JP2002033500A - Photovoltaic device - Google Patents
Photovoltaic deviceInfo
- Publication number
- JP2002033500A JP2002033500A JP2000217372A JP2000217372A JP2002033500A JP 2002033500 A JP2002033500 A JP 2002033500A JP 2000217372 A JP2000217372 A JP 2000217372A JP 2000217372 A JP2000217372 A JP 2000217372A JP 2002033500 A JP2002033500 A JP 2002033500A
- Authority
- JP
- Japan
- Prior art keywords
- film
- microcrystalline
- bond
- photovoltaic device
- silicon
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/545—Microcrystalline silicon PV cells
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】この発明は、微結晶シリコン
ゲルマニウム（μｃ−ＳｉＧｅ）を光活性層に用いた光
起電力素子に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photovoltaic element using microcrystalline silicon germanium (.mu.c-SiGe) for a photoactive layer.
【０００２】[0002]
【従来の技術】従来、原料ガスのグロー放電分解や光Ｃ
ＶＤ法により形成される非晶質シリコン（以下、ａ−Ｓ
ｉと記す。）を主材料にした光起電力装置は、薄膜、大
面積化が容易という特長を持ち、低コスト光起電力装置
として期待されている。2. Description of the Related Art Conventionally, glow discharge decomposition of raw material gas and light C
Amorphous silicon (hereinafter a-S) formed by the VD method
Write i. The photovoltaic device using () as a main material has features that it can be easily formed into a thin film and has a large area, and is expected as a low-cost photovoltaic device.
【０００３】この種の光起電力装置の構造としては、ｐ
ｉｎ接合を有するｐｉｎ型ａ−Ｓｉ光起電力装置が一般
的である。図７はこのような光起電力装置の構造を示
し、ガラス基板２１上に、透明電極２２、ｐ型ａ−Ｓｉ
層２３、真性（ｉ）型ａ−Ｓｉ層２４、ｎ型ａ−Ｓｉ層
２５、金属電極２６を順次積層することにより作成され
る。この光起電力装置は、ガラス基板２１を通して入射
する光により光起電力が発生する。[0003] The structure of this type of photovoltaic device includes p
A pin-type a-Si photovoltaic device having an in-junction is common. FIG. 7 shows the structure of such a photovoltaic device, in which a transparent electrode 22 and a p-type a-Si
It is formed by sequentially laminating a layer 23, an intrinsic (i) type a-Si layer 24, an n-type a-Si layer 25, and a metal electrode 26. In this photovoltaic device, photovoltaic power is generated by light incident through the glass substrate 21.
【０００４】上記したａ−Ｓｉ光起電力装置は、光照射
後、光劣化が生じることが知られている。そこで、薄膜
で且つ光照射に対して安定性の高い材料として、微結晶
シリコンがあり、この微結晶シリコンを光活性層に用い
た光起電力装置が提案されている（例えば、特開平５−
１００５５号公報参照。）。この微結晶シリコンは微結
晶Ｓｉ相とａ−Ｓｉ相とが混在する薄膜である。It is known that the a-Si photovoltaic device described above undergoes photodegradation after light irradiation. Then, microcrystalline silicon is known as a material which is thin and has high stability to light irradiation, and a photovoltaic device using this microcrystalline silicon for a photoactive layer has been proposed (for example, Japanese Patent Application Laid-Open No. H05-205,052).
See No. 10055. ). This microcrystalline silicon is a thin film in which a microcrystalline Si phase and an a-Si phase are mixed.
【０００５】[0005]
【発明が解決しようとする課題】上記したように、非晶
質シリコン（Ｓｉ）系の半導体膜の持つ欠点である光劣
化を克服する技術として、微結晶シリコン（Ｓｉ）が注
目されているが、微結晶シリコンは非晶質シリコンに比
べ吸収係数が小さい。このため、光活性層に用いようと
すると、２μｍもしくはそれ以上の膜厚を要するため、
太陽電池の生産性を考えた場合、非常に速い成膜速度を
要求される。しかしながら、現状では良質な特性を維持
したままこのような成膜速度を達成することはできな
い。As described above, microcrystalline silicon (Si) has been attracting attention as a technique for overcoming the photodegradation which is a disadvantage of the amorphous silicon (Si) based semiconductor film. Microcrystalline silicon has a smaller absorption coefficient than amorphous silicon. For this reason, a film thickness of 2 μm or more is required for use in a photoactive layer.
Considering the productivity of the solar cell, a very high deposition rate is required. However, at present, such a film formation rate cannot be achieved while maintaining good quality characteristics.
【０００６】そこで、この発明者は、微結晶シリコンよ
り光吸収係数が大きい微結晶シリコンゲルマニウム（Ｓ
ｉＧｅ）を光活性層に用い、必要な光活性層の膜厚を薄
くすることで、従来の問題点を解決することを鋭意検討
した。問題解決には以下の点が満足されなくてはならな
い。Accordingly, the present inventor has proposed that microcrystalline silicon germanium (S) having a larger light absorption coefficient than microcrystalline silicon.
