201104898 六、發明說明： 【發明所屬之技術領域】 本發明係關於一種光起電力裝置及其製造方去 【先前技術】 在近年來的光起電力裝置中，以高輸出化為目炉 斷改善素材或製造製程。因此，$了達成更進_步：高不 出化，藉由對於光起電力裝置内的光密封、或表面 中：載體的再結合速度的抑制’實現一種使在從前並無： 充分活用的波長範圍的光有助於發電的構造或製法乃極為 重要。因& ’擔任其一重要部分之基板的背面構造的改呈 即非常重要。 ° '因此，以在基板背面側的反射或在基板背面的再結合 速度的抑制為目標’例如在將背面電極局部印刷、燒成後， 再進行抑制#結合速度之膜之成膜的技術已被^ (例如 參照專利文獻1)。此外，，亦已被提出一種例如在基板背 面進行抑制再結合速度之膜的成膜後，在其一部分設置開 口邛，另外將背面電極膏全面進行印刷、燒成的技術（例 如參照專利文獻2)。 (先前技術文獻） (專利文獻） 專利文獻1 :曰本特開平6_1 69096號公報 專利文獻2 :日本特開2002-246625號公報 201104898 【發明内容】 (發明所欲解決之課題） 但是，在上述專利文獻1之方法中，係在背面電極印 刷、燒成後，進行抑制再結合速度之膜的成膜。此時尤其 在燒成時’由於會對基板背面進行污染物質的附著或固 疋，因此會有以意圖在基板背面之载體的再結合速度的方 式抑制為較低乃極為困難的問題。 ，隹上返寻利文獻2之方法中，以覆蓋抑制再 合速度之膜的大致全面的形式將電極膏印刷而形成兼具 反射功能的背面電極，該f面電極與基板f面的接觸係 局部進行。但是’當將背面電極由含有例如具代表性材 之鋁（A1)的糊膏所構成時’會有無法提高在背面的光 射率，無法獲得對於光起電力裝置内之充分的光密封效 的問題。此外’若將背面電極由含有例如具代表性材料 銀（“）的糊㈣構成時，在電極進㈣成處理時 本的接觸部分以外的區域亦抑制再結合速度的膜因 人（fire through)而被侵钱， 體再結合速度的抑制效果的問題。有…法獲得充分的] 本發明係鑑於上述情形而研創者，目的在獲得一㈣ 括較低再結合速度與較高背面 久射率’光電轉換效率優J 的先起電力袭置及其製造方法。 文手優； (用以解決課題的手段 為了解決上述課題 以達成目的 本發明之光起電力 4 201104898 裝置，其特徵在於包括：在一面側具有擴散有第2導電型 的雜質元素的雜質擴散層的第丨導電型的半導體基板；形 成在前述雜質擴散層上的反射防止膜；貫穿前述反射防止 膜而與前述雜質擴散層作電性連接的第丨電極；具有到達 前述半導體基板之另一面側的複數開口部，形成在前述半 導體基板之另一面側的背面絕緣膜；i少被埋設在前述開 邛且與削述半導體基板的另一面側作電性連接的第2電 極；及由藉由氣相成長法所形成的金屬膜所構成、或者含 有金屬落所構成’ i少覆蓋前述背面絕緣膜上而形成的背 面反射膜。 (發明效果） 稭甶本發明，可達成 ，a %穴另权低丹結 2度與較高背面反射率之雙方的背面構造，可獲得長波 長感度優異、達成光電轉換效率之高效率化的太陽 元。 t 【貫施方式】 以下根據圖示，詳加說明本發明之 劁拌士、也 > 〜 刀衷置及其[Technical Field] The present invention relates to a light-emitting power device and a manufacturer thereof. [Prior Art] In recent years, a light-emitting power device has been improved by high output. Material or manufacturing process. Therefore, $achieves a further step: high-intensity, by means of a light seal in the light-emitting device, or a suppression of the recombination speed of the carrier in the surface, which is achieved in the past without: fully utilizing It is extremely important that the light in the wavelength range contributes to the construction or production of electricity. It is very important to change the back structure of the substrate which is an important part of & Therefore, it is aimed at the reflection on the back side of the substrate or the suppression of the recombination speed on the back surface of the substrate. For example, after partially printing and baking the back surface electrode, the film forming method for suppressing the film of the #binding speed has been used. ^ (for example, refer to Patent Document 1). In addition, for example, a film in which a film having a suppressed recombination speed is formed on the back surface of the substrate is formed, and an opening 邛 is provided in a part of the film, and the back electrode paste is printed and fired in its entirety (for example, see Patent Document 2). ). (Prior Art) (Patent Document) Patent Document 1: JP-A-2002-246625 (Patent Document 2) Japanese Patent Application Publication No. 2002-246625 In the method of Patent Document 1, after the back electrode is printed and fired, film formation of a film that suppresses the recombination speed is performed. In this case, in particular, at the time of firing, since the contaminant adheres or solidifies to the back surface of the substrate, it is extremely difficult to suppress the recombination speed of the carrier on the back surface of the substrate to be low. In the method of returning the document 2, the electrode paste is printed in a substantially comprehensive form covering the film which suppresses the recombination speed to form a back surface electrode having a reflection function, and the contact surface of the f-plane electrode with the substrate f surface Partially. However, 'when the back electrode is composed of a paste containing, for example, aluminum (A1) of a representative material, the light transmittance on the back surface cannot be improved, and sufficient light sealing effect in the light-emitting device cannot be obtained. The problem. Further, when the back electrode is composed of a paste (four) containing, for example, a representative material of silver ("), a region other than the contact portion of the electrode at the time of electrode formation processing also suppresses the speed of the recombination film by fire through The problem of the suppression effect of the invading money and the speed of recombination of the body. The method is fully obtained. The present invention is based on the above situation, and aims to obtain a (four) lower recombination speed and a higher back long-time rate. The first-generation electric power generation of the photoelectric conversion efficiency and the manufacturing method thereof. The method for solving the problem is to solve the above problems, and to achieve the object of the present invention, the light-emitting power 4 201104898 device is characterized by comprising: a second conductivity type semiconductor substrate having an impurity diffusion layer in which an impurity element of a second conductivity type is diffused on one surface side; an antireflection film formed on the impurity diffusion layer; and an antireflection film penetrating the impurity diffusion layer a second electrode electrically connected; a plurality of openings reaching the other surface side of the semiconductor substrate, formed on the other of the semiconductor substrates a back surface insulating film; a second electrode that is less buried in the opening and electrically connected to the other surface of the semiconductor substrate; and a metal film formed by a vapor phase growth method, or The back surface reflection film formed by the metal back is formed to cover the back surface insulating film. (Effect of the invention) According to the present invention, it is achieved that the a% hole has a low density of 2 degrees and a high back surface reflectance. The back surface structure of both sides can obtain a solar cell which is excellent in long-wavelength sensitivity and high in efficiency in achieving photoelectric conversion efficiency. t [Comprehensive method] Hereinafter, the present invention will be described in detail with reference to the present invention. Sincerely
Ik方法之貫施例。其中， ., 非被以下記述所限定， 在未脫離本發明之耍t沾々々 疋 、 赞月之要曰的範圍内可為適當改變。此外+ 以下所示圖示中，我且士人 卜在 有所不同的愔开彡。户 縮尺與貫際 μ」扪/t形。在各圓示之間亦同。 201104898 (實施形態1) 第1-1圖〜第卜3圖係顯示屬於本實施形態之光起電 力裝置的太陽電池單元的構成圖，帛Η圖係用以說明太 陽電池單元之剖面構造的主要部位剖面圖，第id圖係由 受光面側所觀看的太陽電池單元的上視圖，帛卜3圖係由 受光面之相幻則（背^側）戶斤觀看的太陽電池單元的底視 圖第1 1圖係第卜2圖之線段A_A中的主要部位剖面圖。 。…如第卜1圖〜第卜3圖所示，本實施形態之太陽電池 早元係包括：具有光電轉換功能的太陽電池基板且具有即 接。的半導體基板1;形成在半導體基板玉之受光面側的 面（表面），防止在受光面之入射光之反射之由屬於絕緣 膜的氮切膜（SiN膜）所構成的反射防止膜4;在半導體 基板1之受光面側的面（表面），被反射防止膜4包圍所 形成之作為第1電極的受光 &先面側電極5;及形成在半導體 土板1之受光面之相反侧之；，北The embodiment of the Ik method. However, it is not limited by the following description, and may be appropriately changed within the scope of the present invention without departing from the scope of the present invention. In addition, in the illustrations shown below, I am different from the scholars. Household scale and continuous μ"扪/t shape. The same is true between the rounds. 201104898 (Embodiment 1) FIG. 1-1 to FIG. 3 are views showing a configuration of a solar battery unit belonging to the photovoltaic device according to the present embodiment, and the drawings are mainly used to explain the main structure of the solar battery cell. The cross-sectional view of the part, the id image is the upper view of the solar cell unit viewed from the side of the light-receiving surface, and the bottom view of the solar cell unit viewed from the side of the light-receiving surface (the back side) 1 1 is a cross-sectional view of the main part in the line A_A of Fig. 2 . . As shown in Fig. 1 to Fig. 3, the solar cell of the present embodiment includes a solar cell substrate having a photoelectric conversion function and has an instant connection. a semiconductor substrate 1; a surface (surface) formed on the light-receiving surface side of the semiconductor substrate, preventing the reflection of incident light on the light-receiving surface, and an anti-reflection film 4 composed of a nitrogen-cut film (SiN film) belonging to the insulating film; The surface (surface) on the light-receiving surface side of the semiconductor substrate 1 is surrounded by the anti-reflection film 4 to form a light-receiving & front side electrode 5 as a first electrode; and is formed on the opposite side of the light-receiving surface of the semiconductor earth plate 1 North
