KR20130111817A - Solar cell apparatus and method of fabricating the same - Google Patents

Solar cell apparatus and method of fabricating the same Download PDF

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KR20130111817A
KR20130111817A KR1020120034003A KR20120034003A KR20130111817A KR 20130111817 A KR20130111817 A KR 20130111817A KR 1020120034003 A KR1020120034003 A KR 1020120034003A KR 20120034003 A KR20120034003 A KR 20120034003A KR 20130111817 A KR20130111817 A KR 20130111817A
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support substrate
solar cell
layer
light absorbing
back electrode
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최철환
박덕훈
배도원
신민정
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엘지이노텍 주식회사
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    • 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
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    • H01L31/0392—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 characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes including thin films deposited on metallic or insulating substrates ; characterised by specific substrate materials or substrate features or by the presence of intermediate layers, e.g. barrier layers, on the substrate
    • H01L31/03923—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 characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes including thin films deposited on metallic or insulating substrates ; characterised by specific substrate materials or substrate features or by the presence of intermediate layers, e.g. barrier layers, on the substrate including AIBIIICVI compound materials, e.g. CIS, CIGS
    • 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
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    • H01L31/0322—Inorganic materials including, apart from doping materials or other impurities, only compounds not provided for in groups H01L31/0272 - H01L31/0312 comprising only AIBIIICVI chalcopyrite compounds, e.g. Cu In Se2, Cu Ga Se2, Cu In Ga Se2
    • 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
    • H01L31/04—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 adapted as photovoltaic [PV] conversion devices
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    • H01L31/0749—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 adapted as photovoltaic [PV] conversion devices characterised by potential barriers the potential barriers being only of the PN heterojunction type including a AIBIIICVI compound, e.g. CdS/CulnSe2 [CIS] heterojunction solar cells
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    • Y02E10/541—CuInSe2 material PV cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract

PURPOSE: A solar cell and a method for fabricating the same are provided to improve crystallization by forming an alkali metal layer on the surface of the solar cell. CONSTITUTION: A second support substrate (200) is formed on a first support substrate (100). The second support substrate includes an alkali metal. A back electrode layer (300) is formed on the second support substrate. The first support substrate is made of a high strain point glass. The thickness of the first support substrate is 2.5 to 3.0 mm.

Description

태양전지 및 이의 제조방법{SOLAR CELL APPARATUS AND METHOD OF FABRICATING THE SAME}SOLAR CELL AND MANUFACTURING METHOD THEREOF {SOLAR CELL APPARATUS AND METHOD OF FABRICATING THE SAME}

실시예는 태양전지 및 이의 제조방법에 관한 것이다.An embodiment relates to a solar cell and a manufacturing method thereof.

최근 에너지의 수요가 증가함에 따라서, 태양광 에너지를 전기에너지로 변환시키는 태양전지에 대한 개발이 진행되고 있다.Recently, as the demand for energy increases, development of solar cells for converting solar energy into electrical energy is in progress.

태양전지(Solar Cell 또는 Photovoltaic Cell)는 태양광을 직접 전기로 변환시키는 태양광발전의 핵심소자이다.Solar cells (Solar Cells or Photovoltaic Cells) are the key elements of photovoltaic power generation that convert sunlight directly into electricity.

예로서 반도체의 pn접합으로 만든 태양전지에 반도체의 금지대폭(Eg : Band-gap Energy)보다 큰 에너지를 가진 태양광이 입사되면 전자-정공 쌍이 생성되는데, 이들 전자-정공이 pn 접합부에 형성된 전기장에 의해 전자는 n층으로, 정공은 p층으로 모이게 됨에 따라 pn간에 기전력(광기전력 : Photovoltage)이 발생하게 된다. 이때 양단의 전극에 부하를 연결하면 전류가 흐르게 되는 것이 동작원리이다.For example, when solar light having energy greater than the band-gap energy (Eg) is incident on a solar cell made of a pn junction of a semiconductor, electron-hole pairs are generated, and these electron-holes form an electric field formed at a pn junction. As a result, electrons are gathered into the n-layer and holes are gathered into the p-layer, whereby electromotive force (photovoltage) is generated between pn. At this time, when the load is connected to the electrodes at both ends, current flows.

