TWI497733B - Back contact solar cell and module comprising the same - Google Patents
Back contact solar cell and module comprising the same Download PDFInfo
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- TWI497733B TWI497733B TW102121939A TW102121939A TWI497733B TW I497733 B TWI497733 B TW I497733B TW 102121939 A TW102121939 A TW 102121939A TW 102121939 A TW102121939 A TW 102121939A TW I497733 B TWI497733 B TW I497733B
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- 230000005684 electric field Effects 0.000 claims description 77
- 239000000758 substrate Substances 0.000 claims description 50
- 125000006850 spacer group Chemical group 0.000 claims description 21
- 239000000463 material Substances 0.000 claims description 7
- 238000002161 passivation Methods 0.000 description 16
- 238000009792 diffusion process Methods 0.000 description 14
- 239000004065 semiconductor Substances 0.000 description 11
- 238000006243 chemical reaction Methods 0.000 description 7
- 230000006798 recombination Effects 0.000 description 4
- 238000005215 recombination Methods 0.000 description 4
- 239000000969 carrier Substances 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 230000003667 anti-reflective effect Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000005038 ethylene vinyl acetate Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000003071 parasitic effect Effects 0.000 description 2
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000008393 encapsulating agent Substances 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000010329 laser etching Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- MZLGASXMSKOWSE-UHFFFAOYSA-N tantalum nitride Chemical compound [Ta]#N MZLGASXMSKOWSE-UHFFFAOYSA-N 0.000 description 1
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
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Description
本發明是有關於一種太陽能電池及其模組，特別是指一種背接觸太陽能電池及其模組。The invention relates to a solar cell and a module thereof, in particular to a back contact solar cell and a module thereof.
參閱圖1，為一種已知的指叉式背接觸(Interdigitated Back Contact，簡稱IBC)太陽能電池，包含：一基板91、位於該基板91的相反側的一抗反射層92與一鈍化層93、至少一第一電極94，以及至少一第二電極95。Referring to FIG. 1 , a known interdigitated back contact (IBC) solar cell includes a substrate 91 , an anti-reflection layer 92 on the opposite side of the substrate 91 , and a passivation layer 93 . At least one first electrode 94 and at least one second electrode 95.
該基板91為n型半導體基板，並包括一供該抗反射層92配置的受光面911、一與該受光面911相反且供該鈍化層93配置的背面912、一位於該受光面911側且載子濃度大於該基板91的前表面電場部(Front Surface Field Portion)913，以及位於該背面912側且彼此間隔的至少一射極部(Emitter Portion)914與至少一背表面電場部(Back Surface Field Portion)915。該第一電極94位於該鈍化層93上並可穿過該鈍化層93而連接該射極部914，該第二電極95位於該鈍化層93上並可穿過該鈍化層93而連接該背表 面電場部915。The substrate 91 is an n-type semiconductor substrate, and includes a light-receiving surface 911 disposed on the anti-reflection layer 92, a back surface 912 opposite to the light-receiving surface 911 and disposed on the passivation layer 93, and a light-receiving surface 911 on the light-receiving surface 911 side. The carrier concentration is greater than a front surface field portion 913 of the substrate 91, and at least one emitter portion 914 and at least one back surface electric field portion (Back Surface) located on the back surface 912 side and spaced apart from each other Field Portion) 915. The first electrode 94 is located on the passivation layer 93 and can be connected to the emitter portion 914 through the passivation layer 93. The second electrode 95 is located on the passivation layer 93 and can pass through the passivation layer 93 to connect the back electrode. table Surface electric field portion 915.
該背接觸太陽能電池的主要特色在於：該第一電極94與該第二電極95都位於該基板91的背面912，而該受光面911側未設置任何電極，所以可增加該受光面911可受光的面積而提升入光量。又當光線照射在該太陽能電池的受光面911上時，在該基板91內越靠近該受光面911處所生成的載子數量越高，相對地前述載子傳導至位於該背面912的該射極部914或該背表面電場部915的傳輸路徑(Travelling Length)較長，載子有可能在傳導過程中便複合(Recombination)而無法被使用。因此，若能增加載子進入該射極部914或該背表面電場部915的機會以增進載子收集效率，則將可進一步再提升該背接觸太陽能電池的光電轉換效率。The main feature of the back contact solar cell is that the first electrode 94 and the second electrode 95 are both located on the back surface 912 of the substrate 91, and no electrode is disposed on the light receiving surface 911 side, so that the light receiving surface 911 can be increased. The area is increased by the amount of light. Further, when light is incident on the light receiving surface 911 of the solar cell, the higher the number of carriers generated in the substrate 91 toward the light receiving surface 911, the relative carrier is transmitted to the emitter located on the back surface 912. The portion 914 or the back surface electric field portion 915 has a long Travelling Length, and the carrier may be recombined during the conduction process and cannot be used. Therefore, if the opportunity for the carrier to enter the emitter portion 914 or the back surface electric field portion 915 can be increased to enhance the carrier collection efficiency, the photoelectric conversion efficiency of the back contact solar cell can be further improved.
因此，本發明之目的，即在提供一種可增進載子收集效率，進而提升光電轉換效率的背接觸太陽能電池及其模組。Accordingly, it is an object of the present invention to provide a back contact solar cell and a module thereof that can improve carrier collection efficiency and thereby improve photoelectric conversion efficiency.
