JP2012064910A - Photoelectric converter - Google Patents

Photoelectric converter Download PDF

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JP2012064910A
JP2012064910A JP2010226986A JP2010226986A JP2012064910A JP 2012064910 A JP2012064910 A JP 2012064910A JP 2010226986 A JP2010226986 A JP 2010226986A JP 2010226986 A JP2010226986 A JP 2010226986A JP 2012064910 A JP2012064910 A JP 2012064910A
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photoelectric conversion
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constricted
light
conversion device
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Takashi Matsukubo
隆 松窪
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    • YGENERAL 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
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    • Y02E10/546Polycrystalline silicon PV cells

Abstract

PROBLEM TO BE SOLVED: To provide a photoelectric converter with an excellent form adapted to an incident light confinement effect, capable of obtaining larger output energy per primary sunlight incident unit area, in order to solve a problem that a conventional convexoconcave solar battery cannot use most light energy.SOLUTION: For realizing super high performance photoelectric conversion, an outside wall including a constriction forming unit 9 that uses a silicon material and a scoop unit 10 formed on a lower side of a constriction portion, is provided so as to face in a primary sunlight incident direction. A photoelectric conversion region is formed in a constriction form. An effective photoelectric conversion surface area per a primary sunlight incident unit area is set at larger size, and an optical path is set at larger size. The incident light is photoelectrically converted so as to reduce a light amount to be reflected to the primary sunlight incident direction.

Description

本発明は、入射光を電気に変換する光電変換領域を有する超高効率型光電変換装置に関するものである。  The present invention relates to an ultra-high efficiency photoelectric conversion device having a photoelectric conversion region for converting incident light into electricity.

近年、化石燃料の枯渇と石油消費で発生する二酸化炭素による地球温暖化が地球規模の課題となっている。公的機関の石油需要見通しに依ると、特にアジア、中東の石油需要量は膨らむ一方である。世界の電力発電量も増加を続けている。一般に地球の人口増大に対して、エネルギー資源は残り少ないと言われている。そのような中、地球温暖化の環境改善に向けて導入が進む新エネルギーの中で、現在、最も重要な技術と考えられているのが太陽光発電である。  In recent years, global warming due to carbon dioxide generated by fossil fuel depletion and oil consumption has become a global issue. According to public oil demand forecasts, oil demand in Asia and the Middle East is growing. Global power generation continues to increase. In general, it is said that energy resources are scarce as the population of the earth grows. Under such circumstances, solar power generation is currently considered the most important technology among new energies that are being introduced to improve the global warming environment.

これまで太陽光発電は、エネルギー変換効率が低いことから家庭用や小規模での運用が主であった。太陽電池は、クリーンエネルギーの主役として家庭用だけでなく公的施設への導入も拡大している。さらに、大規模な太陽光発電所の設置計画も公表されている。また、再生可能エネルギーの活用を軸とした環境未来都市構想も提唱されてきている。太陽光発電は再生可能エネルギーであり、太陽光発電の需要拡大が見込まれている。  So far, solar power generation has been mainly used for home use and small scale because of its low energy conversion efficiency. Solar cells are being used not only for households but also for public facilities as a leading role in clean energy. In addition, a large-scale solar power plant installation plan has been announced. An environmental future city concept centered on the use of renewable energy has also been proposed. Solar power generation is a renewable energy, and demand for solar power generation is expected to increase.

従来の光電変換領域を有する太陽電池は、太陽光を出来るだけ多く太陽電池内部に取り込もうとして太陽電池表面にピラミッド断面形あるいは上下逆ピラミッド断面形の凹凸(テクスチャー)を設けている。しかし、まだ電力会社から購入する電気を代替するほどの経済性には至っていない。太陽エネルギーの電気への変換効率の向上への取り組みが望まれている。現在の太陽エネルギーの電気への変換効率はおおよそ次である。多接合型太陽電池の集光時セル変換効率は50%程。非集光時で40%程である。多結晶Si型太陽電池セルの光電変換効率は高いもので19%程である。一般的に結晶シリコン型は15%程、薄膜シリコン型は10%程、化合物型は10%程、有機薄膜型は数%程、色素増感型は数%程である。  A conventional solar cell having a photoelectric conversion region is provided with irregularities (textures) having a pyramid cross-sectional shape or an upside-down inverted pyramid cross-sectional shape on the surface of the solar cell so as to capture as much sunlight as possible inside the solar cell. However, it has not yet been economical enough to replace electricity purchased from electric power companies. Efforts to improve the conversion efficiency of solar energy into electricity are desired. The conversion efficiency of current solar energy into electricity is roughly as follows. The cell conversion efficiency of a multi-junction solar cell when condensing is about 50%. About 40% when not condensed. The photoelectric conversion efficiency of the polycrystalline Si solar cell is as high as about 19%. In general, the crystalline silicon type is about 15%, the thin film silicon type is about 10%, the compound type is about 10%, the organic thin film type is about several percent, and the dye-sensitized type is about several percent.

光電変換装置には太陽電池、イメージセンサー等がある。図2はそのような光電変換装置の一例である表面凹凸付き結晶系太陽電池の従来例を示す断面図である。1は裏面電極層、2は酸化膜、3はp型半導体、4はp+拡散層、5はn型半導体、6はn+拡散、7は透明電極層(ITO電極膜等)、8は取り出し電極である。  Photoelectric conversion devices include solar cells and image sensors. FIG. 2 is a cross-sectional view showing a conventional example of a crystal solar cell with surface irregularities, which is an example of such a photoelectric conversion device. 1 is a back electrode layer, 2 is an oxide film, 3 is a p-type semiconductor, 4 is a p + diffusion layer, 5 is an n-type semiconductor, 6 is n + diffusion, 7 is a transparent electrode layer (ITO electrode film, etc.), 8 is an extraction electrode It is.

図2に例示のように従来の太陽電池は太陽電池表面にピラミッド断面形あるいは上下逆ピラミッド断面形の凹凸(テクスチャー)を該太陽電池表面の平板方向に繋がる様に設けている。  As illustrated in FIG. 2, the conventional solar cell is provided with unevenness (texture) having a pyramid cross-sectional shape or a vertically inverted pyramid cross-sectional shape on the surface of the solar cell so as to be connected in the flat plate direction of the solar cell surface.

先行技術文献と本願発明との対比について説明する。
先行技術文献全体として言えることは、該先行技術文献のいづれについても本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。
A comparison between the prior art document and the present invention will be described.
What can be said as a whole of the prior art document is different from the photoelectric conversion device in which any of the prior art documents is provided with a constricted shape in the primary sunlight incident direction of the present invention.