특히, 유리기판, 금속 후면 전극층, p형 CIGS계 광 흡수층, 고 저항 버퍼층, n형 윈도우층 등을 포함하는 기판 구조의 pn 헤테로 접합 장치인 CIGS계 태양전지가 널리 사용되고 있다.Particularly, a CIGS-based solar cell which is a pn heterojunction device of a substrate structure including a glass substrate, a metal back electrode layer, a p-type CIGS light absorbing layer, a high resistance buffer layer, an n-type window layer and the like is widely used.

이러한 태양전지에 있어서 낮은 저항, 높은 투과율 등의 전기적인 특성을 향상시키고 생산성을 향상시키기 위한 연구가 진행되고 있다.In such a solar cell, research is being conducted to improve electrical properties such as low resistance and high transmittance and to improve productivity.

상기 기판이 소다 라임 글래스로 형성되는 경우, 기판은 나트륨(Na)을 포함하여 형성되어 태양전지의 제조공정 중에 CIGS로 형성된 광 흡수층으로 상기 나트륨이 확산될 수 있는데, 이에 의해 광 흡수층의 전하 농도가 증가할 수 있으나, 광 흡수층의 결정성을 향상시키기 위한 고온 공정시 기판이 휘어지므로 신뢰성은 개선의 여지가 있다.When the substrate is formed of soda lime glass, the substrate is formed of sodium (Na), so that the sodium can be diffused into the light absorbing layer formed of CIGS during the manufacturing process of the solar cell, thereby increasing the charge concentration of the light absorbing layer Although it may be increased, the reliability of the substrate may be improved since the substrate is bent at a high temperature process for improving the crystallinity of the light absorbing layer.

최근에는 결정성이 우수한 고온 CIGS 성막을 위해 고왜점(高歪点) 글래스를 사용하려는 기술이 시도되고 있다. 그러나 상기 고왜점 글래스는 나트륨의 함량이 낮기 때문에 광-전 변환 효율향상은 개선의 여지가 있다.Recently, a technique has been attempted to use high strain glass for high temperature CIGS film formation with excellent crystallinity. However, since the high distortion glass has a low sodium content, there is room for improvement in photoelectric conversion efficiency.

발명의 실시예에 따른 태양전지는 고왜점 글라스로 기판 형성시, CIGS의 광 흡수층 형성시 결정성이 개선될 수 있고, 기판의 표면에 알칼리 금속층을 성막하여 광-전 변환 효율이 개선될 수 있다.In the solar cell according to the embodiment of the present invention, crystallinity may be improved when the substrate is formed of high distortion glass, when the light absorbing layer of CIGS is formed, and an alkali metal layer is formed on the surface of the substrate to improve the photoelectric conversion efficiency. .

발명의 실시예에 따른 태양전지는 제1 지지기판; 상기 제1 지지기판 상에 형성되고, 알칼리 금속을 포함하는 제2 지지기판; 및, 상기 제2 지지기판 상에 형성된 후면전극층;을 포함한다.Solar cell according to an embodiment of the present invention is a first support substrate; A second support substrate formed on the first support substrate and comprising an alkali metal; And a back electrode layer formed on the second support substrate.