於是，本發明背接觸太陽能電池，包含：一基板，以及一電極。Thus, the back contact solar cell of the present invention comprises: a substrate, and an electrode.
該基板包括相反的一受光面與一背面、一位於該受光面側的選擇式前表面電場部，以及位於該背面側的一背表面電場部與一射極部。該電極設置於該基板的背面並連接該背表面電場部與該射極部。其中，該選擇式前表面電場部具有一重摻雜區及一輕摻雜區。The substrate includes an opposite light receiving surface and a back surface, a selective front surface electric field portion on the light receiving surface side, and a back surface electric field portion and an emitter portion on the back surface side. The electrode is disposed on a back surface of the substrate and connects the back surface electric field portion and the emitter portion. The selective front surface electric field portion has a heavily doped region and a lightly doped region.
本發明背接觸太陽能電池模組，包含：相對設置的一第一板材與一第二板材、數個如前述且排列於該第一板材與該第二板材之間的背接觸太陽能電池，以及一位於該第一板材與該第二板材之間並包覆在該數個背接觸太陽能電池的周圍的封裝材。The back contact solar cell module of the present invention comprises: a first plate and a second plate disposed oppositely, a plurality of back contact solar cells arranged as described above and arranged between the first plate and the second plate, and a An encapsulating material between the first plate and the second plate and wrapped around the plurality of back contact solar cells.
本發明之功效在於：在該基板內設置該選擇式前表面電場部的創新設計，可縮短載子的傳輸路徑、降低載子複合機率，從而可提升載子進入該背表面電場部的機會而增進載子收集效率，並提升該背接觸太陽能電池的光電轉換效率。The invention has the advantages that the innovative design of the selective front surface electric field portion is arranged in the substrate, the carrier transmission path can be shortened, the carrier composite probability can be reduced, and the opportunity for the carrier to enter the electric field portion of the back surface can be improved. Improve carrier collection efficiency and improve the photoelectric conversion efficiency of the back contact solar cell.
11‧‧‧第一板材11‧‧‧ first plate
12‧‧‧第二板材12‧‧‧Second plate
13‧‧‧背接觸太陽能電池13‧‧‧Back contact solar cell
14‧‧‧封裝材14‧‧‧Package
2‧‧‧基板2‧‧‧Substrate
21‧‧‧背面21‧‧‧Back
22‧‧‧受光面22‧‧‧Glossy surface
23‧‧‧射極部23‧‧‧射极部
24‧‧‧背表面電場部24‧‧‧ Back surface electric field
25‧‧‧間隔部25‧‧‧Interval
26‧‧‧選擇式前表面電場部26‧‧‧Selective front surface electric field
261‧‧‧重摻雜區261‧‧‧ heavily doped area
262‧‧‧輕摻雜區262‧‧‧Lightly doped area
27‧‧‧鈍化層27‧‧‧ Passivation layer
28‧‧‧抗反射層28‧‧‧Anti-reflective layer
3‧‧‧電極3‧‧‧Electrode
31‧‧‧第一接觸電極31‧‧‧First contact electrode
32‧‧‧第二接觸電極32‧‧‧Second contact electrode
81‧‧‧中心線81‧‧‧ center line
82‧‧‧中心線82‧‧‧ center line
83‧‧‧中心線83‧‧‧ center line
d1‧‧‧摻雜深度D1‧‧‧Doping depth
d2‧‧‧摻雜深度D2‧‧‧Doping depth
d3‧‧‧摻雜深度D3‧‧‧Doping depth
d4‧‧‧摻雜深度D4‧‧‧Doping depth
t1‧‧‧寬度Width of t1‧‧‧
t2‧‧‧寬度Width of t2‧‧‧
本發明之其他的特徵及功效，將於參照圖式的實施方式中清楚地呈現，其中：圖1是一種已知的指叉式背接觸太陽能電池的剖視示意圖；圖2是本發明背接觸太陽能電池模組之一第一較佳實施例之一局部剖視示意圖；圖3是該第一較佳實施例之一背接觸太陽能電池之一剖視示意圖；圖4是該背接觸太陽能電池之一俯視示意圖，圖中省略該背接觸太陽能電池之一抗反射層，並顯示該背接觸太陽能電池之一選擇式前表面電場部之形貌；圖5是一類似圖4的示意圖，顯示該選擇式前表面電場部之另一種實施態樣； 圖6是本發明背接觸太陽能電池模組之一第二較佳實施例之一背接觸太陽能電池的剖視示意圖；及圖7是本發明背接觸太陽能電池模組之一第三較佳實施例之一背接觸太陽能電池的剖視示意圖。Other features and effects of the present invention will be apparent from the following description of the drawings, wherein: FIG. 1 is a schematic cross-sectional view of a known interdigitated back contact solar cell; FIG. 2 is a back contact of the present invention. A schematic cross-sectional view of a first preferred embodiment of a solar cell module; FIG. 3 is a schematic cross-sectional view of a back contact solar cell of the first preferred embodiment; FIG. 4 is a schematic view of the back contact solar cell A top view, in which the anti-reflection layer of the back contact solar cell is omitted, and the top surface of the selective front surface electric field of the back contact solar cell is displayed; FIG. 5 is a schematic view similar to FIG. 4, showing the selection Another embodiment of the front surface electric field portion; 6 is a cross-sectional view showing a back contact solar cell of a second preferred embodiment of the back contact solar cell module of the present invention; and FIG. 7 is a third preferred embodiment of the back contact solar cell module of the present invention. A cross-sectional schematic view of one of the back contact solar cells.
