201140867 六、發明說明： 【發明所屬之技術領域】 本發明關於一種可謀求光電轉換效率提高 池及太陽能電池之製造方法。 【先前技術】 以往，作爲關於此領域之技術文獻公知有 7- 1 05 1 66號公報等。該公報中記載之薄膜矽太 形成於玻璃基板上之鹼性阻擋塗布層和形成於 膜（Transparency Conductive Oxide膜）構成 於氟摻雜氧化錫膜之表面電極、甶形成於其上 晶矽構成之光電轉換層及形成於其上之第2導 爲光反射膜、背面電極）構成。又，作爲氧化 方法，公知有利用四氯化錫與水之反應，經由 形成氧化錫膜之方法》 在該薄膜矽太陽能電池中，重要的是，如 錫膜將從玻璃基板側入射之光的大部分光吸進 ，並且由於氧化錫膜作爲電極發揮作用，因此 小，這也重要。爲了吸進光而將氧化錫膜表面 凸之形狀（材質結構）並使光散射，藉此使光 加長光電轉換層內的光之路徑。就氧化錫膜而 片電阻小，透射率高，且將表面設爲材質結構 均勻之膜。其中，霧度係擴散透射光量除以總 値者（參照專利文獻2 )。 之太陽能電 曰本特公平 陽能電池由 其上之TCO ，在此由基 之氫氧化非 電膜（亦稱 錫膜之形成 常壓CVD法 何通過氧化 光電轉換層 薄片電阻較 設爲具有凹 傾斜進行並 言，期待薄 ，霧度高且 透射光量之 -5- 201140867 專利文獻1:日本特公平7-105166號公報 專利文獻2 :日本特開2 0 0 1 - 5 9 1 7 5號公報 【發明內容】 (本發明所欲解決之課題） 爲了改善做爲上述太陽能電池的光電轉換層之轉換效 率，正在開發做爲非晶矽和微晶矽2層之串聯結構。在非 晶矽和微晶矽中，因能帶間隙之差異，所吸收的光之波長 區域亦不同，與只有非晶矽的光電轉換層之情況相比，還 能吸收長波長（ 900〜1200nm)之光並改善轉換效率。該 串聯式太陽能電池用TCO膜中逐漸要求350〜1200nm波長 區域中之透射率高，薄片電阻更小，霧度高至30〜70%之 膜，以基於以往CVD法之TCO膜（氧化錫膜）已無法對應 〇 因此，本發明之目的在於，提供一種太陽能電池及太 陽能電池之製造方法，其可提供該串聯式太陽能電池中所 要求之TCO膜。 (解決課題之手段） 本發明之具備透明基板、表面電極層、光吸收層及背 面電極層的太陽能電池之製造方法，其特徵爲，在於透明 基板的一方主面側形成表面電極層的表面電極形成工程中 ，包括：ixo層形成工程，於主面側形成將摻雜元素x摻 雜於銦氧化物中而成之IXO層；Zno層形成工程，於IXO層 w -6- 201140867 上形成ZnO層；及材質結構形成工程，於Zn0層之光吸收 層側形成材質結構。再者，IXO層是由將摻雜元素X摻雜 於銦氧化物中的化合物構成之層。使用Sn (錫）、W (鎢 )、Mo (鉬）、Si (矽）等各種成分作爲摻雜元素X。作 爲該種IXO層，例如有ITO( Indium Tin Oxide)層》 根據本發明之太陽能電池之製造方法，經由材質結構 使從透明基板側入射之光散射，藉此可使光傾斜進行並加 長光吸收層內的光之路徑。再者，傾斜進行之光由光吸收 層與背面電極層之邊界反射，其反射光由材質結構，亦即 ’光吸收層與表面電極層之邊界再次反射而禁閉於光吸收 層內，故可有效地進行光電轉換。而且，藉由採用電阻低 於氧化錫（Sn02 )層之1X0層作爲表面電極層，可提供更 爲薄膜且低電阻之膜，因此由成膜裝置成膜之部分較少即 可，並可降低成膜裝置之價格。又，亦可縮小成膜裝置之 裝置空間。再者，於IXO層上形成ZnO層，並經由蝕刻於 該ZnO層上形成材質結構，藉此與由以往CVD法形成時相 比，亦容易調整霧度，且亦可形成高霧度之材質結構。因 此，根據該太陽能電池之製造方法，可提供將光吸收層做 爲由非晶矽和微晶矽構成之串聯結構之串聯式太陽能電池 中所要求之 TCO ( Transparent Conductive Oxide)膜。 在本發明之太陽能電池之製造方法中，爲在材質結構 形成工程中，經由蝕刻處理於ZnO層形成材質結構較佳。 藉由採用經由鈾刻處理的材質結構之形成，與經由材 質化顆粒（texturing particles)或噴射處理形成時相比， 201140867 容易實現材質結構形成工程之簡化及短時間化。 又，在本發明之太陽能電池之製造方法中，爲蝕刻處 理係經由酸性蝕刻液進行濕式蝕刻者較佳。 此時，藉由調整蝕刻液之濃度或蝕刻時間，可容易實 現材質結構中的霧度之調整，故可得到按照光吸收層特性 等的所希望之霧度。這有助於提高太陽能電池之光電轉換 效率。 再者，在本發明之太陽能電池之製造方法中，爲在蝕 刻處理中，藉由使蝕刻液之濃度、蝕刻時間及ZnO層中之 摻雜元素量中之至少一種發生變化來調整ZnO層之材質結 構中之霧度較佳。再者，作爲ZnO層中之摻雜成分有Ga( 鎵）等。又，由摻雜元素向太陽能電池單元側之擴散引起 的污染成問題時，亦有爲無摻雜的ZnO層之場合。 本發明之太陽能電池，其特徵爲，具有：透明基板； 表面電極層，形成於透明基板之一方主面側；ITO層，在 形成於表面電極層上之光吸收層中將摻雜元素X摻雜於銦 氧化物中而成；及ZnO層，形成於ITO層上，其中，於ZnO 層之光吸收層側形成有材質結構。 根據本發明，可提供一種上述串聯式太陽能電池中所 要求之TCO膜。 【實施方式】 以下，參照附圖對本發明之太陽能電池之製造方法及 太陽能電池之優選贲施形態進行詳細說明。 -8- 201140867 如第1圖所示般，本實施形態之太陽能電池1於白板玻 璃基板（透明基板）2上按鹼性阻擋層12、表面電極層3、 光吸收層6及背面電極層9之順序層積而構成。在該太陽能 電池1中，若從白板玻璃基板2側入射之光透射表面電極層 3而進入至光吸收層6內，則經由光生伏特效應而於光吸收 層6內轉換成電力，該電力經過表面電極層3及背面電極層 9輸出至外部。 表面電極層3由ITO( Indium Tin Oxide)層4及ZnO層 5構成。ITO層4形成於白板玻璃基板2上。ITO層4由在 Ιη203 (氧化銦）中添加有Sn02 (氧化錫）之化合物構成 ，與Sn02等其他透明導電性材料相比，具有低電阻和作爲 表面電極層3之足夠的透射率。又，ITO層4與用以向外部 輸出電力之外部電極連接。該ITO層4之厚度越薄，在透射 率及成本方面越有利，但根據作爲表面電極層3所需的與 薄片電阻之均衡來決定。具體而言，需要ΙΟΩ/口（ ohm /square)之薄片電阻作爲表面電極層3時，形成爲150nm 左右之厚度。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a photoelectric conversion efficiency improving cell and a solar cell. [Prior Art] Conventionally, as a technical document in this field, Japanese Patent Publication No. 7-105 1 66 and the like are known. The thin film coating layer formed on the glass substrate and the surface electrode formed on the fluorine-doped tin oxide film formed on the glass substrate, and the germanium described in the above-mentioned publication are formed on the upper surface of the fluorine-doped tin oxide film. The photoelectric conversion layer and the second guide formed thereon are a light reflection film and a back surface electrode. Further, as an oxidation method, a method of forming a tin oxide film by reacting tin tetrachloride with water is known. In the film tantalum solar cell, it is important that the tin film enters light from the side of the glass substrate. Most of the light is sucked in, and since the tin oxide film functions as an electrode, it is small, which is also important. In order to absorb light, the surface of the tin oxide film