M422756 五、新型說明： 【新型所屬之技術領域】 本創作係關於一種太陽能電池。 【先前技術】 由於石化能源短缺，人們對環保重要性的認知提高， 沐s自人們近年來^斷地積極研發替代能源與再生能源的 技術’希望可以減少目前人_對於石化能源的依賴輕 处、、及使用石化能源時對環境帶來的影響。在眾多的替代 此源與再生能源的技術中’以太陽能電池（solar cell)最 受嗎曰。 ^M422756 V. New description: [New technical field] This creation is about a solar cell. [Prior Art] Due to the shortage of petrochemical energy, people's awareness of the importance of environmental protection has increased. Muss has been actively researching and developing alternative energy and renewable energy technologies in recent years. 'I hope to reduce the current people's dependence on petrochemical energy. And the impact on the environment when using petrochemical energy. Among the many alternatives to this source and renewable energy technology, solar cells are the most popular. ^
Ab 。主要是因為太陽能電池可直接將太陽能轉換成電 Z且發電過程中不會產生二氧化碳或氮化物等有害物 質’不會對環境造成污染。 般而言，習知矽晶太陽能電池通常是於半導體基板 和用擴政（diffusion )或離子佈植（i〇n impiantaH〇n ) 方式來摻雜反態雜質（c〇unter-doping)以形成摻雜層並製 作電極。當光線由外侧照射至矽晶太陽能電池時，摻雜層 因又光子數發而產生自由電子·電洞對，並藉由p_N接面所 开少成的内電場使電子與電洞分離，且分別往兩端移動，而 產生電能的形態’此時若外加負載電路或電子裝置，便可 提供電能而使電路或裝置進行驅動。 然而，在現行矽晶太陽能電池的摻雜層之表面摻雜濃 度往往高於lxlO21 atoms/cm3，這些濃度過高的表面摻雜 成為大量的再結合中心（recombination center )’使得照光 M422756 產生的自由電子、電洞在這些再結合中心被消除。並且， 在正面電極（front electrode)與摻雜層之間的接觸表面會 有較多的懸浮鍵（dangling bond )，如此，自由電子、電洞 容易在靠近摻雜層與正面電極的接觸表面處產生表面再 結合（surface recombination)’而影響矽晶太陽能電池的 光電轉換效率。 因此，如何提供一種太陽能電池，可減少摻雜層的表 面再結合，進而提升太陽能電池的光電轉換效率，更可有 效保護太陽能電池’已成為太陽能製造產業的重要課題。 【新型内容】 有鑑於上述課題’本創作之目的為提供一種太陽能電 池，有別於現行半導體基板的高表面摻雜濃度，利用較低 表面摻雜濃度方式，達到降低再結合損失（recombination loss)之目的’進而提升光電轉換效率。 有鑑於上述課題，本創作之其他目的為提供一種太陽 能電池’搭配複合多功能保護膜，達到鈍化、抗反射及保 護的功能。 為達上述目的，依據本創作之一種太陽能電池包括一 半導體基板以及一複合多功能保護膜。半導體基板的表面 具有一摻雜層，摻雜層的深度介於200 nm至1000 nm之 間，換雜層的表面換雜濃度介於1χ1〇19至5x 102G atoms/cm3 之間。複合多功能保護膜設置於摻雜層之上，複合多功能 保護膜具有複數膜層，達到鈍化、抗反射及保護的功能。 5 M422756 該些膜層最接近掺雜層的一層，其膜層厚度小於40 nm。 於本創作之一實施例中，半導體基板可為P型半導體 基板或N型半導體基板。當半導體基板為P型半導體基板 時，摻雜層的摻雜元素為N型，其例如但不限於磷、砷、 銻、鉍、或其組合；當半導體基板為N型半導體基板時， 摻雜層的摻雜元素為P型，其例如但不限於硼、鋁、鎵、 銦、銘、或其組合。 於本創作之一實施例中，太陽能電池更可包括複數電 極，該些電極分別設置於太陽能電池的一光入射表面及一 背光表面，以作為正面電極及背面電極。 於本創作之一實施例中，半導體基板可為單晶矽基 板、多晶矽基板或非晶矽基板。 承上所述，本創作之太陽能電池係藉由降低半導體基 板的表面摻雜濃度，進而降低電子電洞的再結合損失。另 外，更設置複數膜層構成的複合多功能保護膜於摻雜層之 上，達到鈍化、抗反射及保護等功能以保護太陽能電池， 避免外力、環境或氣候等因素影響光電轉換效率及外觀。 本創作之太陽能電池不僅能夠降低電池表面的自由電 子、電洞複合速度，達到提高光電流的作用，同時還具有 保護太陽能電池，防到傷、防濕氣等功效，更減少入射光 的反射，進而提升整體太陽能電池的光電轉換效率及性 能0 【實施方式】 M422756 以下將參照相關圖式，說明依本創作較佳實施例之一 種太陽能電池，其中相同的元件將以相同的參照符號加以 說明。 請參照圖1所示，其為本創作較佳實施例之一種太陽 能電池的示意圖，圖1.中各結構的比例關係，為了方便顯 示及說明，故可能於實際結構的比例不符，於此僅作為參 考而非為限制性者。太陽能電池1包括一半導體基板2以 及一複合多功能保護膜4,半導體基板2的表面21具有一 •摻雜層3。 半導體基板2可為光電轉換基板，半導體基板2更可 為單晶矽基板、多晶矽基板、非晶矽基板等。於本實施例 中，半導體基板2為N型半導體基板或P型半導體基板。 本實施例之半導體基板2具有二表面21、22，其分別作為 半導體基板2的正面及背面；其中，表面21可為光入射 表面，而表面22為背光表面。 φ 摻雜層3係藉由半導體基板2的表面摻雜反態雜質所 ' 形成，摻雜方式可藉由擴散或離子佈植方式進行。當半導 體基板2為P型半導體基板時，則反態摻雜為N型摻雜元 素，例如但不限於磷、砷、銻、鉍、或其任二者（含）以 上的組合；當半導體基板2為N型半導體基板時，則反態 摻雜為P型摻雜元素，例如但不限於硼、鋁、鎵、銦、鉈、 或其任二者（含）以上的組合。 半導體基板2的表面21即為摻雜層3的表面，摻雜 層3的底面則構成P-N接面J，此P-N接面J兩端會形成 7 M422756 載子空乏區（depletion region )。載子空乏區提供内建電 場，將產生的自由電子送往N極，電洞送往P極。因此產 生了電流，此時只要外加電路將兩端連接即可利用太陽能 電池所產生的電力。 值得一提的是，本實施例之摻雜層3更具有一表面摻 雜濃度及一深度d ;其中，表面摻雜濃度係指摻雜層3的 表面21的摻雜元素濃度。例如，於本實施例中，係將磷 元素（N型半導體材料）摻雜入P型半導體基板2内，以 形成N型摻雜層3為例，則表面摻雜濃度係指磷元素於摻 雜層3的表面21的濃度，其表面摻雜濃度範圍乃為介於 lxl〇19至5xl02Q atoms/cm3之間，而摻雜層3的深度d範 圍則介於200 nm至1000 nm之間。 本實施例之太陽能電池1藉由降低摻雜層3的表面摻 雜元素之濃度，則摻雜層3内的摻雜元素濃度也隨之降 低，以降低載子再結合損失，進而提升光電轉換效率。 複合多功能保護膜4設置於摻雜層3之上，亦即複合 多功能保護膜4設置於半導體基板2的表面（光入射表面） 21。複合多功能保護膜4係具有複數膜層，本實施例係以 複合多功能保護膜4具有二膜層為例，然其非限制性，本 領域具有通常知識者當知，複合多功能保護膜4依據實際 需求可由更多膜層構成。 複數膜層分別為一第一膜層41及一第二膜層42，第 二膜層42設置於摻雜層3上，第一膜層41設置於第二膜 層42上。需注意的是，本實施例之第二膜層42具有一膜 M422756 層厚度t，其係小於40 nm。 本實施例之第一膜層41例如具有保護的功能，而第 二膜層42例如具有鈍化的功能，可降低太陽能電池表面 的載子複合速度，達到提高光電轉換效率的作用。第一膜 層41與第二膜層42在適當厚度組合下，亦可具有抗反射 的效用，同時還可保護太陽能電池1，達到防刮傷、防濕 氣等功效。 由於空氣與石夕的折射率（reflective index )差異甚大， ® 使得光線通過空氣與矽的介面時會有明顯光線反射情 形，對於單晶矽而言，正常照光下於矽表面的光反射率約 為30〜35%。藉由第一膜層41與第二膜層42的組合作為 光學抗反射層，能夠降低光線的反射率。