JP2001352082A - Method for manufacturing semiconductor thin-film photoelectric converter - Google Patents
Method for manufacturing semiconductor thin-film photoelectric converterInfo
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- JP2001352082A JP2001352082A JP2000167108A JP2000167108A JP2001352082A JP 2001352082 A JP2001352082 A JP 2001352082A JP 2000167108 A JP2000167108 A JP 2000167108A JP 2000167108 A JP2000167108 A JP 2000167108A JP 2001352082 A JP2001352082 A JP 2001352082A
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- photoelectric conversion
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は半導体薄膜光電変換
装置の製造方法に関し、特に、少なくとも１の結晶質光
電変換ユニットを含みかついわゆる光閉じ込め効果を有
する半導体薄膜光電変換装置の製造方法に関するもので
ある。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor thin film photoelectric conversion device, and more particularly to a method for manufacturing a semiconductor thin film photoelectric conversion device including at least one crystalline photoelectric conversion unit and having a so-called light confinement effect. is there.
【０００２】なお、本願明細書において、「多結晶」、
「微結晶」、および「結晶質」の用語は、半導体薄膜光
電変換装置の技術分野において通常用いられているよう
に、体積分率で５０％未満の非晶質部分を含む場合にも
用いられる。[0002] In the present specification, "polycrystal",
The terms “microcrystal” and “crystalline” are also used when including an amorphous portion of less than 50% by volume as commonly used in the technical field of semiconductor thin-film photoelectric conversion devices. .
【０００３】[0003]
【従来の技術】半導体薄膜光電変換装置は、一般に、絶
縁基板上に順に積層された第１の電極、１以上の半導体
薄膜光電変換ユニット、および第２の電極を含んでい
る。そして、１つの光電変換ユニットはｐ型層とｎ型層
でサンドイッチされたｉ型層を含んでいる。2. Description of the Related Art A semiconductor thin-film photoelectric conversion device generally includes a first electrode, one or more semiconductor thin-film photoelectric conversion units, and a second electrode sequentially stacked on an insulating substrate. One photoelectric conversion unit includes an i-type layer sandwiched between a p-type layer and an n-type layer.
【０００４】光電変換ユニットの厚さの大部分を占める
ｉ型層は実質的に真性の半導体層であって、光電変換作
用は主としてこのｉ型層内で生じる。したがって、ｉ型
光電変換層は、光吸収の観点のみからすれば厚い方が好
ましい。他方、ｐ型やｎ型の導電型層は光電変換ユニッ
ト内に拡散電位を生じさせる役割を果たし、この拡散電
位の大きさによって光電変換装置の重要な特性の１つで
ある開放端電圧の値が左右される。しかし、これらの導
電型層は光電変換に直接寄与しない不活性な層であり、
導電型層にドープされた不純物によって吸収される光は
発電に寄与しない損失となる。したがって、ｐ型とｎ型
の導電型層は、十分な拡散電位を生じさせる範囲内であ
れば、できるだけ小さな厚さを有することが好ましい。[0004] The i-type layer that occupies most of the thickness of the photoelectric conversion unit is a substantially intrinsic semiconductor layer, and the photoelectric conversion action mainly occurs in the i-type layer. Therefore, it is preferable that the i-type photoelectric conversion layer is thicker only from the viewpoint of light absorption. On the other hand, the p-type or n-type conductive layer plays a role of generating a diffusion potential in the photoelectric conversion unit, and the value of the open-end voltage, which is one of the important characteristics of the photoelectric conversion device, depends on the magnitude of the diffusion potential. Is affected. However, these conductive layers are inert layers that do not directly contribute to photoelectric conversion,
The light absorbed by the impurities doped in the conductivity type layer is a loss that does not contribute to power generation. Therefore, it is preferable that the p-type and n-type conductive layers have as small a thickness as possible within a range that generates a sufficient diffusion potential.
【０００５】このようなことから、光電変換ユニット
は、それに含まれるｐ型とｎ型の導電型層が非晶質か結
晶質かにかかわらず、その主要部を占めるｉ型の光電変
換層が非晶質のものは非晶質ユニットと称され、ｉ型層
が結晶質のものは結晶質ユニットと称される。[0005] For this reason, the photoelectric conversion unit has an i-type photoelectric conversion layer occupying a main part thereof regardless of whether the p-type and n-type conductive layers contained therein are amorphous or crystalline. Amorphous units are referred to as amorphous units, and those in which the i-type layer is crystalline are referred to as crystalline units.