Using iGe) for the photoactive layer, the present inventors have intensively studied to solve the conventional problems by reducing the required film thickness of the photoactive layer. The following points must be satisfied to solve the problem.
【０００７】活性層の膜厚を１μｍ以下にするためには
少なくとも微結晶シリコンの３倍程度の吸収係数が必要
である。このためには、微結晶シリコンゲルマニウム
（ＳｉＧｅ）の中のゲルマニウム（Ｇｅ）の組成比が２
０原子％以上である必要がある。To reduce the thickness of the active layer to 1 μm or less, an absorption coefficient at least about three times that of microcrystalline silicon is required. For this purpose, the composition ratio of germanium (Ge) in microcrystalline silicon germanium (SiGe) is 2
It must be at least 0 atomic%.
【０００８】この発明は、上記事情に鑑みなされたもの
にして、膜厚の薄い微結晶シリコン系半導体薄膜を光活
性層に用いた光起電力装置を提供することを目的とす
る。The present invention has been made in view of the above circumstances, and has as its object to provide a photovoltaic device using a thin microcrystalline silicon-based semiconductor thin film as a photoactive layer.
【０００９】[0009]
【課題を解決するための手段】この発明は、ゲルマニウ
ムの組成比が２０原子％以上４０原子％以下、且つラマ
ン分光法によって観察されるシリコンとシリコンの結合
からの信号強度に対し、ゲルマニウムとゲルマニウムの
結合からの信号強度が３０％以上６０％以下、シリコン
とゲルマニウムの結合強度が上記２信号強度の間である
微結晶シリコンゲルマニウムを光活性層として用い、且
つその膜厚が１μｍ以下であることを特徴とする。According to the present invention, there is provided a method for controlling the intensity of a signal from a bond between silicon and silicon observed by Raman spectroscopy in which the composition ratio of germanium is not less than 20 atomic% and not more than 40 atomic%. The microcrystalline silicon germanium having a signal intensity of 30% or more and 60% or less from the coupling of silicon and the coupling intensity of silicon and germanium between the two signal intensities is used as a photoactive layer, and the film thickness is 1 μm or less. It is characterized by.
【００１０】また、ラマン分光法によって観察されるシ
リコンとシリコンの結合からの信号強度に対し前記ゲル
マニウムとゲルマニウムの結合からの信号強度が３５％
以上５５％以下にするとよい。The signal intensity from the bond between germanium and germanium is 35% of the signal intensity from the bond between silicon and silicon observed by Raman spectroscopy.
It is better to set it to 55% or less.
【００１１】上記の構成によれば、膜厚の薄い微結晶シ
リコンゲルマニウムを光活性層に用いて、変換効率の良
好な光起電力装置が得られる。According to the above configuration, a photovoltaic device having good conversion efficiency can be obtained by using microcrystalline silicon germanium having a small film thickness for the photoactive layer.
【００１２】[0012]
【発明の実施の形態】以下、この発明の実施の形態につ
き図面を参照して説明する。図１は微結晶シリコンゲル
マニウム（ＳｉＧｅ）膜を光活性層に用いたこの発明の
実施形態にかかる光起電力装置を示す断面図である。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a photovoltaic device according to an embodiment of the present invention using a microcrystalline silicon germanium (SiGe) film as a photoactive layer.
【００１３】図１に示すようにこの発明にかかる光起電
力装置は、ガラス、金属などからなる支持基板１上に、
銀（Ａｇ）などの高反射金属膜２が形成される。なお、
基板１表面には光閉じ込め効果を備えるために、エッチ
ングなどにより微小の凹凸が形成されている。この凹凸
は高反射金属膜２表面に設けてもよい。そして、高反射
金属膜２上に膜厚５００ÅのＺｎＯからなる透明導電膜
３が設けられる。この透明導電膜３は次に形成されるｎ
型微結晶シリコン（Ｓｉ）層４と高反射金属膜２との合
金化反応等を阻止する。As shown in FIG. 1, a photovoltaic device according to the present invention comprises a support substrate 1 made of glass, metal, or the like.
A highly reflective metal film 2 such as silver (Ag) is formed. In addition,
Fine irregularities are formed on the surface of the substrate 1 by etching or the like in order to provide a light confinement effect. The irregularities may be provided on the surface of the highly reflective metal film 2. Then, a transparent conductive film 3 made of ZnO having a thickness of 500 ° is provided on the high-reflection metal film 2. This transparent conductive film 3 is formed by n
An alloying reaction between the type microcrystalline silicon (Si) layer 4 and the highly reflective metal film 2 is prevented.
