201121062 六、發明說明： 【發明所屬之技術領域】 本發明係關於一種光吸收層之製備方法，特別是關於 一種銅銦鎵硒光吸收層之製備方法。 【先前技術】 由於具有低成本的優勢，薄膜太陽能電池（thin film solar cell)逐漸成為發展太陽能發電不可獲缺的要角之一。 現今，有不同種類的半導體化合物被用來製作薄膜太陽能 • 電池’其中使用銅（C〇PPer)、銦Undium}、鎵、硒 (Selenium)化合物之銅銦鎵硒太陽能薄膜電池（cigs让比 filmsolarcells)是最具效率的一種。因此，在不同種類的薄 膜太陽能電池，CIGS太陽能薄膜電池的發展最受矚目。 CIGS薄膜太陽能電池使用的吸光材料為銅銦鎵硒 (CIGS)化合物半導體。CIGS層可以共蒸鍍銅、銦、嫁和砸 來形成。以共蒸鍍製程製作之CIGS層，其光電轉換效率可 達20.0% (為德國公司ZSW所生產之產品但是，共蒸鍍製 籲 程需要較高的溫度，並且會浪費較多的材料。此外，共蒸 鍍製程還需在高真空度下進行’且CIGS層的形成速度慢， 效率低。以共蒸鍍製程製作之CIGS層雖具有高光電轉換效 率’但卻也有高製程成本的問題。 此外，CIGS層亦可利用、踐鍍銅、銦、鎵和石西化 (Selenization)來形成，但是由於在濺鍍製程中，銅、銦、 鎵和硒之比例受限於靶材，使得CIGS層在製作時，無法再 做銅、銦、鎵和硒之比例調整。倘若銅、銦、鎵和硒之比 201121062 例不適當，會影響（：1(35太陽能薄膜電池之效率。 圖3顯示一種以習知形成CIGS層之方法所形成之ci(}s 層。另一種形成CIGS層之方法可先濺鍍一銅層在基板上， 然後再共蒸鍍銦、鎵和硒。在CIGS層總厚度不變的情形下 ，先濺鍍一銅層，然後再共蒸鍍銦、鎵和硒，可降低共蒸 鍍所需的時間，而讓整個製程的時間縮短，降低製作成本 。然而，在根據上述步驟所做的實驗中可發現，由於此種201121062 VI. Description of the Invention: [Technical Field] The present invention relates to a method for preparing a light absorbing layer, and more particularly to a method for preparing a copper indium gallium selenide light absorbing layer. [Prior Art] Due to the advantages of low cost, thin film solar cells have gradually become one of the key points for the development of solar power generation. Nowadays, there are different kinds of semiconductor compounds used to make thin-film solar cells. The battery uses copper (C〇PPer), indium Undium}, gallium, selenium (Selenium) compounds, copper indium gallium selenide solar thin film batteries (cigs to make than filmsolarcells) ) is the most efficient one. Therefore, the development of CIGS solar thin film batteries has attracted the most attention in different types of thin film solar cells. The light absorbing material used in CIGS thin film solar cells is a copper indium gallium selenide (CIGS) compound semiconductor. The CIGS layer can be formed by co-evaporation of copper, indium, marry and tantalum. The CIGS layer produced by the co-evaporation process has a photoelectric conversion efficiency of 20.0% (a product produced by the German company ZSW. However, the co-evaporation process requires a higher temperature and wastes more material. The co-evaporation process also needs to be carried out under high vacuum, and the formation speed of the CIGS layer is slow and the efficiency is low. The CIGS layer produced by the co-evaporation process has high photoelectric conversion efficiency, but it also has a high process cost. In addition, the CIGS layer can also be formed by using copper, indium, gallium, and Selenization, but since the ratio of copper, indium, gallium, and selenium is limited to the target during the sputtering process, the CIGS layer is formed. At the time of production, it is no longer possible to adjust the ratio of copper, indium, gallium and selenium. If the ratio of copper, indium, gallium and selenium is not appropriate, it will affect (: 1 (35 solar thin film battery efficiency. Figure 3 shows a The ci(}s layer formed by the conventional method for forming the CIGS layer. Another method for forming the CIGS layer may be to first deposit a copper layer on the substrate, and then co-deposit the indium, gallium, and selenium. In the case of constant thickness, first sputter a copper The layer, and then co-deposited indium, gallium and selenium, can reduce the time required for co-evaporation, shortening the entire process time and reducing the manufacturing cost. However, in the experiments according to the above steps, it can be found Such