【０００６】ところで、薄膜光電変換装置の変換効率を
向上させる方法の１つとして、いわゆる光閉じ込め効果
を利用する方法が知られている。このような光閉じ込め
効果のためには、透明電極と光電変換ユニットとの界
面、および光電変換ユニットと裏面電極との界面に微小
な凹凸界面構造が形成される。すなわち、これらの凹凸
界面構造による入射光の散乱屈折や散乱反射によって、
薄膜光電変換ユニット中における実質的な光路長が長く
なって、あたかもその中に入射光が閉じ込められたよう
な状態になる。このような光閉じ込め効果によって、薄
膜光電変換ユニットが入射光のほとんどを効率的に吸収
することが可能になって、光電変換効率が高められ得る
のである。Incidentally, as one of the methods for improving the conversion efficiency of a thin film photoelectric conversion device, a method utilizing a so-called light confinement effect is known. To achieve such a light confinement effect, minute uneven interface structures are formed at the interface between the transparent electrode and the photoelectric conversion unit and at the interface between the photoelectric conversion unit and the back electrode. In other words, due to the scattered refraction and scattered reflection of incident light due to these uneven interface structures,
The substantial optical path length in the thin-film photoelectric conversion unit becomes longer, and it becomes as if the incident light is confined therein. With such a light confinement effect, the thin-film photoelectric conversion unit can efficiently absorb most of the incident light, and the photoelectric conversion efficiency can be improved.
【０００７】図２は、特開平５−２０６４９１に開示さ
れた半導体薄膜光電変換装置の模式的な断面図を示して
いる。なお、本願の各図において、厚さや長さなどの寸
法関係は図面の明瞭化と簡略化のために適宜に変更され
ており、実際の寸法関係を表わしてはいない。FIG. 2 is a schematic sectional view of a semiconductor thin film photoelectric conversion device disclosed in Japanese Patent Laid-Open No. Hei 5-206491. In the drawings of the present application, dimensional relationships such as thickness and length are appropriately changed for clarity and simplification of the drawings, and do not represent actual dimensional relationships.
【０００８】図２の光電変換装置においては、ガラス基
板１上に微細な表面凹凸構造を有する酸化錫の透明電極
２が形成される。なお、一般には、このような透明電極
の材料としては、酸化錫の他にもインジウム錫酸化物
（ＩＴＯ）や酸化亜鉛などの透明導電性酸化物（ＴＣ
Ｏ）が用いられ得る。また、透明電極の表面に微細な凹
凸構造を設ける方法の一例は、たとえばIEEE Electron
Device Letters, Vol. EDL-4, 1983, pp.157〜159にお
いて述べられている。In the photoelectric conversion device shown in FIG. 2, a transparent electrode 2 of tin oxide having a fine surface uneven structure is formed on a glass substrate 1. Generally, as a material of such a transparent electrode, in addition to tin oxide, a transparent conductive oxide (TC) such as indium tin oxide (ITO) or zinc oxide is used.
O) can be used. One example of a method of providing a fine uneven structure on the surface of a transparent electrode is, for example, an IEEE Electron
Device Letters, Vol. EDL-4, 1983, pp. 157-159.
【０００９】透明電極２上には、ｐ型非晶質シリコンカ
ーバイド層３ｐとｉ型非晶質シリコン光電変換層３ｉが
プラズマＣＶＤ法によって堆積される。On the transparent electrode 2, a p-type amorphous silicon carbide layer 3p and an i-type amorphous silicon photoelectric conversion layer 3i are deposited by a plasma CVD method.
【００１０】光電変換層３ｉ上には、常圧ＣＶＤ法によ
って酸化シリコン膜４が堆積される。酸化シリコン膜４
は、周知のフォトリソグラフィ技術を利用して、複数の
微細なアイランド状にパターニングされる。こうして形
成されたアイランド状酸化シリコンパターン４をマスク
として用いながら、光電変換層３ｉの表面が水素プラズ
マでエッチングされて、複数の微細な凹部が形成され
る。すなわち、光電変換層３ｉの上面には、アイランド
状酸化シリコンパターン４を含めて微細な表面凹凸構造
が形成される。A silicon oxide film 4 is deposited on the photoelectric conversion layer 3i by a normal pressure CVD method. Silicon oxide film 4
Is patterned into a plurality of fine islands using a known photolithography technique. Using the island-shaped silicon oxide pattern 4 thus formed as a mask, the surface of the photoelectric conversion layer 3i is etched with hydrogen plasma to form a plurality of fine concave portions. That is, a fine surface uneven structure including the island-shaped silicon oxide pattern 4 is formed on the upper surface of the photoelectric conversion layer 3i.
