JP5964713B2 - Method for manufacturing photoelectric conversion device - Google Patents

Description

  The present invention relates to a method for manufacturing a photoelectric conversion device.

As a photoelectric conversion device used for solar power generation or the like, there is one using an I-III-VI group compound such as CIGS having a high light absorption coefficient as a light absorption layer. This photoelectric conversion device has a known structure in which a lower electrode layer such as a metal back electrode, a light absorption layer, a buffer layer, and a transparent conductive film are laminated in this order on a substrate such as glass (for example, , See Patent Document 1).

  In some cases, the transparent conductive film used in such a photoelectric conversion device uses a metal organic chemical vapor deposition method (hereinafter referred to as MOCVD method) that causes little damage to the buffer layer and the light absorption layer. As an MOCVD method, for example, when forming a transparent conductive film of zinc oxide (ZnO), there is a method in which diethyl zinc, diborane, and water (water vapor) are reacted in a gas phase (for example, see Patent Document 2).

JP-A-8-330614 JP 2006-203022 A

  As disclosed in Patent Document 2, when a transparent electrode made of a transparent conductive film is formed by MOCVD on a photoelectric conversion layer including a buffer layer and a light absorption layer, alkylzinc such as diethyl zinc is converted into a photoelectric conversion layer. In some cases, the photoelectric conversion layer may be altered. Such alteration of the photoelectric conversion layer may reduce the photoelectric conversion efficiency of the photoelectric conversion layer device.

  One object of the present invention is to provide a method for manufacturing a photoelectric conversion device in which alteration of a photoelectric conversion layer during film formation of a transparent electrode is reduced.

In the method for manufacturing a photoelectric conversion device according to one embodiment of the present invention, a group I-III-VI compound is formed on a substrate.
A photoelectric conversion layer forming step of forming a photoelectric conversion layer mainly containing an object, and a transparent electrode forming step of forming a transparent electrode on the photoelectric conversion layer. In the present embodiment, the transparent electrode forming step includes a moisture supplying step for supplying moisture onto the photoelectric conversion layer, a heating step for raising the temperature of the substrate to the temperature at which the transparent electrode is formed, and the heating step. And a film forming step of forming the transparent electrode on the photoelectric conversion layer to which the moisture is supplied by reacting an alkylzinc-containing compound gas, a dopant-containing compound gas, and water vapor. And in this embodiment, the said water supply process is performed before the said film-forming process.

  According to one embodiment of the present invention, a decrease in photoelectric conversion efficiency in a photoelectric conversion device is reduced.

It is a top view which shows typically the structure of the photoelectric conversion apparatus manufactured with the manufacturing method which concerns on one Embodiment. It is a figure which shows the XZ cross section in the position shown with the dashed-dotted line II-II in FIG. It is a flowchart which shows the manufacturing flow of a photoelectric conversion apparatus. It is a figure which shows typically the state in the middle of manufacture of a photoelectric conversion apparatus. It is a figure which shows typically the state in the middle of manufacture of a photoelectric conversion apparatus. It is a figure which shows typically the state in the middle of manufacture of a photoelectric conversion apparatus. It is a figure which shows typically the state in the middle of manufacture of a photoelectric conversion apparatus. It is a figure which shows typically the state in the middle of manufacture of a photoelectric conversion apparatus. It is a figure which shows typically the state in the middle of manufacture of a photoelectric conversion apparatus. (A) is a schematic diagram of the film-forming apparatus used for the transparent electrode formation process in the manufacturing method of the photoelectric conversion apparatus which concerns on one Embodiment of this invention. (B) is the schematic diagram of the bubbler provided in the film-forming apparatus of (a). It is a graph which shows the relationship between the time in the heating process of a board | substrate, and the temperature of a board | substrate. It is a figure which shows typically the state in the middle of manufacture of a photoelectric conversion apparatus. It is a figure which shows typically the state in the middle of manufacture of a photoelectric conversion apparatus. It is a schematic diagram of the film-forming apparatus used at the process of the modification of the manufacturing method of the photoelectric conversion apparatus which concerns on one Embodiment of this invention. It is a schematic diagram of the film-forming apparatus used at the process of the modification of the manufacturing method of the photoelectric conversion apparatus which concerns on one Embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, parts having the same configuration and function are denoted by the same reference numerals, and redundant description is omitted in the following description. Further, the drawings are schematically shown, and the sizes, positional relationships, and the like of various structures in the drawings are not accurately illustrated. 1, 2, 4 to 9, 12, and 13, there is a right-handed XYZ coordinate system in which the arrangement direction of photoelectric conversion cells 10 (the right direction in the drawing of FIG. 1) is the + X direction. It is attached.