【００１４】この透明導電膜３上に、膜厚３００Åのｎ
型微結晶Ｓｉ膜４、膜厚５０００Åのこの発明にかかる
ｉ型微結晶ＳｉＧｅ膜５及び膜厚３００Åのｐ型微結晶
Ｓｉ膜６が順次積層形成されている。そして、ｐ型微結
晶Ｓｉ膜６上に膜厚５００ÅのＺｎＯからなる表面透明
導電膜７が設けられている。さらに、透明導電膜７上に
銀などからなる櫛形電極８が設けられる。光は透明導電
膜７側から入射する。On this transparent conductive film 3, a 300-nm thick n
A microcrystalline Si film 4, an i-type microcrystalline SiGe film 5 of 5000 nm in thickness according to the present invention, and a p-type microcrystalline Si film 6 of 300 mm in thickness are sequentially laminated. Then, a surface transparent conductive film 7 made of ZnO having a thickness of 500 ° is provided on the p-type microcrystalline Si film 6. Further, a comb-shaped electrode 8 made of silver or the like is provided on the transparent conductive film 7. Light enters from the transparent conductive film 7 side.
【００１５】上記したＺｎＯ膜はスパッター法、ｎ型微
結晶Ｓｉ膜４とｐ型微結晶Ｓｉ膜６は１３．５６ＭＨｚ
の平行平板型ＲＦプラズマＣＶＤにより形成されてい
る。尚、微結晶ＳｉＧｅ膜５以外の部分は特に作成法の
指定はなく、この発明の効果が得られるものであれば何
でも良い。また、透明導電膜３、７はＺｎＯ膜以外のＳ
ｎＯ2膜、ＩＴＯでも良い。The above ZnO film is formed by sputtering, and the n-type microcrystalline Si film 4 and the p-type microcrystalline Si film 6 are formed at 13.56 MHz.
Is formed by the parallel plate type RF plasma CVD. It should be noted that, except for the microcrystalline SiGe film 5, there is no particular designation of the preparation method, and any material can be used as long as the effects of the present invention can be obtained. Further, the transparent conductive films 3 and 7 are made of S other than ZnO film.
An nO 2 film or ITO may be used.
【００１６】ところで、通常微結晶シリコンを光活性層
に用いた光起電力素子は、２μｍ以上の膜厚を要する
が、使用材料量、スループット、素子の安定性等を考慮
すると、光活性層の膜厚は０．１〜１．０μｍが適当で
ある。そこで、この発明の特徴とするｉ型微結晶ＳｉＧ
ｅ膜５は次のように形成している。By the way, a photovoltaic element using microcrystalline silicon for a photoactive layer usually requires a film thickness of 2 μm or more. However, considering the amount of materials used, the throughput, the stability of the element, etc. The film thickness is suitably from 0.1 to 1.0 μm. Therefore, i-type microcrystalline SiG which is a feature of the present invention
The e film 5 is formed as follows.
【００１７】微結晶ＳｉＧｅ膜５は、１３．５６ＭＨｚ
の平行平板ＲＦプラズマＣＶＤにより、投入電力は２０
０ｍＷ／cm2、圧力は３９．９Ｐａ、基板温度２５０℃
で形成する。そして、水素希釈率（Ｈ2／ＳｉＨ4＋Ｇｅ
Ｈ4）は３０、ゲルマン流量比（ＧｅＨ4／ＳｉＨ4＋Ｇ
ｅＨ4）は１０％の条件で形成した。尚、プラズマＣＶ
Ｄの電源周波数は特に指定するものではなく、さらに高
周波であってもかまわないし、直流であってもかまわな
い。The microcrystalline SiGe film 5 has a frequency of 13.56 MHz.
Input power is 20 by parallel plate RF plasma CVD.
0 mW / cm 2 , pressure 39.9 Pa, substrate temperature 250 ° C.
Formed. Then, the hydrogen dilution rate (H 2 / SiH 4 + Ge)
H 4 ) is 30, the germane flow rate ratio (GeH 4 / SiH 4 + G)
eH 4 ) was formed under the condition of 10%. In addition, plasma CV
The power frequency of D is not particularly specified, and may be higher or DC.
【００１８】上記条件で作成すると、微結晶ＳｉＧｅ膜
５のＧｅ組成比は３０原子％、成膜速度は約２Å／秒で
ある。また、上記微結晶ＳｉＧｅ膜５は２０Å〜３００
Åの粒径のＳｉ、Ｇｅ、ＳｉＧｅ結晶粒と非晶質部から
なり、非晶質部分の比率は１０％未満である。また、光
吸収係数はそれぞれ８００ｎｍで５０００ｃｍ-1、９０
０ｎｍで１５００ｃｍ-1、１０００ｎｍで８００ｃｍ-1
以上であり、これは微結晶シリコンの値の約４倍であ
る。このため、膜厚は微結晶シリコンの場合の１／４で
ある５０００Åとした。When the microcrystalline SiGe film 5 is formed under the above conditions, the Ge composition ratio of the microcrystalline SiGe film 5 is 30 atomic%, and the film forming rate is about 2 ° / sec. The microcrystalline SiGe film 5 has a thickness of 20 ° to 300 °.