is convex (material structure) and light is scattered, whereby the light is lengthened by the path of the light in the photoelectric conversion layer. In the case of a tin oxide film, the sheet resistance is small, the transmittance is high, and the surface is made into a film having a uniform material structure. Among them, the haze is the amount of the diffused transmitted light divided by the total (see Patent Document 2). The solar cell of the solar cell is based on the TCO, and the non-electrolytic film based on the formation of the tin film (also known as the formation of a tin film by the atmospheric pressure CVD method) is controlled by the oxidation of the photoelectric conversion layer. In the case of the slanting, it is expected to be thin, the haze is high, and the amount of transmitted light is -5 - 201140867 Patent Document 1: Japanese Patent Publication No. 7-105166 Patent Document 2: JP-A-KOKAI 2 0 0 1 - 5 9 1 7 5 SUMMARY OF THE INVENTION (Problems to be Solved by the Invention) In order to improve the conversion efficiency of the photoelectric conversion layer of the above solar cell, a series structure of two layers of amorphous germanium and microcrystalline germanium is being developed. In the microcrystalline germanium, the wavelength region of the absorbed light is different due to the difference in the band gap, and the long wavelength (900 to 1200 nm) light can be absorbed and improved as compared with the case of the amorphous germanium photoelectric conversion layer. Conversion efficiency. The tantalum solar cell TCO film is gradually required to have a high transmittance in a wavelength range of 350 to 1200 nm, a sheet resistance is smaller, and a haze is as high as 30 to 70%, to a TCO film based on a conventional CVD method ( Tin oxide film) Accordingly, an object of the present invention is to provide a method for producing a solar cell and a solar cell, which can provide a TCO film required for the tandem solar cell. (Means for Solving the Problem) The present invention has a transparent substrate, A method for producing a solar cell of a surface electrode layer, a light absorbing layer, and a back electrode layer, wherein a surface electrode forming process of forming a surface electrode layer on one main surface side of the transparent substrate includes an ixo layer forming process. Forming an IXO layer formed by doping the doping element x with indium oxide on the surface side; forming a ZnO layer on the IXO layer w -6-201140867; and forming a material structure on the Zn0 layer A material structure is formed on the side of the absorption layer. Further, the IXO layer is a layer composed of a compound doped with a doping element X in indium oxide. Sn (tin), W (tungsten), Mo (molybdenum), Si ( Various components such as 矽) are used as the doping element X. As such an IXO layer, for example, an ITO (Indium Tin Oxide) layer, according to the method for producing a solar cell of the present invention, is made through a material structure. The light incident on the side of the substrate is scattered, whereby the light is tilted and the path of the light in the light absorbing layer is lengthened. Further, the oblique light is reflected by the boundary between the light absorbing layer and the back electrode layer, and the reflected light is made of a material. The structure, that is, the boundary between the light absorbing layer and the surface electrode layer is again reflected and confined in the light absorbing layer, so that photoelectric conversion can be performed efficiently, and by using a 1×0 layer having a lower electric resistance than the tin oxide (Sn02) layer. The surface electrode layer can provide a film having a thinner film and a lower resistance, so that a part of the film formed by the film forming apparatus is less, and