발명의 실시예에 따른 태양전지 제조방법은 고왜점 글라스로 형성된 제1 지지기판상에 Na 및 K을 용해시킨 플로팅(floating) 용액을 사용하여 제2 지지기판을 형성하는 단계; 상기 제2 지지기판 상에 후면전극층을 형성하는 단계; 상기 후면전극층 상에 광 흡수층을 형성하는 단계; 상기 광 흡수층 상에 버퍼층을 형성하는 단계; 및, 상기 버퍼층 상에 윈도우층을 형성하는 단계;를 포함한다.A solar cell manufacturing method according to an embodiment of the present invention comprises the steps of forming a second support substrate using a floating solution in which Na and K are dissolved on a first support substrate formed of high strain glass; Forming a back electrode layer on the second support substrate; Forming a light absorbing layer on the back electrode layer; Forming a buffer layer on the light absorbing layer; And forming a window layer on the buffer layer.

발명의 실시예에 따른 태양전지는 제2 지지기판에 포함된 알칼리 금속이 태양전지의 제조공정 중에 CIGS로 형성된 광 흡수층으로 확산될 수 있는데, 이에 의해 광 흡수층의 전하 농도가 증가하게 될 수 있다. 이는 태양전지의 광-전 변환 효율을 향상시킬 수 있는 요인이 될 수 있다.In the solar cell according to the embodiment of the present invention, the alkali metal included in the second support substrate may be diffused into the light absorbing layer formed of CIGS during the manufacturing process of the solar cell, thereby increasing the charge concentration of the light absorbing layer. This may be a factor to improve the photoelectric conversion efficiency of the solar cell.

도 1은 실시예에 따른 태양전지를 도시한 단면도이다.
도 2 내지 도 5는 실시예에 따른 태양전지 패널을 제조하는 과정을 도시한 도면들이다.1 is a cross-sectional view showing a solar cell according to an embodiment.
2 to 5 are views illustrating a process of manufacturing the solar cell panel according to the embodiment.

실시예의 설명에 있어서, 각 기판, 층, 막 또는 전극 등이 각 기판, 층, 막, 또는 전극 등의 "상(on)"에 또는 "아래(under)"에 형성되는 것으로 기재되는 경우에 있어, "상(on)"과 "아래(under)"는 "직접(directly)" 또는 "다른 구성요소를 개재하여(indirectly)" 형성되는 것을 모두 포함한다. 또한 각 구성요소의 상 또는 아래에 대한 기준은 도면을 기준으로 설명한다. 도면에서의 각 구성요소들의 크기는 설명을 위하여 과장될 수 있으며, 실제로 적용되는 크기를 의미하는 것은 아니다.
In the description of the embodiments, in the case where each substrate, layer, film or electrode is described as being formed "on" or "under" of each substrate, layer, film, , "On" and "under" all include being formed "directly" or "indirectly" through "another element". In addition, the upper or lower reference of each component is described with reference to the drawings. The size of each component in the drawings may be exaggerated for the sake of explanation and does not mean the size actually applied.

도 1은 실시예에 따른 태양전지를 도시한 단면도이다. 도 1을 참조하면, 태양전지 패널은 제1 지지기판(100), 제2 지지기판(200), 후면전극층(300), 광 흡수층(400), 버퍼층(500) 및 윈도우층(600)을 포함한다.1 is a cross-sectional view showing a solar cell according to an embodiment. Referring to FIG. 1, a solar cell panel includes a first support substrate 100, a second support substrate 200, a back electrode layer 300, a light absorbing layer 400, a buffer layer 500, and a window layer 600. do.

상기 제1 지지기판(100)은 플레이트 형상을 가지며, 상기 제2 지지기판(200), 후면전극층(300), 광 흡수층(400), 버퍼층(500) 및 윈도우층(600)을 지지한다.The first support substrate 100 has a plate shape and supports the second support substrate 200, the back electrode layer 300, the light absorbing layer 400, the buffer layer 500, and the window layer 600.

