201023371 九、發明說明： 【發明所屬之技術領域】 本發明係有關銅銦鎵硒太陽能電池與製作方法，尤其 是將熱膨脹緩衝層濺鍍於合金薄膜層與銅銦鎵硒薄膜層 之間的製作方法。 【先前技術】 銅銦鎵砸（Cuprum/Indium/Gall ium/Selenium，CIGS) 太陽能電池被認為是最有潛力的低成本太陽能電池之 一’其主要特點為：（1)在各類薄膜電池技術中，相對效 率較高’目前小面積元件效率已可達19%，大面積效率已 達13% ; (2)其製程可以使用低成本大面積的化學沉積方 法；（3)可抵抗高強輻射且質量又輕。 參閱第一圖’習用技術之銅銦鎵砸太陽能電池之結構 示思圖。CIGS太陽能電池1包含一基板、一錮薄膜層 20、一合金薄膜層50以及一 CIGS薄膜層80，其中該鉬薄 膜層20係以濺錢法在基板1〇上形成’作為背面電極，而 合金薄膜層50係在铜薄膜層20上以賤鍵法形成，用以提 高導電率以及降低阻抗係數。利用同步蒸鍍法或硒化法， 在合金薄膜層50上形成CIGS薄膜層80，當作CIGS太陽 能電池1的吸光層。 然而’習用技術中’由於CIGS太陽能電池持續曝曬 在太陽光下，使得溫度上升，合金薄膜層以及薄膜 層之間會因膨脹係數不同所產生的膨脹性差異而導致薄 201023371 膜龜裂脫膜’使得CIGS太陽能電池的光電轉換效率變差， 甚至失效。 因此，需要一種具較低膨脹差異性的CIGS太陽能電 池，藉加入熱膨脹緩衝層以降低不同薄膜層之間的熱脹差 異性，用以解決習用技術的缺點。 【發明内容】 本發明之主要目的在提供一種銅銦鎵砸太陽能電池 之結構，係包含一基板、一鉬薄膜層、一合金薄膜層、一 熱膨脹緩衝層以及一 CIGS薄膜層’其中熱膨脹緩衝層位 於合金薄膜層與CIGS薄膜層之間，此熱膨脹緩衝層係包 括硫化亞銅(CmS)或砸化亞銅（Qj2Se)。 本發明之另一目的在提供一種銅銦鎵硒太陽能電池 之製作方法，係在位於基底上之合金薄膜層上，利用連續 式藏鐘機形成熱膨脹緩衝層，再於熱膨脹緩衝層上沉積 CIGS薄膜層。 本發明之另一目的在提供一種銅銦鎵硒太陽能電池 之製作方法，係對具有翻薄膜層、合金薄膜層、熱膨脹缓 衝層以及CIGS薄膜層的基板進行熱處理，讓合金薄膜層、 熱膨脹緩衝層以及CIGS薄膜層的銅離子融合，以增加薄 膜層之間的結合性。 因此本發明可解決上述習知技術的缺失，使各層薄膜 的膨脹係數相近，解決在不同溫度下因膨脹性差異而使薄 膜龜裂而脫膜的缺點。 201023371 【實施方式】 以下配合圖式及元件符號對本發明之實施方式做更 詳細的說明，俾使熟習該項技藝者在研讀本說明書後能據 以實施。 參閱第二圖，本發明之銅銦鎵硒太陽能電池之結構示 意圖，CIGS太陽能電池2包括基板10、鉬薄膜層2〇、合 金薄膜層50、熱膨脹緩衝層6〇以及CIGS薄膜層8〇，且 基板10、鉬薄膜層2〇、合金薄膜層5〇、熱膨脹緩衝層6〇 以及CIGS薄膜層80係依序由下而上堆疊。 合金薄膜層50係由鉬、銅或鋁或銀所組成的合金， 其中合金薄膜層的膨脹係數為5. Q〜1G 5 xlG—6Gm/(3c以及 厚度為0· 1〜0. 25um。 _熱膨脹緩衝層6〇為硫化亞銅或砸化亞銅，其中硫化 亞銅以及剛^彌_彡脹係數為5 ()〜1() 5 xi()_Wt5c， 而熱膨脹緩_ 6G厚度約為〇· 2〜G. Sum。CIGS薄膜廣 80的膨脹係數為5 Q〜9. 3 χ1()_6αη/(^以及厚度為〇. 2〜 0. 5um。 參閱第三圖，本發明之熱膨脹緩衝層之製造示意圖。 首先’將含有翻薄膜層20以及合金薄膜層50的基板10 放在-組滾輪9G上，使含有_膜層2{)以及合金薄膜層 50=基板1〇往前頭方向移動。接著，糊濺鑛機⑽， 在°金薄膜層50上形成熱膨脹緩衝層60。雜機1〇〇位 於含有_膜層心及合金的基㈣上方: ;賤鍍機100具有複數個乾材室，而每個乾材室包 材112濺錢搶（圖_未顯示），且具有一濺鑛喷 201023371 頭111 ’、其中乾材112可為硫化亞銅或石西化亞銅。如果靶 材112為硫化亞銅，則熱膨脹緩衝層6〇為硫化亞銅熱膨 脹緩衝層，如果乾材112為碼化亞銅，則熱雜緩衝層60 脹緩觸。藉調魏麟的功率以控制減 鐘喷頭111所噴出的乾材量，進而控制熱賴緩衝層6〇 的形成速率’而且合金薄膜層50係經由複數個麵喷頭 111以連續方式猶而形成，因此可提高厚度的均一性。 熱膨脹緩衝層60的厚度約〇. 2〜〇. 5uffl。 參 取後’在熱膨脹緩衝層60上形成CIGS薄膜層80，再 對基板10、翻薄膜層2〇、合金薄膜層5〇、熱膨脹緩衝層 60以及CIGS f專膜層80進行融合熱處王里，以形成低膨脹差 異性的CIGS太陽能電池。 參閱第四圖，本發明之融合熱處理之示意圖。如第四 圖所示，發明的融合熱處理係先以5〜1(rc/sec的升溫 速度，使溫度在〇. 2〜1· 〇分内上升至400〜800Ϊ，如圖 中的溫度T1以及第-時間tl所示。接著，在怪溫下進行 ❹ 烘烤，持續10〜2〇分，如圖中的溫度T2以及第二時間t2 所不。最後，利用通氬氣或氮氣進行快速冷卻，使溫度於 15〜200分間下降至50〜2〇〇°c，如圖中的溫度”以及 第二時間t3所示。因此’融合熱處理所需的時間為4〇18〇 分。發明的融合熱處理可以讓合金薄膜層5〇、熱膨脹緩衝 層60以及CIGS薄膜層80的銅離子融合，使各薄層相互 附著，增加結合性。熱膨脹緩衝層之功能在使各層薄膜的 膨脹係數相接近，降低在不同溫度下因膨脹性差異而使薄 膜龜裂而脫膜的情形。 8 201023371 八/上_者僅翻以轉本發明之較佳實施例 ，並非 止圖據以對本發明做任何形式上之限制，是以，凡有在相 同之發明精神下所作有關本發明之任何修飾或變更，皆仍 應包括在本發明意圖保護之範疇。 【圖式簡單說明】 第一圖為習用技術之銅銦鎵硒太陽能電池之結構示意圖。 第二圖為本發明銅錮鎵硒太陽能電池之結構示意圖。 第三圖為本發明之熱膨脹緩衝層之製造示意圖。 第四圖為本發明之融合熱處理之示意圖。 