個別の先行技術文献について本願発明と対比すると、特許文献1には薄膜太陽電池についてP型単結晶シリコン板の上に凹凸形状を形成する提案がされている。凹凸は発電層への斜め入射で光の進む距離が長くなり、光の閉じ込めが良好に行われるとしている。特許文献1に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。また、本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献2には透光性絶縁基板上に凹凸を有する光透性樹脂層と、透明導電膜と、非晶質半導体層と、裏面電極層とを順次積層してなる薄膜太陽電池について、前記凹凸は、互いに平行な線状に配設されており、透光性基板側から入射した光は、透明導電膜と非晶質半導体層との界面で散乱を起こし、非晶質半導体層での光の光路長が増加するという提案がなされている。特許文献2に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献3には入射光を電荷に変換する光電変換領域を有する固体光電子装置において光電変換領域の上方部に下側からの光に対して反射機能を持つ反射膜を形成してなり、光電変換領域に入射した光(電磁波)が光電変換領域・反射膜間にて反射を繰り返すように構成されてなることを特徴とする固体光電子装置という提案がなされている。光電変換領域の上面と下面の少なくとも一方を互いに異なる向きをもった複数面で構成したことを特徴としている。特許文献3に記載の凹凸はV字またはU字あるいは半円形を形成するが太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。また、本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献4には複数の光電変換セルが所定の距離を隔てて複数配置され、隣接する光電変換セル同士を電気的に直列に接続した光電変換装置において、隣接する第1の領域間に挟まれる領域を第2の領域とした場合に、第2の領域は、絶縁性透明基板の第2の領域に入射する光の進路を光電変換層の方向に変えるように形成された構成を有する光電変換装置という提案がなされている。特許文献4に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献5には絶縁透光性基板上に基板上に透明導電性材料からなる表面電極層と、バンドギャップの異なる光電変換層を基板面に垂直な方向に複数含む光電変換体と、裏面電極層と、を含むセルが複数配列して形成されるとともに、裏面電極層が形成される光電変換体側面は、側面の下部と表面電極層との交点を含み基板上に垂直に形成した面との間の距離が基板から離れるにしたがって大きくなるように形成されている光電変換装置という提案がなされている。特許文献5に記載の凹凸は本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献6には、太陽電池アセンブリは半導体層を積層した光電変換素子へ入射光を反射して集束させる反射凹面の底部又はその上部に、前記光電変換素子が配置され、前記光電変換素子に前記入射光が到達到達する途中に、その光の一部を波長変換する蛍光剤またはリン光材が配置されているという提案がなされている。特許文献6に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献7には導電性基板と該導電性基板の一主面に多数個接合され、表層に導電型の半導体部を有し、かつ表面が複数の凸部を有する凹凸構造を成した導電型の半導体部を有する結晶半導体粒子と、導電型の半導体部と部分的に接続された透光性導電層と、を備えた光電変換装置という提案がなされている。特許文献7に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献8には透明絶縁基板の表面に凹凸構造を有することを特徴とする薄膜太陽電池という提案がなされている。特許文献8に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献9には絶縁性透光基板上に透明導電膜からなる第1電極層と、半導体膜からなり光電変換を行う光電変換層と、光を反射する導電膜からなる第2電極層と、がこの従順で積層されてなる複数の光電変換セルが配設されるとともに、隣接する前記光電変換セル同士が電気的に直列接続された薄膜光電変換装置であって、前記絶縁性透光基板が略正多角形状を呈し、前記光電変換セルは、前記絶縁性透光基板の面内方向において前記絶縁性透光基板の略中心部から外周に向かって放射線状に配置された扇形の形状を呈すること、を特徴とする薄膜光電変換装置という提案がなされている。特許文献9に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献10には導電性の第1電極層と、この上に形成され、複数の微細孔が形成された誘電体基材および複数の微細孔を充填する金属材料からなる複数の微細金属体を備える金属充填誘電体層と、この上に形成され、光電変換材料からなる光電変換層と、この上に形成された導電性の第2電極とを有し、複数の微細金属体は、誘電体基材の微細孔を充填する充填部と、誘電体基材から光電変換層内に飛び出す突出部とを有し、充填部の他端において第1電極層に導電性の金属体であり、光電変換層は、突出部を覆うように誘電体基材上に形成され、前記微細金属体は前記第1電極層に接続される前記充填部の他端が、前記第1電極層に貫入する脚部を形成するものである光電変換デバイスという提案がなされている。特許文献10に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献11には透光性基板上に、透明導電膜からなる表面電極と、p型半導体層、i型半導体層、n型半導体層の順に積層された光電変換半導体層と、少なくとも光反射性金属電極を備える裏面電極とを順次形成した薄膜太陽電池において、前記透明導電膜が、前記透光性基板側からAl及びGaがドープされた第一の酸化亜鉛膜、Tiがドープされた酸化インジウム膜、Al及びGaがドープされた第二の酸化亜鉛膜の順に設けられた積層体で、前記第一の酸化亜鉛膜の前記酸化インジウム膜側の膜面が凹凸構造であることを特徴とする薄膜太陽電池という提案がなされている。特許文献11に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献12には絶縁性透光基板上に、透明導電膜からなる第1電極層と、非晶質半導体膜からなり光電変換を行う第1発電層と、微結晶質半導体膜からなり光電変換を行う第2発電層と、光を反射する導電膜からなる第2電極層と、がこの順で積層された薄膜太陽電池であって、前記第1電極層は、前記第1発電層側の表面に凹凸形状を有し、前記第1発電層は、前記第1電極層の凹凸形状に対応して前記第2発電層側に凹凸形状が形成され、その凸部の上面が前記絶縁性透光基板の面内方向と略平行な面とされていること、を特徴とする薄膜太陽電池という提案がなされている。特許文献12に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献13には太陽電池セルの受光面側に太陽電池セルを支持する透明電極を備えた太陽電池モジュールにおいて、上記透明基板の入光面側に、錐状の凹みあるいは錐状の突起が形成された光学指向性構造を備えた透明シートが積層されていることを特徴とする太陽電池モジュールという提案がなされている。特許文献13に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。  In contrast to the present invention regarding individual prior art documents, Patent Document 1 proposes to form an uneven shape on a P-type single crystal silicon plate for a thin film solar cell. It is said that the unevenness increases the distance that the light travels when obliquely incident on the power generation layer, and the light is confined well. The unevenness described in Patent Document 1 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. Moreover, there is no mention which forms a constricted form with respect to the primary sunlight incident direction like this invention. Patent Document 2 discloses a thin film solar cell in which a light transmissive resin layer having irregularities on a light transmissive insulating substrate, a transparent conductive film, an amorphous semiconductor layer, and a back electrode layer are sequentially stacked. The projections and depressions are arranged in parallel to each other, and light incident from the translucent substrate side is scattered at the interface between the transparent conductive film and the amorphous semiconductor layer. Proposals have been made to increase the optical path length of light. The unevenness described in Patent Document 2 has a shape connected to the flat plate direction on the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. In Patent Document 3, in a solid-state optoelectronic device having a photoelectric conversion region for converting incident light into electric charge, a reflection film having a function of reflecting light from the lower side is formed above the photoelectric conversion region. There has been proposed a solid-state optoelectronic device characterized in that light (electromagnetic wave) incident on the region is configured to repeatedly reflect between the photoelectric conversion region and the reflective film. It is characterized in that at least one of the upper surface and the lower surface of the photoelectric conversion region is composed of a plurality of surfaces having different directions. The irregularities described in Patent Document 3 are V-shaped, U-shaped or semi-circular, but are connected in the flat plate direction on the surface of the solar cell, and are provided with a constricted shape in the primary sunlight incident direction of the present invention. It is different from the photoelectric conversion device. Moreover, there is no mention which forms a constricted form with respect to the primary sunlight incident direction like this invention. In Patent Document 4, a plurality of photoelectric conversion cells are arranged at a predetermined distance, and are sandwiched between adjacent first regions in a photoelectric conversion device in which adjacent photoelectric conversion cells are electrically connected in series. When the region is the second region, the second region has a configuration formed so as to change the path of light incident on the second region of the insulating transparent substrate in the direction of the photoelectric conversion layer. A device has been proposed. The unevenness described in Patent Document 4 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. Patent Document 5 discloses a surface electrode layer made of a transparent conductive material on an insulating translucent substrate, a photoelectric conversion body including a plurality of photoelectric conversion layers having different band gaps in a direction perpendicular to the substrate surface, and a back electrode. A side surface of the photoelectric conversion body on which the back electrode layer is formed and a surface formed perpendicular to the substrate including the intersection of the lower portion of the side surface and the front surface electrode layer. There has been a proposal of a photoelectric conversion device formed so that the distance between the two becomes larger as the distance from the substrate increases. The unevenness described in Patent Document 5 is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. In Patent Document 6, the solar cell assembly includes the photoelectric conversion element disposed at the bottom or the upper part of a reflective concave surface that reflects and focuses incident light on the photoelectric conversion element on which the semiconductor layers are stacked. There has been a proposal that a fluorescent agent or phosphorescent material that converts a part of the light is disposed in the middle of arrival and arrival of the incident light. The unevenness described in Patent Document 6 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. Patent Document 7 discloses a conductive type having a concavo-convex structure in which a plurality of conductive substrates are bonded to one main surface of the conductive substrate, the surface has a conductive semiconductor portion, and the surface has a plurality of convex portions. There has been proposed a photoelectric conversion device including crystal semiconductor particles having the semiconductor portion and a translucent conductive layer partially connected to the conductive semiconductor portion. The unevenness described in Patent Document 7 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. Patent Document 8 proposes a thin film solar cell characterized by having an uneven structure on the surface of a transparent insulating substrate. The unevenness described in Patent Document 8 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. Patent Document 9 discloses a first electrode layer made of a transparent conductive film on an insulating translucent substrate, a photoelectric conversion layer made of a semiconductor film for performing photoelectric conversion, a second electrode layer made of a conductive film for reflecting light, Is a thin film photoelectric conversion device in which a plurality of photoelectric conversion cells stacked in accordance with the above are disposed and the adjacent photoelectric conversion cells are electrically connected in series, wherein the insulating light-transmitting substrate is Presenting a substantially regular polygonal shape, the photoelectric conversion cell has a fan-like shape arranged radially from the substantially central portion of the insulating light-transmitting substrate toward the outer periphery in the in-plane direction of the insulating light-transmitting substrate. The proposal of the thin film photoelectric conversion device characterized by this is made. The unevenness described in Patent Document 9 has a shape connected to the flat plate direction on the surface of the solar cell, and is different from the photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. Patent Document 10 discloses a conductive first electrode layer, a dielectric base material formed thereon, and a plurality of fine metal bodies made of a metal material filling the plurality of fine holes. A metal-filled dielectric layer, a photoelectric conversion layer formed thereon and made of a photoelectric conversion material, and a conductive second electrode formed thereon. A filling portion that fills the micropores of the base material and a protruding portion that protrudes from the dielectric base material into the photoelectric conversion layer, and is a conductive metal body on the first electrode layer at the other end of the filling portion; The conversion layer is formed on the dielectric base so as to cover the protruding portion, and the other end of the filling portion connected to the first electrode layer of the fine metal body penetrates the first electrode layer. The proposal of the photoelectric conversion device which forms a part is made. The unevenness described in Patent Document 10 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. In Patent Document 11, a surface electrode made of a transparent conductive film on a translucent substrate, a photoelectric conversion semiconductor layer laminated in the order of a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer, and at least light-reflective. In the thin film solar cell in which a back electrode having a metal electrode is sequentially formed, the transparent conductive film is a first zinc oxide film doped with Al and Ga from the translucent substrate side, and indium oxide doped with Ti A laminated body provided in the order of a film and a second zinc oxide film doped with Al and Ga, wherein the film surface on the indium oxide film side of the first zinc oxide film has a concavo-convex structure A proposal of a thin film solar cell has been made. The unevenness described in Patent Document 11 has a shape connected to the flat plate direction on the surface of the solar cell, and is different from the photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. In Patent Document 12, a first electrode layer made of a transparent conductive film, a first power generation layer made of an amorphous semiconductor film for performing photoelectric conversion, and a microcrystalline semiconductor film made of photoelectric conversion are formed on an insulating transparent substrate. And a second electrode layer made of a conductive film that reflects light is laminated in this order, and the first electrode layer is disposed on the first power generation layer side. The first power generation layer has a concavo-convex shape on the second power generation layer side corresponding to the concavo-convex shape of the first electrode layer, and the upper surface of the convex portion has the insulating transparent surface. There has been proposed a thin film solar cell characterized by being a plane substantially parallel to the in-plane direction of the optical substrate. The unevenness described in Patent Document 12 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. In Patent Document 13, in a solar cell module provided with a transparent electrode that supports a solar cell on the light receiving surface side of the solar cell, a conical recess or a conical protrusion is formed on the light incident surface side of the transparent substrate. There has been proposed a solar cell module characterized in that a transparent sheet having an optical directivity structure is laminated. The unevenness described in Patent Document 13 has a shape connected to the flat plate direction on the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention.

特開平11−40832号公報Japanese Patent Laid-Open No. 11-40832 特開平11−191632号公報JP-A-11-191632 特開第2000−208747号公報JP 2000-208747 A 特開第2009−231499号公報JP 2009-231499 A 特開第2009−289817号公報JP 2009-289817 A 特開第2009−206212号公報JP 2009-206212 A 特開第2009−206469号公報JP 2009-206469 A 特開第2009−224427号公報JP 2009-224427 A 特開第2009−295943号公報JP 2009-295943 A 特開第2010−27794号公報JP 2010-27794 A 特開第2010−34230号公報JP 2010-34230 A 特開第2010−62302号公報JP 2010-62302 A 特開第2010−153570号公報JP 2010-153570 A

解決しようとする問題点は、従来の光電変換領域を有する太陽電池は、太陽光を出来るだけ多く太陽電池内部に取り込もうとして太陽電池表面にピラミッド断面形あるいは上下逆ピラミッド断面形の凹凸(テクスチャー)を設けているが、まだ電力会社から購入する電気を代替するほどの経済性には至っていない点である。前記の光電変換効率のように従来の凹凸付き太陽電池では大部分の光エネルギーは活用出来ていないという問題がある。  The problem to be solved is that a conventional solar cell having a photoelectric conversion region has a pyramid cross-section or an upside-down inverted pyramid cross-section (texture) on the surface of the solar cell in order to capture as much sunlight as possible inside the solar cell. However, it is not yet economical enough to replace electricity purchased from electric power companies. As in the photoelectric conversion efficiency described above, there is a problem that most of the light energy cannot be utilized in the conventional uneven solar cell.

本発明はこのような問題点を解決すべく為されたものであり、入射光の閉じ込め作用に優れる形体の光電変換装置であり、一次太陽光入射単位面積当たりについて、より大きな出力エネルギーを得ることができる光電変換装置を提供することを目的とする。  The present invention has been made to solve such problems, and is a photoelectric conversion device having a shape excellent in the confinement function of incident light, and obtains a larger output energy per unit area of primary sunlight incident. It is an object of the present invention to provide a photoelectric conversion device that can perform the following.

本発明は、入射光を電気に変換する光電変換領域を有する光電変換装置において、超高効率光電変換を可能とするため、一次太陽光入射方向に対して括れ形成部9、および括れの下方側に形成してなる抉れ部10を設けてなる外壁、あるいは内壁を設けて、光電変換領域が前記括れ形体状に設けてなり、一次太陽光入射単位面積当たりの実効光電変換表面積をより大きく設けてなり、光路長をより大きく設けてなり、一次太陽光入射方向側に返す光をより少なくする形体で、前記入射光を光電変換することを主要な特徴とする。  In the photoelectric conversion device having a photoelectric conversion region for converting incident light into electricity, the present invention is capable of performing ultra-high efficiency photoelectric conversion. An outer wall or an inner wall provided with the bent portion 10 formed in the above, and a photoelectric conversion region is provided in the shape of the constricted shape, and a larger effective photoelectric conversion surface area per unit area of primary sunlight incidence is provided. Thus, the main feature is that the incident light is photoelectrically converted in a form that has a longer optical path length and that reduces the amount of light returned to the primary sunlight incident direction side.

請求項1、請求項2、請求項3、請求項4、請求項5、請求項6、請求項7の光電変換装置によれば、前記主要な特徴を備えているので、光の利用効率を高めることができる。  According to the photoelectric conversion device of claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, and claim 7, since the main features are provided, the light use efficiency is improved. Can be increased.

請求項1、請求項2、請求項3、請求項4、請求項5、請求項6、請求項7の光電変換装置によれば、一次太陽光入射単位面積当たりの実効光電変換表面積がより大きくなり、加えて、一次太陽光入射方向側に返す光をより少なくすることができるので、光の利用効率を高めることができる。従って、エネルギー変換効率が高くなることで、出力当たりの単価が改善され、出力の増加に伴って、経済性を高めることができる。  According to the photoelectric conversion device of claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, and claim 7, the effective photoelectric conversion surface area per unit area of primary sunlight incidence is larger. In addition, since the amount of light returned to the primary sunlight incident direction can be reduced, the light utilization efficiency can be increased. Therefore, the energy conversion efficiency is increased, the unit price per output is improved, and the economic efficiency can be enhanced as the output increases.

本発明光電変換装置の一つの実施例で、請求項1の例を示す断面図である。It is sectional drawing which shows the example of Claim 1 in one Example of this invention photoelectric conversion apparatus. 光電変換装置の従来例を示す断面図である。It is sectional drawing which shows the prior art example of a photoelectric conversion apparatus. 本発明光電変換装置の一つの実施例で、請求項1の例を示す斜視図である。1 is a perspective view showing an example of claim 1 in one embodiment of the photoelectric conversion device of the present invention. 本発明光電変換装置の一つの実施例で、請求項2の例を示す断面図である。It is sectional drawing which shows the example of Claim 2 in one Example of this invention photoelectric conversion apparatus. 本発明光電変換装置の一つの実施例で、請求項3の例を示す斜視図である。It is a perspective view which shows the example of Claim 3 in one Example of the photoelectric conversion apparatus of this invention. 本発明光電変換装置の一つの実施例で、請求項4の例を示す斜視図である。It is a perspective view which shows the example of Claim 4 in one Example of the photoelectric conversion apparatus of this invention.