상기 제1 지지기판(100)은 절연체일 수 있다. 상기 제1 지지기판(100)은 고왜점 글래스로 형성될 수 있다. 상기 고왜점 글래스는 왜점(점도 1013Pa-s가 되는 온도)이 높고, 열처리시 수축과 변형이 거의 없으므로, 상부에 적층되는 CIGS 광 흡수층을 고온으로 성막할 수 있어 결정성이 향상될 수 있다. 상기 제1 지지기판(100)은 2.5mm 내지 3.0mm의 두께로 형성될 수 있다. The first support substrate 100 may be an insulator. The first support substrate 100 may be formed of high strain glass. The high distortion glass has a high distortion point (temperature of viscosity 1013 Pa-s) and hardly shrinkage and deformation during heat treatment, so that the CIGS light absorbing layer stacked on the upper surface can be formed at a high temperature, thereby improving crystallinity. The first support substrate 100 may be formed to a thickness of 2.5mm to 3.0mm.

상기 제1 지지기판(100)에는 알칼리 금속원소가 포함될 수 있다. The first support substrate 100 may include an alkali metal element.

예를 들어, 나트륨 및 칼륨이 포함될 수 있고, 상기 나트륨은 4 내지 5wt%, 칼륨은 6 내지 8wt%로 포함될 수 있다.For example, sodium and potassium may be included, and sodium may be included in an amount of 4 to 5 wt% and potassium in an amount of 6 to 8 wt%.

상기 제1 지지기판(100) 상에는 제2 지지기판(200)이 형성된다. 상기 제2 지지기판(200)은 상기 제1 지지기판(100)의 5% 내지 20%의 두께로 형성될 수 있다. The second support substrate 200 is formed on the first support substrate 100. The second support substrate 200 may be formed to a thickness of 5% to 20% of the first support substrate 100.

상기 제2 지지기판(200)은 칼륨 및 나트륨 원소를 포함할 수 있고, 상기 제2 지지기판(200)에 포함되는 칼륨은 나트륨의 0% 내지 30%의 비율로 형성될 수 있다.The second support substrate 200 may include potassium and sodium elements, and potassium included in the second support substrate 200 may be formed at a rate of 0% to 30% of sodium.

상기 제2 지지기판(200) 상에 후면전극층(300)이 배치된다. 상기 후면전극층(300)은 도전층이다. 상기 후면전극층(300)은 태양전지 중 광 흡수층(400)에서 생성된 전하가 이동하도록 하여 태양전지의 외부로 전류를 흐르게 할 수 있다. 상기 후면전극층(300)은 이러한 기능을 수행하기 위하여 전기 전도도가 높고 비저항이 작아야 한다.The back electrode layer 300 is disposed on the second support substrate 200. The back electrode layer 300 is a conductive layer. The back electrode layer 300 may allow electric current generated in the light absorbing layer 400 of the solar cell to move so that current flows to the outside of the solar cell. In order to perform this function, the back electrode layer 300 must have high electrical conductivity and low specific resistance.

또한, 상기 후면전극층(300)은 CIGS 화합물 형성시 수반되는 황(S) 또는 셀레늄(Se) 분위기 하에서의 열처리 시 고온 안정성이 유지되어야 한다. 또한, 상기 후면전극층(300)은 열팽창 계수의 차이로 인하여 상기 제2 지지기판(200)과 박리현상이 발생되지 않도록 상기 제2 지지기판(200)과 접착성이 우수하여야 한다.In addition, the back electrode layer 300 must maintain high temperature stability during heat treatment under sulfur (S) or selenium (Se) atmosphere accompanying CIGS compound formation. In addition, the back electrode layer 300 should be excellent in adhesiveness with the second support substrate 200 so that peeling does not occur with the second support substrate 200 due to a difference in thermal expansion coefficient.