方法需先形成一厚銅層，厚銅層容易在CIGS層與其下之陽 極層間形成孔洞(如圖3中箭頭所示），從而可能發生剝離 (peeling)現象。 圖3係申請人按習知形成CIGS層之方法所形成之cigs 層，該方法記載於文獻“Unif〇rm，mgh删仏㈣， C!GS P職ss with Αρρ1— t〇 N〇vei ws” A.E. Delahoy, L. Chen, and B. Sang Energy Photovoltaics, Inc. PrineetGn，New ;ersey中。报明顯厚銅層與其下之陽極 層1之’I面有孔隙’因此推論會於此處產生剝離。因此， 本發明即為解決此一問題，而提出 電池之製備方法。 【發明内容】 一種較佳之薄膜太陽能 本發明之目的係提供一種薄膜太陽能電池之製備方 法’其可以較短的製程時間製備⑽光吸收層，降低製作 成本。 本發明之另 整銅、铜、鎵和碼之比例 目的係提供一種製備方法，其可彈性調 ’以製備高轉換效率之CiGS光吸 201121062 收層。 本發明之再一目的係提供一種製備方法，在該製備方 法中，CIGS光吸收層之製備步驟内係先形成一銅層，而該 銅層形成後不會產生剝離的現象。 根據前述種種目的，本發明一實施例揭示一種薄膜太 陽能電池之製備方法，包含下列步驟：形成一陽極層於一 基板上；形成一銅層於該陽極層上；以及共沈積銅、銦、 鲁 鎵和硒於該銅層上，以形成一銅銦鎵硒光吸收層。 在一實施例中，銅層之銅量為在共沈積銅、銦、鎵和 晒之步驟中之銅量之一半以下。 在一實施例中’銅層之厚度介於1000埃至2500埃。 在一實施例中，形成一銅層於該陽極層上之步驟包含 蒸鐘或減鍍該銅層於該陽極層上。 上文已經概略地敍述本揭露之技術特徵及優點，俾使 下文之本揭露詳細描述得以獲得較佳瞭解。構成本揭露之 φ 申明專利範圍標的之其它技術特徵及優點將描述於下文。 本揭4所屬技術領域中具有通常知識者應可瞭解，下文揭 不之概念與特定實施例可作為基礎而相當輕易地予以修改 或°又汁其它結構或製程而實現與本揭露相同之目的。本揭 露所屬技術領域中具有通常知識者亦應可瞭解，這類等效 &建構並無法脫離後附之中請專利範圍所提出之本揭露的 精神和範圍。 【貫施方式】 圖1顯不本創作一實施例之薄膜太陽能電池1之截面示 201121062 意圖。薄膜太陽能電池丨包含一基板丨丨、一封裝材料i2，以 及一太陽能電池單元13。封裝材料12黏接基板丨丨與太陽能 電池單元13。太陽能電池單元13包含背電極22、一銅銦鎵 硒（CIGS)光吸收層23、—緩衝層24、一絕緣層乃、一透明 導電層26’以及一上電極層27。 背電極22包含鉬（Mo)，其可以濺鍍製程或蒸鍍製程等 方法形成，其厚度可約為0n 〇μιη。CIGS光吸收層設置 於基板11上，其厚度可約為15〜2 0μπι。CIGS光吸收層23 包 3 銅（Copper)、銦（Indium)、鎵（Gallium)、砸（Selenium) 化合物。緩衝層24可包含硫化鎘（CdS),其厚度可約為 〇·〇5μιη«>絕緣層25可包含氧化鋅（Zn0)，其厚度可約為〇1μιη 。絕緣層25可避免漏電流的問題。透明導電層26可為透明 導電氧化物（transparent conductive oxides)，其可包含摻雜 紹之氧化鋅。透明導電層26之厚度可介於0.5〜1·5μιη之間。 透明導電層26可以濺鍍方式製作。上電極層27可包含鋁導 線。 基板11可以不銹鋼或高分子材料製成，較佳地以玻璃 製成。封裝材料12用於結合基板η與太陽能電池單元13。 封裝材料12可包含熱塑型高分子材料。在一實施例中，封 裝·材料12包含乙稀醋酸乙稀（ethylene vinyl acetate)。 本發明另揭示一種之製備方法，其包含下列步驟： 首先提供一基板11。如前所述，基板11可以不銹鋼或 高分子材料製成，較佳地以玻璃製成。 其次’在基板11上形成一陽極層。在一實施例中，陽 201121062 極層可以濺㈣程形成或以蒸鍍製程形成。陽極層的厚度 可約〇.5七_。陽極層可作為背電極㈣於電洞傳導。 接者，形成-薄銅層於該陽極層上。在一實施例中， 該銅層可以濺鍍製程來形成，其厚度可介於刪埃至2· 埃。在本實施财，相較於厚度料1.5〜2.0_之⑽光吸 收層23,銅層厚度為薄。由於銅層厚度薄，故可避免發生 銅層剝離（peeling)現象。The method requires a thick copper layer to be formed. The thick copper layer easily forms a hole between the CIGS layer and the underlying anode layer (as indicated by the arrow in Fig. 3), so that peeling may occur. Figure 3 is a cigs layer formed by the applicant's conventional method of forming a CIGS layer. The method is described in the literature "Unif〇rm, mgh deleted (four), C! GS P jobs ss with Αρρ1 - t〇N〇vei ws" AE Delahoy, L. Chen, and B. Sang Energy Photovoltaics, Inc. Prineet Gn, New; ersey. It is reported that the thick copper layer has a void on the 'I surface of the anode layer 1 below it' and therefore it is inferred that peeling occurs there. Therefore, the present invention solves this problem and proposes a method of preparing a battery. SUMMARY OF THE INVENTION A preferred thin film solar energy The object of the present invention is to provide a method for preparing a thin film solar cell, which can prepare a (10) light absorbing layer in a shorter process time and reduce the manufacturing cost. The ratio of the additional copper, copper, gallium and code of the present invention is intended to provide a method of preparation which is elastically tuned to produce a high conversion efficiency CiGS light absorption 201121062. A further object of the present invention is to provide a preparation method in which a copper layer is formed in the preparation step of the CIGS light absorbing layer, and the copper layer is not peeled off after formation. According to various embodiments of the present invention, a method for fabricating a thin film solar cell includes the steps of: forming an anode layer on a substrate; forming a copper layer on the anode layer; and co-depositing copper, indium, and ru Gallium and selenium are on the copper layer to form a copper indium gallium selenide light absorbing layer. In one embodiment, the amount of copper in the copper layer is less than one-and-a-half the amount of copper in the step of co-depositing