本発明は一次太陽光入射方向に対して光電変換領域に括れ形体を設けて、入射した光を入射元の方向に、より反射させないように構成されてなる。より具体的には、きのこ柱状に、括れと、前記括れの下方側に抉れを設けてなる光電変換領域を形成する態様が好適である。前記括れは、傘状または軒状あるいはその庇状の構造で形成しても良い。穴状にする場合は、瓢箪形状に括れを設けてなる態様が好適である。前記きのこ柱状、前記瓢箪形状は複数段に積み上げるとさらに良い。前記きのこ柱状と、前記瓢箪形状を組み合わせて形成する態様でも良い。前記括れの下方側に形成する抉れ形状は砲弾断面形、あるいは上下逆さJ字状のステッキのように曲がる態様にしても良い。前記きのこ柱状、前記瓢箪形状は複数段に積み上げる場合、前記各段ごとに膜厚、抉れ形状、膜材料を変えて、広い範囲の波長の光を変換できるようにしても良い。前記きのこ柱状、前記瓢箪形状は複数段に積み上げる場合、前記各段は直列の電気接続の態様を形成すると好適である。前記きのこ柱状の頭部、前記瓢箪形状穴と隣接する瓢箪形状穴の間の上層表面に凸形状を設ける場合は、球形、円錐形、多角錐等が良く、傾斜面の角度は大きく尖らす態様を形成すると好適である。  The present invention is configured such that a constricted shape is provided in the photoelectric conversion region with respect to the incident direction of primary sunlight so that incident light is less reflected in the direction of the incident source. More specifically, it is preferable to form a photoelectric conversion region in a mushroom pillar shape by forming a neck and a neck on the lower side of the neck. The constriction may be formed in an umbrella shape, an eave shape, or a bowl-like structure. When making it into a hole shape, the aspect which provides a constriction in the collar shape is suitable. The mushroom pillar shape and the bowl shape are more preferably stacked in a plurality of stages. The aspect which forms combining the said mushroom pillar shape and the said hook shape may be sufficient. The bend shape formed on the lower side of the constriction may be bent like a cannonball cross-sectional shape or an upside down J-shaped stick. When the mushroom pillar shape and the ridge shape are stacked in a plurality of stages, the film thickness, the crease shape, and the film material may be changed for each stage so that light having a wide range of wavelengths can be converted. In the case where the mushroom pillar shape and the bowl shape are stacked in a plurality of stages, it is preferable that the stages form a serial electrical connection mode. When providing a convex shape on the upper layer surface between the mushroom pillar-shaped head and the bowl-shaped hole adjacent to the bowl-shaped hole, a spherical shape, a cone shape, a polygonal pyramid, etc. are good, and the angle of the inclined surface is sharpened Is preferably formed.

以下、本発明を図示実施例に従って説明する。図1は、きのこ柱形体を設けてなる本光電変換装置の一つの実施例である。本光電変換装置の大きな特徴はp型半導体3とn型半導体4の接合で形成される光電変換領域が括れ形体を設けてなることである。p型半導体3に括れ形成部9、および括れの下方側に形成してなる抉れ部10を形成する。次にp型半導体3とn型半導体4の接合を形成し、しかる後、n+拡散層と、透明電極層7を形成してなる。次にp型半導体3の裏面に酸化膜2と、p+拡散層4と、裏面電極層1を形成してなる。  The present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows an embodiment of the present photoelectric conversion device provided with mushroom columnar bodies. A major feature of this photoelectric conversion device is that a photoelectric conversion region formed by the junction of the p-type semiconductor 3 and the n-type semiconductor 4 is provided with a constricted shape. A constriction forming portion 9 and a constricted portion 10 formed on the lower side of the constriction are formed in the p-type semiconductor 3. Next, a junction between the p-type semiconductor 3 and the n-type semiconductor 4 is formed, and then an n + diffusion layer and a transparent electrode layer 7 are formed. Next, the oxide film 2, the p + diffusion layer 4, and the back electrode layer 1 are formed on the back surface of the p-type semiconductor 3.

このような、きのこ柱形体を設けてなる本光電変換装置によれば、外部からの一次入射太陽光は、きのこ柱形体の頭部の光電変換層に入射して、前記太陽光は光電変換される。きのこ柱形体の横を通過した一次入射太陽光については、きのこ柱形体の土台側の光電変換層に入射して、前記太陽光は光電変換される。前記太陽光の一部は反射を繰り返す。その際、きのこ柱形体に設けてなる括れ形成部9、および括れの下方側に形成してなる抉れ部10は反射光を閉じ込めて、一次太陽光入射方向側に返す光をより少なくする機能を果たす。というのは、きのこ柱形体に設けてなる括れ形成部9、および括れの下方側に形成してなる抉れ部10が入射光を前記抉れ部の奥側へ導く作用を生ぜしめるからである。  According to this photoelectric conversion device provided with the mushroom columnar body, primary incident sunlight from the outside enters the photoelectric conversion layer on the head of the mushroom columnar body, and the sunlight is photoelectrically converted. The About the primary incident sunlight which passed the mushroom pillar form side, it injects into the photoelectric conversion layer of the base side of a mushroom pillar form body, and the said sunlight is photoelectrically converted. Part of the sunlight is repeatedly reflected. At that time, the constriction forming part 9 provided on the mushroom columnar shape and the constriction part 10 formed on the lower side of the constriction function to confine the reflected light and reduce the light returned to the primary sunlight incident direction side. Fulfill. This is because the constriction forming part 9 provided on the mushroom columnar shape and the bend part 10 formed on the lower side of the constriction cause the action of guiding incident light to the back side of the constriction part. .

尚、太陽電池の製造プロセスは、蒸着、露光、蝕刻(エッチング)など、従来からの、半導体、液晶パネルの製造プロセスを踏襲しており、前記括れ形成部9、および括れの下方側に形成してなる抉れ部10を形成することは、CVD法や選択式露光、等方性エッチング、選択式エッチング、あるいはCMP(Chemical Mechanical Polishing:化学的機械研磨)法であるダマシン法やデュアルダマシン法を選択的に駆使して形成することが出来る。  The solar cell manufacturing process follows conventional manufacturing processes for semiconductors and liquid crystal panels, such as vapor deposition, exposure, and etching (etching), and is formed on the constriction forming portion 9 and below the constriction. The bent portion 10 is formed by a damascene method or a dual damascene method, which is a CVD method, selective exposure, isotropic etching, selective etching, or CMP (Chemical Mechanical Polishing) method. It can be formed selectively.

前記方法を選択的に駆使して形成した前記括れ形成部9、および括れの下方側に形成してなる抉れ部10を前記光電変換領域に設けることで、太陽光の入射方向から観察すると、本光電変換装置は、より黒体様に見えることになる。  By observing from the incident direction of sunlight by providing the constriction forming portion 9 formed by selectively using the method and the constriction portion 10 formed on the lower side of the constriction in the photoelectric conversion region, This photoelectric conversion device looks more like a black body.

他の実施例として、図4は入射光を電子等の電荷に変換する光電変換領域を有する受光素子部に、入射光の進行方向に対して括れ状の内壁を設けた、穴形体の括れ付き光電変換装置の例で、作用と効果については、前記図1と同様である。図5は入射光を電子等の電荷に変換する光電変換領域を有する受光素子部に、入射光の進行方向に対して括れ状の外壁を設けた柱形体と括れ状の内壁を設けた穴形体のハイブリッド配置の克れ付き光電変換装置の例で、作用と効果については、前記図1と同様である。図6は入射光を電子等の電荷に変換する光電変換領域を有する受光素子部に入射光の進行方向に対して括れ状の外壁を設けて複数積み上げたトーテムポール状形体の括れ付き光電変換装置の例で、作用と効果については、前記図1と同様であり、光電変換領域が多段に設けてなるので、一次太陽光入射単位面積当たりの実効光電変換表面積をより大きく設けてなり、光路長をより大きく設けてなり、一次太陽光入射方向側に返す光をより少なくする形体にすることができる。As another embodiment, FIG. 4 shows a hole-shaped constriction in which a light-receiving element portion having a photoelectric conversion region for converting incident light into charges such as electrons is provided with a constricted inner wall with respect to the traveling direction of incident light. In the example of the photoelectric conversion device, the operation and effect are the same as those in FIG. FIG. 5 shows a hole-shaped body provided with a columnar body provided with a constricted outer wall and a constricted inner wall in a light receiving element portion having a photoelectric conversion region for converting incident light into charges such as electrons. In the example of the photoelectric conversion device with a hybrid arrangement, the operation and effect are the same as those in FIG. FIG. 6 shows a photoelectric conversion device with a constricted totem pole shape in which a light receiving element portion having a photoelectric conversion region for converting incident light into charges such as electrons is provided with a constricted outer wall with respect to the traveling direction of the incident light. In this example, the operation and effect are the same as in FIG. 1 described above, and the photoelectric conversion regions are provided in multiple stages, so that the effective photoelectric conversion surface area per unit area of primary sunlight incidence is larger, and the optical path length Can be formed in a larger shape, and the amount of light returned to the primary sunlight incident direction side can be reduced.

1・・・裏面電極層
2・・・酸化膜
3・・・p型半導体
4・・・p+拡散層
5・・・n型半導体
6・・・n+拡散層
7・・・透明電極層
8・・・取り出し電極
9・・・括れ形成部
10・・・括れの下方側に形成してなる抉れ部
DESCRIPTION OF SYMBOLS 1 ... Back electrode layer 2 ... Oxide film 3 ... p-type semiconductor 4 ... p + diffusion layer 5 ... n-type semiconductor 6 ... n + diffusion layer 7 ... Transparent electrode layer 8 ..Extraction electrode 9 ... neck formation part 10 ... neck part formed on the lower side of the neck

光電変換装置には太陽電池、イメージセンサー等がある。図2はそのような光電変換装置の一例である表面凹凸付き結晶系太陽電池の従来例を示す断面図である。1は裏面電極層、2は酸化膜、3はp型半導体、4はp+拡散層、5はn型半導体、6はn+拡散、7は透明電極層(ITO電極膜等)、8は取り出し電極である。Photoelectric conversion devices include solar cells and image sensors. FIG. 2 is a cross-sectional view showing a conventional example of a crystal solar cell with surface irregularities, which is an example of such a photoelectric conversion device. 1 is a back electrode layer, 2 is an oxide film, 3 is a p-type semiconductor, 4 is a p + diffusion layer, 5 is an n-type semiconductor, 6 is an n + diffusion layer , 7 is a transparent electrode layer (ITO electrode film, etc.), 8 is taken out Electrode.

