JP2011014841A - Method of manufacturing stacked photoelectric converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a stacked photoelectric converter whose intermediate reflection layer is uniform in film quality and film thickness.SOLUTION: This is the method of manufacturing the stacked photoelectric converter including: a transparent electrode layer; a first photoelectric conversion unit which is composed of a p-i-n junction such that an i-type layer is made substantially of amorphous silicon and a part of an n-type layer is an n-type silicon-based composite layer including a silicon crystal layer in an amorphous alloy of silicon and oxygen; a second photoelectric conversion unit which is composed of a pin junction such that an i-type layer is made substantially of crystalline silicon; and a back electrode layer. Here, the photoelectric conversion units are so formed that, when light is made incident from the n-type layer side after the first photoelectric conversion unit is formed and a Raman scattering spectrum is measured, the peak position of a TO mode peak of a crystal silicon component is 516 to 519 cm.

Description

  The present invention relates to a method for manufacturing a stacked photoelectric conversion device, and provides a high-performance stacked photoelectric conversion device, and in particular, manufacture of a stacked photoelectric conversion device that can suppress variation in performance even in a large-area device. It is about the method.

  In recent years, in order to achieve both cost reduction and high efficiency of a photoelectric conversion device, a thin film photoelectric conversion device that has almost no problem in terms of resources has attracted attention and has been vigorously developed. Thin film photoelectric conversion devices are expected to be applied to various applications such as solar cells, optical sensors, and displays.

  A thin film photoelectric conversion device generally includes a first electrode, a surface of a thin film photoelectric conversion unit, and a second electrode, the surfaces of which are sequentially stacked on a transparent substrate. One thin film photoelectric conversion unit includes an i-type layer sandwiched between a p-type layer and an n-type layer.

  Most of the thickness of the thin film photoelectric conversion unit is occupied by the i-type layer which is a substantially intrinsic semiconductor layer, and the photoelectric conversion action mainly occurs in the i-type layer. Therefore, the i-type layer, which is a photoelectric conversion layer, is preferably thicker for light absorption, but if it is thicker than necessary, the deposition takes cost and time.

  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 magnitude of the diffusion potential causes an open-ended voltage that is one of the important characteristics of the thin film photoelectric conversion device. The value depends. However, these conductive layers are inactive layers that do not contribute to photoelectric conversion, and light absorbed by impurities doped in the conductive layers does not contribute to power generation and is lost. Therefore, it is preferable that the thicknesses of the p-type and n-type conductive layers be as thin as possible within a range that generates a sufficient diffusion potential.

  Here, the photoelectric conversion unit or the thin-film solar cell has an amorphous i-type photoelectric conversion layer that occupies the main part regardless of whether the p-type and n-type conductivity type layers included therein are amorphous or crystalline. Those having a high quality are referred to as amorphous photoelectric conversion units or amorphous thin film solar cells, and those having a crystalline i-type layer are referred to as crystalline photoelectric conversion units or crystalline thin film solar cells.

  Generally, a semiconductor used for a photoelectric conversion layer has a light absorption coefficient that decreases as the wavelength increases. In particular, when the photoelectric conversion material is a thin film, sufficient light absorption does not occur in a wavelength region having a small absorption coefficient, so that the photoelectric conversion amount is limited by the film thickness of the photoelectric conversion layer. Therefore, by forming a light scattering structure that makes it difficult for light incident in the photoelectric conversion device to escape to the outside, it has been devised to increase the substantial optical path length, obtain sufficient absorption, and generate a large photocurrent. ing. For example, when light is incident from the substrate side, a textured transparent conductive film having an uneven surface shape is used as the light incident side electrode.

  As a method for improving the conversion efficiency of a thin film photoelectric conversion device, a method of forming a stacked photoelectric conversion device in which two or more photoelectric conversion units are stacked is known. In this method, a front photoelectric conversion unit including a photoelectric conversion layer having a large band gap on the light incident side of the photoelectric conversion device (in this application, a photoelectric conversion unit relatively disposed on the light incident side is referred to as a front photoelectric conversion unit, A photoelectric conversion unit disposed on the side relatively far from the light incident side is referred to as a rear photoelectric conversion unit.) A photoelectric conversion layer having a small band gap (for example, Si-Ge alloy) is sequentially disposed behind the photoelectric conversion unit. By including the rear photoelectric conversion unit including the photoelectric conversion, it is possible to perform photoelectric conversion over a wide wavelength range of incident light, thereby improving the conversion efficiency of the entire apparatus. Among stacked thin film photoelectric conversion devices, a stack of an amorphous photoelectric conversion unit and a crystalline photoelectric conversion unit is referred to as a hybrid photoelectric conversion device. In the hybrid photoelectric conversion device, the wavelength of light that amorphous silicon can photoelectrically convert is about 800 nm on the long wavelength side, but crystalline silicon can photoelectrically convert longer light up to about 1100 nm. Therefore, it is possible to effectively photoelectrically convert a wider range of incident light.