【００１１】この表面凹凸構造上には、ｎ型シリコン層
３ｎがプラズマＣＶＤ法で堆積されるとともに、アルミ
またはクロムなどからなる裏面金属電極５が蒸着法によ
って形成される。なお、一般には、裏面金属電極として
は、アルミやクロムに限られず、良好な光反射性と良好
な導電性を有する他の種々の金属材料をも利用すること
ができ、ＴＣＯ層と金属層の積層として形成される場合
もある。On this surface uneven structure, an n-type silicon layer 3n is deposited by a plasma CVD method, and a back metal electrode 5 made of aluminum or chromium is formed by an evaporation method. In general, the back metal electrode is not limited to aluminum or chromium, and various other metal materials having good light reflectivity and good conductivity can also be used. It may be formed as a laminate.
【００１２】以上のようにして形成される図２の薄膜光
電変換装置においては、入射光６は、まず透明電極２と
光電変換ユニット３との間の凹凸界面２ａによって散乱
屈折されて、光電変換ユニット３内へ斜め方向に入射す
る。その斜め方向の長い光路によっても光電変換層３ｉ
中で吸収されなかった光は、光電変換ユニット３と裏面
電極５との間の凹凸界面５ａによって散乱反射されて、
再び光電変換ユニット３内へ斜め方向に再入射する。さ
らに、再度凹凸界面２ａに至った光はそこで再び散乱反
射され、こうして入射光６は光電変換ユニット３内に閉
じ込められて効率的に吸収され得ることになる。In the thin-film photoelectric conversion device of FIG. 2 formed as described above, the incident light 6 is first scattered and refracted by the uneven interface 2a between the transparent electrode 2 and the photoelectric conversion unit 3, and the photoelectric conversion is performed. The light enters the unit 3 obliquely. Due to the long optical path in the oblique direction, the photoelectric conversion layer 3i
The light not absorbed in the inside is scattered and reflected by the uneven interface 5a between the photoelectric conversion unit 3 and the back surface electrode 5, and
The light again enters the photoelectric conversion unit 3 in an oblique direction. Further, the light that has reached the uneven interface 2a again is scattered and reflected again there, and thus the incident light 6 is confined in the photoelectric conversion unit 3 and can be efficiently absorbed.
【００１３】[0013]
【発明が解決しようとする課題】図２に示されているよ
うな半導体薄膜光電変換装置においては、確かに、光閉
じ込め効果によって光電変換効率を高めることができ
る。しかし、光閉じ込め効果を生じさせるために必要と
される光電変換ユニット３と裏面電極５との間の微細な
凹凸界面構造５ａを形成するために、わざわざ光電変換
層３ｉ上に酸化シリコン膜４を形成して、それを複雑な
フォトリソグラフィを利用してアイランド状にパターニ
ングし、さらにそのアイランド状酸化シリコンパターン
４をマスクとして光電変換層３ｉの上面をエッチングし
なければならないというように、非常に複雑かつコスト
のかかる付加的な工程を必要としている。In the semiconductor thin-film photoelectric conversion device as shown in FIG. 2, the photoelectric conversion efficiency can be certainly enhanced by the light confinement effect. However, in order to form a fine concavo-convex interface structure 5a between the photoelectric conversion unit 3 and the back electrode 5 which is necessary for producing the light confinement effect, the silicon oxide film 4 is bothersomely formed on the photoelectric conversion layer 3i. It is very complicated, for example, that it must be formed and patterned in the form of islands using complicated photolithography, and the upper surface of the photoelectric conversion layer 3i must be etched using the island-shaped silicon oxide pattern 4 as a mask. It also requires costly additional steps.
【００１４】他方、たとえばｉ型非晶質シリコンが光電
変換し得る光の波長は長波長側において８００ｎｍ程度
までであるが、ｉ型結晶質シリコンはそれより長い約１
１００ｎｍ程度の波長の光まで光電変換することができ
る。したがって、近年では、結晶質半導体光電変換ユニ
ットを利用して光電変換効率を高める試みがなされてい
る（たとえば、特開平１１−１４５４９９参照）。On the other hand, for example, the wavelength of light that can be photoelectrically converted by i-type amorphous silicon is up to about 800 nm on the longer wavelength side, while i-type crystalline silicon has a longer wavelength of about 1 nm.
Photoelectric conversion can be performed on light having a wavelength of about 100 nm. Therefore, in recent years, attempts have been made to increase the photoelectric conversion efficiency by using a crystalline semiconductor photoelectric conversion unit (for example, see Japanese Patent Application Laid-Open No. H11-145499).