(者面）之由氮化矽膜（SiN 膜）所構成的背面絕緣膜8 ; 仕牛導體基板1的背面被背 面絕緣膜8包圍所形成之作為 電極的背面側電極9 ; 及在丰導體基板1的背面 9而“… 覆盖旁面絕緣臈8與背面側電極 9而玟的背面反射膜1 〇。 半導體基板1係藉由作為莖 ho 4第1導電型層的P型多晶矽 基板2、及在半導體基板丨 之作A m 9 m φ a 又先面側藉由磷擴散所形成 I作為第2導電型層的雜質 構志nn姥人 文層（n型雜質擴散層）3而 構成pn接合。n型雜f擴 ΙΟΟΩ/D 〇 係使表面片電阻為30〜 201104898 士文光面側電極5係包含太陽電池單元的栅電極6及匯 流排電極7，與η型雜質擴散層3作電性連接。柵電極6 係為了將以半導體基板1所發電的電氣作集電而局部設在 受光面。匯流排電極7係為了取出以柵電極6所集電的電 氣而以與柵電極6大致正交地作設置。 另方面，为面側電極Θ係一部分被埋設在以遍及全 體設在半導體基板1之背面的背面絕緣膜8。亦即，在背 面絕緣膜8設有到達半導體基板1之背面的大致圓形的點 狀開4 8a。接著，以填埋該開口部8a，並且在背面絕緣 膜8的面内方向具有比開口部8a的直徑更寬的外形的方 式，設有由含有鋁、玻璃等的電極材料所構成的背面 極9 〇 背面絕緣膜8係由氮化石夕膜（SiN膜）所構成，藉由 電漿 CVD (Chemical Vapor Dep〇siti〇n)法形成在半導 體基板1之背面的大致全面。以背面絕緣膜8而言，使用 藉由電漿CVD法所形成的氮化矽膜（SiN膜），藉此可在 半導體基板1的背面獲得良好的載體的再結合速^ 效果。 背面反射膜1〇係在半導體基们的背面覆蓋背面側電 極9及背面絕緣膜8而設。藉由包括覆蓋背面絕緣膜8的 背面反射膜1G，可將透過半導體基板以背面絕緣膜8的 光敍射而返回至半導體基板〗，可得良好的光密封效果。 接著’在本實施形態中，背面反射臈1〇係由藉由氣相成長 法所形成之屬於金屬膜之藉由濺鍍法所形成的銀（…膜 201104898 (銀濺鑛膜）所错# 如 冓成。產面反射膜10並非為使用電極膏之 藉由印刷法所形成' Μ胳 — 或的膜，而係藉由濺鍍膜所構成，因此可 實現比藉由印刷法所形成之銀（⑷帛為更高的光反射， 可使透過半導體基& 1及背面絕緣膜8的光更多反射而返 回至半導體基1。因此，本實施形態之太陽電池單元係 由於包括藉由銀濺鍍膜所構成的背面反射膜10,可得優異 的光密封效果β 以背面反射膜10的材料而言，例如最好使用對波長為 nm附近的光的反射率為9〇%以上，較佳為使用以 上的金屬材料。藉此，可實現具有較高的長波長感度，且 •子長波長區域的光的光密封效果優異的太陽電池單元。亦 卩雖亦依半導體基板1的厚度而異，但是可將波長為 9 00nm以上、尤其為1〇〇〇nm〜n〇〇nm左右之長波長的光效 率佳地取入半導體基板1，而可實現較高的發生電流 (Jsc )，而可使輸出特性提升。以如上所示之材料而言， 除了銀（Ag)以外，另外可使用例如鋁（M )。 其中，在本實施形態之太陽電池單元中，如上所述在 半導體基板1的背面形成微細的背面側電極9，且在其上 形成有背面反射膜1〇。因此，在第^圖所示之背面反射 膜1 〇形成有實際上因背面側電極9而起的微細凹凸但是 在第1 - 3圖中則省略該微細凹凸的記載。 此外，在半導體基板1之背面側的區域且為與背面側 電極9相接的區域及其附近係形成有鋁_矽（A1_si)合金 部11。此外在其外周部形成有包圍該鋁-矽（A卜§丨）合金 8 201104898 邰11，與p型多晶矽基板2為相等之導電型的高濃度擴散 層的 BSF ( Back Surface Filed 層）12。 在如上所不所構成的太陽電池單元中，若太陽光由太 陽電池單元的受光面側照射至半導體基板丄的卯接合面（p 型多晶矽基板2與n型雜質擴散層3的接合面）時，即生 成電洞與電子。藉由ρη接合部的電場，所生成的電子係朝 向η型雜質擴散層3移冑，電洞則係朝向ρ型多晶矽基板 2移動。藉此，在η型雜質擴散層3會形成電子過剩在ρ 型多晶矽基板2則形成電洞過剩，結果會發生光起電力。 該光起電力係在將ρη接合以順向偏壓的方向產生，與η型 雜質擴散層3相連接的受光面側電極5會成為負極，與ρ 型夕β曰矽基板2相連接的背面側電極9會成為正極，而在 未圖示的外部電路流通電流。 第2圖係顯示具有不同背 體基板背面之反射率的特性圖 面構造之3種試料中在半導 。在第2圖中係顯示入射至 ㈣之，的波長與反射率的_。其中，各試料係模擬 電池早7L而製作’背面構造以外的基本構造係與本實施 陽 形態之太陽電池單元相同。久$祖从也工城 J各°式科的背面構造詳細内容如 以下所示。 (試料A ) 遍及半導體基板的背面全 «田主囬a栝由含有鋁（A1)的電 極膏所形成的鋁（A1)膏電極（ %征、子日田於習知的—般構造）。 (試料B) # ； 遍及半導體基板的背 面全面形成由氮化矽臈（SiN) 所 201104898 構成的背面絕緣膜，在該背面絕緣膜上的全面包括由含有 銘⑷）的電極膏所形成的銘（Ai)膏電極（相當於先前 技術（專利文獻2))。 (試料C ) 遍及半導體基板的背面全面形成*氮切膜⑴所 構成的背面絕緣膜，而且在半導體基板背面局部具有由含 有鋁（A1)的電極膏所形成的鋁（A1)膏電極，此外在該 背面絕緣膜上的全面包括由銀濺㈣所構成的高反射膜 (相當於本實施形態之太陽電池單元）。 各試料係僅有背面構造不同，其他構造為相同，因此 可由第2圖確認「石夕（半導體基板）―背面構造」間之反射 率的差異。為了觀看背面反射的狀態，將幾乎沒有對矽的 吸收的波長12GGnm附近作比較即可。以i⑽ηπ]以下的波 長，由於會有對於石夕的吸收而已經有助於發電，因此不適 於背面反射的比較之故。其中，在第2圖中所示之反射率， 嚴謹而言在背面的多重反射的結&，為#次在半導體基板 表面洩漏而來的成分。 由第2圖可知，相當於先前技術（專利文獻2)的試 料B，與相當於習知之一般構造的試料A相比，雖然反射 率稍微改善’但是反射率改善效果並無法謂為充分。另一 方面，相當於本實施形態之太陽電池單元的試料c，與試 料A及試料B相比，其反射率較大，被發現「矽（半導體 基板）-背面構造」間的反射率的高度，可知適於根據背面 中之光密封作用的高效率化。 10 201104898 第3圖係顯示與上社〔叫_· Γ 1 ^ , 边忒枓C相同地模擬本實施形態之 陽電池早疋所製作的試料中的背面電極的面積率（背面 電極在半導體基板的背面所佔比率）與開放電壓（V。。）的 關係的特性圖。此外，筮 第4圖係顯示與上述試料C相同地 模擬本實施形態之太陪Φ 電池單7L所製作的試料中的背面電 極的面積率（背面電極在丰 牡千泽體基板的背面所佔比率）與 短路電流（JSC)的關係的特性圖。 由第3圖及第4圖可知，隨著作為背面電極之鋁"。 膏電極的面積率的減少，亦即隨著本實施形態之高反射膜 之面積率的增加’連同開放電壓（Voc) '短路電流（Jsc) 起提升’在半導體基板的背面可得良好的載體再結合速 度的抑制效果。藉此可知藉由本實施形態之太陽電池單元 的構造，可兼顧背面反射改善與半導體基板背面中之載體 再結合速度的抑制，及愈提高本實施形態之高反射膜的面 積率，愈顯著得到上述效果。 以上所示所構成之實施形態1之太陽電池單元中，以 背面絕緣膜8而言，包括藉由電漿CVD法而形成在半導體 基板1的背面的氮化矽膜（SiN膜），藉此可在半導體基 板1的背面獲得良好的载體再結合速度的抑制效果。藉 此，在本實施形態之太陽電池單元中，達成輸出特性的提 升’且實現較高的光電轉換效率。 此外，在實施形態1之太陽電池單元中，包括覆蓋背 面絕緣膜8且由銀濺鍍臈所構成的背面反射膜1〇，藉此可 實現比藉由習知的印刷法所形成的銀（Ag)膜為更高的光 11 201104898 反射，可將透過半導體基板面絕緣膜8的光反射更 多且返回至半導體基板卜因此，在本實施形態之太陽電 池單元中’可得優異的光密封效果，達成輸出特性的提升， 且實現較高的光電轉換效率。 因此，在實施形態1之太陽電池單元中，藉由具有具 較低再結合速度與較高背面反射率之雙方的背面構造，實 現一種長波長感度優異、達成光電轉換效率之高效率化的 太陽電池單元。 接著，參照第5-1圖〜第5-9圖，說明如上所示之太 陽電池單元之製造方法之U 5]圖〜第5_g圖係用 以說明本實施形態之太陽電池單元之製造步驟的剖面圖。 首先，以半導體基板1而言，備妥例如適於民生用太 陽電池而最多被使用的p型多晶矽基板（以下稱為p型多 晶矽基板la)(第5-1圖）。以p型多晶矽基板la而言， 使用例如含有硼（B)等III族元素的電阻為〇5〜3门cm 左右的多晶梦基板。 P型多晶矽基板1 a係利用線鋸將經熔融的矽予以冷卻 固化所成之晶錠作切片（slice)而製造，因此在表面殘留 有切片時的損害。因此’首先亦兼作去除該損害層，將 型多晶石夕基板la浸潰在酸或經加熱後的鹼溶液中、例如氣 氧化鈉水溶液，而將表面進行蝕刻，藉此將在矽基板切出 時發生而存在於p型多晶矽基板la之表面附近的損害區域 去除。損害去除後的p型多晶矽基板1 a的厚度例如為 200 // m ’ 尺寸例如為 15〇mmxi50mm。 12 201104898 此外’亦可與損害去除同時、或接續損害去除，在P 型多晶石夕基板la _面側的表面形成微小凹凸 地構造。藉由將如上所示之f地構造形成在半導體 的受光面側’在太陽電池單元的 早几的表面使光的多重反射產 生’可使入射至太陽電池單元的氺 的先有效率地吸收在Ρ型多 晶石夕基板1a的内部，而可實效性減低反射率而使轉換效率 提升。 牛 其中，本發明係光起電力裝置之背面構造的發明，因 此關於質地構造的形成方法或形狀，並未特別有所限制。 例如’利用使用含有異丙醇的驗水溶液或主要由氫氟酸、 硝酸的混合液所構成的酸蝕刻的方法、將局部設有開口的 遮罩材形成在P型多晶石夕基板13的表面而藉由透過該遮罩 材的钮刻’在P型多晶⑪基板la的表面獲得蜂巢構造或逆 金字塔構造的方法、或使用反應性氣體蝕刻（RlE:Reactive Ion Etching)的手法等任何手法均可。 接著，將該p型多晶t基板13投人至熱氧化爐，在屬 於η型雜質㈣（P)的霧圍氣下進行加熱。藉由該步驟， 使磷（Ρ)擴散在ρ型多晶矽基板la的表面，形成η型雜 質擴散層3而形成半導體ρη接合（第5-2圖）。在本實施 礼*心中，將Ρ型多晶石夕基板1 a在氧氣化碟（p〇c 13)氣體 雾圍氣中’以例如8〇(TC〜85(TC的溫度進行加熱，藉此形 成η型雜質擴散層3。在此，以n型雜質擴散層3的表面 片電阻例如為30〜80Ω/□，較佳為40〜60Ω/□的方式 來控制加熱處理。 201104898 在此，在η型雜質擴散層 玻璃為主成分的磷玻璃層因 除。 3形成瞬後的表面形成有以 此使用氫氟酸溶液等加以去 接著，在形成有η型雜質擴散層3的？型多晶石夕基板 I a的党光面側，為了光a back surface insulating film 8 made of a tantalum nitride film (SiN film); a back surface side electrode 9 as an electrode formed by the back surface insulating film 8 on the back surface of the sirocene conductor substrate 1; The back surface 9 of the substrate 1 "... covers the back surface insulating film 8 and the back surface side electrode 9 and the back surface reflection film 1 〇. The semiconductor substrate 1 is a P-type polycrystalline silicon substrate 2 which is a first conductive type layer of the stem ho 4 And forming a pn junction on the semiconductor substrate by A m 9 m φ a and forming an I as a second conductivity type layer as an impurity structure of the second conductivity type layer (n-type impurity diffusion layer) 3 on the front side. The n-type impurity f is expanded by Ω/D, and the surface sheet resistance is 30 to 201104898. The smooth side electrode 5 includes the gate electrode 6 and the bus bar electrode 7 of the solar cell, and is electrically connected to the n-type impurity diffusion layer 3. The gate electrode 6 is partially provided on the light receiving surface in order to collect electricity generated by the semiconductor substrate 1. The bus bar electrode 7 is substantially the same as the gate electrode 6 in order to extract electricity collected by the gate electrode 6. It is set orthogonally. On the other hand, part of the surface side electrode is The back surface insulating film 8 is provided over the entire back surface of the semiconductor substrate 1. In other words, the back surface insulating film 8 is provided with a substantially circular dot-shaped opening 48 8 that reaches the back surface of the semiconductor substrate 1. The opening portion 8a has a shape in which the surface of the back surface insulating film 8 has a wider outer shape than the diameter of the opening portion 8a, and a back surface electrode 9 made of an electrode material containing aluminum or glass is provided. The 8 series is composed of a nitride nitride film (SiN film), and is formed substantially on the back surface of the semiconductor substrate 1 by a plasma CVD (Chemical Vapor Dep 〇 〇 〇 ) )) method. A tantalum nitride film (SiN film) formed by a plasma CVD method can thereby obtain a good recombination speed effect of the carrier on the back surface of the semiconductor substrate 1. The back surface reflection film 1 is coated on the back surface of the semiconductor substrate. The back side electrode 9 and the back surface insulating film 8 are provided. By including the back surface reflection film 1G covering the back surface insulating film 8, the light transmitted through the semiconductor substrate by the back surface insulating film 8 can be returned to the semiconductor substrate, which is good. Light density Next, in the present embodiment, the back surface reflection 臈1〇 is a silver formed by sputtering by a vapor phase growth method (... film 201104898 (silver splash film)错错#如冓成. The matte reflective film 10 is not a film formed by a printing method using an electrode paste, but is formed by a sputtering film, so that it can be realized by a printing method. The formed silver ((4) 帛 is a higher light reflection, and the light transmitted through the semiconductor substrate & 1 and the back surface insulating film 8 is more reflected and returned to the semiconductor substrate 1. Therefore, the solar cell unit of the present embodiment is included The back surface reflective film 10 made of a silver sputter film can provide an excellent light-sealing effect. β. For the material of the back surface reflective film 10, for example, it is preferable to use a reflectance of 9% or more for light having a wavelength of around nm. Preferably, the above metal material is used. Thereby, a solar cell unit having high long-wavelength sensitivity and excellent light-sealing effect of light in the sub-long wavelength region can be realized. Depending on the thickness of the semiconductor substrate 1, the long-wavelength light having a wavelength of 900 nm or more, particularly about 1 〇〇〇 nm to n 〇〇 nm, can be efficiently taken into the semiconductor substrate 1. A higher generation current (Jsc ) can be achieved, which can improve the output characteristics. As the material shown above, in addition to silver (Ag), for example, aluminum (M) can be additionally used. In the solar battery cell of the present embodiment, as described above, the fine back side electrode 9 is formed on the back surface of the semiconductor substrate 1, and the back surface reflective film 1 is formed thereon. Therefore, the back surface reflection film 1 shown in Fig. 4 is formed with fine irregularities which are actually caused by the back side electrode 9, but the description of the fine unevenness is omitted in Fig. 3-1. Further, an aluminum-arc (A1_si) alloy portion 11 is formed in a region on the back side of the semiconductor substrate 1 in a region in contact with the back-side electrode 9 and in the vicinity thereof. Further, a BSF (Back Surface Filed Layer) 12 which surrounds the aluminum-bismuth alloy 8 201104898 邰11 and has a conductivity type high-concentration diffusion layer equal to the p-type polycrystalline silicon substrate 2 is formed on the outer peripheral portion thereof. In the solar battery unit which is not configured as described above, when the sunlight is irradiated from the light-receiving surface side of the solar battery cell to the 卯 joint surface of the semiconductor substrate ( (the joint surface of the p-type polysilicon substrate 2 and the n-type impurity diffusion layer 3) , that is, the generation of holes and electrons. The generated electrons move toward the n-type impurity diffusion layer 3 by the electric field of the pn junction, and the holes move toward the p-type polycrystalline substrate 2. As a result, excessive electrons are formed in the n-type impurity diffusion layer 3, and excess holes are formed in the p-type polycrystalline silicon substrate 2, and as a result, light-emitting power is generated. The light-emitting power is generated in a direction in which the πn junction is forward biased, and the light-receiving surface side electrode 5 connected to the n-type impurity diffusion layer 3 becomes a negative electrode, and