  By the way, since each photoelectric conversion unit is connected in series in the stacked photoelectric conversion device, the short-circuit current density (Jsc) as the photoelectric conversion device is the lowest value among the current values generated in each photoelectric conversion unit. Is done. Therefore, it is preferable that the current values of the respective photoelectric conversion units are equal, and further, the conversion efficiency can be expected to increase as the absolute value of the current increases. In a stacked thin film photoelectric conversion device, a plurality of stacked thin film photoelectric conversion units may have both light transmittance and light reflectivity, and a conductive intermediate reflection layer may be interposed. In this case, a part of the light reaching the intermediate reflection layer is reflected, the amount of light absorption in the photoelectric conversion unit located on the light incident side of the intermediate reflection layer is increased, and the current value generated in the photoelectric conversion unit Can be increased. That is, the effective film thickness of the photoelectric conversion unit located on the light incident side with respect to the intermediate reflection layer apparently increased. For example, when an intermediate reflective layer is inserted into a hybrid photoelectric conversion device composed of an amorphous silicon photoelectric conversion unit and a crystalline silicon photoelectric conversion unit, the amorphous silicon photoelectric conversion is performed without increasing the film thickness of the amorphous silicon layer. The current generated by the unit can be increased. Alternatively, the amorphous silicon photoelectric conversion unit due to photodegradation that becomes conspicuous as the thickness of the amorphous silicon layer increases because the thickness of the amorphous silicon layer necessary to obtain the same current value can be reduced. It is possible to suppress the deterioration of characteristics.

(Prior Example 1)
The intermediate reflection layer is often composed of a transparent conductive metal oxide layer such as ZnO. However, as described in Patent Document 1, a silicon crystal phase is formed in an amorphous alloy of silicon and oxygen. It is disclosed that the same effect can be obtained even when a conductive type silicon oxide layer containing s (referred to herein as a silicon composite phase) is employed. This silicon composite phase is light-transmitted and conductive in the same way as the transparent conductive metal oxide layer, but plasma CVD is performed in the same manner as amorphous silicon-based photoelectric conversion units and crystalline silicon-based photoelectric conversion units. It can be formed by a method and the like, and can also serve as a part of the conductive type layer of these photoelectric conversion units, so that it can be formed by a simple and advantageous manufacturing method in terms of cost.

(Prior Example 2)
Further, in Patent Document 2, the i-type layer of the first photoelectric conversion unit includes at least one portion sequentially configured by the first photoelectric conversion unit and the second photoelectric conversion unit from the side close to the light incident side. In the stacked photoelectric conversion device having an n-type layer on the side far from the light incident side, at least a part of the n-type layer is an n-type silicon composite layer, and the silicon composite layer is a non-silicon-oxygen layer. It is disclosed to include a silicon crystal phase dispersed in a crystalline alloy matrix. The silicon composite layer also serves as a part of the n-type layer of the first photoelectric conversion unit, thereby increasing the power generation current of the first photoelectric conversion unit due to the reflection effect and at the same time reducing the light absorption loss. It also becomes possible to increase the generated current of the photoelectric conversion unit.

  In order to obtain a sufficient reflection effect, the above silicon composite layer has a refractive index with respect to light having a wavelength of 600 nm of 1.7 to 2.1, and more preferably 1.8 to 2.1. Further, in order to realize a low refractive index, the silicon composite layer has an oxygen concentration in the film of 40 atomic% or more and 60 atomic% or less, and more preferably 40 atomic% or more and 55 atomic% or less. In order to realize the optimum dark conductivity, the peak intensity ratio of the TO mode peak of the crystalline silicon component to the TO mode peak of the amorphous silicon component measured by Raman scattering is 0.5 or more and 1.0 or less. Is preferred.

  However, Patent Document 2 simply discloses TO mode peak values of an amorphous silicon component and a crystalline silicon component when a Raman scattering spectrum is measured for a single layer in which a silicon-based composite layer is formed on a glass substrate. It ’s just that. That is, when a part of the n-type layer of the first photoelectric conversion unit composed of the pin junction forms an n-type silicon-based composite layer, the first photoelectric conversion unit film including the silicon-based composite layer On the other hand, it is not disclosed to measure the peak positions of the TO mode of the amorphous silicon component and the TO mode of the crystalline silicon component by Raman scattered light incident from the n-type layer side. The idea of manufacturing a stacked photoelectric conversion device by applying the above peak data is not disclosed.

  On the other hand, when a stacked photoelectric conversion device is manufactured, each layer is preferably stacked with a uniform film quality and film thickness. In particular, in the intermediate reflection layer, if the film quality and film thickness are not uniform, the amount of light reflected by the intermediate reflection layer varies, and the current value generated in the photoelectric conversion unit varies. As the crystallinity varies, there arises a problem that the resistance varies. When such a plurality of problems occur, it can be a factor of deteriorating the characteristics of the photoelectric conversion device. In addition, the non-uniformity of the film quality and film thickness of the intermediate reflection layer becomes larger as the area becomes larger, which can be a factor that significantly deteriorates the characteristics of the large-area stacked photoelectric conversion device.

JP 2003-258279 A JP 2008-300902 A

  In the stacked photoelectric conversion device, if the film quality and film thickness of the intermediate reflection layer are not uniform, the characteristics of the stacked photoelectric conversion device are significantly deteriorated. In particular, in the case of a large area, non-uniformity in the film quality and film thickness of the intermediate reflective layer appears remarkably. The present invention provides a method for manufacturing a stacked photoelectric conversion device in which the film quality and film thickness of an intermediate reflective layer are uniform.