It is composed of Si, Ge, and SiGe crystal grains having a grain size of Å and an amorphous portion, and the ratio of the amorphous portion is less than 10%. The light absorption coefficients are 5000 cm −1 at 800 nm and 90 cm, respectively.
1500cm -1 in 0nm, 800cm -1 at 1000nm
This is about four times the value of microcrystalline silicon. For this reason, the film thickness was set to 5000 °, which is の of the case of microcrystalline silicon.
【００１９】図２は、上記した方法により形成したのＧ
ｅ組成比が３０原子％の微結晶ＳｉＧｅ膜をラマン分光
法で測定したラマン分光スペクトル図である。なお、物
質に振動数υ0の単色光を当てて散乱させると、ラマン
効果によってストークス線υ0−υmnと反ストークス線
υ0＋υmnのラマン線が表れる。このラマン線の波長や
散乱強度を測定することにより、物質の同定や定量を行
うものをラマン分光法という。FIG. 2 shows the G formed by the method described above.
FIG. 5 is a Raman spectrum diagram of a microcrystalline SiGe film having an e composition ratio of 30 atomic% measured by Raman spectroscopy. Incidentally, the scattering by applying monochromatic light of frequency [upsilon 0 to substances, Raman line of Stokes lines υ 0 -υ mn and anti-Stokes lines υ 0 + υ mn appears by the Raman effect. Raman spectroscopy is used to identify and quantify a substance by measuring the wavelength and scattering intensity of the Raman ray.
【００２０】図２に示すように、上記した方法により形
成したのＧｅ組成比が３０原子％の微結晶ＳｉＧｅ膜に
おいては、５００ｃｍ-1付近のピークがシリコンとシリ
コンの結合（Ｓｉ−Ｓｉ）からの信号、４００ｃｍ-1付
近のピークがシリコンとゲルマニウムの結合（Ｓｉ−Ｇ
ｅ）からの信号、そして、２８０ｃｍ-1付近のピークが
ゲルマニウムとゲルマニウムの結合（Ｇｅ−Ｇｅ）から
の信号である。Ｓｉ−Ｇｅからの信号はピーク高さで比
べるとＳｉ−Ｓｉのものと比べて７０％、Ｇｅ−Ｇｅか
らの信号はＳｉ−Ｓｉのものと比べて５０％である。Ｓ
ｉ−Ｇｅの結合からの信号がＳｉ−ＳｉとＧｅ−Ｇｅか
らの信号の間となる。As shown in FIG. 2, in the microcrystalline SiGe film formed by the above-mentioned method and having a Ge composition ratio of 30 atomic%, the peak near 500 cm -1 is due to the bond between silicon and silicon (Si-Si). Signal, the peak near 400 cm -1 is the bond between silicon and germanium (Si-G
The signal from e) and the peak near 280 cm -1 are the signals from the bond of germanium and germanium (Ge-Ge). The signal from Si-Ge is 70% as compared with that of Si-Si in terms of peak height, and the signal from Ge-Ge is 50% as compared with that of Si-Si. S
The signal from the i-Ge combination is between the signals from Si-Si and Ge-Ge.
【００２１】また、この微結晶シリコンゲルマニウム
（ＳｉＧｅ）膜を光活性層に用いた光起電力装置をＡＭ
−１．５、１００ｍＷ／cm2光照射下で変換効率を測定
したところ、変換効率は８％を示した。これは活性層と
して膜厚２μｍの微結晶Ｓｉを用いた以外は同条件で形
成した光起電力素子と同等の値であり、１／４の光活性
層の膜厚で同じ特性が得られたことになる。A photovoltaic device using this microcrystalline silicon germanium (SiGe) film as a photoactive layer is called AM
When the conversion efficiency was measured under irradiation of -1.5 and 100 mW / cm 2 light, the conversion efficiency was 8%. This is the same value as a photovoltaic element formed under the same conditions except that microcrystalline Si having a film thickness of 2 μm was used as the active layer, and the same characteristics were obtained with a film thickness of １ ／ of the photoactive layer. Will be.
【００２２】次に、比較のためにＧｅの組成比は３０原
子％である微結晶シリコンゲルマニウム（ＳｉＧｅ）で
あるが、ラマン分光法によって測定される信号強度が上
記した実施形態とは異なる微結晶シリコンゲルマニウム
膜を形成した。図３は、この比較のために形成したＧｅ
組成比が３０原子％の微結晶ＳｉＧｅ膜をラマン分光法
で測定したラマン分光スペクトル図である。この形成条
件は、投入電力を１０００ｍＷ／cm2、圧力を３９９Ｐ
ａにした以外は上記の条件と同じである。Next, for comparison, Ge is microcrystalline silicon germanium (SiGe) having a composition ratio of 30 atomic%, but the signal intensity measured by Raman spectroscopy is different from that of the above embodiment. A silicon germanium film was formed. FIG. 3 shows a Ge formed for this comparison.