個別の先行技術文献について本願発明と対比すると、特許文献1には薄膜太陽電池についてP型単結晶シリコン板の上に凹凸形状を形成する提案がされている。凹凸は発電層への斜め入射で光の進む距離が長くなり、光の閉じ込めが良好に行われるとしている。特許文献1に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。また、本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献2には透光性絶縁基板上に凹凸を有する透光性樹脂層と、透明導電膜と、非晶質半導体層と、裏面電極層とを順次積層してなる薄膜太陽電池について、前記凹凸は、互いに平行な線状に配設されており、透光性基板側から入射した光は、透明導電膜と非晶質半導体層との界面で散乱を起こし、非晶質半導体層での光の光路長が増加するという提案がなされている。特許文献2に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献3には入射光を電荷に変換する光電変換領域を有する固体光電子装置において光電変換領域の上方部に下側からの光に対して反射機能を持つ反射膜を形成してなり、光電変換領域に入射した光(電磁波)が光電変換領域・反射膜間にて反射を繰り返すように構成されてなることを特徴とする固体光電子装置という提案がなされている。光電変換領域の上面と下面の少なくとも一方を互いに異なる向きをもった複数面で構成したことを特徴としている。特許文献3に記載の凹凸はV字またはU字あるいは半円形を形成するが光電変換領域表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。また、本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献4には複数の光電変換セルが所定の距離を隔てて複数配置され、隣接する光電変換セル同士を電気的に直列に接続した光電変換装置において、隣接する第1の領域間に挟まれる領域を第2の領域とした場合に、第2の領域は、絶縁性透明基板の第2の領域に入射する光の進路を光電変換層の方向に変えるように形成された構成を有する光電変換装置という提案がなされている。特許文献4に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献5には絶縁透光性基板上に透明導電性材料からなる表面電極層と、バンドギャップの異なる光電変換層を基板面に垂直な方向に複数含む光電変換体と、裏面電極層と、を含むセルが複数配列して形成されるとともに、裏面電極層が形成される光電変換体側面は、側面の下部と表面電極層との交点を含み基板上に垂直に形成した面との間の距離が基板から離れるにしたがって大きくなるように形成されている光電変換装置という提案がなされている。特許文献5に記載の凹凸は本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献6には、太陽電池アセンブリは半導体層を積層した光電変換素子へ入射光を反射して集束させる反射凹面の底部又はその上部に、前記光電変換素子が配置され、前記光電変換素子に前記入射光が到達する途中に、その光の一部を波長変換する蛍光剤またはリン光材が配置されているという提案がなされている。特許文献6に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献7には導電性基板と該導電性基板の一主面に多数個接合され、表層に導電型の半導体部を有し、かつ表面が複数の凸部を有する凹凸構造を成した導電型の半導体部を有する結晶半導体粒子と、導電型の半導体部と部分的に接続された透光性導電層と、を備えた光電変換装置という提案がなされている。特許文献7に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献8には透明絶縁基板の表面に凹凸構造を有することを特徴とする薄膜太陽電池という提案がなされている。特許文献8に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献9には絶縁性透光基板上に透明導電膜からなる第1電極層と、半導体膜からなり光電変換を行う光電変換層と、光を反射する導電膜からなる第2電極層と、がこので積層されてなる複数の光電変換セルが配設されるとともに、隣接する前記光電変換セル同士が電気的に直列接続された薄膜光電変換装置であって、前記絶縁性透光基板が略正多角形状を呈し、前記光電変換セルは、前記絶縁性透光基板の面内方向において前記絶縁性透光基板の略中心部から外周に向かって放射線状に配置された扇形の形状を呈すること、を特徴とする薄膜光電変換装置という提案がなされている。特許文献9に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献10には導電性の第1電極層と、この上に形成され、複数の微細孔が形成された誘電体基材および複数の微細孔を充填する金属材料からなる複数の微細金属体を備える金属充填誘電体層と、この上に形成され、光電変換材料からなる光電変換層と、この上に形成された導電性の第2電極とを有し、複数の微細金属体は、誘電体基材の微細孔を充填する充填部と、誘電体基材から光電変換層内に飛び出す突出部とを有し、充填部の他端において第1電極層に導電性の金属体であり、光電変換層は、突出部を覆うように誘電体基材上に形成され、前記微細金属体は前記第1電極層に接続される前記充填部の他端が、前記第1電極層に貫入する脚部を形成するものである光電変換デバイスという提案がなされている。特許文献10に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献11には透光性基板上に、透明導電膜からなる表面電極と、p型半導体層、i型半導体層、n型半導体層の順に積層された光電変換半導体層と、少なくとも光反射性金属電極を備える裏面電極とを順次形成した薄膜太陽電池において、前記透明導電膜が、前記透光性基板側からAl及びGaがドープされた第一の酸化亜鉛膜、Tiがドープされた酸化インジウム膜、Al及びGaがドープされた第二の酸化亜鉛膜の順に設けられた積層体で、前記第一の酸化亜鉛膜の前記酸化インジウム膜側の膜面が凹凸構造であることを特徴とする薄膜太陽電池という提案がなされている。特許文献11に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献12には絶縁性透光基板上に、透明導電膜からなる第1電極層と、非晶質半導体膜からなり光電変換を行う第1発電層と、微結晶質半導体膜からなり光電変換を行う第2発電層と、光を反射する導電膜からなる第2電極層と、がこの順で積層された薄膜太陽電池であって、前記第1電極層は、前記第1発電層側の表面に凹凸形状を有し、前記第1発電層は、前記第1電極層の凹凸形状に対応して前記第2発電層側に凹凸形状が形成され、その凸部の上面が前記絶縁性透光基板の面内方向と略平行な面とされていること、を特徴とする薄膜太陽電池という提案がなされている。特許文献12に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献13には太陽電池セルの受光面側に太陽電池セルを支持する透明電極を備えた太陽電池モジュールにおいて、上記透明基板の入光面側に、錐状の凹みあるいは錐状の突起が形成された光学指向性構造を備えた透明シートが積層されていることを特徴とする太陽電池モジュールという提案がなされている。特許文献13に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。In contrast to the present invention regarding individual prior art documents, Patent Document 1 proposes to form an uneven shape on a P-type single crystal silicon plate for a thin film solar cell. It is said that the unevenness increases the distance that the light travels when obliquely incident on the power generation layer, and the light is confined well. The unevenness described in Patent Document 1 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. Moreover, there is no mention which forms a constricted form with respect to the primary sunlight incident direction like this invention. Patent Document 2 discloses a thin film solar cell in which a translucent resin layer having irregularities on a translucent insulating substrate, a transparent conductive film, an amorphous semiconductor layer, and a back electrode layer are sequentially laminated. The projections and depressions are arranged in parallel to each other, and light incident from the translucent substrate side is scattered at the interface between the transparent conductive film and the amorphous semiconductor layer. Proposals have been made to increase the optical path length of light. The unevenness described in Patent Document 2 has a shape connected to the flat plate direction on the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. In Patent Document 3, in a solid-state optoelectronic device having a photoelectric conversion region for converting incident light into electric charge, a reflection film having a function of reflecting light from the lower side is formed above the photoelectric conversion region. There has been proposed a solid-state optoelectronic device characterized in that light (electromagnetic wave) incident on the region is configured to repeatedly reflect between the photoelectric conversion region and the reflective film. It is characterized in that at least one of the upper surface and the lower surface of the photoelectric conversion region is composed of a plurality of surfaces having different directions. Although the unevenness | corrugation described in patent document 3 forms V shape, U shape, or a semicircle, it is the shape connected to the flat plate direction of the photoelectric conversion area | region surface , and provides a constricted form with respect to the primary sunlight incident direction of this invention. It is different from the photoelectric conversion device. Moreover, there is no mention which forms a constricted form with respect to the primary sunlight incident direction like this invention. In Patent Document 4, a plurality of photoelectric conversion cells are arranged at a predetermined distance, and are sandwiched between adjacent first regions in a photoelectric conversion device in which adjacent photoelectric conversion cells are electrically connected in series. When the region is the second region, the second region has a configuration formed so as to change the path of light incident on the second region of the insulating transparent substrate in the direction of the photoelectric conversion layer. A device has been proposed. The unevenness described in Patent Document 4 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. In Patent Document 5, a surface electrode layer made of a transparent conductive material on an insulating translucent substrate, a photoelectric conversion body including a plurality of photoelectric conversion layers having different band gaps in a direction perpendicular to the substrate surface, a back electrode layer, The side surface of the photoelectric conversion body on which the back electrode layer is formed is between the surface formed perpendicularly on the substrate including the intersection of the lower portion of the side surface and the front surface electrode layer. There has been a proposal of a photoelectric conversion device formed such that the distance increases as the distance from the substrate increases. The unevenness described in Patent Document 5 is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. Patent Document 6, the solar cell assembly in the bottom or top of the reflecting concave surface for focusing and reflecting incident light to the photoelectric conversion element by laminating a semiconductor layer, the photoelectric conversion element is the arrangement, before the photoelectric conversion element A proposal has been made that a fluorescent agent or phosphorescent material that converts the wavelength of a part of the incident light is disposed on the way of the incident light . The unevenness described in Patent Document 6 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. Patent Document 7 discloses a conductive type having a concavo-convex structure in which a plurality of conductive substrates are bonded to one main surface of the conductive substrate, the surface has a conductive semiconductor portion, and the surface has a plurality of convex portions. There has been proposed a photoelectric conversion device including crystal semiconductor particles having the semiconductor portion and a translucent conductive layer partially connected to the conductive semiconductor portion. The unevenness described in Patent Document 7 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. Patent Document 8 proposes a thin film solar cell characterized by having an uneven structure on the surface of a transparent insulating substrate. The unevenness described in Patent Document 8 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. Patent Document 9 discloses a first electrode layer made of a transparent conductive film on an insulating translucent substrate, a photoelectric conversion layer made of a semiconductor film for performing photoelectric conversion, a second electrode layer made of a conductive film for reflecting light, Is a thin film photoelectric conversion device in which a plurality of photoelectric conversion cells stacked in this order are disposed, and the adjacent photoelectric conversion cells are electrically connected in series, wherein the insulating light-transmitting substrate is Presenting a substantially regular polygonal shape, the photoelectric conversion cell has a fan-like shape arranged radially from the substantially central portion of the insulating light-transmitting substrate toward the outer periphery in the in-plane direction of the insulating light-transmitting substrate. The proposal of the thin film photoelectric conversion device characterized by this is made. The unevenness described in Patent Document 9 has a shape connected to the flat plate direction on the surface of the solar cell, and is different from the photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. Patent Document 10 discloses a conductive first electrode layer, a dielectric base material formed thereon, and a plurality of fine metal bodies made of a metal material filling the plurality of fine holes. A metal-filled dielectric layer, a photoelectric conversion layer formed thereon and made of a photoelectric conversion material, and a conductive second electrode formed thereon. A filling portion that fills the micropores of the base material and a protruding portion that protrudes from the dielectric base material into the photoelectric conversion layer, and is a conductive metal body on the first electrode layer at the other end of the filling portion; The conversion layer is formed on the dielectric base so as to cover the protruding portion, and the other end of the filling portion connected to the first electrode layer of the fine metal body penetrates the first electrode layer. The proposal of the photoelectric conversion device which forms a part is made. The unevenness described in Patent Document 10 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. In Patent Document 11, a surface electrode made of a transparent conductive film on a translucent substrate, a photoelectric conversion semiconductor layer laminated in the order of a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer, and at least light-reflective. In the thin film solar cell in which a back electrode having a metal electrode is sequentially formed, the transparent conductive film is a first zinc oxide film doped with Al and Ga from the translucent substrate side, and indium oxide doped with Ti A laminated body provided in the order of a film and a second zinc oxide film doped with Al and Ga, wherein the film surface on the indium oxide film side of the first zinc oxide film has a concavo-convex structure A proposal of a thin film solar cell has been made. The unevenness described in Patent Document 11 has a shape connected to the flat plate direction on the surface of the solar cell, and is different from the photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. In Patent Document 12, a first electrode layer made of a transparent conductive film, a first power generation layer made of an amorphous semiconductor film for performing photoelectric conversion, and a microcrystalline semiconductor film made of photoelectric conversion are formed on an insulating transparent substrate. And a second electrode layer made of a conductive film that reflects light is laminated in this order, and the first electrode layer is disposed on the first power generation layer side. The first power generation layer has a concavo-convex shape on the second power generation layer side corresponding to the concavo-convex shape of the first electrode layer, and the upper surface of the convex portion has the insulating transparent surface. There has been proposed a thin film solar cell characterized by being a plane substantially parallel to the in-plane direction of the optical substrate. The unevenness described in Patent Document 12 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. In Patent Document 13, in a solar cell module provided with a transparent electrode that supports a solar cell on the light receiving surface side of the solar cell, a conical recess or a conical protrusion is formed on the light incident surface side of the transparent substrate. There has been proposed a solar cell module characterized in that a transparent sheet having an optical directivity structure is laminated. The unevenness described in Patent Document 13 has a shape connected to the flat plate direction on the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention.