【主要元件符號說明】 1銅錮鎵硒太陽能電池 2銅銦鎵硒太陽能電池 10基板 20鉬薄膜層 50合金金屬薄膜層 60熱膨脹緩衝層 80 CIGS薄膜層 90滾輪 100濺鍍機 110靶材室 9 201023371201023371 IX. Description of the invention: [Technical field of the invention] The present invention relates to a copper indium gallium selenide solar cell and a manufacturing method thereof, in particular, a method of sputtering a thermal expansion buffer layer between an alloy thin film layer and a copper indium gallium selenide thin film layer method. [Prior Art] Copper-indium gallium (Cuprum/Indium/Gall ium/Selenium, CIGS) solar cells are considered to be one of the most promising low-cost solar cells. Their main features are: (1) in various types of thin film battery technology. Among them, the relative efficiency is higher. At present, the efficiency of small-area components has reached 19%, and the large-area efficiency has reached 13%. (2) The process can use low-cost large-area chemical deposition methods; (3) It can resist high-intensity radiation. The quality is light. Refer to the first diagram of the structure of the copper indium gallium germane solar cell of the conventional technology. The CIGS solar cell 1 comprises a substrate, a thin film layer 20, an alloy thin film layer 50 and a CIGS thin film layer 80, wherein the molybdenum thin film layer 20 is formed on the substrate 1 by a sputtering method as a back electrode, and the alloy The film layer 50 is formed on the copper film layer 20 by a ruthenium bonding method for improving conductivity and lowering the impedance coefficient. The CIGS thin film layer 80 is formed on the alloy thin film layer 50 by a simultaneous vapor deposition method or a selenization method to serve as a light absorbing layer of the CIGS solar cell 1. However, in the 'practical technology', because the CIGS solar cell is continuously exposed to sunlight, the temperature rises, and the difference between the expansion of the alloy film layer and the film layer due to the difference in expansion coefficient leads to the thin film of the 201023371 film cracking and peeling off. The photoelectric conversion efficiency of the CIGS solar cell is deteriorated or even invalidated. Therefore, there is a need for a CIGS solar cell with a lower expansion differential that incorporates a thermal expansion buffer layer to reduce thermal expansion differences between different film layers to address the shortcomings of conventional techniques. SUMMARY OF THE INVENTION The main object of the present invention is to provide a structure of a copper indium gallium germane solar cell, comprising a substrate, a molybdenum film layer, an alloy film layer, a thermal expansion buffer layer, and a CIGS film layer, wherein the thermal expansion buffer layer Located between the alloy film layer and the CIGS film layer, the thermal expansion buffer layer comprises cuprous sulfide (CmS) or cuprous copper (Qj2Se). Another object of the present invention is to provide a method for fabricating a copper indium gallium selenide solar cell by forming a thermal expansion buffer layer on a thin film layer on a substrate, and depositing a CIGS film on the thermal expansion buffer layer. Floor. Another object of the present invention is to provide a method for fabricating a copper indium gallium selenide solar cell, which comprises heat treating a substrate having a tumbling film layer, an alloy