According to the present invention, (1) a transparent electrode layer sequentially laminated on one main surface of a transparent substrate, a pin junction, the i-type layer is substantially amorphous silicon, and a part of the n-type layer is A first photoelectric conversion unit which is an n-type silicon-based composite layer including a silicon crystal phase in an amorphous alloy of silicon and oxygen; a second photoelectric conversion unit comprising a pin junction and wherein the i-type layer is substantially crystalline silicon In the stacked photoelectric conversion device comprising the photoelectric conversion unit and the back electrode layer, the Raman scattered light is incident on the n-type layer side of the first photoelectric conversion unit in which a part of the n-type layer is a silicon-based composite layer. A stacked photoelectric conversion device in which the measured TO mode peak position of the crystalline silicon component is in the range of 516 cm ⁻¹ or more and 519 cm ⁻¹ or less, and (2) a transparent electrode layer sequentially stacked on one main surface of the transparent substrate I-type consisting of pin junction A first photoelectric conversion unit in which the layer is substantially amorphous silicon; an i-type layer is substantially crystalline silicon composed of a pin junction; and a part of the n-type layer is amorphous of silicon and oxygen In a stacked photoelectric conversion device including a second photoelectric conversion unit, which is an n-type silicon-based composite layer including a silicon crystal layer in an alloy, and a back electrode layer, light is incident from the n-type layer side of the second photoelectric conversion unit. It has been found that in a stacked photoelectric conversion device in which the peak position of the TO mode peak of the crystalline silicon component measured by Raman scattered light is in the range of 516 cm ⁻¹ or more and 519 cm ⁻¹ or less, high photoelectric conversion characteristics can be obtained.

  In the above (1), after forming the first photoelectric conversion unit, a silicon-based silicon layer that can be an intermediate reflection layer depending on the peak position of the TO mode peak of crystalline silicon obtained by measuring the Raman scattering spectrum by making light incident from the n-type layer side Information on the film quality of the composite layer can be obtained. Thereby, even during the production of the stacked photoelectric conversion device, it can be easily determined whether or not it is a high-quality intermediate reflective layer.

  In the above (2), after the second photoelectric conversion unit is formed, an intermediate reflection layer can be formed depending on the peak position of the TO mode peak of crystalline silicon in which light is incident from the n-type layer side and the Raman scattering spectrum is measured. Information on the film quality of the silicon-based composite layer can be obtained. Thereby, even during the production of the stacked photoelectric conversion device, it can be easily determined whether or not it is a high-quality intermediate reflective layer.

That is, according to the present invention, a transparent electrode layer sequentially laminated on one main surface of a transparent substrate, a pin junction, the i-type layer is substantially amorphous silicon, and a part of the n-type layer is silicon and oxygen. A first photoelectric conversion unit which is an n-type silicon composite layer including a silicon crystal layer in an amorphous alloy, and a second photoelectric conversion consisting of a pin junction and wherein the i-type layer is substantially crystalline silicon A method for producing a stacked photoelectric conversion device comprising a unit and a back electrode layer, wherein after the first photoelectric conversion unit is formed, light is incident from the n-type layer side and a Raman scattering spectrum is measured. The present invention relates to a method for manufacturing a stacked photoelectric conversion device, wherein the photoelectric conversion unit is formed so that a peak position of a TO mode peak is 516 cm ⁻¹ or more and 519 cm ⁻¹ or less.

The present invention also comprises a first photoelectric conversion unit comprising a transparent electrode layer sequentially laminated on one main surface of a transparent substrate and a pin junction, and the i-type layer being substantially amorphous silicon, and a pin junction. a second photoelectric conversion in which the i-type layer is substantially crystalline silicon and a part of the n-type layer is an n-type silicon-based composite layer including a silicon crystal layer in an amorphous alloy of silicon and oxygen A method for producing a stacked photoelectric conversion device comprising a unit and a back electrode layer, wherein after the second photoelectric conversion unit is formed, light is incident from the n-type layer side and a Raman scattering spectrum is measured. The present invention relates to a method for manufacturing a stacked photoelectric conversion device, wherein the photoelectric conversion unit is formed so that a peak position of a TO mode peak is 516 cm ⁻¹ or more and 519 cm ⁻¹ or less.

  A preferred embodiment relates to the method of manufacturing the stacked photoelectric conversion device, wherein a Raman scattering spectrum is measured at a plurality of locations on the film forming surface.

  In a preferred embodiment, the photoelectric conversion unit has an area size of 980 cm × 950 cm or more.

According to the present invention, a transparent electrode layer sequentially laminated on one main surface of a transparent substrate, a pin junction, the i-type layer is substantially amorphous silicon, and a part of the n-type layer is made of silicon. A first photoelectric conversion unit, which is an n-type silicon-based composite layer containing a silicon crystal phase in an amorphous alloy with oxygen, and a second photoelectric conversion unit comprising a pin junction and the i-type layer being substantially crystalline silicon In a stacked photoelectric conversion device comprising a conversion unit and a back electrode layer, measurement of Raman scattered light made incident from the n-type layer side of the first photoelectric conversion unit is performed, and the TO mode of the crystalline silicon component is measured. If the peak position of the peak is in the range of 516 cm ⁻¹ or more and 519 cm ⁻¹ or less, more preferably in the range of 518 cm ⁻¹ or more and 519 cm ⁻¹ or less, the light is partially reflected at the interface before and after the silicon-based composite phase, In front of it It is possible to increase the power generation current of the photoelectric conversion unit. For this reason, the characteristics of the stacked photoelectric conversion device can be improved using the measurement result.