在本發明被詳細描述之前，應當注意在以下的說明內容中，類似的元件是以相同的編號來表示。Before the present invention is described in detail, it should be noted that in the following description, similar elements are denoted by the same reference numerals.
參閱圖2，本發明背接觸太陽能電池模組之一第一較佳實施例包含：上下相對設置的一第一板材11與一第二板材12、數個陣列式排列於該第一板材11與該第二板材12之間的背接觸太陽能電池13，以及一位於該第一板材11與該第二板材12之間且包覆在該數個背接觸太陽能電池13周圍的封裝材14。當然在實施上，該背接觸太陽能電池模組可以僅包含一背接觸太陽能電池13。Referring to FIG. 2, a first preferred embodiment of the back contact solar cell module of the present invention comprises: a first plate 11 and a second plate 12 disposed opposite each other, and a plurality of arrays arranged on the first plate 11 and The back contact solar cell 13 between the second sheets 12 and a package 14 between the first sheet 11 and the second sheet 12 and surrounding the plurality of back contact solar cells 13. Of course, in practice, the back contact solar cell module may include only one back contact solar cell 13.
在本實施例中，該第一板材11與該第二板材12的材料在實施上沒有特殊限制，可以使用玻璃或塑膠板材，而且位於該背接觸太陽能電池13之受光側的板材必須可透光。該封裝材14的材質例如可透光的乙烯醋酸乙烯共聚物(EVA)，或其他可用於背接觸太陽能電池模組封裝的相關材料，並不限於本實施例的舉例。此外，該數個背接觸太陽能電池13彼此之間可透過數個圖未示的焊帶導線(Ribbon)電連接。In this embodiment, the material of the first plate 11 and the second plate 12 is not particularly limited in implementation, and a glass or plastic plate may be used, and the plate on the light receiving side of the back contact solar cell 13 must be transparent. . The material of the encapsulant 14 is, for example, a light transmissive ethylene vinyl acetate copolymer (EVA), or other related materials that can be used for the back contact solar cell module package, and is not limited to the examples of the embodiment. In addition, the plurality of back contact solar cells 13 are electrically connected to each other through a plurality of ribbons (not shown).
由於該背接觸太陽能電池模組的結構非本發明改良的重點，不再說明，於圖2中也僅為簡單示意。此 外，由於該數個背接觸太陽能電池13的結構都相同，以下僅以其中一個為例進行說明。當然，在一模組中的該數個背接觸太陽能電池13的結構不以相同為絕對之必要。Since the structure of the back contact solar cell module is not an improvement of the present invention, it will not be described again, and is also simply illustrated in FIG. this In addition, since the structures of the plurality of back contact solar cells 13 are the same, only one of them will be described below as an example. Of course, the structure of the plurality of back contact solar cells 13 in a module is not absolutely necessary.
參閱圖3、4，本實施例的背接觸太陽能電池13包含：一基板2，以及一配置於該基板2上的電極3。Referring to FIGS. 3 and 4, the back contact solar cell 13 of the present embodiment includes a substrate 2 and an electrode 3 disposed on the substrate 2.
本實施例的基板2包括相反的一背面21與一受光面22、兩個位於該背面21側且彼此間隔的射極部(Emitter Portion)23、一位於該背面21側且位於該兩個射極部23之間的背表面電場部(Back Surface Field Portion)24、兩個位於該背面21側且分別將該背表面電場部24與該兩個射極部23間隔開的間隔部25，以及一位於該受光面22側的選擇式前表面電場部(Selective Front Surface Field Portion)26。其中，在實施上，在該背面21上還可設置一鈍化層27，而在該受光面22上還可設置一抗反射層28。The substrate 2 of the present embodiment includes an opposite back surface 21 and a light receiving surface 22, two emitter portions (Emitter Portions) 23 spaced apart from each other on the back surface 21 side, and one on the back surface 21 side and located in the two shots. a back surface field portion 24 between the pole portions 23, and two spacer portions 25 on the side of the back surface 21 and respectively separating the back surface electric field portion 24 from the two emitter portions 23, and A Selective Front Surface Field Portion 26 on the side of the light receiving surface 22 is provided. In the implementation, a passivation layer 27 may be disposed on the back surface 21, and an anti-reflection layer 28 may be disposed on the light-receiving surface 22.
本實施例的基板2為n型半導體基板，並可使用單晶或多晶矽基板。當然在實施上，該基板2的受光面22可製作成粗糙化結構以提高入光量，由於前述粗糙化結構非本發明改良的重點，不再詳述，於圖3中也僅簡單示意該受光面22的結構。The substrate 2 of the present embodiment is an n-type semiconductor substrate, and a single crystal or polycrystalline germanium substrate can be used. Of course, in practice, the light-receiving surface 22 of the substrate 2 can be made into a roughened structure to increase the amount of light incident. Since the roughened structure is not an improvement of the present invention, it will not be described in detail, and the light-receiving is simply illustrated in FIG. The structure of the face 22.