film layer, a thermal expansion buffer layer, and a CIGS film layer to allow the alloy film layer and thermal expansion buffer The layer and the copper ion of the CIGS film layer are fused to increase the bond between the film layers. Therefore, the present invention can solve the above-mentioned drawbacks of the prior art, and the expansion coefficients of the films of the respective layers are similar, and the disadvantages of cracking and peeling off the film due to the difference in the expansion property at different temperatures are solved. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described in more detail below with reference to the drawings and the reference numerals, which can be implemented by those skilled in the art after studying this specification. Referring to the second figure, a schematic structural view of a copper indium gallium selenide solar cell of the present invention, the CIGS solar cell 2 includes a substrate 10, a molybdenum thin film layer 2, an alloy thin film layer 50, a thermal expansion buffer layer 6〇, and a CIGS thin film layer 8〇, and The substrate 10, the molybdenum thin film layer 2, the alloy thin film layer 5, the thermal expansion buffer layer 6A, and the CIGS thin film layer 80 are sequentially stacked from bottom to top. The alloy film layer 50 is an alloy composed of molybdenum, copper or aluminum or silver, wherein the alloy film layer has a coefficient of expansion of 5. Q~1G 5 xlG-6gm/(3c and a thickness of 0·1~0. 25um. The thermal expansion buffer layer 6 is cuprous sulfide or cuprous cuprite, wherein the cuprous sulfide and the coefficient of expansion are 5 ()~1() 5 xi()_Wt5c, and the thermal expansion is _ 6G thickness is about 〇 2~G. Sum. CIGS film 80 has a coefficient of expansion of 5 Q~9. 3 χ1()_6αη/(^ and thickness is 〇. 2~0. 5um. Referring to the third figure, the thermal expansion buffer layer of the present invention First, the substrate 10 including the tumbling film layer 20 and the alloy film layer 50 is placed on the set of rollers 9G so that the film layer 2{{) and the alloy film layer 50=the substrate 1 〇 move toward the front direction. Next, the paste splashing machine (10) forms a thermal expansion buffer layer 60 on the gold film layer 50. The machine 1 is located above the base (4) containing the film core and the alloy: the bismuth plating machine 100 has a plurality of dry materials Room, and each dry material room package 112 splashes money (Figure _ not shown), and has a splash spray 201023371 head 111 ', wherein the dry material 112 can be copper sulfide or If the target 112 is cuprous sulfide, the thermal expansion buffer layer 6 is a cuprous sulfide thermal expansion buffer layer, and if the dry material 112 is coded cuprous, the thermal buffer layer 60 is inflated. The power of the lining is controlled to control the amount of dry material discharged from the clock-reducing nozzle 111, thereby controlling the rate of formation of the thermal lining buffer layer 6', and the alloy thin film layer 50 is formed in a continuous manner via a plurality of surface nozzles 111. The thickness of the thermal expansion buffer layer 60 is about 2. 