the price of the film forming apparatus can be lowered. Further, the space of the film forming apparatus can be reduced. Further, a ZnO layer is formed on the IXO layer, and a material structure is formed on the ZnO layer by etching, whereby the haze can be easily adjusted as compared with the case of the conventional CVD method, and a high haze material can be formed. structure. Therefore, according to the method for producing a solar cell, a TCO (Transparent Conductive Oxide) film which is required for a tandem solar cell having a series structure of amorphous germanium and microcrystalline germanium can be provided. In the method for producing a solar cell of the present invention, it is preferable to form a material structure in the ZnO layer by etching treatment in the material structure forming process. By using the material structure processed by uranium engraving, 201140867 is easier to simplify and shorten the material structure forming process than when it is formed by texturing particles or blasting. Further, in the method for producing a solar cell of the present invention, it is preferred that the etching treatment be wet etching through an acidic etching solution. At this time, by adjusting the concentration of the etching liquid or the etching time, the haze of the material structure can be easily adjusted, so that a desired haze according to the characteristics of the light absorbing layer or the like can be obtained. This helps to improve the photoelectric conversion efficiency of solar cells. Furthermore, in the method of manufacturing a solar cell of the present invention, in the etching process, the ZnO layer is adjusted by changing at least one of a concentration of the etching solution, an etching time, and a doping element amount in the ZnO layer. The haze in the material structure is better. Further, as a doping component in the ZnO layer, Ga (gallium) or the like is used. Further, when the contamination caused by the diffusion of the doping element to the solar cell side is a problem, there is also a case where the ZnO layer is not doped. The solar cell of the present invention has a transparent substrate; a surface electrode layer formed on one side of the main surface of the transparent substrate; and an ITO layer doped with a doping element X in the light absorbing layer formed on the surface electrode layer The ZnO layer is formed on the ITO layer, and a material structure is formed on the light absorbing layer side of the ZnO layer. According to the present invention, a TCO film required in the above tandem solar cell can be provided. [Embodiment] Hereinafter, a method for manufacturing a solar cell of the present invention and a preferred embodiment of a solar cell will be described in detail with reference to the accompanying drawings. -8- 201140867 As shown in Fig. 1, the solar cell 1 of the present embodiment has an alkali barrier layer 12, a surface electrode layer 3, a light absorbing layer 6, and a back electrode layer 9 on a white glass substrate (transparent substrate) 2. The order is laminated. In the solar cell 1, when the light incident from the side of the white glass substrate 2 is transmitted through the surface electrode layer 3 and enters the light absorbing layer 6, it is converted into electric power in the light absorbing layer 6 via the photovoltaic effect, and the electric power passes through. The surface electrode layer 3 and the back electrode layer 9 are output to the outside. The surface electrode layer 3 is composed of an ITO (Indium Tin Oxide) layer 4 and a ZnO layer 5. The ITO layer 4 is formed on the white glass substrate 2. The ITO layer 4 is composed of a compound in which Sn02 (tin oxide) is added to Ιη203 (indium oxide), and has a low electrical resistance and a sufficient transmittance as the surface electrode