該兩個射極部23是在該基板2的背面21側之局部區域進行擴散製程(例如硼擴散)所形成重摻雜的p型半導體，而該背表面電場部24是在該基板2的背面21側之局部區域進行擴散製程(例如磷擴散)所形成載子濃度大 於該基板2的n++ 型半導體。進一步說明的是，若該基板2使用p型半導體基板時，則該背表面電場部24就會製作成摻雜濃度大於前述p型基板2之p++ 型半導體，而該兩個射極部23則製作成n型半導體。The two emitter portions 23 are heavily doped p-type semiconductors formed by a diffusion process (for example, boron diffusion) in a partial region on the back surface 21 side of the substrate 2, and the back surface electric field portion 24 is on the substrate 2. The local region on the side of the back surface 21 is subjected to a diffusion process (for example, phosphorus diffusion) to form a carrier having a concentration higher than that of the n ++ type semiconductor of the substrate 2. Further, when the substrate 2 is a p-type semiconductor substrate, the back surface electric field portion 24 is formed as a p ++ type semiconductor having a doping concentration greater than that of the p-type substrate 2, and the two emitter portions are formed. 23 is made into an n-type semiconductor.
該兩個間隔部25分別位於該兩個射極部23與該背表面電場部24之間，用於隔開該兩個射極部23與該背表面電場部24，以避免寄生分流(Parasitic Shunting)現象而產生漏電流(Leakage Current)。實際上，利用擴散製程製作該兩個射極部23與該背表面電場部24時，可透過適當的製程控制，使該兩個射極部23與該背表面電場部24間隔，則該兩個射極部23與該背表面電場部24之間的區域就成為該兩個間隔部25，亦即，該兩個間隔部25是該基板2未額外進行擴散製程的區域。The two spacers 25 are respectively located between the two emitter portions 23 and the back surface electric field portion 24 for spacing the two emitter portions 23 and the back surface electric field portion 24 to avoid parasitic shunting (Parasitic Shunting) causes leakage current (Leakage Current). Actually, when the two emitter portions 23 and the back surface electric field portion 24 are formed by a diffusion process, the two emitter portions 23 and the back surface electric field portion 24 can be separated by appropriate process control. The area between the emitter portion 23 and the back surface electric field portion 24 becomes the two spacer portions 25, that is, the two spacer portions 25 are regions in which the substrate 2 is not additionally subjected to a diffusion process.
該選擇式前表面電場部26為n型半導體，並可提升載子收集效率及光電轉換效率。在實施上，該選擇式前表面電場部26可利用擴散製程(Diffusion Process)、摻雜膠(Doping Paste)、回蝕(Etching Back)或雷射熱處理誘導擴散(Laser Heat Induced Diffusion)等方式形成於該基板2的受光面22側之內。需要說明的是，若該基板2使用p型半導體基板時，則該選擇式前表面電場部26就會製作成載子濃度大於該p型基板2的p型半導體。The selective front surface electric field portion 26 is an n-type semiconductor and can improve carrier collection efficiency and photoelectric conversion efficiency. In practice, the selective front surface electric field portion 26 can be formed by a diffusion process, a Doping Paste, an Etching Back, or a Laser Heat Induced Diffusion. It is within the light-receiving surface 22 side of the substrate 2. In the case where the substrate 2 is a p-type semiconductor substrate, the selective front surface electric field portion 26 is formed as a p-type semiconductor having a carrier concentration larger than that of the p-type substrate 2.
該選擇式前表面電場部26具有一位置對應該背表面電場部24的重摻雜區261，以及一位置對應該兩個射極部23與該兩個間隔部25的輕摻雜區262。該重摻雜區 261的摻雜濃度與摻雜深度d1皆大於該輕摻雜區262的摻雜濃度與摻雜深度d2，也就是該選擇式前表面電場部26整體的摻雜濃度與摻雜深度非均勻，並選擇地在一些部位的摻雜濃度較重且摻雜深度較深而在另一些部位的摻雜濃度較輕且摻雜深度淺。The selective front surface electric field portion 26 has a heavily doped region 261 corresponding to the back surface electric field portion 24, and a lightly doped region 262 corresponding to the two emitter portions 23 and the two spacer portions 25. Heavy doped region The doping concentration and the doping depth d1 of the 261 are greater than the doping concentration and the doping depth d2 of the lightly doped region 262, that is, the doping concentration and the doping depth of the selective front surface electric field portion 26 are non-uniform, Optionally, the doping concentration is relatively heavy in some places and the doping depth is deep, while in other parts, the doping concentration is lighter and the doping depth is shallow.