FIG. 5 is a Raman spectrum diagram of a microcrystalline SiGe film having a composition ratio of 30 at% measured by Raman spectroscopy. The formation conditions are as follows: input power: 1000 mW / cm 2 , pressure: 399P
The conditions are the same as those described above, except that a is set.
【００２３】この条件で形成すると、気相で重合が起こ
ること、表面反応時間が十分でないなどの原因により、
組成に偏りができやすくなる。このため、Ｓｉ−Ｇｅか
らの信号はピーク高さで比べるとＳｉ−Ｓｉのものと比
べて４５％、Ｇｅ−Ｇｅからの信号は７０％となった。When formed under these conditions, polymerization occurs in the gas phase and the surface reaction time is not sufficient.
The composition tends to be biased. For this reason, the signal from Si-Ge was 45% of the peak height, and the signal from Ge-Ge was 70% as compared with that of Si-Si.
【００２４】この微結晶シリコンゲルマニウム（ＳｉＧ
ｅ）膜を光活性層に用いた光起電力装置をＡＭ−１．
５、１００ｍＷ／cm2光照射下で変換効率を測定したと
ころ、変換効率は３％であった。This microcrystalline silicon germanium (SiG
e) A photovoltaic device using the film for the photoactive layer is referred to as AM-1.
5, When the conversion efficiency was measured under irradiation of 100 mW / cm 2 light, the conversion efficiency was 3%.
【００２５】次に、投入電力及び圧力を変化させてＳｉ
−Ｓｉの結合からの信号強度に対するＧｅ−Ｇｅの結合
からの信号が変化した微結晶ＳｉＧｅを形成し、この膜
を光活性層に用いた光起電力装置を作成した。これら光
起電力装置をＡＭ−１．５、１００ｍＷ／cm2光照射下
で測定した変換効率の変化を図４に示す。Next, by changing the input power and pressure, Si
Microcrystalline SiGe was formed in which the signal intensity from the Ge-Ge bond changed with respect to the signal intensity from the -Si bond, and a photovoltaic device using this film as a photoactive layer was produced. FIG. 4 shows changes in the conversion efficiency of these photovoltaic devices measured under irradiation with light of AM-1.5 and 100 mW / cm 2 .
【００２６】図４から分かるように、ラマン分光法によ
って観察されるＳｉ−Ｓｉの結合からの信号強度に対
し、ピーク高さで比べてＧｅ−Ｇｅの結合からの信号強
度が３０％未満及び６０％を越えると、僅かな変化によ
っても変換効率が大幅に減少する。一方、ラマン分光法
によって観察されるＳｉ−Ｓｉの結合からの信号強度に
対し、ピーク高さで比べてＧｅ−Ｇｅの結合からの信号
強度が３０％以上６０％以下の場合には、信号強度が多
少変化しても変換効率は僅かしか変化しない。量産効率
等を考慮した場合、多少の組成の変化により大幅に変換
効率が変化することは好ましくない。このため、ラマン
分光法によって観察されるＳｉ−Ｓｉの結合からの信号
強度に対し、ピーク高さで比べてＧｅ−Ｇｅの結合から
の信号強度が３０％以上６０％以下の場合であれば、組
成の変化によっても大幅に変換効率が変わらずよい特性
が得られる。さらに、ラマン分光法によって観察される
Ｓｉ−Ｓｉの結合からの信号強度に対し、ピーク高さで
比べてＧｅ−Ｇｅ結合からの信号強度が３５％以上５５
％以下の場合には、より良好な結果が得られる。As can be seen from FIG. 4, the signal intensity from the Ge—Ge bond is less than 30% and 60% as compared to the signal intensity from the Si—Si bond observed by Raman spectroscopy. %, The conversion efficiency is greatly reduced by a small change. On the other hand, when the signal intensity from the Ge—Ge bond is 30% or more and 60% or less compared to the signal intensity from the Si—Si bond observed by Raman spectroscopy, the signal intensity is Slightly changes the conversion efficiency. In consideration of mass production efficiency and the like, it is not preferable that the conversion efficiency greatly changes due to a slight change in composition. Therefore, if the signal intensity from the Ge—Ge bond is 30% or more and 60% or less compared to the signal intensity from the Si—Si bond observed by Raman spectroscopy, Good characteristics are obtained in which the conversion efficiency does not significantly change even when the composition changes. Further, the signal intensity from the Ge—Ge bond is 35% or more 55% higher than the signal intensity from the Si—Si bond observed by Raman spectroscopy.
%, Better results are obtained.