layer 3 as compared with other transparent conductive materials such as Sn02. Further, the ITO layer 4 is connected to an external electrode for outputting electric power to the outside. The thinner the thickness of the ITO layer 4, the more advantageous it is in terms of transmittance and cost, but it is determined according to the balance between the sheet resistance required for the surface electrode layer 3 and the sheet resistance. Specifically, when a sheet resistance of ΙΟΩ/mouth (ohm/square) is required as the surface electrode layer 3, it is formed to a thickness of about 150 nm.
ZnO層5由添加有Ga (鎵）或A1 (鋁）之ZnO(氧化鋅 )及無摻雜元素之ZnO形成。ZnO層5以與光吸收層6相接 觸之方式配置，於ZnO層5之光吸收層6側表面形成有材質 結構T。材質結構T是爲了將從白板玻璃基板2側入射之光 禁閉於光吸收層6而形成之微細凹凸結構，按照太陽能電 池1之規格具有1 〇%〜90%之霧度。再者，本實施形態中的 霧度以由材質結構T散射之光相對於通過材質結構T之全部 201140867 光之比例計算。ZnO層5按照所需要之霧度例如形成爲200 〜400nm範圍之厚度。 光吸收層6由形成於ZnO層5上之非晶矽層7和形成於非 晶矽層7上之微晶矽層8構成。如第2圖所示般，非晶矽層7 和微晶矽層8之光譜靈敏度特性不同。非晶矽層7有效地吸 收太陽光中含可見光區域之低波長成分，而微晶矽層8有 效地吸收到達紅外線區域之長波長成分。 如第1圖所示般，背面電極層9由形成於微晶矽層8上 之ZnO層10和形成於ZnO層10上之Ag層11構成。ZnO層10 爲了防止表面電極層3之微晶矽層8與Ag層1 1之間之干涉而 設置。Ag層〗1形成太陽能電池1之背面，並與用以向外部 輸出電力之外部電極連接。 接著，對以上說明的太陽能電池1的製造方法進行說 明。 (表面電極層形成工程） 首先，於白板玻璃基板2之一方主面上形成作爲鹼性 阻擋層12之Si02層。於其上形成表面電極層3。該表面電 極層形成工程由I τ Ο層形成工程、表面電極側ζ η Ο層形成 工程及材質結構形成工程構成。再者，鹼性阻擋層1 2之形 成並不是必須的，亦有不需要之場合。 在ΙΤΟ層形成工程中，於鹼性阻擋層12上形成ΙΤΟ層4 。該ΙΤΟ層4利用反應氣體之電漿而與蒸發顆粒結合，經由 合成化合物層之 RPD ( Reactive Plasma Deposition，反應 201140867 性電漿蒸鍍）法形成。之後，在表面電極側ΖιιΟ層形成工 程中’於ITO層4上形成添加有Ga或A1之ZnO層5。ZnO層5 與ITO層4相同亦經由RPD法形成。此時，藉由調整ZnO層5 形成時之溫度，可調整ZnO之晶粒尺寸。ZnO晶粒之尺寸 或Ga、A1之摻雜量按照材質結構τ中所需霧度及摻雜元素 對太陽能電池單元之污染問題進行調整。再者，形成ITO 層4及ZnO層5之方法並不限於RPD法，例如亦可利用濺鍍 法。 第3圖是用以說明材質結構形成工程之槪要圖。如第3 圖所示般，材質結構形成工程在向箭頭F方向傳送白板玻 璃基板2之狀態下進行，該白板玻璃基板之鹼性阻擋層1 2 上經由傳送輥13形成有ITO層4及ZnO層5。再者，白板玻 璃基板2以ZnO層5作爲上面而配置於傳送輥13上。 首先，進行基板表面之粗洗處理。在粗洗處理中，由 從清洗噴嘴1 4噴射之清洗水沖掉附著於白板玻璃基板2之 塵土等。之後，由從除水用空氣噴嘴15噴射之高壓空氣進 行白板玻璃基板2之除水處理。 接著，進行對基板的ZnO層5之蝕刻處理。在蝕刻處理 中，使用調整成預定濃度之鹽酸作爲蝕刻液，藉由從蝕刻 用噴射噴嘴16朝向ZnO層5噴射鹽酸而進行濕式蝕刻。被噴 吹到鹽酸的ZnO層5之表面（光吸收層6側）中，經由化學 反應形成微細的凹凸，亦即材質結構T。再者，蝕刻液並 不限於鹽酸，亦可使用其他酸性液體，又，只要是可適當 形成材質結構T之液體，則亦可爲鹼性液體。 -11 - 201140867 在此，第4圖（a)是表示經由濃度0.1 %鹽酸之蝕刻時 間與材質結構T之凹凸粗糙度的關係之圖，第4圖（b )是 表示經由濃度〇 . 5 %鹽酸之蝕刻時間與材質結構T之凹凸粗 糙度的關係之圖。又’第5圖是對應於第4圖（a )之蝕刻 時間、霧度及ZnO層厚度的關係之圖表。 如第4圖及第5圖所示般，形成於ZnO層5之材質結構T 具有隨著蝕刻時間變長，凹凸粗糙度變大（凹凸差變大） ，霧度變高之傾向。又，作爲蝕刻液的鹽酸之濃度越高’ 材質結構T之凹凸在短時間內變大。因此，藉由適當地設 定鹽酸濃度及蝕刻處理時間，可調整材質結構T之霧度。 再者，使成膜時之溫度或ZnO中摻雜Ga等之量發生變化’ 亦可使霧度發生變化。表1表示使Ga相對於ZnO之摻雜量 或成膜溫度等發生變化時之材質結構T之霧度。如表1所示 般，藉由使鹽酸濃度、蝕刻時間、G a摻雜量及成膜溫度發 生變化，可將材質結構T之霧度調整在10〜70%的範圍。 [表1]The ZnO layer 5 is formed of ZnO (ZnO) to which Ga (gallium) or Al (aluminum) is added and ZnO which is not doped. The ZnO layer 5 is disposed in contact with the light absorbing layer 6, and a material structure T is formed on the surface of the ZnO layer 5 on the side of the light absorbing layer 6. The material structure T is a fine concavo-convex structure formed by confining light incident from the side of the white glass substrate 2 to the light absorbing layer 6, and has a haze of 1% to 90% in accordance with the specifications of the solar battery 1. Further, the haze in the present embodiment is calculated by the ratio of the light scattered by the material structure T to the total of the light of the material structure T of 201140867. The ZnO layer 5 is formed, for example, to a thickness in the range of 200 to 400 nm in accordance with a desired haze. The light absorbing layer 6 is composed of an amorphous germanium layer 7 formed on the ZnO layer 5 and a microcrystalline germanium layer 8 formed on the amorphous germanium layer 7. As shown in Fig. 2, the spectral sensitivity characteristics of the amorphous germanium layer 7 and the microcrystalline germanium layer 8 are different. The amorphous germanium layer 7 effectively absorbs the low-wavelength component of the visible light region in the sunlight, and the microcrystalline germanium layer 8 effectively absorbs the