本實施例的重摻雜區261的一中心線81對齊該背表面電場部24的一中心線82，並且該重摻雜區261的寬度t1與該背表面電場部24的寬度t2相同。當然在實施上該中心線81不以對齊該中心線82為必要，而寬度t1與寬度t2亦不以相同為必要，以上設計皆可依實際需求調整。其中，若該重摻雜區261的寬度t1大於該背表面電場部24的寬度t2，則該重摻雜區261可同時對應該背表面電場部24與該兩個間隔部25。A center line 81 of the heavily doped region 261 of the present embodiment is aligned with a center line 82 of the back surface electric field portion 24, and the width t1 of the heavily doped region 261 is the same as the width t2 of the back surface electric field portion 24. Of course, in the implementation, the center line 81 is not necessary to align the center line 82, and the width t1 and the width t2 are not the same. The above designs can be adjusted according to actual needs. Wherein, if the width t1 of the heavily doped region 261 is greater than the width t2 of the back surface electric field portion 24, the heavily doped region 261 can simultaneously correspond to the back surface electric field portion 24 and the two spacer portions 25.
需要說明的是，本實施例對該基板2的受光面22的全部區域進行擴散製程，並選擇地對該受光面22不同的局部區域進行不同摻雜濃度與不同摻雜深度的擴散製程，藉此在該受光面22側之內的全部區域形成該選擇式前表面電場部26，並且該選擇式前表面電場部26的重摻雜區261與輕摻雜區262的載子濃度皆大於該基板2。當然在實施上，也可選擇地僅對該受光面22的局部區域進行擴散製程，此時該基板2內載子濃度高於該基板2的區域即為本發明所述的重摻雜區261，而該基板2內未額外進行擴散製程，且載子濃度與該基板2相同的區域即為本發明所述的輕摻雜區262。It should be noted that, in this embodiment, the entire area of the light-receiving surface 22 of the substrate 2 is subjected to a diffusion process, and the diffusion process of different doping concentrations and different doping depths is selectively performed on different local regions of the light-receiving surface 22, The selective front surface electric field portion 26 is formed in all regions within the light receiving surface 22 side, and the carrier concentration of the heavily doped region 261 and the lightly doped region 262 of the selective front surface electric field portion 26 are both larger than the Substrate 2. Of course, in practice, only a partial region of the light-receiving surface 22 may be selectively subjected to a diffusion process. At this time, the region in which the carrier concentration in the substrate 2 is higher than the substrate 2 is the heavily doped region 261 of the present invention. The region in which the diffusion process is not additionally performed in the substrate 2 and the carrier concentration is the same as that of the substrate 2 is the lightly doped region 262 of the present invention.
進一步說明的是，本實施例的重摻雜區261可為圖4所示的數個彼此間隔的島狀結構，當然在實施上，該重摻雜區261也可為圖5所示的一連續條狀結構，或者其他造型，而不限於本實施例之舉例。It is further noted that the heavily doped region 261 of the present embodiment may be a plurality of island structures spaced apart from each other as shown in FIG. 4 . Of course, in practice, the heavily doped region 261 may also be one as shown in FIG. 5 . A continuous strip structure, or other shape, is not limited to the examples of the embodiment.
請再參閱圖3、4，除此之外，本發明在製造時，還可先在該基板2的受光面22與背面21分別以雷射蝕刻形成上下對應凹溝，作為後續進行擴散製程的對位之用，藉此在製作該兩個射極部23、該背表面電場部24與該選擇式前表面電場部26時，該重摻雜區261的位置能精確地對應該背表面電場部24而增加製造精準度。當然，對位的手段亦不限於前述之舉例。Referring to FIGS. 3 and 4, in addition, in the manufacturing process, the upper and lower corresponding grooves may be formed by laser etching on the light-receiving surface 22 and the back surface 21 of the substrate 2, respectively, as a subsequent diffusion process. For the alignment, whereby the positions of the heavily doped region 261 can accurately correspond to the back surface electric field when the two emitter portions 23, the back surface electric field portion 24 and the selective front surface electric field portion 26 are fabricated Part 24 increases manufacturing precision. Of course, the means of alignment is not limited to the foregoing examples.
該鈍化層27位於該背面21上，並覆蓋於該兩個射極部23、該背表面電場部24與該兩個間隔部25上。該鈍化層27的材料可為氧化物、氮化物或上述材料的組合，並用於鈍化、修補該基板2的表面以減少表面之懸鍵(Dangling Bond)與缺陷，從而可減少載子陷阱(Trap)及降低載子的表面複合速率(Surface Recombination Velocity，簡稱SRV)，以提升該背接觸太陽能電池13的光電轉換效率。而該抗反射層28位於該受光面22，並覆蓋於該選擇式前表面電場部26上，其材料例如氮化矽(SiNx )等，用於提升光線入射量以及降低載子表面複合速率。由於本發明不以設置該鈍化層27及該抗反射層28為絕對之必要，而且本發明的改良不在於此，所以不再詳述。The passivation layer 27 is located on the back surface 21 and covers the two emitter portions 23, the back surface electric field portion 24, and the two spacer portions 25. The material of the passivation layer 27 may be an oxide, a nitride or a combination of the above materials, and used to passivate and repair the surface of the substrate 2 to reduce Dangling Bond and defects of the surface, thereby reducing carrier traps (Trap) And reducing the surface recombination Velocity (SRV) of the carrier to improve the photoelectric conversion efficiency of the back contact solar cell 13. The anti-reflection layer 28 is located on the light-receiving surface 22 and covers the selective front surface electric field portion 26, such as tantalum nitride (SiN x ), for increasing the incident light amount and reducing the surface recombination rate of the carrier. . Since the present invention is not necessary to provide the passivation layer 27 and the anti-reflection layer 28, and the improvement of the present invention is not here, it will not be described in detail.