【００１５】かかる先行技術における状況に鑑み、本発
明は、少なくとも１の結晶質光電変換ユニットを含みか
つ光閉じ込め効果を有することによって高い光電変換効
率を実現し得る半導体薄膜光電変換装置を複雑な工程と
コストの増大を伴うことなく形成し得る製造方法を提供
することを目的としている。In view of the situation in the prior art, the present invention provides a semiconductor thin film photoelectric conversion device that includes at least one crystalline photoelectric conversion unit and has a light confinement effect and can realize high photoelectric conversion efficiency. It is an object of the present invention to provide a manufacturing method which can be formed without increasing the cost.
【００１６】[0016]
【課題を解決するための手段】本発明によれば、絶縁基
板上に順に積層された第１の電極、１以上の半導体薄膜
光電変換ユニット、および第２の電極を含み、この第２
電極に接している薄膜光電変換ユニットは順に積層され
た第１導電型半導体層、実質的に真性半導体の結晶質光
電変換層、および第２導電型半導体層を含む半導体薄膜
光電変換装置の製造方法は、結晶質光電変換層に含まれ
る第１と第２の結晶質光電変換サブ層をプラズマＣＶＤ
法によって順次堆積し、この際のＣＶＤ条件は第１結晶
質光電変換サブ層に比べて第２結晶質光電変換サブ層の
方が体積結晶化分率が小さくなる条件に設定され、第２
結晶質光電変換サブ層の表面近傍において分散して含ま
れる非晶質微小領域を水素プラズマを用いて優先的にエ
ッチングすることによって表面凹凸構造を形成し、この
表面凹凸構造上に第２導電型半導体層と第２電極が順に
堆積されることを特徴としている。According to the present invention, a first electrode, at least one semiconductor thin-film photoelectric conversion unit, and a second electrode are sequentially stacked on an insulating substrate.
A method of manufacturing a semiconductor thin-film photoelectric conversion device including a first conductive semiconductor layer, a crystalline semiconductor photoelectric conversion layer of a substantially intrinsic semiconductor, and a second conductive semiconductor layer, wherein the thin-film photoelectric conversion units in contact with the electrodes are sequentially stacked. Uses plasma CVD to convert the first and second crystalline photoelectric conversion sub-layers contained in the crystalline photoelectric conversion layer.
The second crystalline photoelectric conversion sublayer is set in such a manner that the volume crystallization fraction is smaller in the second crystalline photoelectric conversion sublayer than in the first crystalline photoelectric conversion sublayer.
An amorphous minute region dispersed and contained in the vicinity of the surface of the crystalline photoelectric conversion sublayer is preferentially etched using hydrogen plasma to form a surface uneven structure, and the second conductive type is formed on the surface uneven structure. The semiconductor layer and the second electrode are sequentially deposited.
【００１７】結晶質光電変換層が主成分としてシリコン
を含む場合には、第１と第２の結晶質光電変換サブ層に
おける体積結晶化分率はプラズマＣＶＤ法に用いられる
ＳｉＨ4／Ｈ2混合ガスの混合比率を制御することによっ
て調節され得る。In the case where the crystalline photoelectric conversion layer contains silicon as a main component, the volume crystallization fraction in the first and second crystalline photoelectric conversion sublayers is based on the SiH 4 / H 2 mixture used in the plasma CVD method. It can be adjusted by controlling the mixing ratio of the gas.
【００１８】[0018]
【発明の実施の形態】（実施例）図１の模式的な断面図
において、本発明の一実施例による半導体薄膜光電変換
装置の製造方法が図解されている。(Embodiment) FIG. 1 is a schematic cross-sectional view illustrating a method of manufacturing a semiconductor thin film photoelectric conversion device according to an embodiment of the present invention.
【００１９】まず図１（Ａ）において、絶縁基板１とし
て、白板ガラスが用いられた。ガラス基板１上には、第
１の電極２として、微細な表面凹凸構造を含む酸化錫膜
が熱ＣＶＤ法によって約７００ｎｍの厚さに堆積される
とともに、酸化亜鉛膜がスパッタリング法によって３０
ｎｍの厚さに堆積された。透明電極２上には、周知のプ
ラズマＣＶＤ法によって、ｐ型微結晶シリコン層３ｐが
６ｎｍの厚さに堆積された。First, in FIG. 1A, a white plate glass was used as the insulating substrate 1. On the glass substrate 1, as a first electrode 2, a tin oxide film having a fine surface unevenness is deposited to a thickness of about 700 nm by a thermal CVD method, and a zinc oxide film is formed by a sputtering method to a thickness of 30 nm.
deposited to a thickness of nm. On the transparent electrode 2, a p-type microcrystalline silicon layer 3p was deposited to a thickness of 6 nm by a known plasma CVD method.