【００２７】次に、１３．５６ＭＨｚの平行平板ＲＦプ
ラズマＣＶＤにより、投入電力は２００ｍＷ／cm2、圧
力は３９．９Ｐａ、基板温度２５０℃に設定し、水素希
釈率（Ｈ2／ＳｉＨ4＋ＧｅＨ4）を３０、ゲルマン流量
比（ＧｅＨ4／ＳｉＨ4＋ＧｅＨ4）を５％から５０％ま
で変化させて、Ｇｅの組成比を変化させて微結晶ＳｉＧ
ｅ膜を形成した。この条件で形成した微結晶ＳｉＧｅ膜
は、ラマン分光法によって観察されるＳｉ−Ｓｉの結合
からの信号強度に対し、ピーク高さで比べてＧｅ−Ｇｅ
の結合からの信号強度が３０％以上６０％以下であっ
た。そして、この微結晶シリコンゲルマニウム膜を光活
性層に用いた光起電力装置を作成した。これら光起電力
装置をＡＭ−１．５、１００ｍＷ／cm2光照射下で測定
した変換効率の変化を図５に示す。この図５より、Ｇｅ
の組成比が２０原子％から４０原子％の間で良好な値が
得られていることが分かる。Next, by 13.56 MHz parallel plate RF plasma CVD, the input power was set to 200 mW / cm 2 , the pressure was set to 39.9 Pa, the substrate temperature was set to 250 ° C., and the hydrogen dilution ratio (H 2 / SiH 4 + GeH 4) was set. ) Was changed to 30 and the germane flow rate ratio (GeH 4 / SiH 4 + GeH 4 ) was changed from 5% to 50% to change the Ge composition ratio to change the microcrystalline SiG.
An e film was formed. The microcrystalline SiGe film formed under these conditions has a higher peak height than that of the signal intensity from the Si—Si bond observed by Raman spectroscopy.
Was 30% or more and 60% or less. Then, a photovoltaic device using this microcrystalline silicon germanium film as a photoactive layer was produced. FIG. 5 shows the change in conversion efficiency of these photovoltaic devices measured under irradiation of light of AM-1.5 and 100 mW / cm 2 . As shown in FIG.
It can be seen that a good value is obtained when the composition ratio is between 20 atomic% and 40 atomic%.
【００２８】次に、この発明の第２の実施形態を図６に
示す。図６は、この発明の第２の実施形態にかかる光起
電力装置を示す断面図である。尚、上記した実施の形態
と同じ部分には、同じ符号を付し、説明を省略する。こ
の実施の形態は、ｎｉｐ構造の半導体層を数段階積層し
た構造を持つ。すなわち、支持基板１上に高反射金属膜
２、透明導電膜３を設け、その上にｎ型微結晶Ｓｉ膜４
（４ａ）、ｉ型半導体膜５（５ａ）、ｐ型半導体膜６
（６ａ）をこの順序で数段階積層形成している。Next, a second embodiment of the present invention is shown in FIG. FIG. 6 is a sectional view showing a photovoltaic device according to a second embodiment of the present invention. The same parts as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted. This embodiment has a structure in which semiconductor layers having a nip structure are stacked in several stages. That is, a highly reflective metal film 2 and a transparent conductive film 3 are provided on a support substrate 1, and an n-type microcrystalline Si film 4 is formed thereon.
(4a), i-type semiconductor film 5 (5a), p-type semiconductor film 6
(6a) is laminated in several steps in this order.
【００２９】この図６に示す実施形態は、図１に示す実
施形態の光起電力素子の入射側にｎ型微結晶Ｓｉ膜４
ａ、ｉ型非晶質Ｓｉ膜５ａ、ｐ型非晶質ＳｉＣ膜６ａの
光起電力素子を積層した構造である。ｐ型非晶質ＳｉＣ
膜６ａとｉ型非晶質Ｓｉ膜５ａは１３．５６ＭＨｚの平
行平板型ＲＦプラズマＣＶＤで形成されている。それ以
外は上記した実施形態と同じである。In the embodiment shown in FIG. 6, an n-type microcrystalline Si film 4 is formed on the incident side of the photovoltaic element of the embodiment shown in FIG.
a, an i-type amorphous Si film 5a and a p-type amorphous SiC film 6a are stacked. p-type amorphous SiC
The film 6a and the i-type amorphous Si film 5a are formed by 13.56 MHz parallel plate RF plasma CVD. Otherwise, the configuration is the same as the above-described embodiment.
【００３０】上記した第２の実施形態では、第１の実施
形態と同測定条件下で、短絡電流１２ｍＡ／cm2、開放
電圧１．３０Ｖ、曲線因子０．７１、変換効率１１％を
示した。これも微結晶ＳｉＧｅ活性層を微結晶Ｓｉにし
た以外は同条件で形成した光起電力素子と同等の値であ
り、本発明の効果が示された。In the second embodiment, the short-circuit current was 12 mA / cm 2 , the open-circuit voltage was 1.30 V, the fill factor was 0.71, and the conversion efficiency was 11% under the same measurement conditions as in the first embodiment. . This is also a value equivalent to that of the photovoltaic element formed under the same conditions except that the microcrystalline SiGe active layer is made of microcrystalline Si, and the effect of the present invention was shown.