copper, indium, gallium, and drying. In one embodiment, the thickness of the copper layer ranges from 1000 angstroms to 2500 angstroms. In one embodiment, the step of forming a copper layer on the anode layer comprises vaporizing or plating the copper layer on the anode layer. The technical features and advantages of the present disclosure are summarized above, and the detailed description of the present disclosure will be better understood. Other technical features and advantages of the subject matter of the claims of the present disclosure will be described below. It is to be understood by those of ordinary skill in the art that the present invention may be practiced as the basis of the present invention. It is also to be understood by those of ordinary skill in the art that this invention is not limited to the spirit and scope of the present disclosure. [Comprehensive mode] Fig. 1 shows a cross-section of a thin film solar cell 1 of an embodiment. 201121062 Intent. The thin film solar cell cartridge comprises a substrate stack, a package material i2, and a solar cell unit 13. The encapsulating material 12 is bonded to the substrate 丨丨 and the solar cell unit 13. The solar cell unit 13 includes a back electrode 22, a copper indium gallium selenide (CIGS) light absorbing layer 23, a buffer layer 24, an insulating layer, a transparent conductive layer 26', and an upper electrode layer 27. The back electrode 22 contains molybdenum (Mo) which may be formed by a sputtering process or an evaporation process, and may have a thickness of about 0 n 〇 μηη. The CIGS light absorbing layer is disposed on the substrate 11 and has a thickness of about 15 to 2 0 μm. The CIGS light absorbing layer 23 comprises 3 copper (Copper), indium (Indium), gallium (Gallium), and bismuth (Selenium) compounds. The buffer layer 24 may comprise cadmium sulfide (CdS) having a thickness of about 〇·〇5μιη«> the insulating layer 25 may comprise zinc oxide (Zn0), which may have a thickness of about μ1μηη. The insulating layer 25 can avoid the problem of leakage current. The transparent conductive layer 26 can be a transparent conductive oxide, which can comprise doped zinc oxide. The thickness of the transparent conductive layer 26 may be between 0.5 and 1.5 μm. The transparent conductive layer 26 can be formed by sputtering. The upper electrode layer 27 may contain aluminum wires. The substrate 11 may be made of stainless steel or a polymer material, preferably made of glass. The encapsulation material 12 is used to bond the substrate η with the solar cell unit 13. The encapsulating material 12 may comprise a thermoplastic polymer material. In one embodiment, the package material 12 comprises ethylene vinyl acetate. The invention further discloses a preparation method comprising the following steps: First, a substrate 11 is provided. As described above, the substrate 11 may be made of stainless steel or a polymer material, preferably made of glass. Next, an anode layer is formed on the substrate 11. In one embodiment, the anode 201121062 pole layer may be formed by a splash (four) process or by an evaporation process. The thickness of the anode layer can be about 55. The anode layer can be conducted as a back electrode (4) in the hole. In succession, a thin copper layer is formed on the anode layer. In one embodiment, the copper layer can be formed by a sputtering process and can have a thickness of between 2,000 Å and Å. In the present embodiment, the thickness of the copper layer is thin compared to the (10) light absorbing layer 23 of the thickness of 1.5 to 2.0 mm. Since the copper layer is thin, peeling of the copper layer can be avoided.