Also, a transparent electrode layer sequentially laminated on one main surface of the transparent substrate, a first photoelectric conversion unit comprising a pin junction and the i-type layer being substantially amorphous silicon, an i-type layer comprising a pin junction A second photoelectric conversion unit in which is substantially crystalline silicon, and a part of the n-type layer is an n-type silicon-based composite layer containing a silicon crystal phase in an amorphous alloy of silicon and oxygen, and a back surface In the stacked photoelectric conversion device comprising the electrode layer, the Raman scattered light with light incident from the n-type layer side of the second photoelectric conversion unit is measured, and the peak position of the TO mode peak of the crystalline silicon component is 516cm ^-1 or 519cm ^-1 or less in the range, if more preferably in the range of 518 cm ^-1 or more 519cm ^-1 or less, the light at the interface before and after silicon-based composite phase is partially reflected, photoelectric conversion of the front Unit It is possible to increase the power generation current. For this reason, the characteristics of the stacked photoelectric conversion device can be improved using the result.

  In the method described above, the first photoelectric conversion unit in which a part of the n-type layer is a silicon-based composite layer, or the second photoelectric conversion unit in which a part of the n-type layer is a silicon-based composite layer. Since it is characterized by measuring the Raman scattered light that is incident light from the n-type layer side after the unit is formed, the variation in characteristics can be grasped early in the film forming stage of each photoelectric conversion unit, As a result, productivity can be improved.

1 is a structural cross-sectional view of a stacked photoelectric conversion device according to Example 1 of the present invention. It is structural sectional drawing of the laminated photoelectric conversion apparatus which concerns on Example 2 of this invention. It is structural sectional drawing of the integrated thin film photoelectric conversion apparatus which concerns on Example 3, 4 of this invention. It is a measurement position of Raman scattering of the thin film photoelectric conversion device according to Examples 3 and 4 of the present invention. It is sectional drawing which shows roughly the example of the integrated thin film photoelectric conversion module which connected the multilayer photoelectric conversion apparatus which concerns on Example 4 of this invention in series.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each drawing 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. Moreover, in each figure, the same referential mark represents the same part or an equivalent part.

  FIG. 1 is a cross-sectional view of a stacked photoelectric conversion device according to an example of an embodiment of the present invention. A transparent electrode layer 2, a first (front) photoelectric conversion unit 3, a second (rear) photoelectric conversion unit 4, and a back electrode layer 5 are arranged in this order on the transparent substrate 1.

  A photoelectric conversion semiconductor layer composed of a plurality of photoelectric conversion units is disposed behind the transparent electrode 2. In the case of a structure in which two photoelectric conversion units are stacked as shown in FIG. 1, the first (front) photoelectric conversion unit 3 arranged on the light incident side has a relatively wide band gap, for example, amorphous silicon. A photoelectric conversion unit made of a system material is used. The second (rear) photoelectric conversion unit 4 disposed on the rear side includes a photoelectric conversion unit made of a material having a relatively narrow band gap, for example, a silicon-based material containing a crystalline material, an amorphous silicon germanium photoelectric conversion unit, or the like. A conversion unit or the like is used. In the present invention, the i-type layer in the first photoelectric conversion unit is substantially made of amorphous silicon, and the i-type layer in the second photoelectric conversion unit is substantially made of crystalline silicon.

  Each photoelectric conversion unit is preferably configured by a pin junction including a one-conductivity type layer, an i-type layer that is a substantially intrinsic photoelectric conversion layer, and a reverse conductivity type layer. Among these, those using amorphous silicon for the i-type layer are called amorphous silicon photoelectric conversion units, and those using crystalline silicon are called crystalline silicon photoelectric conversion units. Note that the amorphous or crystalline silicon-based material is not only a case where only silicon is used as a main element constituting a semiconductor, but also an alloy material including elements such as carbon, oxygen, nitrogen, and germanium. Good.

  The one conductivity type layer disposed on the light incident side is preferably a p-type layer, and the opposite conductivity type layer is preferably an n-type layer. For example, in the structure of FIG. 1, the one conductivity type layers 31 and 41 arranged on the light incident side in each photoelectric conversion unit are p-type layers, and the reverse conductivity type layers 33 and 43 on the rear side are n-type layers. Good.

  The main constituent material of the conductive layer is not necessarily the same as that of the i-type layer. For example, amorphous silicon carbide can be used for the p-type (or n-type) layer of the amorphous silicon photoelectric conversion unit. In addition, a silicon layer containing crystalline material in an n-type (or p-type) layer (also called microcrystalline silicon) can be used.

  The two types of conductive layers play a role of generating a diffusion potential in the photoelectric conversion unit, and the open end voltage (Voc), which is one of the characteristics of the thin film photoelectric conversion device, depends on the magnitude of the diffusion potential. However, these conductive layers are inactive layers that do not contribute to photoelectric conversion, and light absorbed here hardly contributes to power generation. Therefore, it is preferable that the conductive layer be as thin or transparent as possible within a range that generates a sufficient diffusion potential.

  In the present invention, in each photoelectric conversion unit that is an n-type silicon-based composite layer comprising a pin junction and part of an n-type layer including a silicon crystal phase in an amorphous alloy of silicon and oxygen, The composite layer is used as an intermediate reflection layer in the stacked photoelectric conversion device. In order for the n-type silicon-based composite layer to function as an intermediate reflection layer, a silicon-based composite layer is disposed on a part of the n-type layer 33 in the first (front) photoelectric conversion unit 3 or the second ( Back) It is necessary to dispose a silicon-based composite layer on a part of the n-type layer 43 of the photoelectric conversion unit 4.