本實施例的電極3位於該基板2的背面21且位 於該鈍化層27上，並連接該兩個射極部23及該背表面電場部24。該電極3包括兩個分別穿過該鈍化層27而分別連接該兩個射極部23的第一接觸電極31，以及一穿過該鈍化層27而連接該背表面電場部24的第二接觸電極32。The electrode 3 of this embodiment is located on the back surface 21 of the substrate 2 and has a position The two emitter portions 23 and the back surface electric field portion 24 are connected to the passivation layer 27. The electrode 3 includes two first contact electrodes 31 respectively passing through the passivation layer 27 to connect the two emitter portions 23, and a second contact connecting the back surface electric field portion 24 through the passivation layer 27. Electrode 32.
需要說明的是，本實施例雖然以兩個射極部23、一個背表面電場部24及兩個間隔部25為例進行說明，但實際上在一背接觸太陽能電池13中，射極部23與背表面電場部24的數量可以為更多個，並以p-n-p-n之交錯方式重複排列配置，任一組相鄰的射極部23與背表面電場部24之間即形成一個間隔部25。而且相對應地，輕摻雜區262與第一接觸電極31對應射極部23的位置，而重摻雜區261與第二接觸電極32則對應背表面電場部24的位置。此外，本發明也可以只針對其中一組射極部23、背表面電場部24及間隔部25來進行改良。It should be noted that in the present embodiment, the two emitter portions 23, the one back surface electric field portion 24, and the two spacer portions 25 are taken as an example. However, in the back contact solar cell 13, the emitter portion 23 is actually used. The number of the back surface electric field portions 24 may be more and arranged in a staggered manner in a pnpn manner, and a spacer portion 25 is formed between any one of the adjacent emitter portions 23 and the back surface electric field portion 24. Correspondingly, the lightly doped region 262 corresponds to the position of the emitter portion 23 of the first contact electrode 31, and the heavily doped region 261 and the second contact electrode 32 correspond to the position of the back surface electric field portion 24. Further, the present invention may be modified only for one of the emitter portion 23, the back surface electric field portion 24, and the spacer portion 25.
在使用時，本實施例的選擇式前表面電場部26除了可作為該受光面22的鈍化層之外，該選擇式前表面電場部26的導電性優於該基板2之未摻雜區域的導電性，且該選擇式前表面電場部26串聯電阻較低之特性，有利於載子之橫向運送，並可作為載子移動的通道。而且本實施例將該選擇式前表面電場部26分成摻雜深度d1較深的該重摻雜區261與摻雜深度d2較淺的該輕摻雜區262，使該重摻雜區261較該輕摻雜區262朝該背面21突出，如此可增加該選擇式前表面電場部26的接觸面積(Junction Area)而增進擷取載子的機會。此外，由於本實施例的基板22為n 型半導體基板，其主要載子為電子，所以本實施例將較突出的該重摻雜區261設置於該背表面電場部24的上方。In use, the selective front surface electric field portion 26 of the present embodiment can be used as the passivation layer of the light receiving surface 22, and the conductivity of the selective front surface electric field portion 26 is superior to that of the undoped region of the substrate 2. The conductivity, and the characteristic that the selective front surface electric field portion 26 has a low series resistance is advantageous for lateral transport of the carrier and can serve as a passage for the carrier to move. Moreover, in this embodiment, the selective front surface electric field portion 26 is divided into the lightly doped region 261 having a deeper doping depth d1 and the lightly doped region 262 having a shallower doping depth d2, so that the heavily doped region 261 is compared. The lightly doped region 262 protrudes toward the back surface 21, which increases the contact area of the selective front surface electric field portion 26 and enhances the chance of picking up the carrier. In addition, since the substrate 22 of the embodiment is n In the semiconductor substrate, the main carrier is electrons. Therefore, in this embodiment, the more heavily doped region 261 is disposed above the back surface electric field portion 24.
因此，當光線照射在該背接觸太陽能電池13的受光面22上時，在該基板2內越靠近該受光面22的部分所生成的載子數量越高，此時載子可進入電阻較低的該選擇式前表面電場部26中傳導，藉此降低該背接觸太陽能電池13的串聯電阻。接著，當主要載子來到該背表面電場部24上方時，由於該重摻雜區261的摻雜深度d1較深而可縮短其與該背面21之間的距離，從而縮短主要載子的傳輸路徑(Travelling Length)並減少載子複合的機率，因而增加主要載子進入該背表面電場部24的機會而增進載子收集效率，並提升該背接觸太陽能電池13的光電轉換效率。Therefore, when light is incident on the light-receiving surface 22 of the back-contact solar cell 13, the higher the number of carriers generated in the portion of the substrate 2 that is closer to the light-receiving surface 22, the lower the resistance of the carrier can be entered. The selected front surface electric field portion 26 conducts, thereby reducing the series resistance of the back contact solar cell 13. Then, when the main carrier comes above the back surface electric field portion 24, since the doping depth d1 of the heavily doped region 261 is deep, the distance between the main carrier and the back surface 21 can be shortened, thereby shortening the main carrier. The Travelling Length reduces the probability of carrier recombination, thereby increasing the chance that the main carrier enters the back surface electric field portion 24 to enhance the carrier collection efficiency and improve the photoelectric conversion efficiency of the back contact solar cell 13.