the back surface of the p-type 曰矽β曰矽 substrate 2 is connected. The side electrode 9 becomes a positive electrode, and an electric current flows through an external circuit (not shown). Fig. 2 shows the three kinds of samples in the characteristic map structure showing the reflectance of the back surface of the different back substrate. In Fig. 2, the _ of the wavelength and reflectance incident to (4) is shown. Here, each of the samples was 7 L earlier than the simulated battery, and the basic structure other than the back surface structure was the same as that of the solar cell of the present embodiment. The details of the back structure of the J. (Sample A) The aluminum (A1) paste electrode formed by the electrode paste containing aluminum (A1) is spread over the back surface of the semiconductor substrate (% 、, 子日田 is a conventional structure). (Sample B) # ; A back surface insulating film made of tantalum nitride (SiN) 201104898 was formed over the back surface of the semiconductor substrate, and the entire surface of the back insulating film was formed of an electrode paste containing Ming (4)). (Ai) Paste electrode (corresponding to the prior art (Patent Document 2)). (Sample C) A back surface insulating film composed of a nitrogen cut film (1) was formed over the back surface of the semiconductor substrate, and an aluminum (A1) paste electrode formed of an electrode paste containing aluminum (A1) was partially provided on the back surface of the semiconductor substrate. The entire back surface insulating film includes a high-reflection film (corresponding to the solar cell unit of the present embodiment) composed of silver splash (four). Since the sample structure differs only in the back surface structure and the other structures are the same, the difference in reflectance between "Shi Xi (semiconductor substrate) - back surface structure" can be confirmed from Fig. 2 . In order to observe the state of the back reflection, it is only necessary to compare the vicinity of the wavelength of 12 GGnm which absorbs erbium. The wavelength of i(10)ηπ] or less, which contributes to power generation due to absorption of the stone eve, is not suitable for comparison of back reflection. Among them, the reflectance shown in Fig. 2 is, strictly speaking, the multi-reflected junction & on the back surface, which is a component that leaks on the surface of the semiconductor substrate # times. As is apparent from Fig. 2, the sample B corresponding to the prior art (Patent Document 2) has a slightly improved reflectance as compared with the sample A corresponding to the conventional structure of the prior art, but the effect of improving the reflectance is not sufficient. On the other hand, the sample c corresponding to the solar battery cell of the present embodiment has a larger reflectance than the sample A and the sample B, and the height of the reflectance between the "矽 (semiconductor substrate) and the back surface structure" is found. It is understood that it is suitable for high efficiency in light sealing action in the back surface. 10 201104898 Fig. 3 shows the area ratio of the back surface electrode in the sample prepared by simulating the positive electrode of the present embodiment in the same manner as that of the above-mentioned 叫 · Γ 1 ^ A characteristic diagram of the relationship between the ratio of the back side and the open voltage (V.). In addition, Fig. 4 shows the area ratio of the back surface electrode in the sample prepared by simulating the Φ battery cell 7L of the present embodiment in the same manner as the sample C described above (the back surface electrode is occupied by the back surface of the Fengmu Qianze substrate). Ratio) A characteristic diagram of the relationship with the short-circuit current (JSC). It can be seen from Fig. 3 and Fig. 4 that the aluminum is used as the back electrode. The reduction in the area ratio of the paste electrode, that is, the increase in the area ratio of the high-reflection film of the present embodiment, together with the open voltage (Voc) 'short current (Jsc), improves the carrier on the back side of the semiconductor substrate. Combined with the speed suppression effect. According to the structure of the solar battery cell of the present embodiment, it is possible to achieve both the improvement of the back surface reflection and the suppression of the carrier recombination speed in the back surface of the semiconductor substrate, and the more the area ratio of the high reflection film of the present embodiment is improved, the more remarkable the above is obtained. effect. In the solar battery cell of the first embodiment configured as described above, the back surface insulating film 8 includes a tantalum nitride film (SiN film) formed on the back surface of the semiconductor substrate 1 by a plasma CVD method. A good effect of suppressing the recombination speed of the carrier can be obtained on the back surface of the semiconductor substrate 1. As a result, in the solar battery cell of the present embodiment, the improvement in output characteristics is achieved and a high photoelectric conversion efficiency is achieved. Further, in the solar battery cell of the first embodiment, the back surface reflection film 1 覆盖 which is covered with the silver back-plated ruthenium covering the back surface insulating film 8 is provided, whereby silver formed by a conventional printing method can be realized ( The Ag) film is reflected by the higher light 11 201104898, and the light transmitted through the semiconductor substrate surface insulating film 8 can be more reflected and returned to the semiconductor substrate. Therefore, an excellent light seal can be obtained in the solar cell unit of the present embodiment. The effect is to achieve an improvement in output characteristics and achieve high photoelectric conversion efficiency. Therefore, in the solar cell of the first embodiment, by having a back surface structure having both a low recombination speed and a high back surface reflectance, it is possible to realize a solar cell having excellent long-wavelength sensitivity and high efficiency in achieving photoelectric conversion efficiency. Battery unit. Next, with reference to FIGS. 5-1 to 5-9, a U 5] diagram to a 5_g diagram of the method for manufacturing a solar cell unit as described above will be described to explain the manufacturing steps of the solar cell unit of the present embodiment. Sectional view. First, a p-type polycrystalline germanium substrate (hereinafter referred to as a p-type polycrystalline germanium substrate la) (hereinafter referred to as a "p-type polycrystalline germanium substrate la") which is used at most for a semiconductor solar cell, for example, is prepared. In the p-type polycrystalline germanium substrate la, for example, a polycrystalline dream substrate having a resistance of about 3 to 3 cm is used for a group III element such as boron (B). The P-type polycrystalline germanium substrate 1 a is produced by slicing an ingot obtained by cooling and solidifying the molten crucible by a wire saw, and thus damage is left on the surface. Therefore, first, the damage layer is also removed, and the polycrystalline spine substrate la is immersed in an acid or heated alkali solution, such as an aqueous sodium oxide solution, and the surface is etched, thereby cutting the substrate. The damage region occurring at the time of occurrence and existing near the surface of the p-type polycrystalline germanium substrate la is removed. The thickness of the p-type polycrystalline germanium substrate 1 a after the damage removal is, for example, 200 // m ', for example, 15 〇 mm x 50 mm. 12 201104898 In addition, it is also possible to form a fine concavo-convex structure on the surface of the P-type polycrystalline substrate on the la _ surface side simultaneously with the damage removal or the subsequent damage removal. By forming the above-described f-structure on the light-receiving surface side of the semiconductor to generate multiple reflections of light on the surface of the solar cell unit, the germanium incident on the solar cell unit can be efficiently absorbed first. The inside of the 多-type polycrystalline slab substrate 1a can effectively reduce the reflectance and improve the conversion efficiency. In the present invention, the present invention is an invention of the back surface structure of the photovoltaic device, and therefore, the method or shape for forming the texture structure is not particularly limited. For example, a mask material partially provided with an opening is formed on the P-type polycrystalline substrate 13 by an acid etching method using an aqueous solution containing isopropyl alcohol or a mixture of mainly hydrofluoric acid and nitric acid. Any method of obtaining a honeycomb structure or a reverse pyramid structure on the surface of the P-type polycrystalline 11 substrate 1a by means of a button that penetrates the mask material, or a method using reactive gas etching (RlE: Reactive Ion Etching) Any method can be used. Next, the p-type polycrystalline t substrate 13 is applied to a thermal oxidation furnace, and heated under a mist surrounding the n-type impurity (4) (P). By this step, phosphorus (germanium) is diffused on the surface of the p-type polycrystalline germanium substrate 1a, and the n-type impurity diffusion layer 3 is formed to form a semiconductor pn junction (Fig. 5-2). In the present embodiment, the 多-type polycrystalline slab substrate 1 a is heated in a gas mist of an oxygenated dish (p〇c 13) by, for example, 8 〇 (TC to 85 (TC temperature), whereby The n-type impurity diffusion layer 3 is formed. Here, the heat treatment is controlled such that the surface sheet resistance of the n-type impurity diffusion layer 3 is, for example, 30 to 80 Ω/□, preferably 40 to 60 Ω/□. 201104898 Here, The phosphorus-glass layer containing the n-type impurity-diffusing layer glass as a main component is formed by the formation of a transient surface, by using a hydrofluoric acid solution or the like, and then forming a polymorph of the n-type impurity diffusion layer 3 Shi Xi substrate I a party glossy side, for the light