The present inventors have disclosed a silicon-based composite phase in which a part of an n-type layer in the first and / or second photoelectric conversion unit comprising a pin junction includes a silicon crystal layer in an amorphous alloy of silicon and oxygen. In this case, the peak position of the TO mode peak of the crystalline silicon component measured by Raman scattered light with light incident from the n-type layer side of each photoelectric conversion unit is preferably 516 cm ^{−1 to} 519 cm ⁻¹ , more preferably 518 cm. It has been found that when the molecular weight is ^{−1 to} 519 cm ⁻¹ , the silicon-based composite phase can be expected to have a large light confinement effect as a reflective layer.

The silicon-based composite phase uses, for example, SiH ₄ , CO ₂ , H ₂ , PH ₃ as a reaction gas, has a large H ₂ / SiH ₄ ratio, so-called microcrystal production conditions, and has a CO ₂ / SiH ₄ ratio. It can be produced by a plasma CVD method using conditions in a range of about 2.5 to 5 and a PH ₃ / SiH ₄ ratio of about 25 to 35. At this time, as the plasma conditions, for example, using capacitively coupled parallel plate electrodes, a power frequency of 10 to 100 MHz, a power density of 50 to 500 mW / cm ² , a pressure of 50 to 1000 Pa, and a substrate temperature of 150 to 200 ° C. And adjust as appropriate.

In addition, the silicon-based composite phase has been experimentally obtained so as to be greatly influenced by the crystal state of the underlayer. In the case where amorphous silicon is used for the i-type layer as in the first photoelectric conversion unit, or in the case where crystalline silicon is used in the i-type layer as in the second photoelectric conversion unit However, by changing the PH ₃ / SiH ₄ ratio or the CO ₂ / SiH ₄ ratio, the peak position of the TO mode peak of the crystalline silicon component measured by Raman scattered light incident from the n-type layer side of each unit Experiments have obtained results that can be adjusted in the range of 516 cm ^{−1 to} 519 cm ⁻¹ .

  A method for measuring Raman scattered light and measurement points in the present invention will be described below. For example, a He—Ne laser may be used as the laser light source, and a measurement method with an exposure time of 90 s and an integration count of 2 may be used. In the present invention, the peak position of the TO mode peak of the crystalline silicon component in the Raman scattered light is a numerical value obtained by this measurement method.

In addition, the measurement position of the Raman scattered light is preferably measured at a plurality of locations regardless of the substrate area (for example, 12.5 cm × 12.5 cm to 1200 cm × 998 cm). Specifically, as shown in FIG. It is more preferable to perform measurement at a proper position, for example, 9 positions in the vertical and horizontal directions including the center (ai in the figure). For example, when measuring an object with a large substrate area, such as when the photoelectric conversion unit has an area size of 980 cm × 950 cm or more, each layer in the substrate plane (two kinds of conductive layers, i-type layers, intermediate layers, etc.) ) Tend to increase in film thickness and film quality distribution. In this case, measurement is performed at least at nine positions shown in FIG. 4, and the peak position of the TO mode peak of the crystalline silicon component at those positions is in the range of 516 cm ⁻¹ or more and 519 cm ⁻¹ or less. It is preferable.

  In the following, as an example of a manufacturing method of a stacked photoelectric conversion device including a stacked structure corresponding to the above-described embodiment, two stacks in which an amorphous silicon photoelectric conversion unit and a crystalline silicon photoelectric conversion unit are stacked A stacked type superconducting photoelectric conversion device will be given and will be described in detail in comparison with a comparative example according to the prior art. In the drawings, the same members are denoted by the same reference numerals, and redundant description is omitted. Moreover, this invention is not limited to a following example, unless the meaning is exceeded.

Example 1
As Example 1, a small area (1 cm × 1 cm) stacked photoelectric conversion device as shown in FIG. A part of the n-type layer 33 of the first photoelectric conversion unit 3 is formed on the transparent substrate 1 and the transparent electrode layer 2 by the n-type silicon composite layer 1 (33a) and the n-type microcrystalline silicon layer 33b. The second photoelectric conversion unit 4 and the back electrode 5 are formed in this order.

The n-type silicon composite layer 1 was formed under the following conditions. SiH ₄ , CO ₂ , H ₂ and PH ₃ were used as the reaction gas, and the gas flow rate was SiH ₄ / CO ₂ / PH ₃ / H ₂ = 5/20/64/980 sccm. The film was formed at a power frequency of 13.56 MHz, a power density of 200 mW / cm ² , a pressure of 400 Pa, and a substrate temperature of 200 ° C. As a result of measuring the Raman scattering spectrum by making light incident from the film surface side when the silicon-based composite layer 1 was formed on the transparent substrate at this time, the peak position of the TO mode peak of the crystalline silicon component was 519 cm ⁻¹ . Indicated.

Further, the n-type silicon-based composite layer 1 is placed in the first photoelectric conversion unit 33a as shown in FIG. 1, and after the first photoelectric conversion unit 3 is formed, light is incident from the n-type layer side to obtain a Raman scattering spectrum. It was measured. As a result, the peak position of the TO mode peak of the crystalline silicon component was 517 cm ⁻¹ .

(Example 2)
As Example 2, a small area (1 cm × 1 cm) stacked photoelectric conversion device as shown in FIG. A part of the n-type layer 43 of the second photoelectric conversion unit 4 is formed such that the n-type silicon-based composite layer 1 (43a) and the n-type microcrystalline silicon layer are formed of 43b, and the second photoelectric conversion unit 4 and the back electrode 5 were formed in this order.