long-wavelength component reaching the infrared region. As shown in Fig. 1, the back electrode layer 9 is composed of a ZnO layer 10 formed on the microcrystalline layer 8 and an Ag layer 11 formed on the ZnO layer 10. The ZnO layer 10 is provided in order to prevent interference between the microcrystalline layer 8 of the surface electrode layer 3 and the Ag layer 11. The Ag layer 1 forms the back surface of the solar cell 1 and is connected to an external electrode for outputting electric power to the outside. Next, a method of manufacturing the solar cell 1 described above will be described. (Surface Electrode Layer Forming Process) First, a SiO 2 layer as the basic barrier layer 12 is formed on one of the main surfaces of the white glass substrate 2. A surface electrode layer 3 is formed thereon. The formation of the surface electrode layer is composed of an I τ Ο layer formation process, a surface electrode side η Ο Ο layer formation process, and a material structure formation process. Further, the formation of the basic barrier layer 12 is not essential, and there is also a need for it. In the tantalum layer forming process, the tantalum layer 4 is formed on the alkaline barrier layer 12. The ruthenium layer 4 is bonded to the evaporated particles by using a plasma of a reaction gas, and is formed by a RPD (Reactive Plasma Deposition) method of synthesizing a compound layer. Thereafter, a ZnO layer 5 to which Ga or Al is added is formed on the ITO layer 4 on the surface electrode side Ζ Ο layer formation process. The ZnO layer 5 is formed similarly to the ITO layer 4 via the RPD method. At this time, the grain size of ZnO can be adjusted by adjusting the temperature at which the ZnO layer 5 is formed. The size of the ZnO crystal grains or the doping amount of Ga and A1 are adjusted according to the desired haze in the material structure τ and the contamination problem of the solar cell by the doping element. Further, the method of forming the ITO layer 4 and the ZnO layer 5 is not limited to the RPD method, and for example, sputtering may be employed. Figure 3 is a schematic diagram for explaining the material structure forming project. As shown in FIG. 3, the material structure forming process is performed in a state where the white glass substrate 2 is conveyed in the direction of the arrow F, and the ITO layer 4 and ZnO are formed on the alkaline barrier layer 1 2 of the white glass substrate via the transfer roller 13. Layer 5. Further, the whiteboard glass substrate 2 is placed on the transport roller 13 with the ZnO layer 5 as the upper surface. First, a rough washing treatment of the surface of the substrate is performed. In the rough washing process, dust or the like adhering to the white glass substrate 2 is washed away by the washing water sprayed from the washing nozzle 14. Thereafter, the water-repellent treatment of the white glass substrate 2 is performed by the high-pressure air jetted from the water removing air nozzle 15. Next, etching treatment of the ZnO layer 5 of the substrate is performed. In the etching treatment, hydrochloric acid adjusted to a predetermined concentration is used as an etching liquid, and wet etching is performed by ejecting hydrochloric acid from the etching nozzle 16 toward the ZnO layer 5. In the surface (on the side of the light absorbing layer 6) of the ZnO layer 5 which is sprayed to the hydrochloric acid, fine irregularities, that is, the material structure T, are formed by chemical reaction. Further, the etching liquid is not limited to hydrochloric acid, and other acidic liquid may be used, and an alkaline liquid may be used as long as it can appropriately form the material T of the material structure. -11 - 201140867 Here, Fig. 4(a) is a view showing the relationship between the etching time of the concentration of 