<(1) One Embodiment>
<(1-1) Schematic configuration of photoelectric conversion device>
As shown in FIG. 1 and FIG. 2, a photoelectric conversion device 100 according to an embodiment includes a substrate 1 and a plurality of photoelectric conversion cells 10 arranged in a plane on the substrate 1. Adjacent photoelectric conversion cells 10 are separated by a groove P3. In FIG. 1 and FIG. 2, only a part of the two photoelectric conversion cells 10 is shown for convenience of illustration.

  In the photoelectric conversion apparatus 100, a predetermined number of photoelectric conversion cells 10 can be arranged in a plane in the left-right direction of the drawing. Here, the predetermined number may be eight, for example. For example, electrodes for outputting voltage and current generated by power generation may be arranged at both ends in the ± X direction of the photoelectric conversion device 100. In the photoelectric conversion device 100, for example, a large number of photoelectric conversion cells 10 may be arranged in a matrix.

  The plurality of photoelectric conversion cells 10 include a first photoelectric conversion cell 10a and a second photoelectric conversion cell 10b that are sequentially arranged in the + X direction as the first direction. Here, the connection part 5 that electrically connects the first photoelectric conversion cell 10a and the second photoelectric conversion cell 10b in series is a second groove part (hereinafter referred to as a groove part) as a gap part located in the first photoelectric conversion cell 10a. P2). A third groove (hereinafter referred to as a groove P3) is disposed on the lower electrode 2 to which the connecting part 5 is connected.

<(1-2) Basic configuration of photoelectric conversion cell>
Each photoelectric conversion cell 10 includes a stacked portion 34 in which the lower electrode 2, the photoelectric conversion layer 3, and the light receiving surface side electrode portion 4 are sequentially stacked on the substrate 1. Each photoelectric conversion cell 10 is provided with a first groove (hereinafter referred to as a groove P1) and a groove P2. And in each photoelectric conversion cell 10, the main surface by which the light-receiving surface side electrode part 4 is arrange | positioned becomes a light-receiving surface.

  The substrate 1 supports a plurality of photoelectric conversion cells 10. As main materials included in the substrate 1, for example, glass, ceramics, resin, metal, and the like can be employed. In the present embodiment, the substrate 1 is soda lime glass. Moreover, the thickness of the board | substrate 1 should just be about 1 mm or more and 3 mm or less, for example. Furthermore, for example, the shape of the substrate 1 may be a flat plate shape.

  The lower electrode 2 is a conductive layer disposed on one main surface (also referred to as an upper surface) of the + Z side of the substrate 1. As main materials contained in the lower electrode 2, for example, various metals having conductivity such as Mo, Al, Ti, Ta, and Au can be adopted. Moreover, the thickness of the lower electrode 2 should just be about 0.2 micrometer or more and 1 micrometer or less, for example. The lower electrode 2 can be formed by, for example, a sputtering method or an evaporation method.

  The photoelectric conversion layer 3 is disposed on the lower electrode 2. The photoelectric conversion layer 3 includes a first semiconductor layer 31 and a second semiconductor layer 32. The first semiconductor layer 31 and the second semiconductor layer 32 are stacked on the lower electrode 2 in this order.

The first semiconductor layer 31 is disposed on one main surface (also referred to as an upper surface) of the + Z side of the lower electrode 2. The first semiconductor layer 31 mainly includes a semiconductor having the first conductivity type, and absorbs light to generate a charge. Here, as the semiconductor having the first conductivity type, for example, a I-III-VI group compound semiconductor which is a chalcopyrite compound semiconductor can be applied. The first conductivity type may be a p-type conductivity, for example.