As shown in FIG. 2, the n-type silicon-based composite layer 1 is inserted into the second photoelectric conversion unit as shown in FIG. 2, and after the second photoelectric conversion unit is formed, light is incident from the n-type layer side and the Raman scattering spectrum is measured. The peak position of the TO mode peak of the silicon component was 518 cm ⁻¹ .

(Example 3)
As Example 3, a small area (1 cm × 1 cm) stacked photoelectric conversion device as shown in FIG. A part of the n-type layer 33 of the first photoelectric conversion unit 3 is configured by the n-type silicon composite layer 1 (33a), and a part of the n-type layer 43 of the second photoelectric conversion unit 4 is the n-type silicon system. The point which is comprised by the composite layer 1 (43a) differs from Example 1 or 2. FIG.

As shown in FIG. 3, after the first photoelectric conversion unit including the n-type silicon-based composite layer 1 was formed, light was incident from the n-type layer side and the Raman scattering spectrum was measured. As a result, the TO mode peak of the crystalline silicon component The peak position of 518 cm ^{−1 was} shown. Furthermore, after forming the second photoelectric conversion unit including the n-type silicon-based composite layer 1, light was incident from the n-type layer side and the Raman scattering spectrum was measured. As a result, the peak position of the TO mode peak of the crystalline silicon component was 519 cm. ^-1 was shown.

(Comparative Example 1)
As Comparative Example 1, a small area (1 cm × 1 cm) stacked photoelectric conversion device having the same structure as in Example 1 was produced. The difference from the first embodiment is that the n-type silicon composite layer 1 of the first photoelectric conversion unit 3 is changed to an n-type silicon composite layer 2.

The n-type silicon composite layer 2 was formed under the following conditions. The gas flow rate was SiH ₄ / CO ₂ / PH ₃ / H ₂ = 5/20 / 0.1 / 1000 sccm. The film was formed at a power frequency of 13.56 MHz, a power density of 100 mW / cm ² , a pressure of 100 Pa, and a substrate temperature of 200 ° C. As a result of measuring the Raman scattering spectrum by making light incident from the film surface side when the n-type silicon composite layer 2 was formed on the transparent substrate at this time, the peak position of the TO mode peak of the crystalline silicon component was 517 cm ^−1. showed that.

In addition, the n-type silicon composite layer 2 is placed at the position 33a of the first photoelectric conversion unit 3 as shown in FIG. As a result, the peak position of the TO mode peak of the crystalline silicon component was 513 cm ⁻¹ .

(Comparative Example 2)
As Comparative Example 2, a small area (1 cm × 1 cm) stacked photoelectric conversion device having the same structure as in Example 2 was produced. The difference from the second embodiment is that the n-type silicon composite layer 1 of the second photoelectric conversion unit 43a is changed to the n-type silicon composite layer 2 described above.

As a result of putting the n-type silicon-based composite layer 2 into the second photoelectric conversion unit 43a as shown in FIG. 2 and forming the second photoelectric conversion unit and then making light incident from the n-type layer side and measuring the Raman scattering spectrum, The peak position of the TO mode peak of the component was 514 cm ⁻¹ .

(Comparative Example 3)
As Comparative Example 3, a small area (1 cm × 1 cm) stacked photoelectric conversion device having the same structure as in Example 3 was produced. The difference from the third embodiment is that the n-type silicon composite layer 1 of the first photoelectric conversion unit 33a and the second photoelectric conversion unit 43a is changed to the n-type silicon composite layer 2.

As shown in FIG. 3, after the first photoelectric conversion unit was formed, light was incident from the n-type layer side and the Raman scattering spectrum was measured. As a result, the peak position of the TO mode peak of the crystalline silicon component showed 515 cm ⁻¹ , and After forming the second photoelectric conversion unit, light was incident from the n-type layer side and the Raman scattering spectrum was measured. As a result, the peak position of the TO mode peak of the crystalline silicon component was 511 cm ⁻¹ .

When the output characteristics were measured at 25 ° C. by irradiating the laminated photoelectric conversion device (light-receiving area 1 cm ² ) manufactured in Example 1 and Comparative Example 1 with AM1.5 light with a light amount of 100 mW / cm ^2. The Eff of Example 1 was 12.5%, while the Eff of Comparative Example 1 was 10.5%.

Further, when the stacked photoelectric conversion device (light receiving area 1 cm ² ) manufactured in Example 2 and Comparative Example 2 was irradiated with AM1.5 light at a light amount of 100 mW / cm ² , the output characteristics were measured at 25 ° C. The Eff of Example 2 was 11.3%, while the Eff of Comparative Example 2 was 9.8%.

When the output characteristics were measured at 25 ° C. by irradiating AM1.5 light with a light amount of 100 mW / cm ² to the stacked photoelectric conversion device (light receiving area 1 cm ² ) prepared in Example 3 and Comparative Example 3, The Eff of Example 3 was 13.8%, while the Eff of Comparative Example 3 was 10.2%.

  The peak position of the TO mode peak of the crystalline silicon component measured with Raman scattered light incident from the n-type layer side of the first and second photoelectric conversion units of Examples 1 to 3 and Comparative Examples 1 to 3 in Table 1, The output characteristics are summarized.