0.1% hydrochloric acid and the roughness of the material structure T, and Fig. 4(b) shows the concentration of 经由. 5 %. A graph showing the relationship between the etching time of hydrochloric acid and the roughness of the material structure T. Further, Fig. 5 is a graph corresponding to the relationship between the etching time, the haze, and the thickness of the ZnO layer in Fig. 4(a). As shown in FIG. 4 and FIG. 5, the material structure T formed in the ZnO layer 5 has a tendency that the etching time becomes longer as the etching time becomes longer (the unevenness becomes larger), and the haze tends to be higher. Further, the concentration of hydrochloric acid as the etching liquid is higher. The unevenness of the material structure T becomes large in a short time. Therefore, the haze of the material structure T can be adjusted by appropriately setting the hydrochloric acid concentration and the etching treatment time. Further, the temperature at the time of film formation or the amount of doped Ga or the like in ZnO is changed', and the haze can also be changed. Table 1 shows the haze of the material structure T when Ga is changed with respect to the doping amount of ZnO or the film formation temperature. As shown in Table 1, the haze of the material structure T can be adjusted in the range of 10 to 70% by changing the hydrochloric acid concentration, the etching time, the G a doping amount, and the film formation temperature. [Table 1]
ZnO層 ZnO膜特伯 Ga摻雜量(％) 成膜溫度(。〇 蝕刻條件鹽酸濃度(％) 薄片電阻(Ω/Ο) 霧度 3 250 0.5 4〜5 35 200 32 150 36 1 250 0.1 5 56 200 72 之後，進行對白板玻璃基板2之除液處理。在除液處 -12- 201140867 理中，由從除液用空氣噴嘴17噴射之高壓空氣吹飛白板玻 璃基板2表面之鹽酸。接著，進行由從沖洗用噴射噴嘴1 8 噴射之蝕刻沖洗液去除附著於白板玻璃基板2的鹽酸之沖 洗處理。而且，最後進行由從除水用空氣噴嘴19噴射之高 壓空氣對附著於白板玻璃基板2之蝕刻沖洗液進行除水之 除水處理，並結束材質結構形成工程。 (光吸收層形成工程） 接著，於形成有材質結構T之ZnO層5上形成光吸收層 6。光吸收形成工程由非晶矽層形成工程及微晶矽層形成 工程構成。 在非晶矽層形成工程中，於白板玻璃基板2上形成鹼 性阻擋層1 2，於其上之Ζ η 0層5上形成非晶矽層7。非晶矽 層7經由電漿CVD法形成。之後，在微晶矽層形成工程中 ，於非晶砂層7上形成微晶砂層8。微晶砂層8亦經由電獎 CVD法形成。再者，非晶矽層7及微晶矽層8之形成方法並 不限於上述方法。 (背面電極層形成工程） 接著，於微晶矽層8上形成背面電極層9。背面電極層 形成工程由背面電極側ZnO層形成工程及Ag層形成工程構 成。在背面電極側ZnO層形成工程中，經由濺鍍法於微晶 矽層8上形成ZnO層1 0。之後，在Ag層形成工程中，與ZnO 層1〇相同，經由濺鍍法於ZnO層10上形成Ag層1 1。再者， -13- 201140867ZnO layer ZnO film Teb Ga doping amount (%) Film formation temperature (. 〇 etching condition hydrochloric acid concentration (%) sheet resistance (Ω / Ο) haze 3 250 0.5 4~5 35 200 32 150 36 1 250 0.1 5 After the removal of the liquid glass substrate 2, the liquid-repellent treatment of the white glass substrate 2 is carried out by the high-pressure air jetted from the liquid-removing air nozzle 17 in the liquid-removing section -12-201140867. The rinsing treatment for removing hydrochloric acid adhering to the white glass substrate 2 by the etching rinsing liquid sprayed from the rinsing nozzle 18 is performed, and finally, the high-pressure air jetted from the water-removing air nozzle 19 is attached to the white glass substrate. The etching rinsing liquid of 2 is subjected to water removal treatment, and the material structure forming process is completed. (Light absorbing layer forming process) Next, the light absorbing layer 6 is formed on the ZnO layer 5 on which the material structure T is formed. Light absorbing forming engineering The amorphous germanium layer forming process and the microcrystalline germanium layer forming process are formed. In the amorphous germanium layer forming process, an alkaline barrier layer 12 is formed on the whiteboard glass substrate 2, and is formed on the η0 layer 5 thereon. Amorphous germanium layer 7 The amorphous germanium layer 7 is formed by a plasma CVD method. Thereafter, in the microcrystalline germanium layer forming process, a microcrystalline sand layer 8 is formed on the amorphous sand layer 7. The microcrystalline sand layer 8 is also formed by a credit CVD method. The method of forming the amorphous germanium layer 