The I-III-VI group compound semiconductor is a semiconductor mainly containing an I-III-VI group compound. Note that the semiconductor mainly containing the I-III-VI group compound means that the semiconductor contains 70 mol% or more of the I-III-VI group compound. Also in the following description, “mainly included” means “70 mol% or more included”. I-III-VI group compounds mainly consist of group IB elements (also referred to as group 11 elements), group III-B elements (also referred to as group 13 elements), and group VI-B elements (also referred to as group 16 elements). It is a compound contained in.

Examples of the I-III-VI group compound include Cu (In, Ga) Se ₂ (also referred to as CIGS), Cu (In, Ga) (Se, S) ₂ (also referred to as CIGSS), and CuInSe ₂ (also referred to as CIS). Say) can be employed. Cu (In, Ga) Se ₂ is a compound mainly containing Cu, In, Ga, and Se. Cu (In, Ga) (Se, S) ₂ is a compound mainly containing Cu, In, Ga, Se, and S. Here, the first semiconductor layer 31 mainly contains CIGS.

In addition, if the 1st semiconductor layer 31 mainly contains the I-III-VI group compound semiconductor, even if the thickness of the 1st semiconductor layer 31 is 10 micrometers or less, the photoelectric conversion efficiency by the 1st semiconductor layer 31 Can be enhanced. For this reason, the thickness of the first semiconductor layer 31 may be about 0.5 μm or more and about 3 μm or less, for example.

  The first semiconductor layer 31 is formed by, for example, a vapor deposition method in which Cu, In, Ga, and Se are vapor-deposited at the same time while heating the substrate to about 550 ° C. Alternatively, the first semiconductor layer 31 may be formed by heating (selenizing) in selenium vapor after forming a Cu—In layer and a Ga layer using a sputtering method. The first semiconductor layer 31 can also be formed by a plating method or a coating method.

The second semiconductor layer 32 is disposed on one main surface (also referred to as an upper surface) of the first semiconductor layer 31 on the + Z side, and has a second conductivity type different from the first conductivity type of the first semiconductor layer 31. It mainly contains semiconductors. Here, semiconductors having different conductivity types are semiconductors having different conductive carriers. The second conductivity type may be an n-type conductivity type, for example. Note that the conductivity type of the first semiconductor layer 31 may be n-type, and the conductivity type of the second semiconductor layer 32 may be p-type. Here, a heterojunction is formed between the first semiconductor layer 31 and the second semiconductor layer 32. For this reason, photoelectric conversion can occur in the first semiconductor layer 31 and the second semiconductor layer 32.

The second semiconductor layer 32 mainly includes a compound semiconductor. Examples of the compound semiconductor included in the second semiconductor layer 32 include CdS, In ₂ S ₃ , ZnS, ZnO, In ₂ Se ₃ , In (OH, S), (Zn, In) (Se, OH), and ( Zn, Mg) O or the like may be employed. If the second semiconductor layer 32 has a resistivity of 1 Ω · cm or more, the generation of leakage current can be reduced. The second semiconductor layer 32 can be formed by, for example, a chemical bath deposition (CBD) method or the like. Further, the thickness of the second semiconductor layer 32 may be about 1 nm or more and about 200 nm or less, for example.

  The light receiving surface side electrode portion 4 is disposed on one main surface (also referred to as an upper surface) of the + Z side of the photoelectric conversion layer 3. The light receiving surface side electrode portion 4 includes a transparent electrode 41 and a plurality of upper electrodes 42. The transparent electrode 41 and the upper electrode 42 are stacked on the photoelectric conversion layer 3 in this order.

  The transparent electrode 41 is disposed on one main surface (also referred to as an upper surface) of the + Z side of the photoelectric conversion layer 3. The transparent electrode 41 is, for example, a transparent conductive layer having an n-type conductivity type. The transparent electrode 41 is an electrode that extracts charges generated in the photoelectric conversion layer 3. The transparent electrode 41 mainly includes a material having a wide forbidden band, transparent, and low resistance. As such a material, for example, a metal oxide semiconductor of a compound of ZnO or ZnO can be employed. The transparent electrode 41 can control the resistance value by containing, for example, any one element of Al, B, Ga, In, and F as a ZnO dopant.