尤電轉換效率改善，形成氮化矽膜（SiN 膜）來作為反射防止膜4 (第5 — 3圖）。在反射防止膜4 的形成，使用例如電漿Γν I GVD + ’且制我與氨的混合氣 形成氮化石夕膜來作為反射防止膜4。反射防止膜4的膜 尽及折射率係設定為最為抑制光反射的値。其中，以反射 防止膜4而言，亦可層積折射率不同之2層以上的膜。此 外，在反射防止膜4的形成，亦可使用㈣法等不同的成 膜方法。此外’亦可形成氧切膜來作為反射防止膜4。 其接著，藉由鱗（P)的擴散，來去除形成在P型多晶石夕 基板la之背面的η型雜暂麻私麻。^ 1雜買擴散層3。藉此獲得藉由屬於第 1導電型層的ρ型多日0基板2、及形成在半導體基板丄的 文光面側之属於第2導電型層的雜質擴散層（η型雜質擴 散層）3構成有Ρη接合的半導體基板1 (第5-4圖）。 形成在ρ型多晶石夕基板la之背面的η型雜質擴散層3 的去除係使用例如單面姓刻裝置來進行。或者，亦可使用 活用反射防止膜4作為遮罩材，使Ρ型多晶♦基板la的全 體浸潰在姓刻液的方法。蚀刻液係使用將氮氧化納、氮氧 化鉀等驗水溶液加熱至室溫〜阶、較佳為5代〜赃 者。此外’亦可使用硝酸與氫敗酸的混合水溶液來作為姓 刻液。 201104898 在η型雜質擴散層3之去除的姓刻後，為了以後述的 成膜將再^ σ速度保持為較低將露出於半導體基板1之 背面的石夕面洗淨。洗淨係使用例％ RCA洗淨、或1%〜m 左右的氫氟酸水溶液來進行。 接著，在半導體基板！的背面側，形成由氮化石夕膜（siN 膜）所構成的背面絕緣膜8 (第5_5圖）。對露出於半導 體基板1之背面側的石夕面’藉由電漿_形成由折射率！ 9 =2、厚度6Gnm〜_ni^氮切膜（⑽膜）所構成的 月面絕緣膜8。藉由使用電漿⑽，可在半導體基板i的背 面側，轉實地形成由氮化矽膜 从 /犋所構成的背面絕緣膜8。接 者’藉由形成如上所示之背面绍 月面、、，邑緣膜8，可抑制半導體基 板1之背面中的載體再社人祙痒 ,,^ 丹、，°口速度’在半導體基板1之背面 之石夕（Si)與氮化矽臈（SiN膜） 、 犋）的界面，可得10〇cm/秒 以下的再結合速度。藉> 貫見為向輸出化所需之充分 的背面界面。 若背面絕緣膜8的折射率不在 r c . λτ _ N · y A 2，則氮化矽膜 (SiN膜）的成膜環境難以安 而且氮化矽膜（SiN膜） 的膜質惡化’結果，與矽（s·、 、7 (Sl)之界面的再結合速度亦會 ‘二。此外’若背面絕緣膜8的厚度小於-，則賴sn 、：面不：定’載體的再結合速度會惡化。若背面絕緣膜 8的厚度大於30〇nm，雖然沒有 胺赵&^ ’刀月b上的不良情形，但是成 膜耗費時間，且成本會增加， 不理想。 右由生產性的觀點來看’較The electric conversion efficiency is improved, and a tantalum nitride film (SiN film) is formed as the anti-reflection film 4 (Fig. 5-3). In the formation of the anti-reflection film 4, a nitride film is formed as a reflection preventing film 4 by using, for example, a plasma Γν I GVD + ' and a mixture of ammonia and ammonia. The film of the anti-reflection film 4 and the refractive index system are set to be the most suppressed light reflection. In addition, in the reflection preventing film 4, a film of two or more layers having different refractive indices may be laminated. Further, in the formation of the anti-reflection film 4, a different film formation method such as the (four) method may be used. Further, an oxygen cut film may be formed as the anti-reflection film 4. Next, by the diffusion of the scale (P), the n-type smear formed on the back surface of the P-type polycrystalline litun substrate la is removed. ^ 1 miscellaneous buy diffusion layer 3. Thereby, the p-type multi-day substrate 2 belonging to the first conductivity type layer and the impurity diffusion layer (n-type impurity diffusion layer) belonging to the second conductivity type layer formed on the surface side of the semiconductor substrate 丄 are obtained. A semiconductor substrate 1 having a Ρn junction is formed (Fig. 5-4). The removal of the n-type impurity diffusion layer 3 formed on the back surface of the p-type polycrystalline silicon substrate la is performed using, for example, a one-sided surrogate device. Alternatively, a method in which the reflection preventing film 4 is used as a masking material and the entire body of the 多-type polycrystalline ♦ substrate la is immersed in a surname can be used. The etching liquid is heated to room temperature to room temperature, preferably 5 generations to 5%, using an aqueous solution of sodium oxynitride or potassium oxynitride. Further, a mixed aqueous solution of nitric acid and hydrogen hydroxy acid can also be used as the surname. 201104898 After the last name of the removal of the n-type impurity diffusion layer 3, the sigma surface exposed on the back surface of the semiconductor substrate 1 is washed for the film formation to be described later. The washing is carried out using an aqueous solution of % RCA or an aqueous solution of hydrofluoric acid of about 1% to about m. Next, on the semiconductor substrate! On the back side, a back surface insulating film 8 made of a nitride film (siN film) is formed (Fig. 5-5). The surface of the stone surface exposed on the back side of the semiconductor substrate 1 is formed by the plasma _ by the refractive index! 9 = 2, a thickness of 6Gnm~_ni^ a nitrogen film ((10) film) is formed by a moon insulating film 8. By using the plasma (10), the back surface insulating film 8 made of a tantalum nitride film can be formed on the back side of the semiconductor substrate i. By forming the back surface of the semiconductor film as shown above, the edge film 8 can suppress the itching of the carrier in the back surface of the semiconductor substrate 1, and the speed of the mouth is 'in the semiconductor substrate. The interface between Shi Xi (Si) and tantalum nitride (SiN film) and ruthenium on the back surface of 1 can obtain a recombination speed of 10 〇cm/sec or less. Borrow > See Through is the full back interface required for export. When the refractive index of the back surface insulating film 8 is not rc. λτ _ N · y A 2 , the film formation environment of the tantalum nitride film (SiN film) is difficult to be cured and the film quality of the tantalum nitride film (SiN film) is deteriorated. The recombination speed of the interface of 矽(s·, 7(S1) will also be 'two. In addition, if the thickness of the back surface insulating film 8 is less than -, then the re-synthesis speed of the carrier will deteriorate. If the thickness of the back surface insulating film 8 is larger than 30 〇 nm, although there is no problem in the amine Zhao & ^ 'knife month b, the film formation takes time and the cost increases, which is not desirable. Right from the viewpoint of productivity Look at 'cf
此外，背面絕緣膜8亦可形忐盔办,1 H T形成為例如層積有藉由熱氧 201104898 化所形成的氧化矽膜（熱 (SiN膜）的2層層 ：1 2、與氮化石夕膜 層積構le。在此的氧化矽膜（Si〇2膜） ^為t製程中形成在半導體基板1之背面側的自然氧化 、而疋例如藉由熱氧化而意圖性形成的氧化 膜）。藉由使用如上所示之氧化石夕膜（S102膜），比氮化 夕膜“以膜）更為安定’可得半導體基们之背面中之 載體再結合速度的抑制效果。 卜藉由熱氧化意圖性形成的氧化石夕膜Further, the back surface insulating film 8 may be formed into a helmet, and the 1 HT is formed, for example, by laminating a yttrium oxide film formed by thermal oxygen 201104898 (a layer of heat (SiN film): 2, and nitride. The yttrium oxide layer (Si 〇 2 film) is an oxide film formed on the back side of the semiconductor substrate 1 in the t process, and is formed by, for example, thermal oxidation. ). By using the oxidized stone film (S102 film) as shown above, the effect of suppressing the recombination speed of the carrier in the back surface of the semiconductor substrate can be obtained by making the film more stable than the film of the film. Oxidizing oxide formed by oxidative intention
的厚度係以形成A 1nnIT1 ^ J ^ A烕為1〇nm〜50隨左右為佳。若藉由熱氧化所 /、的氧化砂膜（Si〇2膜）㉔厚度小於10nm，與矽（Si) :面不t疋’冑冑的再結合速度會惡化。料由熱氧化 斤,成的氧化矽膜（Si〇2膜）的厚度大於50nm，雖然沒有 j忐上的不良情形’但是成膜耗費時間，且成本會增加， 右由生產性的觀點來看，較不理想。此外，為縮短時間， 而以高溫進行成膜處理時，結晶石夕本身的品質會降低，而 造成使用期限降低。 ^為取得與半導體基板1的背面側的接觸，在背 二邑緣膜8的-部分或全面，形成具有預定間隔的點狀開 口部8a (第5_6圖）。開口部8“系例如藉由對背面絕緣 ' 8的雷射照射來直接進行圖案化所形成。 4為了形成與半導體基板1之背面側良好的接觸，以加 士 :者面絕緣膜8之面内方向中的開口部8a的剖面積，且加 :背面絕緣膜8之面内中的開口部8a的開口密度為佳。但 疋為了在半導體基板1的背面側獲得較高的光反射率（背 16 201104898 ;反射率），相反地以開口部8a的剖面積較小、開口部 8a的開口密度較低為佳。因此，開口部 係以限於供實現良好接觸 、㊉狀及密度 接觸之所需最小限度程度為佳。 具體而言’以開口部8 幅為一 20。…大……舉有直徑或寬 〇 , ' 、，鄰接開口部8a間的間隔為 0.5襲〜2_之大致圓形點狀或大致矩形形狀。此外，以盆 他開口部8a的形狀而言，列舉有寬 八 鄰接開口部8a間的間隔為〇 5 “ m 2〇0 “ m、 本實施形態中，藉由對的條紋狀形狀。在 狀的開口部8a “絕緣膜8的雷射照射來形成點 :著，將為背面側電極9的電極材料且含有叙、玻璃 ⑽面側電極材料膏9a填埋開口部8a，並且在背面絕 緣膜8之面内方向覆蓋比開口部8a的直徑稍微寬的區域， 而且以不與填埋鄰接開口部^的背面側電極材料f 9a相 接觸的方式’藉由網版印刷法而限定性進行塗佈，且使其 乾燥（第5-7圖）。f面側電極材料f &的塗佈形狀、塗 佈量等係可藉由在後述之燒成步驟中，A卜Si合金部_ BSF12中之鋁的擴散濃度等各條件來作變更。 、 …必須在開口部8a中確保充分的膏量，在燒成步驟中確 實形成A卜Si合金部n與BSF| 12。另一方面，在半導 體基板1的背面上層積有背面絕緣膜8(氮化石夕膜）與背 面側電極9的區域中因f面側電極9所造成的光反射率（背 面反射率）並無法謂為足夠。因此，背面絕緣膜$上的背 面側電極9的形成區域變寬時，對於光起電力裝置内的光 17 201104898 :封::果會降低。因此’印刷背面側電極材料膏9&的區域 係必須在取得A1-Sl合金部的形成條件 光起電力裝置内的光密封效果的均衡之後，縮小至; 斤需最 小限度。 所需最 料膏Ϊ本由實：形態中，以使含有紹（A1)的背面側電極材 =由開…之端分別以，m的寬幅重疊在背面 絕緣膜8上的形式以屋_ 9 Π j, 式厚度20㈣來進行印刷。此時，择由 使其重疊在背面絕緣膜8上， 9 ^ ^ 會有防止所形成背面電極9 "絕緣膜8的開口部8a剝離的效果。第6]圖及第 6 2圖係顯不背面絕緣膜8上 t 月面側電極材料膏9a之印 =之例的俯視圖。第6]圖係顯示將開 :致圓形點狀之例’第6-2圖係顯示將開口 = 致矩形形狀之例。 〜风马大 重曼量係由開口部8a之端以剖面積 佳為4°°的範圍内進行控制 為且。在本實施形態中， 膏h的膏厚為心 的背面側電極材料 ，相a 因此若以重疊程度的表現方式來 二相备於由開口部8a之端分別為…… 為20/zm至50/zni的詖^ 于乂往 的觀圍。若重疊程度未達 :能發揮防止背面絕緣…離的效果，在燒成時，= 。金t成時’亦無法順利供給紹⑺） 生，、： 形成BSF構造的部分 會發生未良好 則膏印刷部分所佔面積1;會::若重疊程度…^ 率會減少，而大幅脫離本旨亦即高反射膜的面積 18 201104898 如第6-1圖所示當開口部8a為大致圓形的點狀時，在 背面絕緣膜8上之開口部8a的外周部，以包含有寬幅為 20"m的環狀重疊區域9b之大致圓形狀，藉由網版印刷 法，將背面側電極材料膏9a限定性地塗佈在背面絕緣膜8 上。當例如開口部8a的直徑d為200 時，背面側電極 材料膏9a係被印刷成具有「20〇#m+2〇#m+2()"m = 240 μ m」的直徑的大致圓形狀。 此外，如第6-2圖所示當開口部8a為大致矩形形狀 時’在背面絕緣膜8上之開口部8 a的外周部，設置寬幅為 20 // m的框狀重疊區域9b，將背面側電極材料膏9a藉由網 版印刷法限定性地塗佈在背面絕緣膜8上。例如若開口部 8a的寬幅w為100 A m時，背面側電極材料膏9a係被印刷 成具有「100em+20/zin+20#m=14CUm」之寬幅的大致 矩形形狀。 接著’在半導體基板1的反射防止膜4上，將屬於受 光面側電極5的電極材料且含有銀（Ag)、玻璃等的受光 面電極材料膏5a，選擇性地藉由網版印刷法塗佈成受光面 側電極5的形狀’並予以乾燥（第5_7圖）。受光面電極 材料膏53係例如印刷：8〇Am〜15〇//m寬幅、2_〜3關間 隔之長邊狀的柵電極6的圖案、及以與該圖案呈大致正交 的方向，lmm〜3mm寬幅、5inm〜10mm間隔之帶狀的匯流排 電極7的圖案。但是，關於受光面側電極5的形狀，由於 與本發明並沒有直接的關係，故可一面在電極電阻與印刷 遮光率之間取得均衡，一面自由設定。 19 201104898 之後’例如使用紅外爐加熱器，以峰值溫度7 6 〇。〇 900 C來進行燒成。