他の実施例として、図4は入射光を電子等の電荷に変換する光電変換領域を有する受光素子部に、入射光の進行方向に対して括れ状の内壁を設けた、穴形体の括れ付き光電変換装置の例で、作用と効果については、前記図1と同様である。図5は入射光を電子等の電荷に変換する光電変換領域を有する受光素子部に、入射光の進行方向に対して括れ状の外壁を設けた柱形体と括れ状の内壁を設けた穴形体のハイブリッド配置のれ付き光電変換装置の例で、作用と効果については、前記図1と同様である。図6は入射光を電子等の電荷に変換する光電変換領域を有する受光素子部に入射光の進行方向に対して括れ状の外壁を設けて複数積み上げたトーテムポール状形体の括れ付き光電変換装置の例で、作用と効果については、前記図1と同様であり、光電変換領域が多段に設けてなるので、一次太陽光入射単位面積当たりの実効光電変換表面積をより大きく設けてなり、光路長をより大きく設けてなり、一次太陽光入射方向側に返す光をより少なくする形体にすることができる。As another embodiment, FIG. 4 shows a hole-shaped constriction in which a light-receiving element portion having a photoelectric conversion region for converting incident light into charges such as electrons is provided with a constricted inner wall with respect to the traveling direction of incident light. In the example of the photoelectric conversion device, the operation and effect are the same as those in FIG. FIG. 5 shows a hole-shaped body provided with a columnar body provided with a constricted outer wall and a constricted inner wall in a light receiving element portion having a photoelectric conversion region for converting incident light into charges such as electrons. in the example of Batch been with the photoelectric conversion device of a hybrid arrangement, the operation and effects are similar to the Figure 1. FIG. 6 shows a photoelectric conversion device with a constricted totem pole shape in which a light receiving element portion having a photoelectric conversion region for converting incident light into charges such as electrons is provided with a constricted outer wall with respect to the traveling direction of the incident light. In this example, the operation and effect are the same as in FIG. 1 described above, and the photoelectric conversion regions are provided in multiple stages, so that the effective photoelectric conversion surface area per unit area of primary sunlight incidence is larger, and the optical path length Can be formed in a larger shape, and the amount of light returned to the primary sunlight incident direction side can be reduced.

本発明は、入射光を電気に変換する光電変換領域を有する超高効率型光電変換装置に関するものである。  The present invention relates to an ultra-high efficiency photoelectric conversion device having a photoelectric conversion region for converting incident light into electricity.

近年、化石燃料の枯渇と石油消費で発生する二酸化炭素による地球温暖化が地球規模の課題となっている。公的機関の石油需要見通しに依ると、特にアジア、中東の石油需要量は膨らむ一方である。世界の電力発電量も増加を続けている。一般に地球の人口増大に対して、エネルギー資源は残り少ないと言われている。そのような中、地球温暖化の環境改善に向けて導入が進む新エネルギーの中で、現在、最も重要な技術と考えられているのが太陽光発電である。  In recent years, global warming due to carbon dioxide generated by fossil fuel depletion and oil consumption has become a global issue. According to public oil demand forecasts, oil demand in Asia and the Middle East is growing. Global power generation continues to increase. In general, it is said that energy resources are scarce as the population of the earth grows. Under such circumstances, solar power generation is currently considered the most important technology among new energies that are being introduced to improve the global warming environment.

これまで太陽光発電は、エネルギー変換効率が低いことから家庭用や小規模での運用が主であった。太陽電池は、クリーンエネルギーの主役として家庭用だけでなく公的施設への導入も拡大している。さらに、大規模な太陽光発電所の設置計画も公表されている。また、再生可能エネルギーの活用を軸とした環境未来都市構想も提唱されてきている。太陽光発電は再生可能エネルギーであり、太陽光発電の需要拡大が見込まれている。  So far, solar power generation has been mainly used for home use and small scale because of its low energy conversion efficiency. Solar cells are being used not only for households but also for public facilities as a leading role in clean energy. In addition, a large-scale solar power plant installation plan has been announced. An environmental future city concept centered on the use of renewable energy has also been proposed. Solar power generation is a renewable energy, and demand for solar power generation is expected to increase.

従来の光電変換領域を有する太陽電池は、太陽光を出来るだけ多く太陽電池内部に取り込もうとして太陽電池表面にピラミッド断面形あるいは上下逆ピラミッド断面形の凹凸(テクスチャー)を設けている。しかし、まだ電力会社から購入する電気を代替するほどの経済性には至っていない。太陽エネルギーの電気への変換効率の向上への取り組みが望まれている。現在の太陽エネルギーの電気への変換効率はおおよそ次である。多結晶Si型太陽電池セルの光電変換効率は高いもので19%程である。一般的に結晶シリコン型は15%程、薄膜シリコン型は10%程である。 A conventional solar cell having a photoelectric conversion region is provided with irregularities (textures) having a pyramid cross-sectional shape or an upside-down inverted pyramid cross-sectional shape on the surface of the solar cell so as to capture as much sunlight as possible inside the solar cell. However, it has not yet been economical enough to replace electricity purchased from electric power companies. Efforts to improve the conversion efficiency of solar energy into electricity are desired. The conversion efficiency of current solar energy into electricity is roughly as follows. The photoelectric conversion efficiency of the polycrystalline Si solar cell is as high as about 19%. Generally, the crystalline silicon type is about 15%, and the thin film silicon type is about 10%.

光電変換装置には太陽電池、イメージセンサー等がある。図2はそのような光電変換装置の一例である表面凹凸付き結晶系太陽電池の従来例を示す断面図である。1は裏面電極層、2は酸化膜、3はp型半導体、4はp+拡散層、5はn型半導体、6はn+拡散層、7は透明電極層(ITO電極膜等)、8は取り出し電極である。  Photoelectric conversion devices include solar cells and image sensors. FIG. 2 is a cross-sectional view showing a conventional example of a crystal solar cell with surface irregularities, which is an example of such a photoelectric conversion device. 1 is a back electrode layer, 2 is an oxide film, 3 is a p-type semiconductor, 4 is a p + diffusion layer, 5 is an n-type semiconductor, 6 is an n + diffusion layer, 7 is a transparent electrode layer (ITO electrode film, etc.), 8 is taken out Electrode.

図2に例示のように従来の太陽電池は太陽電池表面にピラミッド断面形あるいは上下逆ピラミッド断面形の凹凸(テクスチャー)を該太陽電池表面の平板方向に繋がる様に設けている。  As illustrated in FIG. 2, the conventional solar cell is provided with unevenness (texture) having a pyramid cross-sectional shape or a vertically inverted pyramid cross-sectional shape on the surface of the solar cell so as to be connected in the flat plate direction of the solar cell surface.

先行技術文献と本願発明との対比について説明する。
先行技術文献全体として言えることは、該先行技術文献のいづれについても本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。前記括れについての定義と、前記太陽光入射方向についての詳しい説明は、段落[0012]に記載する。
A comparison between the prior art document and the present invention will be described.
What can be said as a whole of the prior art document is different from the photoelectric conversion device in which any of the prior art documents is provided with a constricted shape in the primary sunlight incident direction of the present invention. The definition of the constriction and the detailed description of the sunlight incident direction are described in paragraph [0012].

個別の先行技術文献について本願発明と対比すると、特許文献1には薄膜太陽電池についてP型単結晶シリコン板の上に凹凸形状を形成する提案がされている。凹凸は発電層への斜め入射で光の進む距離が長くなり、光の閉じ込めが良好に行われるとしている。特許文献1に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。また、本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献2には入射光を電荷に変換する光電変換領域を有する固体光電子装置において光電変換領域の上方部に下側からの光に対して反射機能を持つ反射膜を形成してなり、光電変換領域に入射した光(電磁波)が光電変換領域・反射膜間にて反射を繰り返すように構成されてなることを特徴とする固体光電子装置という提案がなされている。光電変換領域の上面と下面の少なくとも一方を互いに異なる向きをもった複数面で構成したことを特徴としている。特許文献2に記載の凹凸はV字またはU字あるいは半円形を形成するが光電変換領域表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。また、本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献3には複数の光電変換セルが所定の距離を隔てて複数配置され、隣接する光電変換セル同士を電気的に直列に接続した光電変換装置において、隣接する第1の領域間に挟まれる領域を第2の領域とした場合に、第2の領域は、絶縁性透明基板の第2の領域に入射する光の進路を光電変換層の方向に変えるように形成された構成を有する光電変換装置という提案がなされている。特許文献3に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献4には絶縁透光性基板上に透明導電性材料からなる表面電極層と、バンドギャップの異なる光電変換層を基板面に垂直な方向に複数含む光電変換体と、裏面電極層と、を含むセルが複数配列して形成されるとともに、裏面電極層が形成される光電変換体側面は、側面の下部と表面電極層との交点を含み基板上に垂直に形成した面との間の距離が基板から離れるにしたがって大きくなるように形成されている光電変換装置という提案がなされている。特許文献4に記載の凹凸は本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献5には、太陽電池アセンブリは半導体層を積層した光電変換素子へ入射光を反射して集束させる反射凹面の底部又はその上部に、前記光電変換素子が配置され、前記光電変換素子に前記入射光が到達する途中に、その光の一部を波長変換する蛍光剤またはリン光材が配置されているという提案がなされている。特許文献5に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献6には導電性基板と該導電性基板の一主面に多数個接合され、表層に導電型の半導体部を有し、かつ表面が複数の凸部を有する凹凸構造を成した導電型の半導体部を有する結晶半導体粒子と、導電型の半導体部と部分的に接続された透光性導電層と、を備えた光電変換装置という提案がなされている。特許文献6に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献7には透明絶縁基板の表面に凹凸構造を有することを特徴とする薄膜太陽電池という提案がなされている。特許文献7に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献8には絶縁性透光基板上に透明導電膜からなる第1電極層と、半導体膜からなり光電変換を行う光電変換層と、光を反射する導電膜からなる第2電極層と、がこの順で積層されてなる複数の光電変換セルが配設されるとともに、隣接する前記光電変換セル同士が電気的に直列接続された薄膜光電変換装置であって、前記絶縁性透光基板が略正多角形状を呈し、前記光電変換セルは、前記絶縁性透光基板の面内方向において前記絶縁性透光基板の略中心部から外周に向かって放射線状に配置された扇形の形状を呈すること、を特徴とする薄膜光電変換装置という提案がなされている。特許文献8に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。特許文献9には絶縁性透光基板上に、透明導電膜からなる第1電極層と、非晶質半導体膜からなり光電変換を行う第1発電層と、微結晶質半導体膜からなり光電変換を行う第2発電層と、光を反射する導電膜からなる第2電極層と、がこの順で積層された薄膜太陽電池であって、前記第1電極層は、前記第1発電層側の表面に凹凸形状を有し、前記第1発電層は、前記第1電極層の凹凸形状に対応して前記第2発電層側に凹凸形状が形成され、その凸部の上面が前記絶縁性透光基板の面内方向と略平行な面とされていること、を特徴とする薄膜太陽電池という提案がなされている。特許文献9に記載の凹凸は太陽電池表面の平板方向に繋がってなる形状で、本願発明の一次太陽光入射方向に対して括れ形体を設けてなる光電変換装置とは異なる。本願発明の様な一次太陽光入射方向に対して括れ形体を設けてなる言及は無い。 In contrast to the present invention regarding individual prior art documents, Patent Document 1 proposes to form an uneven shape on a P-type single crystal silicon plate for a thin film solar cell. It is said that the unevenness increases the distance that the light travels when obliquely incident on the power generation layer, and the light is confined well. The unevenness described in Patent Document 1 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. Moreover, there is no mention which forms a constricted form with respect to the primary sunlight incident direction like this invention . In Patent Document 2, in a solid-state optoelectronic device having a photoelectric conversion region for converting incident light into electric charge, a reflection film having a function of reflecting light from the lower side is formed above the photoelectric conversion region. There has been proposed a solid-state optoelectronic device characterized in that light (electromagnetic wave) incident on the region is configured to repeatedly reflect between the photoelectric conversion region and the reflective film. It is characterized in that at least one of the upper surface and the lower surface of the photoelectric conversion region is composed of a plurality of surfaces having different directions. The unevenness described in Patent Document 2 forms a V-shape, U-shape, or semicircle, but is connected to the flat plate direction on the surface of the photoelectric conversion region, and has a constricted shape with respect to the primary sunlight incident direction of the present invention. It is different from the photoelectric conversion device. Moreover, there is no mention which forms a constricted form with respect to the primary sunlight incident direction like this invention. In Patent Document 3, a plurality of photoelectric conversion cells are arranged at a predetermined distance, and are sandwiched between adjacent first regions in a photoelectric conversion device in which adjacent photoelectric conversion cells are electrically connected in series. When the region is the second region, the second region has a configuration formed so as to change the path of light incident on the second region of the insulating transparent substrate in the direction of the photoelectric conversion layer. A device has been proposed. The unevenness described in Patent Document 3 has a shape connected to the flat plate direction on the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. In Patent Document 4, a surface electrode layer made of a transparent conductive material on an insulating translucent substrate, a photoelectric conversion body including a plurality of photoelectric conversion layers having different band gaps in a direction perpendicular to the substrate surface, a back electrode layer, The side surface of the photoelectric conversion body on which the back electrode layer is formed is between the surface formed perpendicularly on the substrate including the intersection of the lower portion of the side surface and the front surface electrode layer. There has been a proposal of a photoelectric conversion device formed such that the distance increases as the distance from the substrate increases. The unevenness described in Patent Document 4 is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. In Patent Document 5, the photovoltaic cell assembly is arranged on the bottom or the upper part of a reflective concave surface for reflecting and focusing incident light onto a photovoltaic device on which a semiconductor layer is laminated. A proposal has been made that a fluorescent agent or phosphorescent material that converts the wavelength of a part of the incident light is disposed on the way of the incident light. The unevenness described in Patent Document 5 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. In Patent Document 6, a conductive substrate and a conductive type having a concavo-convex structure in which a plurality of conductive substrates are bonded to one main surface of the conductive substrate, the surface has a conductive semiconductor portion, and the surface has a plurality of convex portions. There has been proposed a photoelectric conversion device including crystal semiconductor particles having the semiconductor portion and a translucent conductive layer partially connected to the conductive semiconductor portion. The unevenness described in Patent Document 6 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. Patent Document 7 proposes a thin film solar cell characterized by having an uneven structure on the surface of a transparent insulating substrate . The unevenness described in Patent Document 7 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. Patent Document 8 discloses a first electrode layer made of a transparent conductive film on an insulating translucent substrate, a photoelectric conversion layer made of a semiconductor film for performing photoelectric conversion, a second electrode layer made of a conductive film for reflecting light, Is a thin film photoelectric conversion device in which a plurality of photoelectric conversion cells stacked in this order are disposed, and the adjacent photoelectric conversion cells are electrically connected in series, wherein the insulating light-transmitting substrate is Presenting a substantially regular polygonal shape, the photoelectric conversion cell has a fan-like shape arranged radially from the substantially central portion of the insulating light-transmitting substrate toward the outer periphery in the in-plane direction of the insulating light-transmitting substrate. The proposal of the thin film photoelectric conversion device characterized by this is made. The unevenness described in Patent Document 8 has a shape connected to the flat plate direction of the surface of the solar cell, and is different from a photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention. In Patent Document 9, a first electrode layer made of a transparent conductive film, a first power generation layer made of an amorphous semiconductor film for performing photoelectric conversion, and a microcrystalline semiconductor film made of photoelectric conversion on an insulating light-transmitting substrate. And a second electrode layer made of a conductive film that reflects light is laminated in this order, and the first electrode layer is disposed on the first power generation layer side. The first power generation layer has a concavo-convex shape on the second power generation layer side corresponding to the concavo-convex shape of the first electrode layer, and the upper surface of the convex portion has the insulating transparent surface. There has been proposed a thin film solar cell characterized by being a plane substantially parallel to the in-plane direction of the optical substrate. The unevenness described in Patent Document 9 has a shape connected to the flat plate direction on the surface of the solar cell, and is different from the photoelectric conversion device in which a constricted shape is provided in the primary sunlight incident direction of the present invention. There is no mention that a constricted shape is provided in the primary sunlight incident direction as in the present invention.