然後，共沈積銅、銦、録和碼於銅層上。在一實施例 中，銅、銦、鎵和栖係共蒸鏟於銅層上。在共蒸鑛的製程 中，基板11之溫度可高達400〜65〇。〇，因此在鐘銅、铜、錄 和砸共蒸時’銅層内的銅會與蒸錢之銅、自、鎵和砸形成 銅銦鎵硒化合物半導體。在本揭露之製程中’在cigs光吸 收層23的總厚度不變的情形下，由於先鑛—層銅，故可減 少蒸鍍之銅、銦、鎵和硒所需的時間，從而使形成cigs光 吸收層23之製程時間可縮短。通常，高效率之CK}s光吸收 層 23 之組成落在 Ga/(In+Ga)=〇.3〜0.4和 Cu/(ln+Ga)=〇.9~l。 如此小範圍的組成，共蒸鍍較容易達成。是故，相較於先 鍍銅，後蒸鍍銦、鎵和硒之製程，本揭露之製程更易達成 前述的範圍。再者，本揭露之製程具另一個優點，即在共 蒸鍍銅、銦、鎵和硒之步驟，可彈性調整銅、銦、鎵和硒 的比例’以獲得高效率之CIGS光吸收層23。 在一實施例中，銅層之銅量為在共沈積銅、銦、鎵和 栖之步驟中之銅量之一半以下。 之後，在CIGS光吸收層23上，形成一作為緩衝層之硫 201121062 ，硫化錦（CdS)薄膜可利用 為0·05μιη。硫化鋅或硫化 化鎘(cdS)薄膜。在一實施例中 化學水浴製程製作，其厚度可約 銦亦可作為緩衝層之材料。 再者，形成一絕緣層在硫化鎘（Cds)薄膜之上。在一實 =例中’絕緣層包含氧化鋅。而在絕緣層_L，可接著形成 導電層。Then, copper, indium, and a code are co-deposited on the copper layer. In one embodiment, copper, indium, gallium, and stalks are co-steamed onto the copper layer. In the process of co-steaming, the temperature of the substrate 11 can be as high as 400 to 65 Torr. Oh, so when copper is co-evaporated, the copper in the copper layer forms a copper-indium gallium selenide compound semiconductor with the copper, self-, gallium and germanium. In the process of the present disclosure, in the case where the total thickness of the cigs light absorbing layer 23 is constant, since the first ore-layer copper is used, the time required for vapor deposition of copper, indium, gallium and selenium can be reduced, thereby forming The process time of the cigs light absorbing layer 23 can be shortened. Generally, the composition of the high-efficiency CK}s light absorbing layer 23 falls in Ga/(In + Ga) = 〇. 3 to 0.4 and Cu / (ln + Ga) = 〇. 9 - l. With such a small range of compositions, co-evaporation is easier to achieve. Therefore, the process of the present disclosure is easier to achieve the aforementioned range than the process of first depositing copper, post-depositing indium, gallium and selenium. Furthermore, the process of the present disclosure has another advantage in that the ratio of copper, indium, gallium and selenium can be elastically adjusted in the steps of co-evaporation of copper, indium, gallium and selenium to obtain a highly efficient CIGS light absorbing layer 23 . In one embodiment, the amount of copper in the copper layer is less than one-and-a-half the amount of copper in the step of co-depositing copper, indium, gallium, and habitat. Thereafter, on the CIGS light absorbing layer 23, a sulfur 201121062 as a buffer layer is formed, and a CdS film can be utilized as 0.05 μm. A zinc sulfide or cadmium sulfide (cdS) film. In one embodiment, a chemical water bath process is fabricated, the thickness of which may be about indium or a material of the buffer layer. Furthermore, an insulating layer is formed over the cadmium sulfide (Cds) film. In a real example, the insulating layer contains zinc oxide. In the insulating layer _L, a conductive layer can be formed next.