更詳細來說，當 第一膜層41與第二膜層42的材料具備介於空氣與矽之折 射率，並且在適當的厚度下，利用光學破壞性干涉的原 理，可有效地降低入射光反射的反射率，增加進入太陽能 φ 電池的入光量，進而提高光電轉換效率。 ' 本實施例之第一膜層41的材質例如為氮化矽 (SiNx)，而第二膜層42的材質例如為氧化矽（Si02)或 _ 氧化鋁（A1203 )，然其非可用以限制本創作。第一膜層41 的材質亦可為其他可對矽表面進行抗反射的材質，而第二 膜層42的材質亦可為其他可進行鈍化的材質。 本實施例之太陽能電池1更可包括複數電極（圖未繪 示）。更詳細來說，於太陽能電池1的一光入射表面設置 一金屬電極作為正面電極，而相對地，於一背光表面設置 9 M422756 一金屬電極作為背面電極，且於光入射表面上所形成的電 極係可由複數匯流電極（bus bar electrode )及複數指狀電 極（finger electrode)配置連接於匯流電極兩侧所構成。 因此’當太陽能電池1將吸收的光線轉變為電子或電洞 時’指狀電極係可用於將太陽能電池1所產生的電子或電 洞匯集至相連接之匯流電極’最後再藉由匯流電極與外部 負載的連結’以將經過光電轉換反應所產生的電子或電洞 聚集並傳遞至外界。 综上所述，本創作之太陽能電池係藉由降低半導體基 板的表面摻m進而降低電子電洞的再結合損失。另 外’更設置複數膜層構成的複合多功能保護膜於掺雜層之 上達到純化、抗反射及保護等功能以保護太陽能電池， 避免外力、糾或氣候等因素f彡響光電轉換效率及外觀。 與習知技術相比較，本創作之太陽能電池利用較低表 =摻雜濃度的方式搭配複合多功能保護膜，不僅能夠降低 ^也表面載子的複合速度，達到提高光電流的作用，同時 返具有保護太陽能電池，_傷、防濕氣等功效，更減少 的反射，進而提升整體太陽能電池的光 及性能。 从上収1皇马舉例性，而非為限制 本創作之精神與料，而對其進行之等致修 ^ 應包含於後附之申請專利範圍中。 > ^ 【圖式簡單說明】 M422756 圖1為依據本創作較佳實施例之一種太陽能電池的示 意圖。 【主要元件符號說明】 〔習知〕 益 '〔本創作〕 1 :太陽能電池 _ 2:半導體基板 21、22 :表面 3 :摻雜層 4:複合多功能保護膜 41 :第一膜層 42 :第二膜層 d :深度 赢 J · P-N接面 t :厚度 11Ab. The main reason is that solar cells can directly convert solar energy into electricity and generate no harmful substances such as carbon dioxide or nitride during power generation, which will not pollute the environment. In general, conventional silicon solar cells are usually formed on a semiconductor substrate and doped with a diffusion or ion implantation (c〇unter-doping) to form a c〇unter-doping. Doped layers and fabricated electrodes. When the light is irradiated from the outside to the twinned solar cell, the doped layer generates a free electron/hole pair due to the number of photons, and the electron is separated from the hole by the internal electric field generated by the p_N junction. Moving to both ends, and generating the form of electric energy. If a load circuit or an electronic device is added at this time, electric energy can be supplied to drive the circuit or device. However, the doping concentration of the doped layer of the current twinned solar cell tends to be higher than lxlO21 atoms/cm3, and the excessively high surface doping becomes a large number of recombination centers, which makes the illumination M422756 free. Electrons and holes are eliminated at these recombination centers. Moreover, there are more dangling bonds on the contact surface between the front electrode and the doped layer, so that free electrons and holes are easily located near the contact surface of the doped layer and the front electrode. The surface recombination is generated to affect the photoelectric conversion efficiency of the twinned solar cell. Therefore, how to provide a solar cell can reduce the surface recombination of the doped layer, thereby improving the photoelectric conversion efficiency of the solar cell, and effectively protecting the solar cell has become an important issue in the solar manufacturing industry. [New content] In view of the above-mentioned problems, the purpose of the present invention is to provide a solar cell that is different from the high surface doping concentration of the current semiconductor substrate, and uses a lower surface doping concentration method to achieve a reduction of recombination loss. The purpose of 'to further improve the photoelectric conversion efficiency. In view of the above problems, the other purpose of the present invention is to provide a solar cell battery with a composite multifunctional protective film to achieve passivation, anti-reflection and protection functions. To achieve the above object, a solar cell according to the present invention comprises a semiconductor substrate and a composite multifunctional protective film. The surface of the semiconductor substrate has a doped layer having a depth between 200 nm and 1000 nm, and the surface modification concentration of the exchange layer is between 1χ1〇19 and 5x102G atoms/cm3. The composite multifunctional protective film is disposed on the doped layer, and the composite multifunctional protective film has a plurality of layers to achieve passivation, anti-reflection and protection functions. 