參閱圖6，本發明背接觸太陽能電池模組之一第二較佳實施例，與該第一較佳實施例的結構大致相同，不同的地方在於：該背接觸太陽能電池13的選擇式前表面電場部26的結構設計與位置。Referring to FIG. 6, a second preferred embodiment of the back contact solar cell module of the present invention is substantially the same as the structure of the first preferred embodiment, except that the back surface of the back contact solar cell 13 is selected. The structural design and position of the electric field portion 26.
本實施例的選擇式前表面電場部26具有兩個位置分別對應該兩個間隔部25的重摻雜區261，以及一個位置對應該兩個射極部23與該背表面電場部24的輕摻雜區262。該兩個重摻雜區261的中心線81分別對齊該兩個間隔部25的一中心線83，當然在實施上該兩個中心線81不以對齊該兩個中心線83之設計為必要。The selective front surface electric field portion 26 of the present embodiment has two heavily doped regions 261 respectively corresponding to the two spacer portions 25, and one position corresponding to the light of the two emitter portions 23 and the back surface electric field portion 24 Doped region 262. The centerlines 81 of the two heavily doped regions 261 are respectively aligned with a centerline 83 of the two spacers 25, although it is of course necessary in practice to design the two centerlines 81 not to align the two centerlines 83.
本實施例的重摻雜區261是透過雷射熱處理誘導擴散方式製成，並具有漸變摻雜濃度(Graded Doped)結 構，即每一重摻雜區261的摻雜濃度與摻雜深度皆由外側朝該中心線81增加。每一重摻雜區261之摻雜濃度最高且摻雜深度d3最深的區域位於中央，且位置對應該兩個間隔部25，而每一重摻雜區261之摻雜濃度最低且摻雜深度d4最淺的區域位於外側，且位置對應該兩個射極部23與該背表面電場部24。該輕摻雜區262的摻雜濃度與摻雜深度d2皆小於每一重摻雜區261之摻雜濃度最低且摻雜深度d4最淺的區域，換句話說，該輕摻雜區262的摻雜深度d2小於該等重摻雜區261的摻雜深度d4，當然代表該輕摻雜區262的摻雜深度d2小於該等重摻雜區261的任一部位的摻雜深度。The heavily doped region 261 of the present embodiment is formed by a laser heat treatment induced diffusion method and has a graded doped concentration (Graded Doped) junction. The doping concentration and the doping depth of each heavily doped region 261 are increased from the outer side toward the center line 81. The region with the highest doping concentration of each heavily doped region 261 and the deepest doping depth d3 is located at the center, and the position corresponds to the two spacers 25, and the doping concentration of each heavily doped region 261 is the lowest and the doping depth d4 is the most. The shallow regions are located on the outside and correspond to the two emitter portions 23 and the back surface electric field portion 24. The doping concentration and the doping depth d2 of the lightly doped region 262 are both smaller than the region where the doping concentration of each heavily doped region 261 is the lowest and the doping depth d4 is the shallowest, in other words, the doping of the lightly doped region 262 The impurity depth d2 is smaller than the doping depth d4 of the heavily doped regions 261, which of course represents that the doping depth d2 of the lightly doped region 262 is smaller than the doping depth of any portion of the heavily doped regions 261.
由於該背接觸太陽能電池13為背接觸的形式，因此該基板2的位於該兩個間隔部25上方的部位所生成的主要載子的數量最多，因此本實施例將該兩個重摻雜區261分別設置於該兩個間隔部25上方，藉此一方面減少電屏蔽效應(Electrical Shading Effect)於該背表面電場部24上方所造成的影響，另一方面可將該兩個間隔部25內高濃度的載子推向該兩個射極部23，故能提升填充因子(Fill Factor)。Since the back contact solar cell 13 is in the form of a back contact, the number of main carriers generated by the portion of the substrate 2 above the two spacers 25 is the largest, so the two heavily doped regions in this embodiment 261 is respectively disposed above the two spacers 25, thereby reducing the influence of the electrical shielding effect on the back surface electric field portion 24 on the one hand, and the two spacers 25 on the other hand. The high concentration of the carrier is pushed toward the two emitter portions 23, so that the fill factor can be increased.
參閱圖7，本發明背接觸太陽能電池模組之一第三較佳實施例，與該第二較佳實施例的結構大致相同，兩者之間的差別在於：該選擇式前表面電場部26具有一個為漸變摻雜濃度結構的重摻雜區261，以及一輕摻雜區262。Referring to FIG. 7, a third preferred embodiment of the back contact solar cell module of the present invention is substantially the same as the structure of the second preferred embodiment. The difference between the two is that the selective front surface electric field portion 26 There is a heavily doped region 261 having a graded doping concentration structure, and a lightly doped region 262.