  In the present embodiment, the transparent electrode 41 can be formed by the MOCVD method. The thickness of the transparent electrode 41 may be, for example, about 0.08 μm or more and about 2 μm or less.

  The upper electrode 42 is disposed on one main surface (also referred to as an upper surface) of the transparent electrode 41 on the + Z side. The upper electrode 42 has a linear shape, and a plurality of upper electrodes 42 are arranged on the upper surface of the transparent electrode 41. The upper electrode 42 can be formed, for example, by applying a conductive paste on the upper surface of the transparent electrode 41 and then drying and solidifying the conductive paste.

  The plurality of upper electrodes 42 are separated in the + Y direction perpendicular to the + X direction as the first direction, and each upper electrode 42 extends in the + X direction. Here, the photoelectric conversion layer 3 is provided with a slit-like groove P2 as a gap. And the upper electrode 42 is electrically connected to the lower electrode 2 of the adjacent photoelectric conversion cell 10 by the connection part 5 distribute | arranged to the groove part P2. Specifically, the plurality of first upper electrodes 42a in the first photoelectric conversion cell 10a are extended from the second photoelectric conversion cell 10b to the inside of the first photoelectric conversion cell 10a by the connection portion 5 disposed in the groove portion P2. Connected to the second lower electrode 2b. That is, between the adjacent first photoelectric conversion cell 10a and the second photoelectric conversion cell 10b, the first light receiving surface side electrode portion 4a disposed in the first photoelectric conversion cell 10a and the adjacent second photoelectric conversion cell. The second lower electrode 2b disposed in 10b is connected by the connecting portion 5.

  The upper electrode 42 plays a role of collecting charges generated in the photoelectric conversion layer 3 and taken out by the transparent electrode 41. By providing the upper electrode 42, the conductivity of the transparent electrode 41 is supplemented. For this reason, the transparent electrode 41 can be thinned. As a result, it is possible to ensure both the charge extraction efficiency and the improvement of light transmittance in the transparent electrode 41.

  The charges collected by the transparent electrode 41 and the upper electrode 42 are transmitted to the adjacent photoelectric conversion cell 10 through the connection portion 5. Thereby, in the photoelectric conversion apparatus 100, the adjacent photoelectric conversion cells 10 are electrically connected in series.

<(1-3) Photoelectric Conversion Device Manufacturing Process>
Here, an example of a manufacturing process of the photoelectric conversion device 100 having the above configuration will be described.

  In step Sp1 of FIG. 3, the substrate 1 (see FIG. 4) is prepared. The board | substrate 1 should just be a flat thing which has a substantially rectangular board surface which consists of soda-lime glass etc., for example.

  In step Sp2, the lower electrode 2 (see FIG. 5) is formed on substantially the entire main surface of the cleaned substrate 1 by using a sputtering method or a vapor deposition method. In the present embodiment, the lower electrode 2 is preferably made of molybdenum, which has a high melting point, a low reactivity with selenium, and a practical material.

  In Step Sp3, a groove portion P1 (see FIG. 6) extending in the + Y direction is formed from a predetermined formation target position on the upper surface of the lower electrode 2 to the upper surface of the substrate 1 immediately below it. The groove portion P1 can be formed, for example, by irradiating a predetermined formation target position while scanning with a YAG (yttrium, aluminum, garnet) laser or other laser light. At this time, a plurality of lower electrodes 2 arranged in the + X direction are formed on the substrate 1. Specifically, for example, as shown in FIG. 6, in the lower electrode 2, the first lower electrode 2a and the second lower electrode 2b are alternately arranged at intervals of the groove portion P1 along the + X direction. Is formed. That is, Step Sp2 and Step Sp3 correspond to the lower electrode forming step. In FIG. 6, the first lower electrode 2a and the second lower electrode 2b are formed one by one, but a plurality of each are formed.

  In Step Sp4, the first semiconductor layer 31 (see FIG. 7) is formed on the lower electrode 2. Here, for example, a film 310 (see FIG. 7) containing a metal element mainly contained in the first semiconductor layer 31 is formed on the lower electrode 2.