7 and the microcrystalline germanium layer 8 is not limited to the above method. (Back electrode layer formation process) Next, the back electrode layer 9 is formed on the microcrystalline germanium layer 8. The back electrode layer is formed by the back surface. The electrode side ZnO layer formation process and the Ag layer formation process are formed. In the ZnO layer formation process on the back electrode side, the ZnO layer 10 is formed on the microcrystalline germanium layer 8 by sputtering, and then, in the Ag layer formation process, The ZnO layer is the same, and the Ag layer 1 1 is formed on the ZnO layer 10 by sputtering. Further, -13- 201140867
ZnO層10及Ag層11之形成方法並不限於濺鍍法。 根據以上說明的太陽能電池1之製造方法及太陽能電 池1，藉由於光吸收層6採用非晶矽層7及微晶矽層8之層積 結構，與利用其中一方時相比，所吸收的太陽光之波長區 域顯著擴大。再者，藉由採用ITO層4及ZnO層5的層積結 構作爲表面電極層3，與利用以往Sn02 (氧化錫）層時相 比，低電阻且到900〜1 200nm之長波長光亦可改善透射率 。其結果，可充分應用由非晶矽層7及微晶矽層8構成之光 吸收層6之性能，並可謀求光電轉換效率之大幅提高。 又，根據該太陽能電池1之製造方法及太陽能電池1， 經由材質結構T使從白板玻璃基板2側入射之光散射，藉此 使光傾斜進行並可加長光吸收層6內的光之路徑。再者， 傾斜進行之光由光吸收層6與背面電極層9之邊界反射，其 反射光由材質結構T，亦即光吸收層6與表面電極層3之邊 界再次反射而禁閉於光吸收層6內，故可有效地進行光電 轉換。而且，藉由採用電阻低於氧化錫（Sn02 )層之ITO 層4作爲表面電極層3，可提供更爲薄膜且低電阻之膜，由 成膜裝置成膜之部分較少即可，故可降低成膜裝置之價格 。又，亦可縮小成膜裝置之裝置空間。再者，於ITO層4上 形成ZnO層5，並經由蝕刻於該ZnO層5上形成材質結構， 藉此與由以往CVD法形成時相比，亦容易調整霧度，且亦 可形成高霧度之材質結構。因此，根據該太陽能電池1之 製造方法及太陽能電池1，可提供光吸收層6由非晶矽層7 及微晶矽層8構成之串聯式太陽能電池中所要求之TCO ( -14- 201140867The method of forming the ZnO layer 10 and the Ag layer 11 is not limited to the sputtering method. According to the method for manufacturing the solar cell 1 and the solar cell 1 described above, since the light absorbing layer 6 has a laminated structure of the amorphous germanium layer 7 and the microcrystalline germanium layer 8, the absorbed sun is used as compared with the case where one of the solar cells 1 is used. The wavelength region of light has expanded significantly. Further, by using the laminated structure of the ITO layer 4 and the ZnO layer 5 as the surface electrode layer 3, the long-wavelength light having a low resistance of 900 to 1 200 nm can be used as compared with the case of using the conventional Sn02 (tin oxide) layer. Improve the transmittance. As a result, the performance of the light absorbing layer 6 composed of the amorphous germanium layer 7 and the microcrystalline germanium layer 8 can be sufficiently utilized, and the photoelectric conversion efficiency can be greatly improved. Further, according to the method for manufacturing the solar cell 1, and the solar cell 1, the light incident from the white glass substrate 2 side is scattered by the material structure T, whereby the light is inclined and the path of the light in the light absorbing layer 6 can be lengthened. Further, the oblique light is reflected by the boundary between the light absorbing layer 6 and the back electrode layer 9, and the reflected light is reflected again by the material structure T, that is, the boundary between the light absorbing layer 6 and the surface electrode layer 3, and is confined to the light absorbing layer. Within 6, photoelectric conversion can be performed efficiently. Further, by using the ITO layer 4 having a lower electric resistance than the tin oxide (SnO 2 ) layer as the surface electrode layer 3, a film having a thinner film and a lower resistance can be provided, and a film formed by the film forming apparatus is less, so that it can be used. Reduce the price of the film forming device. Moreover, the device space of the film forming apparatus can also be reduced. Further, the ZnO layer 5 is formed on the ITO layer 4, and a material structure is formed on the ZnO layer 5 by etching, whereby the haze can be easily adjusted and high fog can be formed as compared with the case of the conventional CVD method. The material structure of the degree. Therefore, according to the method for manufacturing the solar cell 1 and the solar cell 1, the TCO required for the tandem solar cell comprising the amorphous germanium layer 7 and the microcrystalline germanium layer 8 can be provided (-14-201140867)