藉此，形成受光面側電極5及背面侧電 極9，並且在半導體基板1之背面側的區域且為與背面側 電極9相接的區域及其附近形成有A1_Si合金部再者， 在其外周部，係包圍該A1-Si合金部11，形成有由背面側The thickness is preferably about 1 〇 nm to 50 with the formation of A 1nnIT1 ^ J ^ A 随. When the thickness of the oxidized sand film (Si 〇 2 film) 24 by thermal oxidation is less than 10 nm, the recombination speed with 矽(Si) : surface is not deteriorated. The thickness of the yttrium oxide film (Si〇2 film) is more than 50 nm, although there is no problem on the film, but film formation takes time and the cost increases, right from the viewpoint of productivity. Less than ideal. Further, in order to shorten the time and perform film formation treatment at a high temperature, the quality of the crystallized stone itself is lowered, and the lifespan is lowered. In order to obtain contact with the back side of the semiconductor substrate 1, a dot-like opening portion 8a having a predetermined interval is formed in a portion or all of the back edge film 8 (Fig. 5-6). The opening portion 8 is formed by directly performing patterning by laser irradiation of the back surface insulating '8. 4) In order to form a good contact with the back side of the semiconductor substrate 1, the surface of the insulating film 8 is applied. The cross-sectional area of the opening 8a in the inner direction is preferably the opening density of the opening 8a in the surface of the back surface insulating film 8. However, in order to obtain a high light reflectance on the back side of the semiconductor substrate 1 ( Back 16 201104898; reflectance), conversely, the cross-sectional area of the opening 8a is small, and the opening density of the opening 8a is preferably low. Therefore, the opening is limited to a place for achieving good contact, ten-shape and density contact. Specifically, it is preferable that the width of the opening portion is 20 and the width of the opening portion 8a is 0.5 or more. In the shape of the opening portion 8a of the pot, the interval between the wide eight adjacent openings 8a is 〇5" m 2〇0" m, in the present embodiment, The stripe shape of the pair. The opening portion 8a in the shape of the The laser beam of the film 8 is formed to form a dot: the electrode material of the back side electrode 9 and the glass (10) surface side electrode material paste 9a are filled in the opening portion 8a, and are covered in the in-plane direction of the back surface insulating film 8. A region which is slightly wider than the diameter of the opening portion 8a and which is not limited to be in contact with the back surface side electrode material f 9a of the adjacent opening portion, is coated by a screen printing method and dried. (Figures 5-7). The coating shape, the coating amount, and the like of the f-side electrode material f & can be changed by various conditions such as the diffusion concentration of aluminum in the A-Si alloy portion_BSF12 in the firing step to be described later. It is necessary to ensure a sufficient amount of paste in the opening portion 8a, and to form the A-Si alloy portion n and the BSF|12 in the firing step. On the other hand, in the region where the back surface insulating film 8 (nitriding film) and the back surface side electrode 9 are laminated on the back surface of the semiconductor substrate 1, the light reflectance (back surface reflectance) due to the f-plane side electrode 9 cannot be obtained. It is enough. Therefore, when the formation region of the back side electrode 9 on the back surface insulating film $ is widened, the light in the light-emitting device is lowered. Therefore, the area of the printed back side electrode material paste 9 & must be reduced to the minimum of the light sealing effect in the formation condition of the A1-Sl alloy portion. The most suitable paste is required to be in the form: in the form of the back side electrode material containing the layer (A1) = the end of the opening ..., the width of m is superimposed on the back surface insulating film 8 9 Π j, thickness 20 (four) for printing. At this time, it is preferable to superimpose it on the back surface insulating film 8, and the effect of preventing the formation of the back surface electrode 9 " the opening portion 8a of the insulating film 8 is peeled off. Fig. 6 and Fig. 6 are views showing a top view of the t-plane side electrode material paste 9a on the back surface insulating film 8. Fig. 6] shows an example in which the opening is turned into a circular dot shape. Fig. 6-2 shows an example in which the opening = the rectangular shape is formed. ~ The wind and the horse are controlled by the end of the opening 8a with a sectional area of preferably 4°. In the present embodiment, the thickness of the paste h is the back side electrode material of the core, and the phase a is formed so as to be two-phase at the end of the opening 8a as 20/zm to 50, respectively. /zni's 詖^ 乂 的 。 。. If the degree of overlap is not reached: It can prevent the effect of preventing the back insulation from being separated. When firing, =. When gold is formed, it cannot be supplied smoothly (7)), and: the portion where the BSF structure is formed may have an area of 1 where the paste printing portion is not good; if: the degree of overlap is reduced, and the rate is greatly reduced. In other words, when the opening portion 8a has a substantially circular dot shape as shown in Fig. 6-1, the outer peripheral portion of the opening portion 8a of the back surface insulating film 8 includes a width. The substantially circular shape of the annular overlapping region 9b of 20 "m is applied to the back surface insulating film 8 in a limited manner by a screen printing method. When, for example, the diameter d of the opening portion 8a is 200, the back side electrode material paste 9a is printed as a substantially circular circle having a diameter of "20〇#m+2〇#m+2()"m = 240 μm". shape. Further, when the opening portion 8a has a substantially rectangular shape as shown in Fig. 6-2, 'the outer peripheral portion of the opening portion 8a on the back surface insulating film 8 is provided with a frame-shaped overlapping region 9b having a width of 20 // m, The back side electrode material paste 9a is applied to the back surface insulating film 8 by a screen printing method. For example, when the width w of the opening 8a is 100 mA, the back side electrode material paste 9a is printed in a substantially rectangular shape having a width of "100em+20/zin+20#m=14CUm". Then, the light-receiving surface electrode material paste 5a containing silver (Ag), glass, or the like, which is an electrode material of the light-receiving surface side electrode 5, is selectively applied by screen printing on the anti-reflection film 4 of the semiconductor substrate 1. The shape of the light-receiving surface side electrode 5 is laid out and dried (Fig. 5-7). The light-receiving surface electrode material paste 53 is, for example, printed in a pattern of a gate electrode 6 having a width of 8 〇Am to 15 〇//m and a length of 2 to 3 Å, and a direction substantially orthogonal to the pattern. A pattern of strip-shaped bus bar electrodes 7 having a width of 1 mm to 3 mm and a spacing of 5 inm to 10 mm. However, since the shape of the light-receiving surface side electrode 5 is not directly related to the present invention, it can be freely set while achieving an equalization between the electrode resistance and the printing shading rate. 19 201104898 After the 'infrared furnace heater, for example, at a peak temperature of 7 6 〇. 〇 900 C to burn. Thereby, the light-receiving surface side electrode 5 and the back surface side electrode 9 are formed, and in the region on the back side of the semiconductor substrate 1 and in the region in contact with the back surface side electrode 9 and the vicinity thereof, the A1_Si alloy portion is formed, and the outer periphery thereof is formed. a portion surrounding the A1-Si alloy portion 11 and formed by the back side
電極9以尚濃度擴散有鋁之屬於p+區域的BSF1 2，使該BSF 層12與背面側電極9作電性連接（第5_8圖）。其中，在 該連接部位雖然界面的再結合速度惡化，但是BSF層12可 將該影響無效化。此外，受光面側電極5中的銀會貫穿反 射防止膜4 ’使n型雜質擴散層3與受光面側電極5作電 性連接。 此時，在半導體基板i的背面未塗佈有背面側電極材 料膏9㈣區域係被由氮化㈣膜）㈣成的背面絕 緣膜8所保護，因此即使在藉由燒成所為之加熱，亦對半 導體基板1的背面不會有污染物質附著或固定的發展，不 會使再結合速度劣化，而維持良好的狀態。 接著’如第7圖所示，將半導體基板i排列在晶舟^ 上，按每個晶舟35放人處理槽3卜帛7圖侧以說明實 施形態1之太陽電池單元之劁止 干凡步驟中之強化鈍化步驟的 模式圖。在將處理槽31的肉却ϋ丄# 日w的内部藉由蓋部34而與外部相隔 離的狀態下藉由排氣系部36作直* D作具空抽吸，之後，藉由供給 系部33將含氫的零圍翁齑辦道χ 士 囷轧轧體導入處理槽31的内部。接著， 藉由加熱器32而將處理样Ή…The electrode 9 is made to have BSF1 2 which is a p+ region of aluminum diffused at a constant concentration, and the BSF layer 12 and the back side electrode 9 are electrically connected (Fig. 5-8). However, although the recombination speed of the interface deteriorates at the joint portion, the BSF layer 12 can invalidate the influence. Further, the silver in the light-receiving surface side electrode 5 penetrates the reflection preventing film 4' to electrically connect the n-type impurity diffusion layer 3 and the light-receiving surface side electrode 5. At this time, the back surface side electrode material paste 9 (four) region is not coated on the back surface of the semiconductor substrate i, and is protected by the back surface insulating film 8 made of the nitride (tetra) film (4). Therefore, even if it is heated by firing, There is no development of adhesion or fixation of contaminants to the back surface of the semiconductor substrate 1, and the recombination speed is not deteriorated, and a good state is maintained. Then, as shown in FIG. 7, the semiconductor substrate i is arranged on the wafer boat, and the wafer boat 35 is placed on the side of the processing tank 3 to illustrate the solar cell unit of the first embodiment. A pattern diagram of the intensive passivation step in the step. In the state in which the inside of the meat of the processing tank 31 is separated from the outside by the lid portion 34, the exhaust system portion 36 is used for straight suction, and then supplied by the air. The line portion 33 introduces a hydrogen-containing zero-cone-shaped crucible into the processing tank 31. Then, the processing is performed by the heater 32...