  As shown in Table 1, in the stacked photoelectric conversion device in which a part of the n-type layer of the first photoelectric conversion unit and / or the second photoelectric conversion unit is formed of the n-type silicon-based composite layer 1, the highest output characteristics are obtained. showed that. This is because the n-type silicon-based composite layer 1 serving as an intermediate reflection layer is placed in the portion 33a of the first photoelectric conversion unit and / or the portion 43a of the second photoelectric conversion unit, so that light entering from the transparent substrate side can be obtained. This is because the photoelectric conversion layer 32 and / or 42 can be efficiently reflected.

Example 4
As Example 4, a large area (1200 cm × 998 cm) integrated thin film photoelectric conversion module having the same structure as that of Example 1 was produced. The conditions similar to those in Example 1 were used for the film forming conditions of the silicon-based composite layer 1, which is a part of the n-type layer of the first photoelectric conversion unit at this time.

  FIG. 5 is a cross-sectional view schematically showing an example of an integrated thin film photoelectric conversion module in which a plurality of stacked photoelectric conversion devices are connected in series. An integrated thin film photoelectric conversion module 101 shown in FIG. 5 has a transparent electrode layer 103, a first photoelectric conversion unit 104a that is an amorphous silicon photoelectric conversion unit, and a second that is a crystalline silicon photoelectric conversion unit on a transparent substrate 102. The photoelectric conversion unit 104b, the silicon-based composite layer 105, and the back electrode layer 106 are sequentially stacked.

  As shown in FIG. 5, the integrated thin film photoelectric conversion module 101 is provided with first and second separation grooves 121 and 122 and a connection groove 123 for dividing the thin film. The first and second separation grooves 121 and 122 and the connection groove 123 are parallel to each other and extend in a direction perpendicular to the paper surface. Note that the boundary between the adjacent photoelectric conversion cells 110 is defined by the first and second separation grooves 121 and 122.

  The first separation groove 121 divides the transparent electrode layer 103 corresponding to each photoelectric conversion cell 110, has an opening at the interface between the transparent electrode layer 103 and the amorphous silicon photoelectric conversion unit 104a, and The surface of the transparent substrate 102 is the bottom surface. The first separation groove 121 is filled with an amorphous material constituting the amorphous silicon photoelectric conversion unit 104a, and electrically insulates the adjacent transparent electrode films 103 from each other.

  The second separation groove 122 is provided at a position away from the first separation groove 121. The second separation groove 122 divides the first photoelectric conversion unit 104 a, the second photoelectric conversion unit 104 b, and the back electrode layer 106 corresponding to the respective photoelectric conversion cells 110. There is an opening on the top surface, and the interface between the transparent electrode layer 103 and the first photoelectric conversion unit is the bottom surface. The second separation grooves 122 electrically insulate the back electrode layers 106 between the adjacent photoelectric conversion cells 110.

  The connection groove 123 is provided between the first separation groove 121 and the second separation groove 122. The connection groove 123 divides the first photoelectric conversion unit 104a and the second photoelectric conversion unit 104b, has an opening at the interface between the second photoelectric conversion unit 104b and the back electrode layer 106, and is a transparent electrode layer The bottom surface is an interface between the first photoelectric conversion unit 104a and the first photoelectric conversion unit 104a. The connection groove 123 is embedded with a metal material constituting the back electrode layer 106 and electrically connects one back electrode layer 106 and the other transparent electrode layer 103 of the adjacent photoelectric conversion cells 110. . That is, the connection groove 123 and the metal material filling it have a role of connecting the photoelectric conversion cells 110 juxtaposed on the glass substrate 102 in series.

(Example 5)
As Example 5, a large area (1200 cm × 998 cm) integrated thin film photoelectric conversion module having the same structure as that of Example 2 was produced. At this time, the film forming conditions of a part of the silicon composite layer 1 of the n-type layer of the second photoelectric conversion unit are the same as those in Example 2.

(Comparative Example 4)
As Comparative Example 4, an integrated thin film photoelectric conversion module having a large area (1200 cm × 998 cm) having the same structure as that of Example 1 was produced. The film forming conditions of the silicon composite layer 2 that is a part of the n-type layer of the first photoelectric conversion unit at this time are the same as those in Comparative Example 1. The difference from the fourth embodiment is that the silicon-based composite layer 1 that is a part of the n-type layer of the first photoelectric conversion unit 3 is replaced with the silicon-based composite layer 2.

(Comparative Example 5)
As Comparative Example 5, an integrated thin film photoelectric conversion module having a large area (1200 cm × 998 cm) having the same structure as that of Example 2 was produced. The film-forming conditions of the silicon-based composite layer 2 that is a part of the n-type layer of the second photoelectric conversion unit at this time are the same as those in Comparative Example 1. The difference from the fifth embodiment is that the silicon-based composite layer 1 that is a part of the n-type layer of the second photoelectric conversion unit 4 is replaced with the silicon-based composite layer 2.

  FIG. 4 shows locations (ai) where Raman scattering spectra are measured by making light incident from the film surface when an integrated thin film photoelectric conversion module having a large area (1200 cm × 998 cm) is formed.

  The TO mode of the crystalline silicon component in which the Raman scattering spectrum was measured by making light incident from the n-type layer side after the formation of the first photoelectric conversion unit of Example 4 and Comparative Example 4 at the location shown in FIG. 4 in Table 2 The peak positions of the peaks are summarized.

As shown in Table 2, in Example 4, it can be confirmed that the peak position of the TO mode peak of the crystalline silicon component is 516 cm ⁻¹ or more and 519 cm ⁻¹ or less at each point. However, in Comparative Example 4, it can be confirmed that the peak positions of the TO mode peak of the crystalline silicon component are all less than 516 cm ⁻¹ .