Transparent Conductive Oxide)膜。 再者，根據該太陽能電池1之製造方法，藉由採用經 由蝕刻處理的材質結構之形成，與經由以往常壓C V D法形 成材質結構時相比，進行經由濕式蝕刻之蝕刻處理而可容 易實現基於蝕刻液濃度或蝕刻時間之調整的霧度調整，故 可得到按照光吸收層6之特性等的所希望之霧度。這有助 於提高太陽能電池1之光電轉換效率。 本發明並不限於上述實施形態。 例如亦可替代將Sn (錫）作爲摻雜元素之ITO層4而採 用將摻雜元素設爲W (鎢）、Μ 〇 (鉬）、S i (矽）等之層 〇 又’材質結構T不僅經由濕式蝕刻，還可以經由幹式 蝕刻來形成，亦可經由其他噴射處理等來形成。又，材質 結構T之形成係經由控制Zn〇層5之形成環境所成zn〇晶粒 尺寸之調整所實現之形態亦可。 又’光吸收層6並不限於由非晶矽層7及微晶矽層8構 成之層積結構’亦可僅由非晶矽層7及微晶矽層8中之任意 一方構成。 再者’本發明還可應用於矽系太陽能電池以外，例如 還可優選利用於例如CdTe (碲化镉）-CdS (硫化镉）系太 陽能電池中。 【圖式簡單說明】 第1圖是表示本發明之太陽能電池之一實施形態之結 -15- 201140867 構圖。 第2圖是表示非晶矽層及微晶矽層之光譜靈敏度特性 之圖表。 第3圖是用以說明材質結構形成工程之圖。 第4圖之（a)是表示經由濃度0.1 %鹽酸之蝕刻時間與 材質結構之凹凸粗糙度的關係之圖’ （b)是表示經由濃 度0.5 %鹽酸之蝕刻時間與材質結構之凹凸粗糙度的關係之 圖。 第5圖是表示對應於第4圖（a)之蝕刻時間、霧度及 ZnO層厚度的關係之圖表。 【主要元件符號說明】 1 :太陽能電池 2 :白板玻璃基板（透明基板） 3 :表面電極層 4 : ITO層 5 ： ZnO層 6 :光吸收層 7 :非晶砂層 8 :微晶矽層 9 :背面電極層 1 0 : ZnO層 1 1 : Ag層 12 :鹼性阻擋層（Si02層） T :材質結構 -16 -Transparent Conductive Oxide) film. Further, according to the method for manufacturing the solar cell 1, the formation of the material structure by the etching treatment can be easily performed by etching by wet etching as compared with the case of forming a material structure by the conventional atmospheric pressure CVD method. The haze is adjusted based on the adjustment of the etching solution concentration or the etching time, so that a desired haze according to the characteristics of the light absorbing layer 6 or the like can be obtained. This helps to improve the photoelectric conversion efficiency of the solar cell 1. The present invention is not limited to the above embodiment. For example, instead of using ITO layer 4 in which Sn (tin) is used as a doping element, a doping element may be used as a layer of W (tungsten), yttrium (molybdenum), S i (矽), or the like. It may be formed not only by wet etching but also by dry etching, or may be formed by other blast processing or the like. Further, the formation of the material structure T may be achieved by controlling the zn 〇 grain size by the formation environment of the Zn layer 5 . Further, the light absorbing layer 6 is not limited to the laminated structure composed of the amorphous germanium layer 7 and the microcrystalline germanium layer 8, and may be composed of only one of the amorphous germanium layer 7 and the microcrystalline germanium layer 8. Further, the present invention is also applicable to, for example, a lanthanide solar cell, and is preferably used, for example, in a CdTe (cadmium telluride)-CdS (cadmium sulfide) solar cell. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing the composition of an embodiment of a solar cell of the present invention -15 - 201140867. Fig. 2 is a graph showing the spectral sensitivity characteristics of the amorphous germanium layer and the microcrystalline germanium layer. Figure 3 is a diagram for explaining the material structure forming process. Fig. 4(a) is a view showing the relationship between the etching time of the concentration of 0.1% hydrochloric acid and the roughness of the material structure. (b) shows the etching time and the roughness of the material structure by the concentration of 0.5% hydrochloric acid. Diagram of the relationship. Fig. 5 is a graph showing the relationship between the etching time, the haze and the thickness of the ZnO layer corresponding to Fig. 4(a). [Description of main component symbols] 1 : Solar cell 2 : Whiteboard glass substrate (transparent substrate) 3 : Surface electrode layer 4 : ITO layer 5 : ZnO layer 6 : Light absorbing layer 7 : Amorphous sand layer 8 : Microcrystalline germanium layer 9 : Back electrode layer 1 0 : ZnO layer 1 1 : Ag layer 12 : Alkaline barrier layer (SiO 2 layer) T : Material structure - 16 -