이러한 후면전극층(300)은 몰리브덴(Mo), 금(Au), 알루미늄(Al), 크롬(Cr), 텅스텐(W) 및 구리(Cu) 중 어느 하나로 형성될 수 있다. 이 가운데, 특히 몰리브덴(Mo)은 다른 원소에 비해 상기 제2 지지기판(200)과 열팽창 계수의 차이가 적기 때문에 접착성이 우수하여 박리현상이 발생하는 것을 방지할 수 있고 상술한 후면전극층(300)에 요구되는 특성을 전반적으로 충족시킬 수 있다. 상기 후면전극층(300)은 400nm 내지 1000nm의 두께로 형성될 수 있다.The back electrode layer 300 may be formed of any one of molybdenum (Mo), gold (Au), aluminum (Al), chromium (Cr), tungsten (W), and copper (Cu). Among them, in particular, molybdenum (Mo) has a smaller difference between the second support substrate 200 and the coefficient of thermal expansion than other elements, and thus, excellent adhesion can prevent the peeling phenomenon from occurring and the rear electrode layer 300 described above. ) Can meet the overall required characteristics. The back electrode layer 300 may be formed to a thickness of 400nm to 1000nm.

상기 후면전극층(300) 상에는 광 흡수층(400)이 형성될 수 있다. 상기 광 흡수층(400)은 p형 반도체 화합물을 포함한다. 더 자세하게, 상기 광 흡수층(400)은 Ⅰ-Ⅲ-Ⅵ족 계 화합물을 포함한다. 예를 들어, 상기 광 흡수층(400)은 구리-인듐-갈륨-셀레나이드계(Cu(In,Ga)Se2;CIGS계) 결정 구조, 구리-인듐-셀레나이드계 또는 구리-갈륨-셀레나이드계 결정 구조를 가질 수 있다. 상기 광 흡수층(400)의 에너지 밴드갭(band gap)은 약 1.1eV 내지 1.2eV일 수 있고, 상기 광 흡수층(400)은 1.5μm 내지 2.5μm의 두께로 형성될 수 있다.The light absorbing layer 400 may be formed on the back electrode layer 300. The light absorbing layer 400 includes a p-type semiconductor compound. In more detail, the light absorbing layer 400 includes a group I-III-VI compound. For example, the light absorbing layer 400 may be formed of a copper-indium-gallium-selenide-based (Cu (In, Ga) Se 2 ; CIGS-based) crystal structure, copper-indium-selenide-based, or copper-gallium-selenide It may have a system crystal structure. The energy band gap of the light absorbing layer 400 may be about 1.1 eV to 1.2 eV, and the light absorbing layer 400 may be formed to a thickness of 1.5 μm to 2.5 μm.

상기 광 흡수층(400) 상에 버퍼층(500)이 배치된다. CIGS 화합물을 광 흡수층(400)으로 갖는 태양전지는 p형 반도체인 CIGS 화합물 박막과 n형 반도체인 윈도우층(600) 간에 pn 접합을 형성한다. 하지만 두 물질은 격자상수와 밴드갭 에너지의 차이가 크기 때문에 양호한 접합을 형성하기 위해서는 밴드갭이 두 물질의 중간에 위치하는 버퍼층이 필요하다.The buffer layer 500 is disposed on the light absorbing layer 400. The solar cell having the CIGS compound as the light absorbing layer 400 forms a pn junction between the CIGS compound thin film as the p-type semiconductor and the window layer 600 as the n-type semiconductor. However, since the two materials have a large difference between the lattice constant and the band gap energy, a buffer layer in which a band gap is located between two materials is required in order to form a good junction.

상기 버퍼층(500)을 형성하는 물질로는 CdS, ZnS등이 있고 태양전지의 발전 효율 측면에서 CdS가 상대적으로 우수하여 일반적으로 사용되고 있다. 상기 버퍼층(500)은 50nm 내지 80nm의 두께로 형성될 수 있다. Materials for forming the buffer layer 500 include CdS, ZnS and the like, and CdS is relatively used in terms of power generation efficiency of solar cells. The buffer layer 500 may be formed to a thickness of 50nm to 80nm.