处槽31的内部加熱至200°C〜400〇C 的溫度範圍且保持3分鐘〜6()八絲 a 刀頌b0分鐘，進行藉由氫所為之退 20 201104898 火（FGA : Forming Gas Anneal)。退火處理後係與投入時 相反地藉由排氣系部36而將雾圍氣氣體進行排氣，暫時進 行真空抽吸後，藉由供給系部33而將外氣導入處理槽W 的内部而進行真空解除。接著，打開蓋部34,按每個晶舟 35取出半導體基板其中’該強化鈍化步驟若可在含氮 的雾圍氣中，在20(TC〜40(rc之溫度範圍進行3分鐘〜= 分鐘的退火處理，除了上述以外，裝置亦並未特別有所特 定。 接著，在半導體基板1的背面側形成高反射構造。亦 即，以覆蓋背面側電極9及背面絕緣膜8的方式，藉由濺 鍍法在半導體基板1的背面全面形成銀（Ag) _ (銀濺鍍 膜）作為背面反射膜10 (第5_9圖）。可藉由濺鍍法來形 成背面反射膜10,藉此形成緻密的背面反射膜1〇，相較於 藉由印刷法所形成的銀（Ag)膜，可形成實現較高光反射 的背面反射膜10。其中，背面反射膜10亦可藉由蒸鍍法 來形成。此外，在此係在半導體基板i的背面全面形成背 面反射膜10,但是若背面反射膜1〇係以至少覆蓋半導體 基板1之背面側的背面絕緣膜8的方式所形成即可。 藉由以上製作第1 — 1圖〜第1-3圖所示之實施形態1 之太陽電池單元。纟中，亦可將屬於電極材料之膏的塗佈 順序，在受光面側與背面側作替換。 在結晶系矽太陽電池、尤其多晶矽太陽電池的製造 中，風鈍化在實用上係非常重要的處理。所謂氫純化係指 藉由任何步驟或處理，使氫與結晶内的懸鍵 21 201104898 (dangling-bond)(不具鍵έ士斟免々“丄你 比〇 · 、埏，、、°對象之狀態的原子鍵結鍵t 使作為半導體結晶的特性降 賴降低）鍵結，使作為半導體結晶 的矽的特性提升的處理。 關於該氫鈍化，在習4〇 •姑你+ 在1知技術中，亦藉由電漿CVD來形 成S相（正確而言為非晶…：㈣），利用該成膜時的 加…、、及之後之電極燒成時的加熱，冑Μ膜内的氫浸透 至結晶内部而與懸鍵鍵結，關於結晶内部，業已獲得 的效果。 但是，燒成所用的加熱由於主要目標在於屬於該步驟 '、目的之電極膏燒成、及使氫遍及結晶内部因此關於 界面’若過於高溫’會發生—部分脫離’而使效果減退。 ^若為本實施形態的構造，為了將太陽電池特性保持為 較南，必須良好地保持背面側的結晶特性、界面狀態（再 結合速度）’該些微的減退的影響並不少。該步驟係用以 補完該影響者’藉由在上述環境下進行退火處理，使在界 面附近的氫鈍化安定化，而改善在界面附近、尤其背面側 的界面（半導體基板1的另一面側與形成在該另一面側上 的背面絕緣膜8的界面）附近的狀態。 第8圖係用以說明太陽電池單元之開放電壓（v〇c)中 的強化鈍化（藉由氫所為之FGA)效果的特性圖。在第8 圖中係一併顯示藉由上述實施形態1之太陽電池單元之製 造方法所製作的太陽電池單元、與在實施形態1之太陽電 池單7L之製造方法中未實施強化鈍化步驟而製作的太陽電 池單元的開放電壓（V〇c)。第9圖係用以說明太陽電池單 22 201104898 %之短路雷、、， 吩电机C Jsc )中的強化鈍化效果的特性圖。在第9 '、併顯示藉由上述實施形態1之太陽電池單元之製 k方法所製作的太陽電池單元、及在實施形態i之太陽電 早兀之製ΐς方法中未實施強化鈍化步驟所製作的太陽電 池單元的短路電流（JSC)。 ，由第8圖可知，明確呈現藉由實施強化鈍化（藉由氫 所為之FGA)所達成之開放電壓（v〇c)的改善效果。此外， 由第9圖可知，明確呈現藉由實施強化鈍化（藉由氫所為 之FGA)所達成之短路電流（Jsc )的改善效果。尤其，開 放電壓（V0C)顯著提升，此意指不僅結晶品質，連界面狀 L亦包含在内而受到良好改善。 如上所述，在實施形態1之太陽電池單元之製造方法 中將具有開口部8a的背面絕緣膜8形成在半導體基板J 的背面之後，塗佈背面側電極材料膏9a來進行燒成，因此 未塗佈有背面側電極材料膏9a的區域係藉由背面絕緣膜8 予^保5蒦。藉此，在藉由燒成所致之加熱中，對半導體美 ,'勺月面不會附著或固定污染物質，不會使再結合速度 劣化’而維持良好的狀態，而使光電轉換效率提升。 此外’在實施形態1之太陽電池單元之製造方法中， 以至少覆蓋背面絕緣膜8的方式將背面反射膜1〇形成在半 導體基板1的背面。藉此，可將透過半導體基板1及背面 、'邑緣膜8的光在背面反射膜10作反射而返回至半導體基板 可得良好的光密封效果，因此達成輸出特性的提升，可 貫現較高的光電轉換效率。 23 201104898 此外，在實施形態1之太陽電池單元之製造方法中 係藉由激鍍法來形成背面反射膜10。並非為使用電極膏的 印刷法，而是藉由濺鍍膜來形成背面反射膜1〇，藉此可形 成緻密的背面反射膜10，相較於藉由印刷法所形成的膜: 可形成貫現較尚之光反射的背面反射膜10,可得優異的光 密封效果。 此外，在實施形態1之太陽電池單元之製造方法中， 由於在形成受光面側電極5及背面側電極9之後實施強化 鈍化步驟，因此可良好改善半導體基板丨之矽結晶的結晶 品質及界面狀態’可使太陽電池特性提升。 因此，藉由實施形態1之太陽電池單元之製造方法， 可獲得具有較低再結合速度與較高背面反射率之雙方的背 面構造，可製作出長波長感度優異、達成光電轉換效率之 高效率化的太陽電池單元。此外，可達成太陽電池單元之 光電轉換效率的高效率化，因此使半導體基板丨的薄板化 成為可能，可達成製造成本降低，可廉價製作電池單元特 性優異之高品質的太陽電池單元。 (實施形態2) 在實施形態2中，係以背面反射膜丨〇之其他形態而 。，針對藉由金屬箔來構成背面反射膜丨〇的情形加以說 明。第10圖係用以說明本實施形態之太陽電池單元之剖面 構造的主要部位剖面圖，為與第丨_丨圖相對應的圖。實施 形態2之太陽電池單元與實施形態丨之太陽電池單元不同 24 201104898 之處在於：背面反射膜並非為銀濺鍍膜，而係藉由鋁箔 (aluminuin foil)所構成。除此之外的構成與實施形態\ 之太陽電池單元相同，因此省略詳細說明。 如第10圖所示，在本實施形態之太陽電池單元中，由 Μ所構成的背面反射冑22 ’藉由在半導體基& i的背面 被配置在背面側電極9上的導電性接著劑21來覆蓋背面側 電極9及背面絕緣膜8而接設，並且透過該導電性接著劑 21而與背面側電極9作電性連接。在如上所示之構成中， 亦與實施形態1之情形同樣地，可將透過半導體基板丨及 者面絕緣膜8的光作反射而返回至半導體基板丨，可以廉 價的構成來獲得良好的光密封效果。 接著，在本實施形態中’背面反射膜22係藉由屬於金 屬箔的鋁箔所構成。背面反射膜22並非為藉由使用電極膏 的印刷法所形成的膜，而是藉由金屬箔所構成，因此相較 於藉由印刷法所形成的金屬膜，可實現較高的光反射，且 可將透過半導體基板丨及背面絕緣膜8的光更加大量反射 而返回至半導體基板丨。因此，本實施形態之太陽電池單 几係由於包括藉由屬於金屬箔之鋁箔所構成的背面反射膜 2 2 ’與貫施形態1相同地可得優異的光密封效果。 以背面反射膜22的材料而言，可使用可加工成箔片的 金屬材料，與背面反射膜1〇的情形相同，較佳為使用例如 相對波長為ll〇〇nm附近的光的反射率為9〇%以上、更佳為 95%以上的金屬材料。藉此可實現具有較高的長波長感度、 相對長波長區域之光的光密封效果優異的太陽電池單元。 25 201104898 亦即，雖然亦依半導體基板i的厚度而異，但是 為900nm以上、尤其為1〇〇〇 丨 ， α 之長波長的光 地取入半導體^】，可實現較高的發生電流 (J-) ’而可使輸出特性提升。以如上所示之材料而言， 除了紹（A1)以外，另外可使用例如銀（Ag)。 如上所示所構成之本實施形態之太陽電池單元係在實 施形態！中使用第5]圖〜帛5_8圖及帛1G圖加以說明之 步驟之後，可在背面側電極9上塗佈導電性接著劑Η，藉 由該導電性接著劑21，覆蓋背面側電極9及背面絕緣膜8 來接設背面反射膜22,藉此予以製作。其中，此㈣面反 射膜22亦可以至少覆蓋半㈣基板丨之背面側中的背面絕 緣膜8的方式來形成。 以上所示所構成之在實施形態2之太陽電池單元中， 由於在半導體基板i的背面包括藉由電衆aD法所形成的 氮化矽膜（SiN膜）作為背面絕緣膜8，因此可在半導體基 板1的背面獲得良好之載體的再結合速度的抑制效果。藉 此’在本實施形態之太陽電池單元中，達成輸出特性的提 升’且實現較高的光電轉換效率。 此外，在實施形態2之太陽電池單元中，由於包括覆 蓋背面絕緣膜8而由屬於金屬箔的鋁箔所構成的背面反射 膜22，因此相較於藉由習知的印刷法所形成的金屬膜可 實現較高的光反射，且可使透過半導體基板丨及背面絕緣 膜8的光更加大量反射而返回至半導體基板丨。因此，在 本實施形態之太陽電池單元中，可得優異的光密封效果， 26 201104898 達成輸出特性的提升，且實現較高的光電轉換效率。 因此，在實施形態2之太陽電池單元中，由於具有具 較低再結合速度與較高背面反射率之雙方的背面構造，因 此實現長波長感度優異、達成光電轉換效率之高效率化的 太陽電池單元。 此外’在實施形態2之太陽電池單元之製造方法中， 在將具有開口部8a的背面絕緣膜8形成在半導體基板】的 背面之後’再塗佈背面側電極材料膏9a來進行燒成，因此 未塗佈有背面側電極材料膏9a的區域係受到背面絕緣膜8 所保護#此，在藉由燒成所為之力。熱中 1的背面不會附著或固定污染物質，…使 4化的情形’而維持良好的狀態’使光電轉換效率提升。 此外，在實施形態2之太陽電池單元之製造方法中， Μ少覆蓋背面絕緣膜8的方式將背面反射膜22形成在半 導體基板1的背面。藉此，可將透過半導體基板i及背面 絕緣膜8的光在背面反射膜22作反射而返回至半導體基板 1，可得良好的光密封效果，因此達成輸出特性的提升，可 實現較高的光電轉換效率。 此外，在實施形態2之太陽電池單元之製造方法中， 藉由在背面側電極9上裝設屬於金屬荡的鋁箱來形成背面 反射膜22。並非為使用電極膏的印刷法，而係藉由使用屬 於金屬箔的鋁箔而形成背面反射膜22來作蛊昝 个IF句穹面反射膜 22,藉此可形成緻密的背面反射膜22，可形成實現比藉由 印刷法所形成的膜還高的光反射的背面反射臈22，可^優 27 201104898 異的光密封效果。 因此，藉由實施形態2之太陽電池單元之製造方法， 可知具有較低再結合速度與較高背面反射率之雙方的背面 構造，可製作長波長感度優異、達成光電轉換效率之高效 率化的太陽電池單元。此外，由於可^太陽電池單元之 光電轉換效率的高效率化，因此使半導體基板1的薄板化 成為可能，可達成製造成本降低，可廉價製作電池單元特 性優異的南品質太陽電池單元。 此外，在實施形態2之太陽電池單元之製造方法中， 由於在形成受光面側電極5及背面側電極9之後實施強化 鈍化步驟，因此可良好改善半導體純i之⑪結晶的結晶 品質及界面狀態、可使太陽電池特性提升。 其中，在上述實施形態中，係針對使用p型的矽基板 作為半導體基板的情形加以說明，但是亦可使用n型的_ 基板而形成為形成p型擴散層的逆導電型太陽電池單元。 此外，雖然使用多晶矽基板作為半導體基板，但是亦可使 用單晶碎基板。此外’在上述中係將半導體基板的基板厚 設為200 # m，但是亦可使用可自我保持之程度的基板厚、 例如至50 左右為止經薄型化的半導體基板。此外，在 上述中，係將半導體基板的尺寸設為15〇mmxl5〇關，但是 半導體基板的尺寸並非限定於此。 (產業上利用可能性） 如以上所示，本發明之光起電力裝置係有用於藉由較 28 201104898 低再結合速度與較高背面反射率，來實現高效率之光起電 力裝置的情形。 【圖式簡單說明】 …第Η圖係用以說明本發明之實施形態工之太陽電池 單疋之剖面構造的主要部位剖面圖。 第卜2圖係由受光面側觀看本發明之實施形態】 %電池單元的上視圖。 雷油1 3圖係由背面側觀看本發明之實施形態1之太陽 电池早元的底視圖。 2圖係顯不具有不同背面構造的3種試料中在半 體基板背面的反射率的特性圖。 的試料中US讀擬實施形態1之太陽電池單元所製作 特性圖。 電極的面積率與開放電壓(V。。之關係的 的試料心面二:==態1之太陽電池單元所製作 特性圖。 f極的面料與短路電流（W之關係的 1圖係用以說明本發明之實施形態1之太陽 ^之製造步驟的剖面圖。 陽電池 第5_2圖係田 單元之製造步驟：Γ明本發明之實施形態1之太陽電池 7鄉的剖面圖。 第5-3圖係田 單元之製造說明本發明之實施形·態1之太陽電池 W步驟的剖面圖。 也 29 201104898 第5-4圏係 '用以說明本發 單元之製造步不發 鄉的剖面圖。 第5一5圖係用以說明本發 早兀之製造步驟的剖面圖。第5-6圖仓；E 、 ’、用以說明本發 單元之製造步驟的剖面圖。 第5_?圖係用以說明本發 單元之製造步驟的剖面圆。 明之實施形態 明之實施形態 明之實施形態 明之實施形態 1之太陽電池 1之太陽電池 1之太陽電池 1之太陽電池 第5-8圖你田、， ’、 以說明本發明之實施形態1之太陽電池 單元之製造步驟的剖面圖。 w $ 5 9圖係用以說明本發明之實施形態1之太陽電池 單元之製造步驟的剖面圖。 第6 1圖係顯示本發明之實施形態J之太陽電池單元 之背面絕緣膜上夕推工i , 、 是面側電極材料膏之印刷區域之例的俯 視圖。 第6-2圖係顯示本發明之實施形態i之太陽電池單元 之背面絕緣膜上之背面側電極材料f之印刷區域之例的俯 視圖。 第7圖係用以說明本發明之實施形態1之太陽電池單 疋之製造步驟中的強化鈍化步驟的模式圖。 第8圖係顯示因強化鈍化步驟之實施的有無所造成之 本發明之實施形態1之太陽電池單元的開放電壓特性之不 同的特性圖。 第9圖係顯示因強化鈍化步驟之實施的有無所造成之 30 201104898 本發明之實施形態1之太陽電池單元的短路電流特性之不 同的特性圖。 第1 0圖係用以說明本發明之實施形態2之太陽電池單 元之剖面構造的主要部位剖面圖。 【主要元件符號說明】 1 半導體基板 la p型多晶矽基板 2 p型多晶碎基板 3 η型雜質擴散層 4 反射防止膜 5 受光面側電極 5a 受光面電極材料膏 6 栅電極 7 匯流排電極 8 背面絕緣膜 8a 開口部 9 背面側電極 9a 背面側電極材料膏 9b 重疊區域 10 背面反射膜 11 鋁-矽（Α卜Si )合金部 12 BSF層 21 導電性接著劑 31 201104898 22 背面反射膜 31 處理槽 32 加熱器 33 供給系部 34 蓋部 3 5 晶舟 36 排氣系部 32The inside of the tank 31 is heated to a temperature range of 200 ° C to 400 ° C and held for 3 minutes to 6 () eight wire a knife b0 minutes, and is returned by hydrogen 20 201104898 fire (FGA : Forming Gas Anneal) . After the annealing treatment, the mist-containing gas is exhausted by the exhaust system 36 in the opposite manner to the time of the injection, and after the vacuum suction is temporarily performed, the external air is introduced into the processing tank W by the supply system 33. Vacuum is released. Next, the lid portion 34 is opened, and the semiconductor substrate is taken out for each wafer boat 35. The step of strengthening the passivation can be performed in a nitrogen-containing mist enclosure at 20 (TC to 40 (the temperature range of rc is 3 minutes to == minutes). The annealing treatment is not particularly limited as described above. Next, a high reflection structure is formed on the back side of the semiconductor substrate 1. That is, the back side electrode 9 and the back surface insulating film 8 are covered by the back surface side electrode 9 and the back surface insulating film 8 In the sputtering method, silver (Ag) _ (silver sputtering film) is formed on the back surface of the semiconductor substrate 1 as the back surface reflection film 10 (Fig. 5-9). The back surface reflection film 10 can be formed by sputtering to form a dense film. The back surface reflective film 10 can form a back surface reflection film 10 which achieves high light reflection compared to a silver (Ag) film formed by a printing method. The back surface reflection film 10 can also be formed by a vapor deposition method. Further, although the back surface reflective film 10 is entirely formed on the back surface of the semiconductor substrate i, the back surface reflection film 1 may be formed so as to cover at least the back surface insulating film 8 on the back surface side of the semiconductor substrate 1. Making the first 1 - 1 In the solar battery cell of the first embodiment shown in Figs. 1-3, the coating procedure of the paste belonging to the electrode material may be replaced on the light receiving surface side and the back surface side. In the manufacture of polycrystalline germanium solar cells, wind passivation is a very important treatment in practice. Hydrogen purification refers to the dangling-bond of hydrogen and crystals by any step or treatment (no dangling-bond)斟 々 々 々 丄 丄 丄 丄 丄 丄 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子 原子The hydrogen passivation is also formed by the plasma CVD to form the S phase (correctly amorphous...: (4)) in the first known technique, and the use of the film formation is... And heating after the electrode is fired, hydrogen in the ruthenium film penetrates into the inside of the crystal and is bonded to the dangling bond, and the effect obtained in the inside of the crystallization is obtained. However, the heating used for the firing is mainly aimed at belonging to this step. ', purpose of electricity When the paste is fired and the hydrogen is allowed to pass through the inside of the crystal, the interface is 'overheated', and