5 M422756 These layers are closest to the layer of the doped layer and have a film thickness of less than 40 nm. In one embodiment of the present invention, the semiconductor substrate may be a P-type semiconductor substrate or an N-type semiconductor substrate. When the semiconductor substrate is a P-type semiconductor substrate, the doping element of the doped layer is N-type, such as but not limited to phosphorus, arsenic, antimony, antimony, or a combination thereof; when the semiconductor substrate is an N-type semiconductor substrate, doping The doping elements of the layer are P-types such as, but not limited to, boron, aluminum, gallium, indium, indium, or combinations thereof. In one embodiment of the present invention, the solar cell may further include a plurality of electrodes respectively disposed on a light incident surface of the solar cell and a backlight surface to serve as a front electrode and a back electrode. In one embodiment of the present invention, the semiconductor substrate may be a single crystal germanium substrate, a polycrystalline germanium substrate, or an amorphous germanium substrate. As described above, the solar cell of the present invention reduces the recombination loss of the electron hole by reducing the surface doping concentration of the semiconductor substrate. In addition, a composite multifunctional protective film composed of a plurality of layers is disposed on the doped layer to achieve functions such as passivation, anti-reflection and protection to protect the solar cell, and to avoid the influence of external force, environment or climate on the photoelectric conversion efficiency and appearance. The solar cell of the present invention can not only reduce the free electron and hole recombination speed on the surface of the battery, but also improve the photocurrent, and also protect the solar cell, prevent damage and moisture, and reduce the reflection of incident light. Further, the photoelectric conversion efficiency and performance of the entire solar cell are improved. [Embodiment] M422756 Hereinafter, a solar cell according to the preferred embodiment will be described with reference to the related drawings, wherein the same elements will be described with the same reference numerals. Please refer to FIG. 1 , which is a schematic diagram of a solar cell according to a preferred embodiment of the present invention. The proportional relationship of each structure in FIG. 1 may be inconsistent with the actual structure for convenience of display and description. It is intended to be a reference and not a limitation. The solar cell 1 includes a semiconductor substrate 2 and a composite multifunctional protective film 4, and the surface 21 of the semiconductor substrate 2 has a doped layer 3. The semiconductor substrate 2 may be a photoelectric conversion substrate, and the semiconductor substrate 2 may be a single crystal germanium substrate, a polycrystalline germanium substrate, an amorphous germanium substrate or the like. In the present embodiment, the semiconductor substrate 2 is an N-type semiconductor substrate or a P-type semiconductor substrate. The semiconductor substrate 2 of the present embodiment has two surfaces 21, 22 which serve as the front and back surfaces of the semiconductor substrate 2, respectively; wherein the surface 21 can be a light incident surface and the surface 22 is a backlight surface. The φ doped layer 3 is