상기 버퍼층(500) 상에 고저항 버퍼층(미도시)이 배치될 수 있다. 상기 고저항 버퍼층은 불순물이 도핑되지 않은 징크 옥사이드(i-ZnO)를 포함할 수 있다. 상기 고저항 버퍼층의 에너지 밴드갭은 약 3.1eV 내지 3.3eV이고 50nm 내지 60nm의 두께로 형성될 수 있다.A high resistance buffer layer (not shown) may be disposed on the buffer layer 500. The high-resistance buffer layer may include zinc oxide (i-ZnO) that is not doped with impurities. The energy bandgap of the high resistance buffer layer is about 3.1 eV to 3.3 eV and may be formed to a thickness of 50 nm to 60 nm.

상기 버퍼층(500) 상에 윈도우층(600)이 배치된다. 상기 윈도우층(600)은 투명하며, 도전층이다. 또한, 상기 윈도우층(600)의 저항은 상기 후면전극층(300)의 저항보다 높다.The window layer 600 is disposed on the buffer layer 500. The window layer 600 is transparent and is a conductive layer. In addition, the resistance of the window layer 600 is higher than the resistance of the back electrode layer 300.

상기 윈도우층(600)은 산화물을 포함한다. 예를 들어, 상기 윈도우층(600)은 징크 옥사이드(zinc oxide), 인듐 틴 옥사이드(induim tin oxide;ITO) 또는 인듐 징크 옥사이드(induim zinc oxide;IZO) 등을 포함할 수 있다. 또한, 상기 윈도우층(600)은 알루미늄 도핑된 징크 옥사이드(Al doped zinc oxide;AZO) 또는 갈륨 도핑된 징크 옥사이드(Ga doped zinc oxide;GZO) 등을 포함할 수 있다. 상기 윈도우층(600)은 800nm 내지 1000nm의 두께로 형성될 수 있다.The window layer 600 includes an oxide. For example, the window layer 600 may include zinc oxide, indium tin oxide (ITO), or indium zinc oxide (IZO). In addition, the window layer 600 may include aluminum doped zinc oxide (AZO) or gallium doped zinc oxide (GZO). The window layer 600 may be formed to a thickness of 800nm to 1000nm.

본 발명의 실시예에 따른 태양전지에 따르면, 제2 지지기판에 포함된 알칼리 금속이 태양전지의 제조공정 중에 CIGS로 형성된 광 흡수층으로 확산될 수 있는데, 이에 의해 광 흡수층의 전하 농도가 증가하게 되어 태양전지의 광-전 변환 효율을 향상시킬 수 있다.
According to the solar cell according to the embodiment of the present invention, the alkali metal contained in the second support substrate may diffuse into the light absorbing layer formed of CIGS during the manufacturing process of the solar cell, thereby increasing the charge concentration of the light absorbing layer. It is possible to improve the photoelectric conversion efficiency of the solar cell.

도 2 내지 도 5는 실시예에 따른 태양전지의 제조방법을 도시한 단면도들이다. 본 제조방법에 관한 설명은 앞서 설명한 태양전지에 대한 설명을 참고한다. 앞서 설명한 태양전지에 대한 설명은 본 제조방법에 관한 설명에 본질적으로 결합될 수 있다.2 to 5 are cross-sectional views illustrating a method of manufacturing a solar cell according to an embodiment. For a description of the present manufacturing method, refer to the description of the solar cell described above. The description of the solar cell described above may be essentially combined with the description of the present manufacturing method.

도 2를 참조하면, 제1 지지기판(100) 상에 제2 지지기판(200)이 형성된다. 상기 제2 지지기판(200)은 상기 제2 지지기판(200)은 일정 비율의 Na 및 K을 용해시켜 플로팅(floating) 용액을 사용하여 형성한다.Referring to FIG. 2, a second support substrate 200 is formed on the first support substrate 100. The second supporting substrate 200 is formed by using a floating solution by dissolving Na and K in a predetermined ratio.