the effect is reduced. Partially, the effect is reduced. ^If the structure of the present embodiment is maintained, in order to keep the solar cell characteristics relatively south, it is necessary to maintain the solar cell characteristics to be relatively south. Goodly maintain the crystal characteristics on the back side, the interface state (recombination speed) 'The effect of these slight reductions is not too much. This step is used to complete the influence of the person's 'by annealing in the above environment to make the interface The hydrogen passivation in the vicinity is stabilized, and the state near the interface, particularly the interface on the back side (the interface between the other surface side of the semiconductor substrate 1 and the back surface insulating film 8 formed on the other surface side) is improved. A characteristic diagram for illustrating the effect of enhanced passivation (FGA by hydrogen) in the open voltage (v〇c) of the solar cell. In the eighth embodiment, the solar battery unit produced by the method for manufacturing a solar battery cell according to the first embodiment and the method for manufacturing the solar battery unit 7L according to the first embodiment are not subjected to the step of strengthening the passivation. The open voltage (V〇c) of the solar cell. Fig. 9 is a characteristic diagram for explaining the effect of strengthening passivation in the solar cell single 22 20110489% short-circuited lightning, and the pheno-motor C Jsc ). In the ninth aspect, the solar cell produced by the method for producing a solar cell according to the first embodiment and the method for preparing the solar cell according to the first embodiment are not subjected to the strengthening passivation step. Short circuit current (JSC) of the solar cell. As can be seen from Fig. 8, the effect of improving the open voltage (v〇c) achieved by intensifying passivation (FGA by hydrogen) is clearly exhibited. Further, as is apparent from Fig. 9, the effect of improving the short-circuit current (Jsc) achieved by the enhanced passivation (FGA by hydrogen) is clearly exhibited. In particular, the open voltage (V0C) is significantly improved, which means that not only the crystal quality but also the interface L is included and is well improved. As described above, in the method of manufacturing a solar cell according to the first embodiment, the back surface insulating film 8 having the opening 8a is formed on the back surface of the semiconductor substrate J, and the back side electrode material paste 9a is applied and fired. The region to which the back side electrode material paste 9a is applied is protected by the back surface insulating film 8. Therefore, in the heating by firing, the semiconductor conversion is improved, the scooping moon surface does not adhere or fix the contaminant, and the recombination speed is not deteriorated, and the photoelectric conversion efficiency is improved. . In the method of manufacturing a solar cell according to the first embodiment, the back surface reflective film 1 is formed on the back surface of the semiconductor substrate 1 so as to cover at least the back surface insulating film 8. Thereby, the light transmitted through the semiconductor substrate 1 and the back surface and the edge film 8 can be reflected back to the semiconductor substrate to obtain a good light-sealing effect, so that the output characteristics can be improved and the comparison can be achieved. High photoelectric conversion efficiency. Further, in the method of manufacturing a solar cell according to the first embodiment, the back surface reflective film 10 is formed by a sputtering method. It is not a printing method using an electrode paste, but a back surface reflection film 1 is formed by a sputtering film, whereby a dense back surface reflection film 10 can be formed, which can be formed in comparison with a film formed by a printing method. The back reflection film 10 which is reflected by the light is excellent in light sealing effect. Further, in the method for manufacturing a solar battery cell according to the first embodiment, since the reinforced passivation step is performed after the light-receiving surface side electrode 5 and the back surface side electrode 9 are formed, the crystal quality and interface state of the ruthenium crystal of the semiconductor substrate can be improved. 'Enable solar cell characteristics. Therefore, according to the method for manufacturing a solar battery cell of the first embodiment, a back surface structure having both a low recombination speed and a high back surface reflectance can be obtained, and excellent long-wavelength sensitivity and high photoelectric conversion efficiency can be obtained. Solar cell unit. In addition, the efficiency of the photoelectric conversion efficiency of the solar cell can be increased, so that the thinning of the semiconductor substrate can be achieved, and the manufacturing cost can be reduced, and a high-quality solar cell having excellent battery cell characteristics can be produced at low cost. (Embodiment 2) In Embodiment 2, other forms of the back surface reflective film are used. The case where the back surface reflective film 构成 is formed by a metal foil will be described. Fig. 10 is a cross-sectional view showing the main part of the cross-sectional structure of the solar battery cell of the embodiment, and corresponds to the 丨_丨 diagram. The solar cell of the second embodiment is different from the solar cell of the embodiment. 24 201104898 is that the back reflective film is not a silver sputter film but is formed of an aluminum foil. The other configuration is the same as that of the solar battery cell of the embodiment, and thus detailed description thereof will be omitted. As shown in Fig. 10, in the solar battery cell of the present embodiment, the back surface reflection 胄 22' composed of ruthenium is provided on the back surface side electrode 9 by a conductive adhesive on the back surface of the semiconductor base & i. 21 is provided so as to cover the back side electrode 9 and the back surface insulating film 8, and is electrically connected to the back side electrode 9 through the conductive adhesive 21. In the configuration as described above, as in the case of the first embodiment, the light transmitted through the semiconductor substrate 者 and the surface insulating film 8 can be reflected and returned to the semiconductor substrate 丨, and good light can be obtained at a low cost. Sealing effect. Next, in the present embodiment, the back surface reflection film 22 is composed of an aluminum foil belonging to a metal foil. The back surface reflective film 22 is not formed of a film formed by a printing method using an electrode paste, but is formed of a metal foil, so that higher light reflection can be realized than a metal film formed by a printing method. Further, the light transmitted through the semiconductor substrate 丨 and the back surface insulating film 8 can be more widely reflected and returned to the semiconductor substrate 。. Therefore, the solar cell of the present embodiment has an excellent light-sealing effect in the same manner as in the first embodiment, since the back surface reflection film 2 2 ' including the aluminum foil belonging to the metal foil is included. As the material of the back surface reflective film 22, a metal material which can be processed into a foil can be used. As in the case of the back surface reflective film 1 ,, it is preferable to use, for example, a reflectance of light having a relative wavelength of around ll 〇〇 nm. More than 9〇%, more preferably 95% or more of metal materials. Thereby, a solar cell unit having high long-wavelength sensitivity and excellent light-sealing effect of light in a relatively long wavelength region can be realized. 25 201104898 That is, although it varies depending on the thickness of the semiconductor substrate i, it is a semiconductor having a long wavelength of 900 nm or more, particularly 1 Å, α, and a high current can be generated ( J-) 'can improve the output characteristics. In the case of the material shown above, in addition to (A1), for example, silver (Ag) may be additionally used. The solar battery unit of the embodiment constructed as described above is in the embodiment! After the steps described in FIGS. 5 to 5 and FIG. 1G and FIG. 1G are used, a conductive adhesive Η can be applied to the back side electrode 9, and the back side electrode 9 can be covered by the conductive adhesive 21 and The back surface insulating film 8 is connected to the back surface reflective film 22 to be produced. Here, the (four) plane reflection film 22 may be formed to cover at least the back surface insulating film 8 on the back side of the half (four) substrate 。. In the solar battery cell of the second embodiment, the tantalum nitride film (SiN film) formed by the electric aD method is included as the back surface insulating film 8 on the back surface of the semiconductor substrate i. The back surface of the semiconductor substrate 1 obtains a good effect of suppressing the recombination speed of the carrier. Thus, in the solar battery cell of the present embodiment, the improvement in output