formed by doping the surface of the semiconductor substrate 2 with a reverse impurity, and the doping method can be performed by diffusion or ion implantation. When the semiconductor substrate 2 is a P-type semiconductor substrate, the opposite state is doped with an N-type doping element, such as, but not limited to, phosphorus, arsenic, antimony, antimony, or a combination of two or more thereof; when the semiconductor substrate When 2 is an N-type semiconductor substrate, the opposite state is doped with a P-type doping element, such as, but not limited to, boron, aluminum, gallium, indium, antimony, or a combination of two or more thereof. The surface 21 of the semiconductor substrate 2 is the surface of the doped layer 3, and the bottom surface of the doped layer 3 constitutes a P-N junction J, and a 7 M422756 carrier depletion region is formed at both ends of the P-N junction J. The carrier depletion zone provides a built-in electric field, and the generated free electrons are sent to the N pole, and the hole is sent to the P pole. Therefore, a current is generated, and the power generated by the solar battery can be utilized as long as the external circuit is connected at both ends. It is worth mentioning that the doped layer 3 of the present embodiment has a surface doping concentration and a depth d; wherein the surface doping concentration refers to the doping element concentration of the surface 21 of the doped layer 3. For example, in the present embodiment, a phosphorus element (N-type semiconductor material) is doped into the P-type semiconductor substrate 2 to form an N-type doped layer 3, and the surface doping concentration refers to a phosphorus element in the doping. The concentration of the surface 21 of the impurity layer 3 has a surface doping concentration ranging from 1xl〇19 to 5xl02Q atoms/cm3, and the doping layer 3 has a depth d ranging from 200 nm to 1000 nm. In the solar cell 1 of the present embodiment, by reducing the concentration of the surface doping element of the doped layer 3, the doping element concentration in the doped layer 3 is also reduced, thereby reducing carrier recombination loss, thereby improving photoelectric conversion. effectiveness. The composite multifunctional protective film 4 is disposed on the doped layer 3, that is, the composite multifunctional protective film 4 is provided on the surface (light incident surface) 21 of the semiconductor substrate 2. The composite multifunctional protective film 4 has a plurality of film layers. In this embodiment, the composite multifunctional protective film 4 has a two-layered layer as an example. However, it is not limited, and those skilled in the art know that the composite multifunctional protective film is known. 4 can be composed of more layers according to actual needs. The plurality of layers are a first film layer 41 and a second film layer 42, respectively, the second film layer 42 is disposed on the doped layer 3, and the first film layer 41 is disposed on the second film layer 42. It should be noted that the second film layer 42 of this embodiment has a film M422756 layer thickness t which is less than 40 nm. The first film layer 41 of the present embodiment has, for example, a protective function, and the second film layer 42 has, for example, a function of passivation, which can reduce the carrier recombination speed on the surface of the solar cell and achieve the effect of improving the photoelectric conversion efficiency. The first film layer 41 and the second film layer 42 can also have an anti-reflection effect under the combination of appropriate thicknesses, and at the same time protect the solar cell 1 to achieve effects such as scratch resistance and moisture resistance. Since the