特開平11−40832号公報Japanese Patent Laid-Open No. 11-40832 特開第2000−208747号公報JP 2000-208747 A 特開第2009−231499号公報JP 2009-231499 A 特開第2009−289817号公報JP 2009-289817 A 特開第2009−206212号公報JP 2009-206212 A 特開第2009−206469号公報JP 2009-206469 A 特開第2009−224427号公報JP 2009-224427 A 特開第2009−295943号公報JP 2009-295943 A 特開第2010−62302号公報JP 2010-62302 A

解決しようとする問題点は、従来の光電変換領域を有する太陽電池は、太陽光を出来るだけ多く太陽電池内部に取り込もうとして太陽電池表面にピラミッド断面形あるいは上下逆ピラミッド断面形の凹凸(テクスチャー)を設けているが、まだ電力会社から購入する電気を代替するほどの経済性には至っていない点である。前記の光電変換効率のように従来の凹凸付き太陽電池では大部分の光エネルギーは活用出来ていないという問題がある。  The problem to be solved is that a conventional solar cell having a photoelectric conversion region has a pyramid cross-section or an upside-down inverted pyramid cross-section (texture) on the surface of the solar cell in order to capture as much sunlight as possible inside the solar cell. However, it is not yet economical enough to replace electricity purchased from electric power companies. As in the photoelectric conversion efficiency described above, there is a problem that most of the light energy cannot be utilized in the conventional uneven solar cell.

本発明はこのような問題点を解決すべく為されたものであり、入射光の閉じ込め作用に優れる形体の光電変換装置であり、一次太陽光入射単位面積当たりについて、より大きな出力エネルギーを得ることができる光電変換装置を提供することを目的とする。  The present invention has been made to solve such problems, and is a photoelectric conversion device having a shape excellent in the confinement function of incident light, and obtains a larger output energy per unit area of primary sunlight incident. It is an object of the present invention to provide a photoelectric conversion device that can perform the following.

ここで、本願発明における括れの定義について説明する。図4は本願発明の特徴である括れの定義を示した図である。日射量が最も多い本願装置の真上方向からの光入射を基準として、つまりn型半導体5に対して光入射基準方向11の位置関係となるように前記装置を設置し、太陽光の一般的光路変化である、前記光入射基準方向に対しての光入射角がプラス90度、マイナス90度の範囲を考慮に入れて、前記装置を使用想定する場合に、1次入射光を電子等の電荷に変換する光電変換領域を有する受光素子部に、1次入射光の進行方向に対して、前記光電変換領域、例えばn型半導体5が1次入射光の進行方向に沿って形を成す曲線において、前記曲線上に任意の2点、12、13を取る。前記2点、12、13を通る仮想の直線を設けると、点13を点12に限りなく近づけた時の極限が、点12における接線である。また、点12を点13に限りなく近づけた時の極限が、点13における接線である。前記点12、点13における接線の傾きについて、前記1次入射光側の点12の接線14の傾きを、正とすると、前記残りの本願装置の基板寄りの点13の接線15の傾きが負となるように設けてなる形を括れと定義する。本発明は、入射光を電気に変換する光電変換領域を有する光電変換装置において、超高効率光電変換を可能とするため、一次太陽光入射方向に対してシリコン系材料を使用する括れ形成部9、および括れの下方側に形成してなる抉れ部10を設けてなる外壁を設けて、光電変換領域が前記括れ形体状に設けてなり、一次太陽光入射単位面積当たりの実効光電変換表面積をより大きく設けてなり、光路長をより大きく設けてなり、一次太陽光入射方向側に返す光をより少なくする形体で、前記入射光を光電変換することを主要な特徴とする。 Here, the definition of the binding in the present invention will be described. FIG. 4 is a diagram showing the definition of the narrowing that is a feature of the present invention. The above-mentioned device is installed on the basis of the light incident from directly above the device of the present application with the largest amount of solar radiation, that is, so as to be in the positional relationship of the light incident reference direction 11 with respect to the n-type semiconductor 5. When the apparatus is assumed to be used in consideration of the range of the light incident angle with respect to the light incident reference direction, which is an optical path change, plus 90 degrees and minus 90 degrees, the primary incident light is converted into electrons or the like. A curve in which the photoelectric conversion region, for example, the n-type semiconductor 5 forms a shape along the traveling direction of the primary incident light with respect to the traveling direction of the primary incident light in the light receiving element portion having the photoelectric conversion region that converts the charge. , Take two arbitrary points 12, 13 on the curve. When a virtual straight line passing through the two points 12, 13 is provided, the limit when the point 13 is brought as close as possible to the point 12 is the tangent at the point 12. The limit when the point 12 is brought as close as possible to the point 13 is a tangent at the point 13. Regarding the slope of the tangent line at the points 12 and 13, if the slope of the tangent line 14 of the point 12 on the primary incident light side is positive, the slope of the tangent line 15 of the point 13 near the substrate of the remaining device of the present application is negative. The form that is established so that In the photoelectric conversion device having a photoelectric conversion region that converts incident light into electricity, the present invention uses a silicon-based material for the primary sunlight incident direction in order to enable ultra-high efficiency photoelectric conversion 9 And an outer wall provided with a bend 10 formed on the lower side of the constriction, and a photoelectric conversion region is provided in the form of the constricted body, and an effective photoelectric conversion surface area per unit area of primary sunlight incident is obtained. The main feature is that the incident light is photoelectrically converted in a form that is provided larger, has a longer optical path length, and reduces the amount of light returned to the primary sunlight incident direction side.

請求項1の光電変換装置によれば、前記主要な特徴を備えているので、光の利用効率を高めることができる。 According to the photoelectric conversion device of the first aspect, since the main feature is provided, the light use efficiency can be increased.

請求項1の光電変換装置によれば、一次太陽光入射単位面積当たりの実効光電変換表面積がより大きくなり、加えて、一次太陽光入射方向側に返す光をより少なくすることができるので、光の利用効率を高めることができる。従って、エネルギー変換効率が高くなることで、出力当たりの単価が改善され、出力の増加に伴って、経済性を高めることができる。 According to the photoelectric conversion device of claim 1, the effective photoelectric conversion surface area per unit area of primary sunlight incidence becomes larger, and in addition, the light returned to the primary sunlight incidence direction side can be reduced, so that the light Can improve the efficiency of use. Therefore, the energy conversion efficiency is increased, the unit price per output is improved, and the economic efficiency can be enhanced as the output increases.

本発明光電変換装置の一つの実施例で、請求項1の例を示す断面図である。It is sectional drawing which shows the example of Claim 1 in one Example of this invention photoelectric conversion apparatus. 光電変換装置の従来例を示す断面図である。It is sectional drawing which shows the prior art example of a photoelectric conversion apparatus. 本発明光電変換装置の一つの実施例で、請求項1の例を示す斜視図である。1 is a perspective view showing an example of claim 1 in one embodiment of the photoelectric conversion device of the present invention. 本発明光電変換装置の括れの定義を示す図である。It is a figure which shows the definition of the narrowing of the photoelectric conversion apparatus of this invention.

本発明は一次太陽光入射方向に対して光電変換領域に括れ形体を設けて、入射した光を入射元の方向に、より反射させないように構成されてなる。より具体的には、きのこ柱状に、括れと、前記括れの下方側に抉れを設けてなる光電変換領域を形成する態様が好適である。前記括れは、傘状または軒状あるいはその庇状の構造で形成しても良い。前記括れの下方側に形成する抉れ形状は砲弾断面形、あるいは上下逆さJ字状のステッキのように曲がる態様にしても良い。前記きのこ柱状の頭部は、球形、円錐形、多角錐等が良く、傾斜面の角度は大きく尖らす態様を形成すると好適である。 The present invention is configured such that a constricted shape is provided in the photoelectric conversion region with respect to the incident direction of primary sunlight so that incident light is less reflected in the direction of the incident source. More specifically, it is preferable to form a photoelectric conversion region in a mushroom pillar shape by forming a neck and a neck on the lower side of the neck. The constriction may be formed in an umbrella shape, an eave shape, or a bowl-like structure. The bend shape formed on the lower side of the constriction may be bent like a cannonball cross-sectional shape or an upside down J-shaped stick. The mushroom columnar head is preferably spherical, conical, polygonal pyramid, etc., and it is preferable that the angle of the inclined surface is sharpened.

以下、本発明を図示実施例に従って説明する。図1は、きのこ柱形体を設けてなる本光電変換装置の一つの実施例である。本光電変換装置の大きな特徴はp型半導体3とn型半導体4の接合で形成される光電変換領域が括れ形体を設けてなることである。p型半導体3に括れ形成部9、および括れの下方側に形成してなる抉れ部10を形成する。次にp型半導体3とn型半導体4の接合を形成し、しかる後、n+拡散層と、透明電極層7を形成してなる。次にp型半導体3の裏面に酸化膜2と、p+拡散層4と、裏面電極層1を形成してなる。  The present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows an embodiment of the present photoelectric conversion device provided with mushroom columnar bodies. A major feature of this photoelectric conversion device is that a photoelectric conversion region formed by the junction of the p-type semiconductor 3 and the n-type semiconductor 4 is provided with a constricted shape. A constriction forming portion 9 and a constricted portion 10 formed on the lower side of the constriction are formed in the p-type semiconductor 3. Next, a junction between the p-type semiconductor 3 and the n-type semiconductor 4 is formed, and then an n + diffusion layer and a transparent electrode layer 7 are formed. Next, the oxide film 2, the p + diffusion layer 4, and the back electrode layer 1 are formed on the back surface of the p-type semiconductor 3.