2~〇. 5uffl. After the reference, the CIGS film layer 80 is formed on the thermal expansion buffer layer 60, and then the substrate 10, the film layer 2, and the alloy are laminated. The thin film layer 5, the thermal expansion buffer layer 60 and the CIGS f-specific film layer 80 are fused to form a CIGS solar cell with low expansion difference. Referring to the fourth figure, a schematic diagram of the fusion heat treatment of the present invention is as follows. As shown in the figure, the fusion heat treatment of the invention is first carried out at a temperature increase rate of 5 to 1 (rc/sec, and the temperature is raised to 〜2 to 1·〇 within a range of 400 to 800 Ϊ, as shown by the temperature T1 and the first time in the figure. Tl is shown. Then, at a strange temperature烘烤 Bake, lasting 10~2 minutes, as shown in the temperature T2 and the second time t2. Finally, use argon or nitrogen to cool rapidly, and let the temperature drop to 50~2 in 15~200 minutes. 〇°c, as shown in the figure, and the second time t3. Therefore, the time required for the fusion heat treatment is 4〇18〇. The fusion heat treatment of the invention allows the alloy film layer 5〇, the thermal expansion buffer layer 60, and The copper ions of the CIGS film layer 80 are fused to each other to adhere to each other to increase the bonding. The function of the thermal expansion buffer layer is such that the expansion coefficients of the respective layers of the film are close to each other, and the film is cracked and peeled off due to the difference in the expansion property at different temperatures. 8 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 Modifications or alterations are still intended to be included within the scope of the invention. [Simple description of the diagram] The first figure is a schematic diagram of the structure of a copper indium gallium selenide solar cell of conventional technology. The second figure is a schematic structural view of a copper-germanium gallium selenide solar cell of the present invention. The third figure is a schematic view showing the manufacture of the thermal expansion buffer layer of the present invention. The fourth figure is a schematic view of the fusion heat treatment of the present invention. [Main component symbol description] 1 copper-germanium gallium selenide solar cell 2 copper indium gallium selenide solar cell 10 substrate 20 molybdenum film layer 50 alloy metal film layer 60 thermal expansion buffer layer 80 CIGS film layer 90 roller 100 sputtering machine 110 target room 9 201023371
❿ 111濺鍍喷頭 112靶材 ΤΙ、T2、T3 溫度 tl第一時間 t2第二時間 t3第三時間❿ 111 Sputtering nozzle 112 Target ΤΙ, T2, T3 Temperature tl first time t2 second time t3 third time