refractive index of air and stone eve is very different, ® causes light to reflect through the interface between air and helium. For single crystal yttrium, the light reflectance of the normal illuminating surface on the 矽 surface is about It is 30~35%. By combining the first film layer 41 and the second film layer 42 as an optical anti-reflection layer, the reflectance of light can be reduced. In more detail, when the materials of the first film layer 41 and the second film layer 42 are provided with a refractive index of air and helium, and at a suitable thickness, the principle of optical destructive interference is utilized, and the incident light can be effectively reduced. The reflectivity of the reflection increases the amount of light entering the solar φ battery, thereby increasing the photoelectric conversion efficiency. The material of the first film layer 41 of the present embodiment is, for example, tantalum nitride (SiNx), and the material of the second film layer 42 is, for example, yttrium oxide (SiO 2 ) or _ alumina (A1203 ), which is not available to be limited. This creation. The material of the first film layer 41 may be other materials that can resist the reflection of the surface of the crucible, and the material of the second film layer 42 may be other materials that can be passivated. The solar cell 1 of the present embodiment may further include a plurality of electrodes (not shown). More specifically, a metal electrode is disposed on the light incident surface of the solar cell 1 as a front electrode, and oppositely, a metal electrode is disposed on the backlight surface as a back electrode, and the electrode is formed on the light incident surface. It can be configured by connecting a bus bar electrode and a plurality of finger electrodes to both sides of the bus electrode. Therefore, 'when the solar cell 1 converts the absorbed light into electrons or holes, the finger electrode system can be used to collect the electrons or holes generated by the solar cell 1 to the connected bus electrode' and finally by the bus electrode and The connection of the external load ' gathers and transmits electrons or holes generated by the photoelectric conversion reaction to the outside. In summary, the solar cell of the present invention reduces the recombination loss of the electron hole by reducing the surface doping of the semiconductor substrate. In addition, a composite multifunctional protective film composed of a plurality of layers is provided on the doped layer to achieve functions such as purification, anti-reflection and protection to protect the solar cell, and to avoid external force, correction or climate, etc. . Compared with the prior art, the solar cell of the present invention uses a lower table=doping concentration to match the composite multifunctional protective film, which can not only reduce the composite speed of the surface carrier, but also improve the photocurrent. It has the functions of protecting solar cells, _ injury, moisture resistance, etc., and reducing reflection, thereby improving the light and performance of the overall solar cell. The acceptance of 1 Real Madrid is an example, not a limitation of the spirit and material of the creation, and the repairs to it should be included in the scope of the patent application attached. > ^ [Simple Description of the Drawings] M422756 Fig. 1 is a schematic view of a solar cell according to a preferred embodiment of the present invention. [Explanation of main component symbols] [Practical] 益 '[This creation] 1 : Solar cell _ 2: Semiconductor substrate 21, 22: Surface 3: Doped layer 4: Composite multifunctional protective film 41: First film layer 42: Second film layer d: depth win J · PN junction t: thickness 11