  In the present embodiment, the precursor layer 310 is formed as follows.

  First, a Cu-Ga layer is formed on the substrate 1 by performing DC magnetron sputtering using a Cu-Ga alloy target. Next, an In / Cu—Ga precursor layer is formed by performing DC magnetron sputtering using an In target to form an In layer on the Cu—Ga layer.

Next, the substrate 1 on which the precursor layer is formed is heated to about 400 ° C. or more and about 600 ° C. or less in a hydrogen gas atmosphere containing hydrogen selenide (H ₂ Se) gas. In this heat treatment step, the precursor becomes a first conductivity type first semiconductor layer 31 by combining selenium. This film thickness is increased by combining selenium, and is finally adjusted to be about 0.5 μm to 3 μm.

  In step Sp5, the second conductivity type second semiconductor layer 32 (see FIG. 8) is formed on the first semiconductor layer 31. Thereby, the photoelectric conversion layer 3 in which the first semiconductor layer 31 and the second semiconductor layer 32 are stacked is formed.

The second semiconductor layer 32 can be formed by, for example, a chemical bath deposition (CBD) method. Specifically, for example, the first semiconductor layer 31 is immersed in a solution prepared by dissolving cadmium acetate and thiourea in aqueous ammonia, so that the second semiconductor layer 32 mainly containing CdS is formed. Can be formed.

  In this way, the photoelectric conversion layer 3 is formed by Step Sp4 and Step Sp5. That is, Step Sp4 and Step Sp5 correspond to the photoelectric conversion layer forming step.

  Step Sp6 is a transparent electrode forming step in which the transparent electrode 41 (see FIG. 9) is formed on the photoelectric conversion layer 3. Specifically, for example, a transparent transparent electrode 41 mainly containing ZnO to which boron (B) is added is formed on the second semiconductor layer 32. This transparent electrode forming step is performed by the MOCVD method.

  Next, an example of a film forming apparatus used in the transparent electrode forming process will be described. As shown in FIG. 10A, the film forming apparatus 50 includes a chamber 51, a mounting table 52, an exhaust pipe 53, a vacuum pump 54, and introduction pipes 55 and 56.

  In the chamber 51, the substrate 1 on which the photoelectric conversion layer 3 is formed is disposed. The substrate 1 is disposed on a mounting table 52 located substantially in the center of the chamber 51. The chamber 51 functions as a film forming chamber for forming the transparent electrode 41. The mounting table 52 is provided with a heater for raising the temperature of the substrate 1 to a predetermined temperature and maintaining it (not shown). In addition, this heater may be arrange | positioned under the mounting base 52. FIG. The heater may be disposed inside the mounting table 52.

  The exhaust pipe 53 has a function of exhausting the gas introduced into the chamber 51. The exhaust pipe 53 is provided with a vacuum pump 54 and a pressure adjusting valve (not shown) for adjusting the pressure in the chamber. The vacuum pump 54 evacuates the chamber 51 to reduce the pressure, and the pressure adjustment valve has a function of controlling the pressure and pressure when the transparent electrode 41 is formed.

  The introduction pipe 55 and the introduction pipe 56 have a function of supplying a gas (hereinafter also referred to as a source gas) as a raw material of the transparent electrode 41 to the chamber 51. The introduction pipe 55 has an introduction pipe 55a for supplying an alkylzinc-containing compound gas and an introduction pipe 55b for supplying a dopant-containing compound gas. That is, the introduction pipe 55 is formed to be branched into the introduction pipe 55a and the introduction pipe 55b from the middle. Gases (alkyl zinc-containing compound gas and dopant-containing compound gas) introduced into the introduction pipe 55a and the introduction pipe 55b, respectively, are mixed before being supplied to the chamber 51, as shown in FIG. Therefore, the chamber 51 is supplied in a mixed gas state of the alkylzinc-containing compound gas and the dopant-containing compound gas. The introduction pipe 56 supplies water vapor, which is one of the raw material gases for the transparent electrode 41, to the chamber 51.