characteristics is achieved and a high photoelectric conversion efficiency is achieved. Further, in the solar battery cell of the second embodiment, since the back surface reflection film 22 composed of the aluminum foil belonging to the metal foil is covered by the back surface insulating film 8, the metal film formed by a conventional printing method is used. High light reflection can be achieved, and light transmitted through the semiconductor substrate 丨 and the back surface insulating film 8 can be more widely reflected and returned to the semiconductor substrate 丨. Therefore, in the solar battery cell of the present embodiment, an excellent light sealing effect can be obtained, and 26 201104898 achieves an improvement in output characteristics and achieves high photoelectric conversion efficiency. Therefore, in the solar battery cell of the second embodiment, since the back surface structure having both the low recombination speed and the high back surface reflectance is provided, the solar cell having excellent long-wavelength sensitivity and high photoelectric conversion efficiency can be realized. unit. In the method of manufacturing a solar cell according to the second embodiment, after the back surface insulating film 8 having the opening 8a is formed on the back surface of the semiconductor substrate, the back side electrode material paste 9a is recoated and fired. The region where the back side electrode material paste 9a is not applied is protected by the back surface insulating film 8, which is a force by firing. The back surface of the heat 1 does not adhere or fix the contaminant, and the state of the heat is maintained, and the photoelectric conversion efficiency is improved. Further, in the method of manufacturing a solar cell according to the second embodiment, the back surface reflective film 22 is formed on the back surface of the semiconductor substrate 1 so as to cover the back surface insulating film 8. Thereby, the light transmitted through the semiconductor substrate i and the back surface insulating film 8 can be reflected by the back surface reflection film 22 and returned to the semiconductor substrate 1, and a good light-sealing effect can be obtained, so that the output characteristics can be improved and a high level can be achieved. Photoelectric conversion efficiency. Further, in the method of manufacturing a solar battery cell according to the second embodiment, the back surface reflection film 22 is formed by mounting an aluminum case belonging to the metal sill on the back side electrode 9. It is not a printing method using an electrode paste, but the back surface reflection film 22 is formed by using an aluminum foil belonging to a metal foil as an IF sentence surface reflection film 22, whereby a dense back surface reflection film 22 can be formed. Forming a backside reflection 臈22 that achieves a higher light reflection than a film formed by a printing method can provide a light sealing effect of 27 201104898. Therefore, according to the method for producing a solar battery cell of the second embodiment, it is understood that the back surface structure having both a low recombination speed and a high back surface reflectance can be excellent in long-wavelength sensitivity and high in photoelectric conversion efficiency. Solar battery unit. Further, since the photoelectric conversion efficiency of the solar battery cell can be increased, the thinning of the semiconductor substrate 1 can be achieved, and the manufacturing cost can be reduced, and the south-quality solar battery cell having excellent battery cell characteristics can be produced at low cost. Further, in the method for manufacturing a solar battery cell according to the second embodiment, since the strengthening passivation step is performed after the light-receiving surface side electrode 5 and the back surface side electrode 9 are formed, the crystal quality and interface state of the 11 crystal of the semiconductor pure i can be improved. It can improve the characteristics of solar cells. In the above embodiment, a case where a p-type germanium substrate is used as the semiconductor substrate will be described. However, an n-type substrate may be used to form a reverse conductivity type solar cell in which a p-type diffusion layer is formed. Further, although a polycrystalline germanium substrate is used as the semiconductor substrate, a single crystal broken substrate can also be used. In the above, the thickness of the substrate of the semiconductor substrate is set to 200 #m. However, a semiconductor substrate having a thickness that is self-retaining, for example, to a thickness of about 50, may be used. Further, in the above description, the size of the semiconductor substrate is set to 15 〇 mm x 15 ,, but the size of the semiconductor substrate is not limited thereto. (Industrial Applicability) As described above, the light-emitting power device of the present invention has a case where a high-efficiency light-emitting device is realized by a low recombination speed and a high back surface reflectance of 28 201104898. BRIEF DESCRIPTION OF THE DRAWINGS The figure is a cross-sectional view of a main part for explaining a cross-sectional structure of a solar cell unit according to an embodiment of the present invention. Fig. 2 is a top view of the embodiment of the present invention viewed from the light-receiving side. A view of the solar cell of the first embodiment of the present invention is viewed from the back side. Fig. 2 is a characteristic diagram showing the reflectance of the three kinds of samples having different back structures on the back surface of the semiconductor substrate. In the sample, US read the characteristic diagram of the solar cell unit of the first embodiment. The area ratio of the electrode and the opening voltage (V.) of the sample surface 2: == state 1 solar cell unit characteristic map. The f-pole fabric and short-circuit current (W relationship of 1 map is used A cross-sectional view showing a manufacturing process of the solar cell according to the first embodiment of the present invention. A fifth embodiment of the present invention is a cross-sectional view of a solar cell 7 in the first embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 3 is a cross-sectional view showing a solar cell W step of the embodiment of the present invention. Also, 29 201104898, section 5-4, is a cross-sectional view for explaining the manufacturing steps of the present invention. Figure 5-5 is a cross-sectional view for explaining the manufacturing steps of the present invention. Sections 5-6 are warehouses; E, ', and sectional views for explaining the manufacturing steps of the hair unit. Fig. 5_? The cross-sectional circle of the manufacturing process of the present invention will be described. In the embodiment of the present invention, the solar cell of the solar cell 1 of the solar cell 1 of the solar cell 1 of the first embodiment is shown in the fifth embodiment of the solar cell. To illustrate the embodiment 1 of the present invention. A cross-sectional view showing a manufacturing step of a solar cell unit. Fig. 6 is a cross-sectional view showing a manufacturing step of a solar cell according to Embodiment 1 of the present invention. Fig. 6 is a view showing the sun of Embodiment J of the present invention. The back surface insulating film of the battery unit is a top view of an example of the printing area of the surface side electrode material paste. Fig. 6-2 shows the back surface insulating film of the solar cell unit of the embodiment i of the present invention. A plan view showing an example of a printing region of the back side electrode material f. Fig. 7 is a schematic view for explaining a step of strengthening the passivation in the manufacturing process of the solar cell unit according to the first embodiment of the present invention. A characteristic diagram showing the difference in the open voltage characteristics of the solar cell according to the first embodiment of the present invention caused by the presence or absence of the passivation step. Fig. 9 is a view showing the presence or absence of the enhancement passivation step. 30 201104898 The present invention A characteristic diagram showing the difference in short-circuit current characteristics of the solar battery cells of the first embodiment. Fig. 1 is a cross-sectional view showing the solar battery cells according to the second embodiment of the present invention. Cross-sectional view of main part of the surface structure. [Description of main components] 1 semiconductor substrate la p-type polycrystalline substrate 2 p-type polycrystalline substrate 3 n-type impurity diffusion layer 4 anti-reflection film 5 light-receiving side electrode 5a light-receiving electrode material paste 6 Gate electrode 7 Bus bar electrode 8 Back surface insulating film 8a Opening portion 9 Back side electrode 9a Back side electrode material paste 9b Overlapping region 10 Back surface reflective film 11 Aluminum-bismuth (Si) alloy portion 12 BSF layer 21 Conductive adhesive 31 201104898 22 Back reflection film 31 Treatment tank 32 Heater 33 Supply system part 34 Cover part 3 5 Crystal boat 36 Exhaust system part 32