【００２０】ｐ型微結晶シリコン層３ｐ上には、同じく
プラズマＣＶＤ法によって、ノンドープ多結晶シリコン
からなる第１の光電変換サブ層３ｉ1が１．６μｍの厚
さに堆積された。これに続いて、同じくノンドープ多結
晶シリコンからなる第２の光電変換サブ層３ｉ2が１．
０μｍの厚さに堆積された。ただし、第１の結晶質光電
変換サブ層３ｉ1に比べて、第２の結晶質光電変換サブ
層３ｉ2は小さな体積結晶化分率を有している。このよ
うな体積結晶化分率は、プラズマＣＶＤ法において用い
られるＳｉＨ4／Ｈ2混合ガスの混合比率を制御すること
によって調節することができる。すなわち、第１の結晶
質光電変換サブ層３ｉ1の堆積の際にはＳｉＨ4／Ｈ2の
比率が１／８０に設定されたのに対して、第２の結晶質
光電変換サブ層３ｉ2の堆積の際にはＳｉＨ4／Ｈ2の比
率が１／６５に設定された。[0020] On the p-type microcrystalline silicon layer 3p, the same plasma CVD method, a first photoelectric conversion sublayer 3i 1 made of non-doped polycrystalline silicon is deposited to a thickness of 1.6 [mu] m. Following this, also the non-doped polycrystalline second photoelectric conversion sublayer 3i made of silicon 2 is 1.
Deposited to a thickness of 0 μm. However, compared to the first crystalline photoelectric conversion sublayer 3i 1, crystalline photoelectric conversion sublayer 3i 2 of the second has a small volume crystallization fraction. Such a volume crystallization fraction can be adjusted by controlling the mixing ratio of the SiH 4 / H 2 mixed gas used in the plasma CVD method. That is, while the first crystalline photoelectric conversion sub-layer 3i 1 is deposited, the ratio of SiH 4 / H 2 is set to 1/80, whereas the second crystalline photoelectric conversion sub-layer 3i 2 is set. Was deposited, the ratio of SiH 4 / H 2 was set to 1/65.
【００２１】すなわち、第２結晶質光電変換サブ層３ｉ
2のプラズマＣＶＤ条件は第１結晶質光電変換サブ層３
ｉ1の場合に比べて結晶化しにくい条件であり、非晶質
部分の含まれる割合が増大することを意味している。し
たがって、図１（Ａ）に示されているように、第２結晶
質光電変換サブ層３ｉ2の成長初期においては、その下
地となっている大きな体積結晶化分率を有する第１結晶
質光電変換層３ｉ1からの結晶成長を引き継いで結晶化
されやすい状態にあるが、成長が進むに従って非晶質部
分３ｉaの割合が増大する傾向にある。That is, the second crystalline photoelectric conversion sub-layer 3i
The plasma CVD condition 2 is the first crystalline photoelectric conversion sublayer 3
This is a condition that is less likely to be crystallized than in the case of i 1 , which means that the proportion of the amorphous portion is increased. Thus, as shown in FIG. 1 (A), in the second initial growth of the crystalline photoelectric conversion sublayer 3i 2, first crystalline photoelectric having a large volume crystallinity fraction has its foundation Although the crystal inheriting the growth crystallized susceptible state from conversion layer 3i 1, there is a tendency that the proportion of amorphous portion 3i a accordance growth proceeds is increased.
【００２２】図１（Ｂ）においては、第２結晶質光電変
換サブ層３ｉ2の表面が水素プラズマによってエッチン
グされる。このとき、非晶質シリコンは結晶シリコンに
比べてはるかに大きなエッチング速度によってエッチン
グされる。その結果、図１（Ｂ）に示されているよう
に、第２結晶質光電変換サブ層３ｉ2の表面に微細な凹
凸構造が形成される。なお、このような微細な凹凸構造
の凹部の底部において非晶質部分３ｉaが残存しても何
ら問題を生じることはない。[0022] In FIG. 1 (B), second crystalline photoelectric conversion sublayer 3i 2 surface is etched by hydrogen plasma. At this time, the amorphous silicon is etched at a much higher etching rate than the crystalline silicon. As a result, as shown in FIG. 1 (B), the fine uneven structure is formed in the second crystalline photoelectric conversion sublayer 3i 2 of surface. It is not to cause any problem even if residual amorphous portion 3i a at the bottom of the recess of such a fine uneven structure.