도 3을 참조하면, 상기 제2 지지기판(200) 상에 후면전극층(300)이 형성된다. 상기 후면전극층(300)은 몰리브덴을 사용하여 증착될 수 있다. 상기 후면전극층(300)은 스퍼터링(Sputtering)의 방법으로 형성될 수 있다. 또한, 상기 제1 지지기판(100) 및 후면전극층(300) 사이에 확산방지막 등과 같은 추가적인 층이 개재될 수 있다.Referring to FIG. 3, a back electrode layer 300 is formed on the second support substrate 200. The back electrode layer 300 may be deposited using molybdenum. The back electrode layer 300 may be formed by a sputtering method. In addition, an additional layer such as a diffusion barrier may be interposed between the first support substrate 100 and the back electrode layer 300.

도 4를 참조하면, 상기 후면전극층(300) 상에 광 흡수층(400)이 형성된다. 상기 광 흡수층(400)은 예를 들어, 구리, 인듐, 갈륨, 셀레늄을 동시 또는 구분하여 증발(evaporation)시키면서 구리-인듐-갈륨-셀레나이드계(Cu(In,Ga)Se2;CIGS계)의 광 흡수층(400)을 형성하는 방법과 금속 프리커서 막을 형성시킨 후 셀레니제이션(Selenization) 공정에 의해 형성시키는 방법이 폭넓게 사용되고 있다.Referring to FIG. 4, a light absorbing layer 400 is formed on the back electrode layer 300. For example, the light absorbing layer 400 may be formed of copper-indium-gallium-selenide (Cu (In, Ga) Se2; CIGS-based) while simultaneously evaporating copper, indium, gallium, and selenium. A method of forming the light absorbing layer 400 and a method of forming a metal precursor film and then forming it by a selenization process are widely used.

상기 광 흡수층은 570℃ 내지 580℃의 고온에서 형성될 수 있다.The light absorbing layer may be formed at a high temperature of 570 ℃ to 580 ℃.

이와는 다르게, 상기 구리 타겟, 인듐 타겟, 갈륨 타겟을 사용하는 스퍼터링 공정 및 상기 셀레니제이션 공정은 동시에 진행될 수 있다. 또한, 구리 타겟 및 인듐 타겟 만을 사용하거나, 구리 타겟 및 갈륨 타겟을 사용하는 스퍼터링 공정 및 셀레니제이션 공정에 의해서, CIS계 또는 CIG계 광 흡수층(400)이 형성될 수 있다.Alternatively, the copper target, the indium target, the sputtering process using the gallium target, and the selenization process may be performed simultaneously. In addition, a CIS-based or CIG-based light absorbing layer 400 may be formed by a sputtering process and a selenization process using only a copper target and an indium target, or using a copper target and a gallium target.

도 5를 참조하면, 상기 광 흡수층(400) 상에 버퍼층(500)이 형성된다. 상기 버퍼층(500)은 CdS의 화학식으로 형성될 수 있으며, PVD(Physical Vapor Deposition) 또는 MOCVD (Metal-Organic Chemical Vapor Deposition)의 방법으로 형성될 수 있고, 이에 대해 한정하는 것은 아니다.Referring to FIG. 5, a buffer layer 500 is formed on the light absorbing layer 400. The buffer layer 500 may be formed by the chemical formula of CdS, and may be formed by a method of physical vapor deposition (PVD) or metal-organic chemical vapor deposition (MOCVD), but is not limited thereto.

다음으로, 상기 버퍼층(500) 상에 윈도우층(600)이 형성된다. 상기 윈도우층(600)은 상기 버퍼층(500) 상에 투명한 도전물질, 예를 들어, 알루미늄 도핑된 징크 옥사이드(Al doped zinc oxide;AZO)가 스퍼터링의 방법으로 증착되어 형성될 수 있다.Next, the window layer 600 is formed on the buffer layer 500. The window layer 600 may be formed by depositing a transparent conductive material, for example, aluminum doped zinc oxide (AZO) on the buffer layer 500 by sputtering.