このような、きのこ柱形体を設けてなる本光電変換装置によれば、外部からの一次入射太陽光は、きのこ柱形体の頭部の光電変換層に入射して、前記太陽光は光電変換される。きのこ柱形体の横を通過した一次入射太陽光については、きのこ柱形体の土台側の光電変換層に入射して、前記太陽光は光電変換される。前記太陽光の一部は反射を繰り返す。その際、きのこ柱形体に設けてなる括れ形成部9、および括れの下方側に形成してなる抉れ部10は反射光を閉じ込めて、一次太陽光入射方向側に返す光をより少なくする機能を果たす。というのは、きのこ柱形体に設けてなる括れ形成部9、および括れの下方側に形成してなる抉れ部10が入射光を前記抉れ部の奥側へ導く作用を生ぜしめるからである。  According to this photoelectric conversion device provided with the mushroom columnar body, primary incident sunlight from the outside enters the photoelectric conversion layer on the head of the mushroom columnar body, and the sunlight is photoelectrically converted. The About the primary incident sunlight which passed the mushroom pillar form side, it injects into the photoelectric conversion layer of the base side of a mushroom pillar form body, and the said sunlight is photoelectrically converted. Part of the sunlight is repeatedly reflected. At that time, the constriction forming part 9 provided on the mushroom columnar shape and the constriction part 10 formed on the lower side of the constriction function to confine the reflected light and reduce the light returned to the primary sunlight incident direction side. Fulfill. This is because the constriction forming part 9 provided on the mushroom columnar shape and the bend part 10 formed on the lower side of the constriction cause the action of guiding incident light to the back side of the constriction part. .

尚、太陽電池の製造プロセスは、蒸着、露光、蝕刻(エッチング)など、従来からの、半導体、液晶パネルの製造プロセスを踏襲しており、前記括れ形成部9、および括れの下方側に形成してなる抉れ部10を形成することは、CVD法や選択式露光、等方性エッチング、選択式エッチング、あるいはCMP(Chemical Mechanical Polishing:化学的機械研磨)法であるダマシン法やデュアルダマシン法を選択的に駆使して形成することが出来る。次に詳しく説明する。シリコン系は結晶の状態により 結晶シリコンと薄膜シリコンに分類できる。結晶シリコンは単結晶シリコンと多結晶シリコンに分類できる。薄膜シリコンは微結晶シリコンとアモルファス(非晶質)シリコンに分類できる。シリコン系の結晶型の違いはシリコンの結晶粒界面、つまり結晶欠陥の数の違いであり、結晶欠陥の少ない順に、単結晶シリコン、多結晶シリコン、微結晶シリコン、アモルファス(非晶質)シリコンとなる。一般的に前記結晶欠陥の数が少ない、および前記結晶欠陥に伴う不純物の数が少ないほど太陽電池の変換効率は高くなる。つまり、結晶欠陥が多いほど、電気が効率良く流れなくなる。本願発明の括れをどのように生成するかを詳しく説明する。本光電変換装置の基板にp型半導体3を使用する。結晶シリコン太陽電池は一般的に高純度シリコンインゴットからシリコンウエーハという薄い板状にしたものを使用する。薄膜シリコンの場合はシリコンウエーハもしくはガラス基板などが使用される。p型半導体3はホウ素原子をp型不純物として熱拡散により混ぜて作る。薄膜シリコンの場合は一般的にプラズマCVD(化学的気相成長法)装置を使用して、シランガスを放電により分解し、結晶シリコンやガラスなどの基板に化学的にシリコンを付着させる。次いで、ホウ素原子をp型不純物として熱拡散により混ぜて作り、p型半導体3を形成する。次に括れ形成について説明する。結晶シリコンでは、前記状態のp型半導体3の表面にフォトリソグラフィを使用して、露光の深さ方向のフォーカス位置をずらすことで、レジストのパターンプロファイルが少々肩部が垂れる形状になることを利用してパターンを形成し、次にウエットまたはドライエッチングを行って、きのこ柱状の頭部側を形成できる。あるいは、前記状態のp型半導体3の表面を薄く酸化した後、シリコンナイトライド膜をCVDで堆積する。次いでフォトリソグラフィを使用してパターンを形成した後に、シリコンナイトライド膜をウエットまたはドライエッチングする。レジストを除去し、残ったシリコンナイトライド膜をマスクにして、前記酸化膜をフッ酸でエッチングする。次いで異方性エッチングをするとV字的形状に形成される。一般的にはKOH−IPA系水溶液が知られている。残った酸化膜とシリコンナイトライド膜はウエットまたはドライエッチングする。この方法でも、きのこ柱状の頭部側を形成できる。次いでフォトリソグラフィを使用して前記V字的形状の開口パターンより小さいパターンをレジストで形成した後に、等方性エッチングのドライエッチングまたはウエットエッチングをする。エッチングが回り込むことによって、アンダーカット(サイドエッチング)が得られる。次いでレジストは除去する。このようにして括れ形成部9を得ることができる。エッチング底面も同時に波形状を得ることができる。薄膜シリコンの場合は、前記薄膜シリコンのp型半導体3を形成後に前記結晶シリコンと同様に、エッチングを2段階に行って、括れ形成部9を得ることができる。あるいは、前記プラズマCVD装置を使用して、シランガスを放電により分解し、結晶シリコンやガラスなどの基板に、化学的にシリコンを付着させた後に、酸化膜またはシリコンナイトライド膜を堆積し、次いでフォトリソグラフィを使用してパターンを形成した後に、前記パターンをマスクにして前記酸化膜または前記シリコンナイトライド膜をドライエッチングすると、開口が得られる。次いで前記プラズマCVD装置を使用して、シランガスを放電により分解し、前記開口パターン形成済の酸化暎またはシリコンナイトライド膜上に化学的にシリコンを付着させる。次いで、余分な薄膜シリコンをCMPして、薄膜シリコン柱を形成する。次いで、前記薄膜シリコン柱を形成済みの上面に、酸化膜またはシリコンナイトライド膜を堆積し、次いで、フォトリソグラ フィを使用して前記薄膜シリコン柱の上面サイズより少々大きいレジストパターンを形成した後に、前記レジストパターンをマスクにして前記酸化膜または前記シリコンナイトライド膜をドライエッチングする。次いで、前記プラズマCVD装置を使用して、シランガスを放電により分解し、前記パターン形成済の酸化膜またはシリコンナイトライド膜上に化学的にシリコンを付着させる。次いで、余分な薄膜シリコンをCMPすると、T字状断面形を成す薄膜シリコン柱が形成される。つまり、ダマシン法を2回行うことで、T字状断面形を成す薄膜シリコン柱が形成される。あるいは、デュアルダマシン法を利用しても良い。デュアルダマシン法を利用する場合は、前記プラズマCVD装置を使用して、シランガスを放電により分解し、結晶シリコンやガラスなどの基板に、化学的にシリコンを付着させた後に、第1の酸化膜を堆積し、次いで前記プラズマCVD装置を使用してシリコンナイトライド膜を堆積し、さらに前記プラズマCVD装置を使用して第2の酸化膜を堆積する。次いでフォトリソグラフィを使用してレジストパターンを形成した後に、前記レジストパターンをマスクにして前記第2の酸化膜と、前記シリコンナイトライド膜と、前記第1の酸化膜をドライエッチングして開口する。次いで、フォトリソグラフィを使用して前記開口より少々大きいレジスト開口パターンを形成した後に、前記レジストパターンをマスクにして前記第2の酸化膜をドライエッチングする。前記第2の酸化膜の開口サイズは、前記シリコンナイトライド膜と、前記第1の酸化膜の開口サイズより少々大きくなる。これはシリコンナイトライド膜のエッチング速度が酸化膜のエッチング速度に比べて十分小さく、シリコンナイトライド膜がエッチングストップの作用を生じるからである。次いで、前記プラズマCVD装置を使用して、シランガスを放電により分解し、前記パターン形成済の酸化膜またはシリコンナイトライド膜上に化学的にシリコンを付着させる。次いで、余分な薄膜シリコンをCMPすると、T字状断面形を成す薄膜シリコン柱が形成される。前記T字状断面形を成す薄膜シリコン柱の表面に、フォトリソグラフィを使用して、露光の深さ方向のフォーカス位置をずらすことで、レジストのパターンプロファイルが少々肩部が垂れる形状になることを利用してパターンを形成し、次に、ウエットまたはドライエッチングを行って、きのこ柱状の頭部側を形成できる。次いで、フォトリソグラフィを使用して、きのこ柱状の頭部サイズと同等の開口パターンをレジストで形成した後に、等方性エッチングのドライエッチングまたはウエットエッチングをする。エッチングが回り込むことによって、アンダーカット(サイドエッチング)が得られる。次いでレジストは除去する。このようにして括れ形成部9を得ることができる。エッチング底面も同時に波形状を得ることができる。p型半導体3に括れ形成部9および括れの下方側に形成してなる抉れ部10を得た後は、n型半導体5を作る。n型半導体5はリン元素をn型不純物として熱拡散により混ぜて作る。前記p型不純物、n型不純物濃度を微調整するときは、フォトリソグラフィを使用してパターンを形成し、前記レジストパターンをマスクにしてホウ素イオンやリンイオンを使用してイオン注入を行う。前記イオン注入後に、p+拡散層4やn+拡散層6が得られる。その後に加熱アニールにより、結晶性を整えてpn接合ができる。p+拡散層4を作るためのリンイオン注入の実施順は、加熱アニールの前であれば良い。次に、光が当たるn型半導体5に、蒸着等を利用してITO等の透明電極層7をつける。次に、蒸着等を利用して全面にアルミニウムやAg等をつける。次いで、フォトリソグラフィを使用してパターンを形成し、次いで、ドライエッチング等で取り出 し電極8を形成する。裏面については残していた酸化膜2に、フォトリソグラフィを使用してパターンを形成し、裏面からの電極取り出しのパターンを形成する。次いで、スクリーン印刷や蒸着を使用して、裏面電極層1を形成する。前記裏面電極層1については、一般的にアルミニウムやAg等の使用が知られている。 The solar cell manufacturing process follows conventional manufacturing processes for semiconductors and liquid crystal panels, such as vapor deposition, exposure, and etching (etching), and is formed on the constriction forming portion 9 and below the constriction. The bent portion 10 is formed by a damascene method or a dual damascene method, which is a CVD method, selective exposure, isotropic etching, selective etching, or CMP (Chemical Mechanical Polishing) method. It can be formed selectively. Next, it explains in detail. Silicon systems can be classified into crystalline silicon and thin film silicon according to the crystalline state . Crystalline silicon can be classified into single crystal silicon and polycrystalline silicon. Thin film silicon can be classified into microcrystalline silicon and amorphous (amorphous) silicon. The difference in the silicon crystal type is the crystal grain interface of silicon, that is, the difference in the number of crystal defects, and in order of increasing crystal defects, single crystal silicon, polycrystalline silicon, microcrystalline silicon, and amorphous (amorphous) silicon. Become. Generally, the conversion efficiency of a solar cell increases as the number of crystal defects decreases and the number of impurities associated with the crystal defects decreases. That is, as the number of crystal defects increases, electricity cannot flow efficiently. A detailed description will be given of how to generate the binding of the present invention. A p-type semiconductor 3 is used for the substrate of the photoelectric conversion device. A crystalline silicon solar cell generally uses a high-purity silicon ingot made into a thin plate shape called a silicon wafer. In the case of thin film silicon, a silicon wafer or a glass substrate is used. The p-type semiconductor 3 is made by mixing boron atoms as p-type impurities by thermal diffusion. In the case of thin film silicon, a plasma CVD (Chemical Vapor Deposition) apparatus is generally used to decompose silane gas by electric discharge and chemically attach silicon to a substrate such as crystalline silicon or glass. Next, boron atoms are mixed as a p-type impurity by thermal diffusion to form a p-type semiconductor 3. Next, constriction formation will be described. In crystalline silicon, the pattern profile of the resist has a slightly drooping shape by using photolithography on the surface of the p-type semiconductor 3 in the above state and shifting the focus position in the exposure depth direction. Then, a pattern is formed, and then wet or dry etching can be performed to form a mushroom columnar head side. Alternatively, after thinly oxidizing the surface of the p-type semiconductor 3 in the above state, a silicon nitride film is deposited by CVD. Next, after forming a pattern using photolithography, the silicon nitride film is wet or dry etched. The resist is removed, and the oxide film is etched with hydrofluoric acid using the remaining silicon nitride film as a mask. Next, anisotropic etching is performed to form a V shape. In general, a KOH-IPA aqueous solution is known. The remaining oxide film and silicon nitride film are wet or dry etched. This method can also form a mushroom columnar head side. Next, a pattern smaller than the V-shaped opening pattern is formed with a resist using photolithography, and then dry etching or wet etching of isotropic etching is performed. Undercut (side etching) is obtained by etching. The resist is then removed. In this way, the constriction forming part 9 can be obtained. A corrugated shape can also be obtained at the same time on the etching bottom. In the case of thin-film silicon, after forming the thin-film silicon p-type semiconductor 3, the constriction forming portion 9 can be obtained by performing etching in two stages, similarly to the crystalline silicon. Alternatively, using the plasma CVD apparatus, silane gas is decomposed by discharge, silicon is chemically attached to a substrate such as crystalline silicon or glass, and then an oxide film or a silicon nitride film is deposited, and then photo After forming a pattern using lithography, the oxide film or the silicon nitride film is dry-etched using the pattern as a mask to obtain an opening. Next, using the plasma CVD apparatus, silane gas is decomposed by electric discharge, and silicon is chemically deposited on the oxide film or silicon nitride film having the opening pattern formed thereon. Next, the extra thin film silicon is CMPed to form thin film silicon pillars. Then, the upper surface already formed the thin silicon pillar, depositing an oxide film or a silicon nitride film, and then, after forming a slightly larger resist pattern from the upper surface the size of the thin film silicon pillar using photolithography Gras Fi, The oxide film or the silicon nitride film is dry-etched using the resist pattern as a mask. Next, using the plasma CVD apparatus, silane gas is decomposed by discharge, and silicon is chemically deposited on the patterned oxide film or silicon nitride film. Next, when excess thin film silicon is CMPed, thin film silicon pillars having a T-shaped cross section are formed. That is, by performing the damascene method twice, a thin film silicon pillar having a T-shaped cross section is formed. Alternatively, a dual damascene method may be used. When using the dual damascene method, the plasma CVD apparatus is used to decompose the silane gas by electric discharge, and after chemically attaching silicon to a substrate such as crystalline silicon or glass, the first oxide film is formed. Then, a silicon nitride film is deposited using the plasma CVD apparatus, and a second oxide film is deposited using the plasma CVD apparatus. Next, after forming a resist pattern using photolithography, the second oxide film, the silicon nitride film, and the first oxide film are opened by dry etching using the resist pattern as a mask. Next, after forming a resist opening pattern slightly larger than the opening using photolithography, the second oxide film is dry-etched using the resist pattern as a mask. The opening size of the second oxide film is slightly larger than the opening sizes of the silicon nitride film and the first oxide film. This is because the etching rate of the silicon nitride film is sufficiently smaller than the etching rate of the oxide film, and the silicon nitride film has an etching stop effect. Next, using the plasma CVD apparatus, silane gas is decomposed by discharge, and silicon is chemically deposited on the patterned oxide film or silicon nitride film. Next, when excess thin film silicon is CMPed, thin film silicon pillars having a T-shaped cross section are formed. By using photolithography to shift the focus position in the depth direction of exposure on the surface of the thin film silicon pillar having the T-shaped cross section, the resist pattern profile has a shape in which the shoulder portion hangs slightly. The pattern can be formed by using a wet process, and then wet or dry etching can be performed to form a mushroom columnar head side. Next, using photolithography, an opening pattern equivalent to the size of a mushroom columnar head is formed with a resist, and then dry etching or wet etching of isotropic etching is performed. Undercut (side etching) is obtained by etching. The resist is then removed. In this way, the constriction forming part 9 can be obtained. A corrugated shape can also be obtained at the same time on the etching bottom. After obtaining the narrowed portion 9 formed on the p-type semiconductor 3 and the narrowed portion 10 formed on the lower side of the narrowed portion, the n-type semiconductor 5 is formed. The n-type semiconductor 5 is made by mixing phosphorus element as an n-type impurity by thermal diffusion. When finely adjusting the p-type impurity concentration and the n-type impurity concentration, a pattern is formed using photolithography, and ion implantation is performed using boron ions or phosphorus ions using the resist pattern as a mask. After the ion implantation, the p + diffusion layer 4 and the n + diffusion layer 6 are obtained. Thereafter, by heat annealing, the crystallinity is adjusted and a pn junction can be formed. The order in which phosphorus ions are implanted to form the p + diffusion layer 4 may be before heat annealing. Next, a transparent electrode layer 7 made of ITO or the like is attached to the n-type semiconductor 5 that is exposed to light by vapor deposition or the like. Next, aluminum, Ag, or the like is applied to the entire surface using vapor deposition or the like. Then, a pattern is formed using photolithography, and then, an electrode 8 Eject by dry etching or the like. On the back surface, a pattern is formed on the remaining oxide film 2 using photolithography, and a pattern for taking out the electrode from the back surface is formed. Next, the back electrode layer 1 is formed using screen printing or vapor deposition. For the back electrode layer 1, the use of aluminum, Ag, or the like is generally known.