【００２３】図１（Ｃ）においては、第２結晶質光電変
換サブ層３ｉ2の凹凸表面上に、ｎ型微結晶シリコン層
がプラズマＣＶＤ法によって１５ｎｍの厚さに堆積され
た。こうして、ｐｉｎ接合を含む結晶質光電変換ユニッ
ト３が形成された。[0023] In FIG. 1 (C) to a second crystalline photoelectric conversion sublayer 3i 2 of irregularities on the surface, n-type microcrystalline silicon layer is deposited to a thickness of 15nm by plasma CVD. Thus, the crystalline photoelectric conversion unit 3 including the pin junction was formed.
【００２４】ここで、第２結晶質光電変換サブ層３ｉ2
の凹凸表面上に形成されたｎ型微結晶シリコン層は極め
て薄い１５ｎｍの厚さを有するだけなので、そのｎ型微
結晶シリコン層３ｎの上面も、第２結晶質光電変換サブ
層３ｉ2の上面の凹凸構造を反映した凹凸構造を有する
ことになる。なお、光電変換ユニット３に含まれるいず
れの半導体層の堆積の場合にも、基板温度は２５０℃に
設定された。Here, the second crystalline photoelectric conversion sub-layer 3i 2
Because of the uneven n-type microcrystalline silicon layer formed on the surface only has a thickness of very thin 15 nm, even upper surface of the n-type microcrystalline silicon layer 3n, a second upper surface of the crystalline photoelectric conversion sublayer 3i 2 Has an uneven structure that reflects the uneven structure of FIG. Note that the substrate temperature was set to 250 ° C. in any of the depositions of the semiconductor layers included in the photoelectric conversion unit 3.
【００２５】ｎ型微結晶シリコン層３ｎの凹凸表面上に
は、第２の電極５として、厚さ９０ｎｍの酸化亜鉛膜、
厚さ２００ｎｍの銀膜、および厚さ５ｎｍのチタン膜が
この順序でスパッタリング法によって堆積された。な
お、この酸化亜鉛膜は銀膜の高い反射率を維持するとと
もに、銀原子が光電変換ユニット３内へ拡散混入するこ
とを防止するように作用し得る。また、チタン膜は銀膜
を大気から保護するように作用し得る。On the uneven surface of the n-type microcrystalline silicon layer 3n, as a second electrode 5, a 90 nm thick zinc oxide film,
A silver film having a thickness of 200 nm and a titanium film having a thickness of 5 nm were deposited in this order by a sputtering method. Note that this zinc oxide film can maintain the high reflectance of the silver film and can also act to prevent silver atoms from diffusing into the photoelectric conversion unit 3. Also, the titanium film can act to protect the silver film from the atmosphere.
【００２６】こうして形成された実施例による半導体薄
膜光電変換装置を第２電極側から１ｃｍ角の受光面積を
有する光電変換素子に分離し、その光電変換特性が測定
された。すなわち、ＡＭ１．５のスペクトル分布を有す
る擬似太陽光を２５℃の下で１００ｍＷ／ｃｍ2のエネ
ルギ密度で照射したところ、開放端電圧が０．４７０
Ｖ、短絡電流密度が２２．８ｍＡ／ｃｍ2、曲線因子が
０．７６０、そして変換効率が８．１４％であった。The semiconductor thin film photoelectric conversion device according to the embodiment thus formed was separated from the second electrode side into photoelectric conversion elements having a light receiving area of 1 cm square, and the photoelectric conversion characteristics were measured. That is, when simulated sunlight having a spectrum distribution of AM1.5 was irradiated at 25 ° C. with an energy density of 100 mW / cm 2 , the open-circuit voltage was 0.470.
V, short-circuit current density was 22.8 mA / cm 2 , fill factor was 0.760, and conversion efficiency was 8.14%.
【００２７】（比較例）上述の実施例による半導体薄膜
光電変換装置に類似して、比較例による薄膜半導体光電
変換装置が作製された。この比較例による薄膜光電変換
装置においては、厚さ１．６μｍの第１結晶質光電変換
サブ層３ｉ1と厚さ１．０μｍの第２結晶質光電変換サ
ブ層３ｉ2の代わりに、それらの合計厚さに相当する厚
さ２．６μｍのノンドープ多結晶シリコンからなる光電
変換層が第１結晶質光電変換サブ層３ｉ1のＣＶＤ条件
と同じ条件で堆積されたことのみにおいて実施例と異な
っていた。Comparative Example A thin-film semiconductor photoelectric conversion device according to a comparative example was manufactured similarly to the semiconductor thin-film photoelectric conversion device according to the above-described embodiment. In the thin-film photoelectric conversion device according to this comparative example, instead of the first crystalline photoelectric conversion sub-layer 3i 1 having a thickness of 1.6 μm and the second crystalline photoelectric conversion sub-layer 3i 2 having a thickness of 1.0 μm, these different from the embodiment only in that the photoelectric conversion layer made of non-doped polycrystalline silicon with a thickness of 2.6μm which corresponds to the total thickness was deposited under the same conditions as the 1 CVD condition of the crystalline photoelectric conversion sublayer 3i 1 Was.