  Next, a method for preparing the source gas will be described. The source gas is prepared using a bubbler, which is one of devices for vaporizing a liquid. The bubbler is a part of the film forming apparatus 50. As shown in FIG. 10B, the bubbler 60 includes a main body container 61, a thermostatic chamber 62, a carrier gas introduction pipe 63, and a mixed gas outlet pipe 64.

In the main body container 61, the carrier gas introduction pipe 63 and the mixed gas outlet pipe 64 are made of metal such as stainless steel, for example. The main body container 61 is provided with a raw material in a liquid state. The main body container 61 is arranged in a thermostatic chamber 62. The constant temperature bath 62 has a function of holding the main body container 61 at a predetermined temperature. Therefore, the thermostat 62 is provided with a heating mechanism and a cooling mechanism (not shown).

The carrier gas introduction pipe 63 has a function of introducing a carrier gas such as nitrogen or argon into the liquid raw material L arranged in the main body container 61. Therefore, the opening end on one end side of the carrier gas introduction pipe 63 is provided so as to be positioned in the liquid raw material L as shown in FIG. The carrier gas derived from the carrier gas introduction pipe 63 is bubbled in the liquid raw material L. By this bubbling, the liquid raw material L is vaporized and becomes a raw material gas. This source gas flows from the mixed gas outlet pipe 64 to the introduction pipe 55 (introduction pipe 55a) or the introduction pipe 56 as a mixed gas combined with the carrier gas. When preparing alkyl zinc-containing compound gas, liquid material L is an alkyl zinc _{(Zn (C n H 2n +} 1) 2) ( n is an integer), for example, diethyl zinc, dimethyl zinc, preferably using diethylzinc. When using diethyl zinc, the temperature of the liquid raw material L in a bubbler should just adjust between 20 degreeC or more and 65 degrees C or less. Moreover, when preparing water vapor, as the liquid raw material L, for example, pure water is used. At this time, in order to vaporize the pure water, the pure water is heated to about 20 to 100 ° C.

  In addition, the dopant containing compound gas which is one of source gas is not the bubbler 60, for example, is prepared with the following method. First, a gas cylinder is prepared in which a gas obtained by diluting diborane, which is a dopant-containing compound, with hydrogen to 0.1% or more and about 3% or less is injected. Next, the pressure of the gas derived from the gas cylinder is lowered to a desired value by using a pressure control valve or the like, the flow rate is controlled by a mass flow controller or the like, and the gas is supplied to the introduction pipe 55b for introducing the dopant-containing compound gas.

  This transparent electrode forming step includes a moisture supplying step, a heating step, and a film forming step. Each step will be described below.

  The moisture supply step is a step of supplying moisture onto the photoelectric conversion layer 3 before forming the transparent electrode 41. In the moisture supply step, the substrate 1 on which the photoelectric conversion layer 3 is formed is placed on the placement table 52, and then moisture is supplied from the introduction tube 56 to the chamber 51 in the state of water vapor.

  The heating step is a step of raising the temperature of the substrate 1 to the temperature at which the transparent electrode 41 is formed. For example, after the pressure inside the chamber 51 is reduced to about several Pa by the vacuum pump 54, the heating process is performed at a temperature of 80 ° C. or higher and about 230 ° C. or lower, which is the temperature at which the substrate 1 is formed by the heater provided on the mounting table 52. This is done by raising the temperature.

  And in this embodiment, the above-mentioned moisture supply process is performed simultaneously with a heating process or before this heating process. The relationship between the moisture supply to the photoelectric conversion layer 3 and the heating of the substrate 1 will be described with reference to FIG. In FIG. 11, the temperature T1 is the temperature of the substrate 1 before the heating step, and is, for example, a temperature equivalent to room temperature. The temperature T3 is the temperature of the substrate 1 after the heating step, and is the temperature of the substrate 1 at the time of film formation. That is, the heating process is performed until time M1 shown in FIG. Therefore, the water supply process is also performed by time M1. The temperature T2 is the temperature of the substrate 1 at a certain time during which the substrate 1 is being heated.