圖2顯不利用本揭露一實施例之製程所製作之CIGS光 ，收層之照片。從圖2可看出，本揭露先形成薄鋼層，再共 袤鍍銅、銦、鎵和硒，以形成(：1〇5光吸收層之製程方法， 不會在CIGS光吸收層與陽極層之間形成孔洞。此可證明， 本揭露之製程方法可避免銅層產生剝離現象。 本揭露所揭示之製程，其係於陽極層上先形成一薄銅 層，接著在共蒸鍍銅、銦、鎵和硒。如此之製程可減少形 成C1GS光吸收層之時間，且可避免陽極層上形成銅層之剝 離問題。此外’本揭露之製程可在共蒸鍍銅，、鎵和硒 之步驟中，彈性地調整銅、銦、鎵和硒，以獲得高轉換效 率之CIGS光吸收層。 本揭露之技術内容及技術特點已揭示如上，然而熟系 本項技術之人士仍可能基於本揭露之教示及揭示而作種種 不背離本揭露精神之替換及修飾。因此，本揭露之保護範 圍應不限於實施例所揭示者，而應包括各種不背離本揭露 之替換及修飾，並為以下之申請專利範圍所涵蓋。 【圖式簡單說明】 圖1顯示本創作一實施例之薄膜太陽能電池之截面示 201121062 意圖； 矛呈所製作之CIGS光 圖2顯示利用本揭露—實施例之製 吸收層之照片；及 圖3顯示一種以 層。 習知形成CIGS層之 方法所形Fig. 2 shows a photograph of a CIGS light and a layer which are produced by the process of the present embodiment. As can be seen from Fig. 2, the present disclosure first forms a thin steel layer, and then co-plats copper, indium, gallium and selenium to form (: 1 〇 5 light absorbing layer process method, will not be in the CIGS light absorbing layer and anode Holes are formed between the layers. This proves that the process of the present disclosure can avoid the peeling phenomenon of the copper layer. The process disclosed in the present disclosure is to form a thin copper layer on the anode layer, followed by co-evaporation of copper, Indium, gallium and selenium. Such a process can reduce the time for forming the C1GS light absorbing layer, and can avoid the problem of peeling off the copper layer formed on the anode layer. Further, the process of the present disclosure can be used for co-evaporation of copper, gallium and selenium. In the step, the copper, indium, gallium and selenium are elastically adjusted to obtain a CIGS light absorbing layer with high conversion efficiency. The technical content and technical features of the disclosure have been disclosed above, but those skilled in the art may still be based on the disclosure. The invention is not limited to the spirit and scope of the disclosure, and the scope of the present disclosure should not be limited by the embodiment, but should include various alternatives and modifications without departing from the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS [Brief Description] FIG. 1 shows a cross-sectional view of a thin film solar cell according to an embodiment of the present invention. 201121062. The spear is produced by a CIGS light pattern 2 showing an absorbent layer using the present disclosure-embodiment Photograph; and Figure 3 shows a layer in the form of a conventional method for forming a CIGS layer.
成之CIGS 【主要元件符號說明】Cheng CIGS [Main component symbol description]
1 薄膜太陽能電池 11 基板 12 封裝材料 13 太陽能電池單元 22 背電極 23 銅銦鎵碼光吸收層 24 緩衝層 25 絕緣層 26 透明導電層 27 上電極層1 Thin film solar cell 11 Substrate 12 Packaging material 13 Solar cell 22 Back electrode 23 Copper indium gallium code light absorbing layer 24 Buffer layer 25 Insulating layer 26 Transparent conductive layer 27 Upper electrode layer