【００３１】なお、この発明は、上記した第１の実施形
態のように、基板上にｎｉｐ構造の半導体層を単層に形
成した構造、第２の実施形態のように、基板上にｎｉｐ
構造の半導体層を２層に形成した構造の光起電力装置に
限らず、３層以上の構造を有する積層型光起電力装置に
も適用することはもちろん可能である。さらに、上記実
施の形態とは逆の方向から光が入射するタイプ、すなわ
ち、基板側から光が入射するタイプの光起電力装置にも
もちろんこの発明は適用できる。The present invention has a structure in which a semiconductor layer having a nip structure is formed as a single layer on a substrate as in the first embodiment described above, and a nip is formed on a substrate as in the second embodiment.
The present invention can be applied not only to a photovoltaic device having a structure in which two semiconductor layers are formed but also to a stacked photovoltaic device having a structure having three or more layers. Further, the present invention is naturally applicable to a photovoltaic device in which light is incident from the opposite direction to the above-described embodiment, that is, a type in which light is incident from the substrate side.
【００３２】[0032]
【発明の効果】以上説明したように、この発明によれ
ば、膜厚の薄い微結晶シリコンゲルマニウムを光活性層
に用いて、変換効率の良好な光起電力装置を得ることが
できる。As described above, according to the present invention, a photovoltaic device having good conversion efficiency can be obtained by using microcrystalline silicon germanium having a small thickness for the photoactive layer.
【図１】微結晶シリコンゲルマニウム（ＳｉＧｅ）膜を
光活性層に用いたこの発明の実施形態にかかる光起電力
装置を示す断面図である。FIG. 1 is a sectional view showing a photovoltaic device according to an embodiment of the present invention using a microcrystalline silicon germanium (SiGe) film as a photoactive layer.
【図２】この発明の実施形態にかかるＧｅ組成比が３０
原子％の微結晶ＳｉＧｅ膜をラマン分光法で測定したラ
マン分光スペクトル図である。FIG. 2 shows a Ge composition ratio of 30 according to an embodiment of the present invention.
FIG. 4 is a Raman spectrum diagram of a microcrystalline SiGe film of atomic% measured by Raman spectroscopy.
【図３】比較のために形成したＧｅ組成比が３０原子％
の微結晶ＳｉＧｅ膜をラマン分光法で測定したラマン分
光スペクトル図である。FIG. 3 shows a Ge composition ratio of 30 atomic% formed for comparison.
FIG. 3 is a Raman spectrum diagram of the microcrystalline SiGe film of FIG. 1 measured by Raman spectroscopy.
【図４】Ｓｉ−Ｓｉの結合からの信号強度に対するＧｅ
−Ｇｅの結合からの信号が変化した微結晶ＳｉＧｅを光
活性層に用いた光起電力装置の変換効率を測定した特性
図である。FIG. 4 shows Ge versus signal intensity from a Si—Si bond.
FIG. 9 is a characteristic diagram showing a measurement of the conversion efficiency of a photovoltaic device using microcrystalline SiGe in which a signal from -Ge coupling has changed in a photoactive layer.
【図５】Ｇｅ組成比を変化させた微結晶ＳｉＧｅを光活
性層に用いた光起電力装置の変換効率を測定した特性図
である。FIG. 5 is a characteristic diagram obtained by measuring the conversion efficiency of a photovoltaic device using microcrystalline SiGe with a changed Ge composition ratio for a photoactive layer.
【図６】この発明の第２の実施形態にかかる光起電力素
子を示す断面図である。FIG. 6 is a sectional view showing a photovoltaic device according to a second embodiment of the present invention.
【図７】従来の光起電力素子の構造を示す断面図であ
る。FIG. 7 is a cross-sectional view illustrating a structure of a conventional photovoltaic element.
１ 支持基板 ２ 高反射金属膜 ３ 透明導電膜 ４ ｎ型微結晶Ｓｉ膜 ５ ｉ型微結晶ＳｉＧｅ膜 ６ ｐ型微結晶Ｓｉ膜 ７ 表面透明導電膜 ８ 櫛形電極 REFERENCE SIGNS LIST 1 support substrate 2 highly reflective metal film 3 transparent conductive film 4 n-type microcrystalline Si film 5 i-type microcrystalline SiGe film 6 p-type microcrystalline Si film 7 surface transparent conductive film 8 comb-shaped electrode
【手続補正書】[Procedure amendment]
【提出日】平成１３年７月１９日（２００１．７．１
９）[Submission date] July 19, 2001 (2001.7.1)
9)
【手続補正１】[Procedure amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】特許請求の範囲[Correction target item name] Claims
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【特許請求の範囲】[Claims]
【手続補正２】[Procedure amendment 2]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】０００４[Correction target item name] 0004
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【０００４】上記したａ−Ｓｉ光起電力装置は、光照射
後、光劣化が生じることが知られている。そこで、薄膜
で且つ光照射に対して安定性の高い材料として、微結晶
シリコンがあり、この微結晶シリコンを光活性層に用い
た光起電力装置が提案されている。この微結晶シリコン
は微結晶Ｓｉ相とａ−Ｓｉ相とが混在する薄膜である。It is known that the a-Si photovoltaic device described above undergoes photodegradation after light irradiation. Therefore, microcrystalline silicon is available as a thin film material having high stability to light irradiation, and a photovoltaic device using this microcrystalline silicon for a photoactive layer has been proposed . This microcrystalline silicon is a thin film in which a microcrystalline Si phase and an a-Si phase are mixed.