【００２８】このような比較例による半導体薄膜光電変
換装置に対して実施例の場合と同様の擬似太陽光を照射
して光電変換特性を測定したところ、開放端電圧が０．
４７２Ｖ、短絡電流密度が２０．３ｍＡ／ｃｍ2、曲線
因子が０．７５５、そして変換効率が７．２３％であっ
た。When the photoelectric conversion characteristics of the semiconductor thin film photoelectric conversion device according to the comparative example were measured by irradiating the same pseudo-sunlight as that of the embodiment, the open-ended voltage was 0.1%.
472 V, short-circuit current density was 20.3 mA / cm 2 , fill factor was 0.755, and conversion efficiency was 7.23%.
【００２９】以上のような実施例と比較例との比較から
わかるように、実施例による半導体薄膜光電変換装置に
おいては、比較例に比べて、開放端電圧がほぼ同等であ
るが他のすべての光電変換特性が向上していることがわ
かる。特に、短絡電流密度が顕著に改善しており、これ
に伴って変換効率も改善している。このことは、実施例
における第２電極５の下面における凹凸構造５ａが光閉
じ込め効果を高めているからであると考えられる。As can be seen from the comparison between the embodiment and the comparative example, in the semiconductor thin-film photoelectric conversion device according to the embodiment, the open-circuit voltage is almost equal to that of the comparative example, but all other devices are different. It can be seen that the photoelectric conversion characteristics have been improved. In particular, the short-circuit current density has been remarkably improved, and the conversion efficiency has been accordingly improved. This is considered to be because the uneven structure 5a on the lower surface of the second electrode 5 in the embodiment enhances the light confinement effect.
【００３０】なお、上述の実施例ではｐｉｎの順に積層
された光電変換ユニットについて説明されたが、ｎｉｐ
の順に積層された光電変換ユニットを含む半導体薄膜光
電変換装置に対しても本発明が適用され得ることは言う
までもない。また、上述の実施例では単一の光電変換ユ
ニットのみを含む半導体薄膜光電変換装置について説明
されたが、第１電極２と結晶質光電変換ユニット３との
間にさらに１以上の非晶質光電変換ユニットおよび／ま
たは結晶質光電変換ユニットが積層されたタンデム型薄
膜光電変換装置に対しても本発明が適用され得ることも
言うまでもない。In the above embodiment, the photoelectric conversion units stacked in the order of pins have been described.
It is needless to say that the present invention can also be applied to a semiconductor thin film photoelectric conversion device including a photoelectric conversion unit stacked in the following order. In the above-described embodiment, a semiconductor thin film photoelectric conversion device including only a single photoelectric conversion unit has been described. However, one or more amorphous photoelectric conversion devices may be further provided between the first electrode 2 and the crystalline photoelectric conversion unit 3. It goes without saying that the present invention can also be applied to a tandem thin-film photoelectric conversion device in which a conversion unit and / or a crystalline photoelectric conversion unit are stacked.
【００３１】[0031]
【発明の効果】以上のように、本発明によれば、少なく
とも１つの結晶質光電変換ユニットを含みかつ光閉じ込
め効果を有することによって高い光電変換効率を有する
半導体薄膜光電変換装置を複雑な工程とコストの増大を
伴うことなく製造することが可能となる。As described above, according to the present invention, a semiconductor thin film photoelectric conversion device including at least one crystalline photoelectric conversion unit and having a high photoelectric conversion efficiency by having a light confinement effect can be manufactured by a complicated process. It can be manufactured without increasing the cost.
【図１】 本発明の一実施例による半導体薄膜光電変換
装置の製造工程を示す模式的な断面図である。FIG. 1 is a schematic sectional view showing a manufacturing process of a semiconductor thin film photoelectric conversion device according to one embodiment of the present invention.
【図２】 先行技術による半導体薄膜光電変換装置の一
例を示す模式的な断面図である。FIG. 2 is a schematic sectional view showing an example of a semiconductor thin film photoelectric conversion device according to the prior art.