Further, when the integrated thin film photoelectric module was irradiated with AM 1.5 light at a light quantity of 100 mW / cm ² and the output characteristics were measured at 25 ° C., Example 4 showed Eff 13.5%. However, in Comparative Example 4, Eff was 11.5%. The peak position of the TO mode peak of the crystalline silicon component varies depending on the measurement location because the conditions vary depending on the location when the stacked photoelectric conversion device is formed with a large area.

  The TO mode of the crystalline silicon component in which the Raman scattering spectrum was measured by making light incident from the n-type layer side after the formation of the second photoelectric conversion unit of Example 5 and Comparative Example 5 at the location shown in FIG. The peak positions of the peaks are summarized.

As shown in Table 2, in Example 5, it can be confirmed that the peak position of the TO mode peak of the crystalline silicon component is 516 cm ⁻¹ or more and 519 cm ⁻¹ or less at each point. However, in Comparative Example 5, it can be confirmed that the peak positions of the TO mode peak of the crystalline silicon component are all less than 516 cm ⁻¹ .

Further, when the integrated thin film photoelectric module was irradiated with AM 1.5 light at a light amount of 100 mW / cm ² and the output characteristics were measured at 25 ° C., Example 5 showed Eff 12.4%. However, in Comparative Example 5, Eff was 10.5%.

In an integrated thin film photoelectric conversion module with a large area, an n-type silicon-based composite in which a part of the n-type layer of the first and second photoelectric conversion units includes a silicon crystal phase in an amorphous alloy of silicon and oxygen When the peak position of the TO mode peak of the crystalline silicon component of the silicon-based composite layer including the first and second photoelectric conversion units at each measurement place is not 516 cm ⁻¹ or more and 519 cm ⁻¹ or less, It can be seen that the system composite layer does not exhibit sufficient efficacy as an intermediate reflective layer.

1. Transparent substrate 2. Transparent electrode layer First photoelectric conversion unit 31. Amorphous silicon carbide layer, which is a p-type layer in the first photoelectric conversion unit 32. I-type amorphous silicon photoelectric conversion layer, which is a photoelectric conversion layer in the first photoelectric conversion unit 33. N-type microcrystalline silicon layer 33a, which is a reverse conductivity type layer in the first photoelectric conversion unit. N-type silicon-based composite layer (silicon-based composite layers 1 and 2) in the first photoelectric unit
33b. 3. n-type microcrystalline silicon layer in the first photoelectric unit Crystalline silicon photoelectric conversion unit as the second photoelectric conversion unit 41. 42. p-type microcrystalline silicon layer which is one conductivity type layer in the second photoelectric conversion unit. Non-doped i-type crystalline silicon photoelectric conversion layer, which is one conductivity type layer in the second photoelectric conversion unit 43. N-type microcrystalline silicon layer 43a. Which is a reverse conductivity type layer in the second photoelectric conversion unit. N-type silicon-based composite layer (silicon-based composite layers 1 and 2) in the second photoelectric unit
44b. 4. n-type microcrystalline silicon in the second photoelectric unit Back electrode layer 101. Integrated thin film photoelectric conversion module 102. Transparent substrate 103. Transparent electrode layer 104a. First photoelectric conversion unit 104b. Second photoelectric conversion unit 105. Back electrode layer 121. First separation groove 122. Second separation groove 123. Connection groove

Claims (4)

Transparent electrode layer sequentially laminated on one main surface of transparent substrate, i-type layer consisting of pin junction is substantially amorphous silicon, and part of n-type layer is amorphous of silicon and oxygen A first photoelectric conversion unit that is an n-type silicon-based composite layer including a silicon crystal layer in an alloy, a second photoelectric conversion unit that is composed of a pin junction, and whose i-type layer is substantially crystalline silicon, and a back electrode A method for producing a stacked photoelectric conversion device comprising layers,
When light is incident from the n-type layer side after the first photoelectric conversion unit is formed and a Raman scattering spectrum is measured, the photoelectric conversion is performed so that the peak position of the TO mode peak of the crystalline silicon component is 516 cm ⁻¹ or more and 519 cm ⁻¹ or less. A method for producing a stacked photoelectric conversion device, comprising forming a conversion unit. A transparent electrode layer sequentially laminated on one main surface of a transparent substrate, a first photoelectric conversion unit composed of a pin junction and an i-type layer being substantially amorphous silicon, and a pin junction comprising an i-type layer substantially A second photoelectric conversion unit which is crystalline silicon and is an n-type silicon-based composite layer in which a part of the n-type layer includes a silicon crystal layer in an amorphous alloy of silicon and oxygen, and a back electrode A method for producing a stacked photoelectric conversion device comprising layers,
When light is incident from the n-type layer side and the Raman scattering spectrum is measured after forming the second photoelectric conversion unit, the photoelectric conversion is performed so that the peak position of the TO mode peak of the crystalline silicon component is 516 cm ⁻¹ or more and 519 cm ⁻¹ or less. A method for producing a stacked photoelectric conversion device, comprising forming a conversion unit.   The method of manufacturing a stacked photoelectric conversion device according to claim 1, wherein a Raman scattering spectrum is measured at a plurality of locations on the film forming surface.   The method for manufacturing a stacked photoelectric conversion device according to any one of claims 1 to 3, wherein the photoelectric conversion unit has an area size of 980 cm x 950 cm or more.

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