前記方法により形成した前記括れ形成部9、および括れの下方側に形成してなる抉れ部10を前記光電変換領域に設けることで、太陽光の入射方向から観察すると、本光電変換装置は、より黒体様に見えることになる。 By observing from the incident direction of sunlight, the photoelectric conversion device is provided with the constriction forming portion 9 formed by the method and the constriction portion 10 formed on the lower side of the constriction in the photoelectric conversion region. It will look more like a black body.

本願発明によって、一次太陽光入射単位面積当たりの実効光電変換表面積をより大きく設けてなり、光路長をより大きく設けてなり、一次太陽光入射方向側に返す光をより少なくする形体にすることができる。According to the present invention, the effective photoelectric conversion surface area per unit area of primary sunlight incident is increased, the optical path length is increased, and the light returned to the primary sunlight incident direction side is reduced. it can.

1・・・裏面電極層
2・・・酸化膜
3・・・p型半導体
4・・・p+拡散層
5・・・n型半導体
6・・・n+拡散層
7・・・透明電極層
8・・・取り出し電極
9・・・括れ形成部
10・・・括れの下方側に形成してなる抉れ部
11・・・光入射基準方向
12・・・光電変換領域が1次入射光の進行方向に沿って形を成す曲線における前記曲線上の任意の点
13・・・光電変換領域が1次入射光の進行方向に沿って形を成す曲線における前記曲線上の点12から少し離れた下方側の前記曲線上に位置する点
14・・・括れを定義するための点12における接線
15・・・括れを定義するための点13における接線
DESCRIPTION OF SYMBOLS 1 ... Back electrode layer 2 ... Oxide film 3 ... p-type semiconductor 4 ... p + diffusion layer 5 ... n-type semiconductor 6 ... n + diffusion layer 7 ... Transparent electrode layer 8 ..Extraction electrode 9 ... neck formation part 10 ... neck part formed on the lower side of the neck
11 ... Light incident reference direction
12: Arbitrary point on the curve in the curve in which the photoelectric conversion region forms along the traveling direction of the primary incident light
13: A point where the photoelectric conversion region is located on the lower curve that is slightly apart from the point 12 on the curve in the curve formed along the traveling direction of the primary incident light.
14 ... Tangent at point 12 to define the neck
15 ... Tangent at point 13 to define the neck

Claims (7)

本発明は、入射光を電子等の電荷に変換する光電変換領域を有する受光素子部に入射光の進行方向に対して括れ状の外壁を設けた柱形体の括れ付き光電変換装置。  The present invention relates to a columnar photoelectric conversion device in which a light-receiving element portion having a photoelectric conversion region that converts incident light into charges such as electrons is provided with a constricted outer wall with respect to the traveling direction of incident light. 本発明は、入射光を電子等の電荷に変換する光電変換領域を有する受光素子部に入射光の進行方向に対して括れ状の内壁を設けた穴形体の括れ付き光電変換装置。  The present invention is a constricted photoelectric conversion device having a hole shape in which a light receiving element portion having a photoelectric conversion region for converting incident light into charges such as electrons is provided with a constricted inner wall with respect to the traveling direction of incident light. 本発明は、入射光を電子等の電荷に変換する光電変換領域を有する受光素子部に入射光の進行方向に対して括れ状の外壁を設けた柱形体と括れ状の内壁を設けた穴形体のハイブリッド配置の克れ付き光電変換装置。  The present invention provides a light receiving element portion having a photoelectric conversion region for converting incident light into charges such as electrons, and a hole-shaped body in which a conical outer wall is provided in a traveling direction of incident light and a constricted inner wall is provided. A photoelectric conversion device with a hybrid arrangement. 本発明は、入射光を電子等の電荷に変換する光電変換領域を有する受光素子部に入射光の進行方向に対して括れ状の外壁を設けて複数積み上げたトーテムポール状形体の括れ付き光電変換装置。  The present invention relates to a photoelectric conversion with a constricted totem pole shape in which a light receiving element portion having a photoelectric conversion region for converting incident light into an electric charge or the like is provided with a constricted outer wall with respect to the traveling direction of the incident light. apparatus. 本発明は、入射光を電子等の電荷に変換する光電変換領域を有する受光素子部に入射光の進行方向に対して括れ状の内壁を複数積み上げた穴形体の括れ付き光電変換装置。  The present invention is a constricted photoelectric conversion device having a hole shape in which a plurality of constricted inner walls are stacked in a light receiving element portion having a photoelectric conversion region for converting incident light into charges such as electrons. 本発明は、入射光を電子等の電荷に変換する光電変換領域を有する受光素子部に入射光の進行方向に対して括れ状の外壁を設けて複数積み上げたトーテムポール状形体の括れ付き光電変換装置において、前記複数積み上げる中心軸が各々オフセットを設けてなる、あるいはスパイラル状の積み上げ配置を設けてなる括れ付き光電変換装置。  The present invention relates to a photoelectric conversion with a constricted totem pole shape in which a light receiving element portion having a photoelectric conversion region for converting incident light into an electric charge or the like is provided with a constricted outer wall with respect to the traveling direction of the incident light. In the apparatus, the plurality of central axes to be stacked are each provided with an offset, or a photoelectric conversion device with a constriction in which a spiral stacked arrangement is provided. 本発明は、入射光を電子等の電荷に変換する光電変換領域を有する受光素子部に入射光の進行方向に対して括れ状の内壁を複数積み上げた穴形体の括れ付き光電変換装置において、前記複数積み上げる中心軸が各々オフセットを設けてなる、あるいはスパイラル状の積み上げ配置を設けてなる括れ付き光電変換装置。  The present invention relates to a constricted photoelectric conversion device having a hole shape in which a plurality of constricted inner walls are stacked with respect to a traveling direction of incident light on a light receiving element portion having a photoelectric conversion region that converts incident light into charges such as electrons. A concatenated photoelectric conversion device in which a plurality of central axes are provided with an offset or a spiral stacked arrangement.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0575150A (en) * 1991-09-11 1993-03-26 Isuzu Motors Ltd Manufacture of fine particle sheet
JP2005159168A (en) * 2003-11-27 2005-06-16 Kyocera Corp Photoelectric converter and its manufacturing method
WO2008097258A2 (en) * 2006-07-11 2008-08-14 The Trustees Of Princeton University Controlled growth of larger heterojunction interface area for organic photosensitive devices

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0575150A (en) * 1991-09-11 1993-03-26 Isuzu Motors Ltd Manufacture of fine particle sheet
JP2005159168A (en) * 2003-11-27 2005-06-16 Kyocera Corp Photoelectric converter and its manufacturing method
WO2008097258A2 (en) * 2006-07-11 2008-08-14 The Trustees Of Princeton University Controlled growth of larger heterojunction interface area for organic photosensitive devices

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