本實施例的重摻雜區261的位置同時對應該背表面電場部24、該兩個間隔部25與該兩個射極部23。該重摻雜區261摻雜濃度最高且摻雜深度d3最深的區域位於中央，且位置對應該背表面電場部24，且該重摻雜區261摻雜濃度最低且摻雜深度d4最淺的區域位於外側，且位置對應該兩個射極部23。而該輕摻雜區262的位置對應該兩個射極部23，且其摻雜濃度與摻雜深度d2皆小於該重摻雜區261摻雜濃度最低且摻雜深度d4最淺的區域。The position of the heavily doped region 261 of the present embodiment simultaneously corresponds to the back surface electric field portion 24, the two spacer portions 25, and the two emitter portions 23. The heavily doped region 261 has the highest doping concentration and the deepest doping depth d3 is located at the center, and the position corresponds to the back surface electric field portion 24, and the heavily doped region 261 has the lowest doping concentration and the shallowest doping depth d4. The area is located on the outside and the position corresponds to the two emitter sections 23. The position of the lightly doped region 262 corresponds to the two emitter portions 23, and the doping concentration and the doping depth d2 are smaller than the region where the doping concentration of the heavily doped region 261 is the lowest and the doping depth d4 is the shallowest.
綜合以上三個較佳實施例可知，本發明在基板內設置選擇式前表面電場部，使重摻雜區的位置對應背表面電場部或/及間隔部，同時配合重摻雜區的摻雜深度較深而相對輕摻雜區朝背面突出的結構，前述創新設計除了增加選擇式前表面電場部的接觸面積而增進擷取載子的機會之外，還可縮短載子的傳輸路徑而增加載子進入背表面電場部的機會，藉此減少載子複合的機會而增進載子收集效率，並提升本發明之背接觸太陽能電池的光電轉換效率。According to the above three preferred embodiments, the present invention provides a selective front surface electric field portion in the substrate such that the position of the heavily doped region corresponds to the back surface electric field portion and/or the spacer portion, and at the same time, the doping of the heavily doped region is matched. The structure with deeper depth and relatively lightly doped regions protruding toward the back side, the aforementioned innovative design can increase the contact area of the selective front surface electric field portion and increase the chance of picking up the carrier, and can shorten the transmission path of the carrier and increase The opportunity for the carrier to enter the electric field portion of the back surface, thereby reducing the chance of carrier recombination, enhances the efficiency of carrier collection, and enhances the photoelectric conversion efficiency of the back contact solar cell of the present invention.
惟以上所述者，僅為本發明之較佳實施例而已，當不能以此限定本發明實施之範圍，即大凡依本發明申請專利範圍及專利說明書內容所作之簡單的等效變化與修飾，皆仍屬本發明專利涵蓋之範圍內。The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the patent application scope and patent specification content of the present invention, All remain within the scope of the invention patent.
13‧‧‧背接觸太陽能電池13‧‧‧Back contact solar cell
2‧‧‧基板2‧‧‧Substrate
21‧‧‧背面21‧‧‧Back
22‧‧‧受光面22‧‧‧Glossy surface
23‧‧‧射極部23‧‧‧射极部
24‧‧‧背表面電場部24‧‧‧ Back surface electric field
25‧‧‧間隔部25‧‧‧Interval
26‧‧‧選擇式前表面電場部26‧‧‧Selective front surface electric field
261‧‧‧重摻雜區261‧‧‧ heavily doped area
262‧‧‧輕摻雜區262‧‧‧Lightly doped area
27‧‧‧鈍化層27‧‧‧ Passivation layer
28‧‧‧抗反射層28‧‧‧Anti-reflective layer
3‧‧‧電極3‧‧‧Electrode
31‧‧‧第一接觸電極31‧‧‧First contact electrode
32‧‧‧第二接觸電極32‧‧‧Second contact electrode
81‧‧‧中心線81‧‧‧ center line
82‧‧‧中心線82‧‧‧ center line
d1‧‧‧摻雜深度D1‧‧‧Doping depth
d2‧‧‧摻雜深度D2‧‧‧Doping depth
t1‧‧‧寬度Width of t1‧‧‧
t2‧‧‧寬度Width of t2‧‧‧
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| US7820475B2 (en) * | 2005-12-21 | 2010-10-26 | Sunpower Corporation | Back side contact solar cell structures and fabrication processes |
| WO2012036760A1 (en) * | 2010-09-16 | 2012-03-22 | Specmat, Inc. | Method, process and fabrication technology for high-efficency low-cost crytalline silicon solar cells |
| TW201220369A (en) * | 2010-10-01 | 2012-05-16 | Varian Semiconductor Equipment | Method of implanting ions into a substrate, method of performing multiple ion implants using different patterns to a plurality of substrates, and a carrier |
| TW201222851A (en) * | 2010-11-16 | 2012-06-01 | Mosel Vitelic Inc | Manufacturing method of bifacial solar cells |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7820475B2 (en) * | 2005-12-21 | 2010-10-26 | Sunpower Corporation | Back side contact solar cell structures and fabrication processes |
| WO2012036760A1 (en) * | 2010-09-16 | 2012-03-22 | Specmat, Inc. | Method, process and fabrication technology for high-efficency low-cost crytalline silicon solar cells |
| TW201220369A (en) * | 2010-10-01 | 2012-05-16 | Varian Semiconductor Equipment | Method of implanting ions into a substrate, method of performing multiple ion implants using different patterns to a plurality of substrates, and a carrier |
| TW201222851A (en) * | 2010-11-16 | 2012-06-01 | Mosel Vitelic Inc | Manufacturing method of bifacial solar cells |
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