１ 絶縁基板、２ 第１の電極、３ｐ ｐ型半導体層、
３ｉ 実質的に真性半導体の光電変換層、３ｉ1 ｉ型
多結晶シリコン光電変換層、３ｉ2 比較的小さな体積
結晶化分率を有するｉ型結晶質シリコン光電変換層、３
ｎ ｎ型半導体層、５ 第２の電極。1 insulating substrate, 2 first electrode, 3 pp p-type semiconductor layer,
3i Substantially intrinsic semiconductor photoelectric conversion layer, 3i 1 i-type polycrystalline silicon photoelectric conversion layer, 3i 2 i-type crystalline silicon photoelectric conversion layer having relatively small volume crystallization fraction, 3
n n-type semiconductor layer, 5 second electrode.
Claims (2)
極、１以上の半導体薄膜光電変換ユニット、および第２
の電極を含み、前記第２電極に接している前記薄膜光電
変換ユニットは順に積層された第１導電型半導体層、実
質的に真性半導体の結晶質光電変換層、および第２導電
型半導体層を含む半導体薄膜光電変換装置の製造方法で
あって、 前記結晶質光電変換層に含まれる第１と第２の結晶質光
電変換サブ層をプラズマＣＶＤによって順次堆積し、こ
の際のＣＶＤ条件は第１結晶質光電変換サブ層に比べて
第２結晶質光電変換サブ層の方が体積結晶化分率が小さ
くなる条件に設定され、 前記第２結晶質光電変換サブ層の表面近傍において分散
して含まれる非晶質微小領域を水素プラズマを用いて優
先的にエッチングすることによって表面凹凸構造を形成
し、 その表面凹凸構造上に前記第２導電型半導体層と前記第
２電極が順に堆積されることを特徴とする半導体薄膜光
電変換装置の製造方法。1. A first electrode, one or more semiconductor thin film photoelectric conversion units, and a second electrode, which are sequentially stacked on an insulating substrate.
The thin film photoelectric conversion unit in contact with the second electrode includes a first conductive semiconductor layer, a crystalline semiconductor photoelectric conversion layer of a substantially intrinsic semiconductor, and a second conductive semiconductor layer. A method for manufacturing a semiconductor thin-film photoelectric conversion device, comprising: sequentially depositing first and second crystalline photoelectric conversion sublayers included in the crystalline photoelectric conversion layer by plasma CVD, wherein the CVD conditions are: The second crystalline photoelectric conversion sub-layer is set to have a smaller volume crystallization fraction than the crystalline photoelectric conversion sub-layer, and is dispersed and included in the vicinity of the surface of the second crystalline photoelectric conversion sub-layer. Forming a surface uneven structure by preferentially etching the amorphous minute region to be formed using hydrogen plasma, and the second conductivity type semiconductor layer and the second electrode are sequentially deposited on the surface uneven structure. Especially The method of manufacturing a semiconductor thin film photoelectric conversion device according to.
リコンを含み、前記第１と第２の結晶質光電変換サブ層
における前記体積結晶化分率は前記プラズマＣＶＤ法に
用いられるＳｉＨ4／Ｈ2混合ガスの混合比率を制御する
ことによって調節されることを特徴とする請求項１に記
載の半導体薄膜光電変換装置の製造方法。2. The crystalline photoelectric conversion layer contains silicon as a main component, and the volume crystallization fraction in the first and second crystalline photoelectric conversion sub-layers is SiH 4 / Si used in the plasma CVD method. the method of manufacturing a semiconductor thin film photoelectric conversion device according to claim 1, characterized in that it is adjusted by controlling the mixing ratio of H 2 gas mixture.
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Cited By (2)
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|---|---|---|---|---|
| JP2003332605A (en) * | 2002-05-15 | 2003-11-21 | Sharp Corp | Surface roughening method of semiconductor substrate and solar battery |
| JP2010147412A (en) * | 2008-12-22 | 2010-07-01 | Fuji Electric Holdings Co Ltd | Thin film solar cell battery and method of manufacturing the same |
-
2000
- 2000-06-05 JP JP2000167108A patent/JP4247947B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003332605A (en) * | 2002-05-15 | 2003-11-21 | Sharp Corp | Surface roughening method of semiconductor substrate and solar battery |
| JP4518731B2 (en) * | 2002-05-15 | 2010-08-04 | シャープ株式会社 | Method for forming irregularities on the surface of a polycrystalline silicon substrate |
| JP2010147412A (en) * | 2008-12-22 | 2010-07-01 | Fuji Electric Holdings Co Ltd | Thin film solar cell battery and method of manufacturing the same |
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