이상에서 실시예들에 설명된 특징, 구조, 효과 등은 본 발명의 적어도 하나의 실시예에 포함되며, 반드시 하나의 실시예에만 한정되는 것은 아니다. 나아가, 각 실시예에서 예시된 특징, 구조, 효과 등은 실시예들이 속하는 분야의 통상의 지식을 가지는 자에 의해 다른 실시예들에 대해서도 조합 또는 변형되어 실시 가능하다. 따라서 이러한 조합과 변형에 관계된 내용들은 본 발명의 범위에 포함되는 것으로 해석되어야 할 것이다.The features, structures, effects and the like described in the embodiments are included in at least one embodiment of the present invention and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

Claims (9)

제1 지지기판;
상기 제1 지지기판 상에 형성되고, 알칼리 금속을 포함하는 제2 지지기판; 및,
상기 제2 지지기판 상에 형성된 후면전극층;을 포함하는 태양전지A first support substrate;
A second support substrate formed on the first support substrate and comprising an alkali metal; And
A solar cell comprising a back electrode layer formed on the second support substrate 제1항에 있어서,
상기 제1 지지기판은 고왜점 글래스로 형성되는 태양전지.The method of claim 1,
The first support substrate is a solar cell formed of high strain glass. 제1항에 있어서,
상기 제1 지지기판은 2.5mm 내지 3.0mm의 두께로 형성되는 태양전지.The method of claim 1,
The first support substrate is a solar cell formed to a thickness of 2.5mm to 3.0mm. 제1항에 있어서,
상기 제2 지지기판은 상기 제1 지지기판의 5% 내지 20%의 두께로 형성되는 태양전지.The method of claim 1,
The second support substrate is a solar cell formed to a thickness of 5% to 20% of the first support substrate. 제1항에 있어서,
상기 알칼리 금속은 Na 또는 K 중 적어도 하나를 포함하는 태양전지.The method of claim 1,
The alkali metal is at least one of Na or K solar cell. 제5항에 있어서,
상기 제2 지지기판은 나트륨 및 칼륨을 포함하고, 상기 칼륨은 나트륨의 0% 내지 30%의 비율로 형성되는 태양전지.The method of claim 5,
The second support substrate comprises sodium and potassium, wherein the potassium is formed in a ratio of 0% to 30% of sodium. 고왜점 글라스로 형성된 제1 지지기판상에 Na 및 K을 용해시킨 플로팅(floating) 용액을 사용하여 제2 지지기판을 형성하는 단계;
상기 제2 지지기판 상에 후면전극층을 형성하는 단계;
상기 후면전극층 상에 광 흡수층을 형성하는 단계;
상기 광 흡수층 상에 버퍼층을 형성하는 단계; 및,
상기 버퍼층 상에 윈도우층을 형성하는 단계;를 포함하는 태양전지 제조방법.Forming a second support substrate using a floating solution in which Na and K are dissolved on the first support substrate formed of high strain glass;
Forming a back electrode layer on the second support substrate;
Forming a light absorbing layer on the back electrode layer;
Forming a buffer layer on the light absorbing layer; And
Forming a window layer on the buffer layer; 제7항에 있어서,
상기 제2 지지기판은 상기 제1 지지기판의 5% 내지 20%의 두께로 형성되는 태양전지 제조방법.The method of claim 7, wherein
The second support substrate is a solar cell manufacturing method is formed to a thickness of 5% to 20% of the first support substrate. 제7항에 있어서,
상기 제2 지지기판은 나트륨 및 칼륨을 포함하고, 상기 칼륨은 나트륨의 0% 내지 30%의 비율로 형성되는 태양전지 제조방법.The method of claim 7, wherein
The second support substrate comprises sodium and potassium, wherein the potassium is formed in a ratio of 0% to 30% of sodium solar cell manufacturing method.
KR1020120034003A 2012-04-02 2012-04-02 Solar cell apparatus and method of fabricating the same KR20130111817A (en)

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