that it replaces ITO. In particular, the boron- additional doped zinc oxide based transparent conductive film according to the present invention is advantageous in that it exhibits good properties when it is used in a flexible substrate. Moreover, the method of manufacturing the boron- additional doped zinc oxide based transparent conductive film according to the present invention is advantageous in that the structural stability of a thin film is improved. Brief Description of Drawings
[19] FIG. 1 is a graph showing XRD spectra of AZO and AZOB transparent conductive films;
[20] FIGS. 2A and 2E are photographs showing SEM images of AZO and AZOB transparent conductive films;
[21] FIG. 3 is a graph showing transmittances of AZO and AZOB transparent conductive films;
[22] FIG. 4 is a graph showing crystal characteristics of an AZOB thin film based on boron (B) content; and
[23] FIGS. 5A to 5D are schematic sectional views showing transparent conductive films according to a conventional technology and embodiments of the present invention.
[24] * Description of the elements in the drawings *
[25] 10 : substrate
[26] 21 : transparent conductive film
[27] 22, 23 : electrode layer
Best Mode for Carrying out the Invention
[28] A transparent conductive film is used as a transparent electrode of thin film displays, such as solar cells, liquid crystal displays and the like. Such a transparent electrode must have high optical transmittance, low electrical resistance and high chemical stability.
[29] The present invention is characterized in that an AZO or GZO thin film doped with boron (B), which is a zinc compound based thin film, is formed on a silicon substrate, a glass substrate or a plastic substrate, so that its structural stability is improved, thereby improving chemical stability, increasing optical transmittance and decreasing electrical resistance.
[30] More specifically, a method of manufacturing a transparent conductive film according to the present invention includes: additional doping an aluminum(Al)-doped ZnO target or a gallium(Ga)-doped ZnO target with boron (B) to form a transparent conductive film (Sl); and depositing the transparent conductive film on a substrate (S2).
[31] A zinc oxide based transparent conductive film has a hexagonal wurzite crystal structure. Therefore, when aluminum (Al) or gallium (Ga) is added thereto, it is located at vacancies existing in zinc oxide crystal, and thus replaces zinc (Zn).
[32] For example, in the case of aluminum (Al), since the added aluminum (Al) is located at the vacancy as interstitial aluminum (Al), only the crystallinity of zinc oxide (ZnO) is exhibited without the crystallinity of aluminum (Al) being exhibited at the time of XRD (X-ray diffraction) measurement. In this case, unlike zinc oxide having a resistance of several tens of mega ohms, low resistance or specific resistance is exhibited.
[33] When boron (B) is additionally added thereto, the boron (B), which is the quantitatively smallest element among Group III elements, is located at vacancies existing on AlZnO (AZO), and thus serves to complement the vacancies. This principle is identically applied to GZO.
[34] This complement of vacancies due to boron (B) is effective as follows. First, electrically, unexpected results, such as the occurrence of an energy loss (current leakage) due to the absence (vacancies) of elements, the decrease of local fields due to the increase of the distance between elements in grains, and the like, can be prevented by electrons moving between crystals.
[35] Second, crystal-structurally, the electrical force between atoms is increased due to boron (B) located at vacancies, thus forming a stronger crystal structure. When this boron- additional doped zinc oxide based transparent conductive film is produced, its fatigue or aging, which is a common specific characteristic of materials, can be prevented for a long time compared to a conventional AZO thin film.
[36] Third, chemically, this boron- additional doped zinc oxide-based transparent conductive film is not easily oxidized compared to other transparent conductive films when it is exposed to the air. The reason for this is that this transparent conductive film is electrically and structurally stable, and thus it is not easily bonded with oxygen even when it is exposed to the air. Further, this transparent conductive film has improved durability, by which it is not easily dissolved in various solvents used to manufacture a solar cell compared to a conventional AZO thin film. [37] In the method of manufacturing a transparent conductive film according to the present invention, in step 1 (Sl), it is preferred that the transparent conductive film include 1 - 3 wt% of (aluminum + boron) or (gallium + boron). That is, it is preferred that the total amount of the added III group elements be 1 ~ 3 wt%.
[38] In the case of an AZO or GZO transparent conductive film currently known, generally, the amount of aluminum (Al) or gallium (Ga) added is 1 — 3 wt%. In the present invention, although the fact that boron (B) is additionally added is different from the related art in which only aluminum (Al) or gallium (Ga) is added, the present invention follows the related art from the point of view of maintenance of the total amount of Group III elements.
[39] Further, in step 1 (Sl), it is preferred that the amount of the added boron (B) be 0.1 ~
1 wt%.
[40] Further, in step 2 (S2), it is preferred that sputtering be used as the deposition method.
[41] FIG. 1 is a graph showing XRD spectra of AZO and AZOB transparent conductive films. Here, for example, a flexible substrate is made of polycarbonate (PC), and a rigid substrate is made of glass. As shown in FIG. 1, it can be seen that voids are formed near about 34 degrees. Further, it can be seen that an AZOB transparent conductive film is more easily crystallized than an AZO transparent conductive film, and that the AZOB or AZO transparent conductive film is more easily crystallized on a flexible substrate than on a rigid substrate. From these results, it can be seen that the crystallization of the AZOB or AZO transparent conductive film can be further accelerated by the addition of boron (B).
[42] FIGS. 2A and 2E are photographs showing SEM images and a cross-sectional image of AZO and AZOB transparent conductive films. FIGS. 2A and 2E also show the influence according to the kind of substrate as well as the presence of boron (B). From FIGS. 2A and 2E, it can be seen that a transparent conductive film deposited on a flexible substrate is denser than a transparent conductive film deposited on a rigid substrate.
[43] FIG. 3 is a graph showing transmittances of AZO and AZOB transparent conductive films. From FIG. 3, it can be seen that the average transmittance of the AZO and AZOB transparent conductive films is about 80% at a visible region (400 ~ 700 nm).
[44] FIG. 4 is a graph showing crystal characteristics of an AZOB thin film based on boron (B) content, and the following Table 1 shows specific resistance characteristics of the AZOB thin film depending on the addition of boron (B).
[45] FIG. 4 and Table 1 show the crystal characteristics and specific resistance characteristics of a pure AZO thin film (boron (B) content: 0%) to AZO thin films manufactured by increasing the additional doping concentration of the pure AZO thin film by 0.2 wt%. From FIG. 4 and Table 1, it can be seen that an AZO thin film having a boron content of 0.2 wt% exhibits higher crystallinity than a pure AZO thin film, and that the crystallinity and electrical properties values are decreased with the increase of boron (B) content, and thus the state of the AZO thin film becomes good.
[46] Table 1 [Table 1] [Table ]
Figure imgf000008_0001
[47] In the method of manufacturing a transparent conductive film according to the present invention, it can be seen that when the amount of boron (B) added is about 0.2 wt%, the transparent conductive film begins to exhibit good properties, and when the amount thereof is about 1.0 wt%, its good properties begin to be deteriorated.
[48] Therefore, in the method of manufacturing a transparent conductive film according to the present invention, in step 1 (Sl), it is preferred that the minimum amount of boron (B) be 0.1 wt% and the maximum amount thereof be 1.0 wt%. In experimental examples of the present invention, although boron (B) was added by 0.2 wt%, it is obvious that the transparent conductive film exhibits good properties. For this reason, it is proposed that the minimum amount of boron (B) is 0.1 wt%.
[49] Hereinafter, a transparent conductive film according to the present invention will be described. A boron-additional doped zinc oxide based transparent conductive film according to the present invention includes a substrate 10, and a transparent conductive film 21 formed on the substrate 10. The conductive transparent film is formed by additional doping an aluminum(Al)-doped ZnO target or a gallium(Ga)-doped ZnO target with boron (B).
[50] The substrate 10 of the transparent conductive film according to the present invention may be a rigid substrate or a flexible substrate. [51] It is preferred that the amount of (aluminum + boron) or (gallium + boron) doped in the transparent conductive film according to the present invention be 1 ~ 3 wt%. Moreover, it is preferred that the amount of boron be 0.1 ~ 1 wt%.
[52] FIG. 5A shows a conventional transparent conductive film. As shown in FIG. 5A, an
ITO thin film 20 is formed between a substrate 10 and a solar cell/ a light-emitting device 30.
[53] FIG. 5B shows a transparent conductive film according to an embodiment of the present invention. As shown in FIG. 5B, an AZOB or GZOB thin film is formed between a substrate 10 and a solar cell/ a light-emitting device 30.
[54] FIG. 5C shows a transparent conductive film according to another embodiment of the present invention. As shown in FIG. 5C, an electrode layer 22 may be disposed between a substrate 10 and a transparent conductive film 21. FIG. 5D shows a transparent conductive film according to still another embodiment of the present invention. As shown in FIG. 5D, different electrode layers 22 and 23 may be disposed between a substrate 10 and a transparent conductive film 21.
[55] In this case, the electrode layer may be a metal layer, and the metal layer may be made of transparent conductive oxide.
[56] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