【手続補正３】[Procedure amendment 3]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】０００９[Correction target item name] 0009
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【０００９】[0009]
【課題を解決するための手段】この発明は、ゲルマニウ
ムの組成比が２０原子％以上４０原子％以下、且つラマ
ン分光法によって観察されるシリコンとシリコンの結合
からの信号強度に対し、ゲルマニウムとゲルマニウムの
結合からの信号強度が３０％以上６０％以下、シリコン
とゲルマニウムの結合からの信号強度が上記２信号強度
の間である微結晶シリコンゲルマニウムを光活性層とし
て用い、且つその膜厚が１μｍ以下であることを特徴と
する。According to the present invention, there is provided a method for controlling the intensity of a signal from a bond between silicon and silicon observed by Raman spectroscopy in which the composition ratio of germanium is not less than 20 atomic% and not more than 40 atomic%. Microcrystalline silicon germanium having a signal intensity of 30% or more and 60% or less and a signal intensity of the combination of silicon and germanium between the above two signal intensities is used as a photoactive layer, and the film thickness is 1 μm or less. It is characterized by being.
Claims (2)
４０原子％以下、且つラマン分光法によって観察される
シリコンとシリコンの結合からの信号強度に対し、ゲル
マニウムとゲルマニウムの結合からの信号強度が３０％
以上６０％以下、シリコンとゲルマニウムの結合強度が
上記２信号強度の間である微結晶シリコンゲルマニウム
を光活性層として用い、且つその膜厚が１μｍ以下であ
ることを特徴とする光起電力装置。1. The composition ratio of germanium is not less than 20 at% and not more than 40 at%, and the signal intensity from the bond between germanium and germanium is 30 times the signal intensity from the bond between silicon and silicon observed by Raman spectroscopy. %
A photovoltaic device characterized in that microcrystalline silicon germanium having a bond strength of silicon and germanium between the above two signal intensities of 60% or less is used as a photoactive layer, and the film thickness is 1 μm or less.
ンとシリコンの結合からの信号強度に対し前記ゲルマニ
ウムとゲルマニウムの結合からの信号強度が３５％以上
５５％以下であることを特徴とする請求項１に記載の光
起電力装置。2. The method according to claim 1, wherein the signal intensity from the bond between germanium and germanium is 35% or more and 55% or less with respect to the signal intensity from the bond between silicon and silicon observed by Raman spectroscopy. The photovoltaic device according to claim 1.
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|---|---|---|---|
| JP2000217372A JP4289768B2 (en) | 2000-07-18 | 2000-07-18 | Photovoltaic device |
| US09/901,629 US6521883B2 (en) | 2000-07-18 | 2001-07-11 | Photovoltaic device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000217372A JP4289768B2 (en) | 2000-07-18 | 2000-07-18 | Photovoltaic device |
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| Publication Number | Publication Date |
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| JP2002033500A true JP2002033500A (en) | 2002-01-31 |
| JP4289768B2 JP4289768B2 (en) | 2009-07-01 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7075052B2 (en) | 2002-10-08 | 2006-07-11 | Sanyo Electric Co., Ltd. | Photoelectric conversion device |
| WO2007114432A1 (en) * | 2006-04-03 | 2007-10-11 | Mitsubishi Heavy Industries, Ltd. | Photoelectric converter device and process for producing the same |
| JP2012522403A (en) * | 2009-05-06 | 2012-09-20 | シンシリコン・コーポレーション | Photovoltaic cell and method for enhancing light capture in a semiconductor layer stack |
-
2000
- 2000-07-18 JP JP2000217372A patent/JP4289768B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7075052B2 (en) | 2002-10-08 | 2006-07-11 | Sanyo Electric Co., Ltd. | Photoelectric conversion device |
| WO2007114432A1 (en) * | 2006-04-03 | 2007-10-11 | Mitsubishi Heavy Industries, Ltd. | Photoelectric converter device and process for producing the same |
| JP2007281018A (en) * | 2006-04-03 | 2007-10-25 | Mitsubishi Heavy Ind Ltd | Photoelectric conversion device, and its manufacturing method |
| JP2012522403A (en) * | 2009-05-06 | 2012-09-20 | シンシリコン・コーポレーション | Photovoltaic cell and method for enhancing light capture in a semiconductor layer stack |
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| Publication number | Publication date |
|---|---|
| JP4289768B2 (en) | 2009-07-01 |
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