Claims
[1] A method of manufacturing a boron- additional doped zinc oxide based transparent conductive film on a substrate, comprising: additional doping an aluminum(Al)-doped ZnO target or a gallium(Ga)-doped
ZnO target with boron (B) to form a transparent conductive film (Sl); and depositing the transparent conductive film on a substrate (S2). [2] The method of manufacturing a boron- additional doped zinc oxide based transparent conductive film according to claim 1, wherein, in step 1 (Sl), the transparent conductive film includes 1 - 3 wt% of (aluminum + boron) or
(gallium + boron). [3] The method of manufacturing a boron- additional doped zinc oxide based transparent conductive film according to claim 2, wherein an amount of the boron is 0.1 ~ 1 wt%. [4] The method of manufacturing a boron- additional doped zinc oxide based transparent conductive film according to claim 1, wherein, in step 2 (S2), the transparent conductive film is deposited on the substrate through a sputtering process. [5] A boron-additional doped zinc oxide based transparent conductive film, comprising: a substrate; and a transparent conductive film formed on the substrate, wherein the conductive transparent film is formed by additional doping an aluminum(Al)-doped ZnO target or a gallium(Ga)-doped ZnO target with boron
(B). [6] The boron- additional doped zinc oxide based transparent conductive film according to claim 5, wherein the substrate is a rigid substrate or a flexible substrate. [7] The boron- additional doped zinc oxide based transparent conductive film according to claim 5, wherein an amount of (aluminum + boron) or (gallium + boron) doped is 1 ~ 3 wt%. [8] The boron- additional doped zinc oxide based transparent conductive film according to claim 7, wherein an amount of the boron is 0.1 ~ 1 wt%. [9] The boron- additional doped zinc oxide based transparent conductive film according to claim 5, wherein at least one electrode layer is disposed between the substrate and the transparent conductive film. [10] The boron- additional doped zinc oxide based transparent conductive film according to claim 9, wherein the electrode layer is a metal layer. [11] The boron- additional doped zinc oxide based transparent conductive film according to claim 10, wherein the metal layer is made of transparent conductive oxide.
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CN110724922A (en) * 2019-10-31 2020-01-24 汕头大学 Epitaxial AZO film with controllable crystal orientation and polarity on flexible substrate and preparation method thereof

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KR101315002B1 (en) * 2013-04-05 2013-10-04 군산대학교산학협력단 Method for manufacturing abzo transparent conductive oxide

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