  The moisture supply process may be started before the heating process, that is, when the substrate 1 is at the temperature T1. Further, the moisture supply process may be performed at a temperature T2 that is a temperature when the substrate 1 is heated in the heating process. In other words, the moisture supply step may be performed before the temperature of the substrate 1 reaches the temperature T3 that is the temperature at the time of film formation.

In the film-forming process described later, when diethyl zinc (Zn (C ₂ H ₅ ) ₂ ) is used as the alkyl zinc-containing compound, the following chemical reaction occurs.
Zn (C ₂ H ₅ ) ₂ + H ₂ O → ZnO + 2C ₂ H ₆
Since diethyl zinc has a strong reducing property, it reacts with water vapor (H ₂ O) simultaneously supplied into the chamber 51, and zinc oxide (ZnO) is formed on the photoelectric conversion layer 3 as the transparent electrode 41. Be filmed. At this time, when unreacted diethyl zinc remains, a part of the surface of the photoelectric conversion layer 3 may be deteriorated by the strong reduction action.

  Therefore, in this embodiment, a step of supplying moisture to the surface of the photoelectric conversion layer 3 is performed before the transparent electrode 41 is formed. Thereby, the surface of the photoelectric conversion layer 3 is covered with water molecules or hydroxyl groups. Therefore, diethyl zinc (alkyl zinc-containing compound gas) is difficult to contact the photoelectric conversion layer 3. As a result, alteration of the photoelectric conversion layer 3 that can be caused by the alkylzinc-containing compound gas is reduced. Reduction in photoelectric conversion efficiency can be reduced by reducing such alteration.

  In the present embodiment, since the moisture supply step is performed before reaching the temperature at the time of film formation as described above, water is supplied at the temperature at the time of film formation (about 80 ° C. or more and about 230 ° C. or less). It is possible to supply moisture at a temperature closer to room temperature than to do. Therefore, it is easy to adsorb moisture on the surface of the photoelectric conversion layer 3.

  The film forming process is performed after the heating process described above. In addition, this film forming step is performed so that the transparent electrode 41 is formed on the photoelectric conversion layer 3 to which water has been supplied in the above-described water supplying step. In the film formation step, after the temperature of the substrate 1 reaches the temperature T3 at which film formation starts, a mixed gas of an alkylzinc-containing compound gas and a dopant-containing compound gas is introduced into the chamber 51 from the introduction pipe 55. By introducing water vapor from the introduction pipe 56, these raw material gases (mixed gas and water vapor) are reacted. Note that the water vapor introduced into the chamber 51 from the introduction pipe 56 during the film forming process may be continuously supplied into the chamber 51 from the moisture supply process and the heating process. Further, in the film forming process, a heater of the mounting table 52 may be used in order to keep the temperature of the substrate 1 at the temperature T3 during film formation. The transparent electrode 41 is formed by the above process.

  In addition, you may perform a film-forming process in the atmosphere whose molar concentration of water vapor | steam is higher than the molar concentration of alkyl zinc containing compound gas and dopant containing compound gas. Thereby, the probability that the unreacted alkylzinc-containing compound gas directly contacts the photoelectric conversion layer 3 can be reduced. Thereby, the alteration of the photoelectric conversion layer 3 is further reduced. At this time, the molar concentration of water vapor may be about twice the molar concentration of the alkylzinc-containing compound gas and the dopant-containing compound gas.

  In Step Sp7, a gap portion (hereinafter referred to as a groove portion P2, see FIG. 12) extending in the + Y direction is formed in a region extending from the upper surface of the transparent electrode 41 to the upper surface of the lower electrode 2. This step Sp7 corresponds to a gap forming step. The groove portion P2 is formed by partially removing the photoelectric conversion layer 3 and the transparent electrode 41 on the lower electrode 2. As a method for forming the groove portion P2, for example, a mechanical scribing method in which mechanical removal is performed using a processing tool such as a metal needle or a metal blade is used. That is, in the mechanical scribing method, the photoelectric conversion layer 3 and the transparent electrode of the portion where the processing tool is moved by linearly moving the processing tool, which is arranged at a predetermined position on the transparent electrode 41 by applying a predetermined pressure. By removing 41, a groove portion P2 is formed so that the upper surface of the lower electrode is exposed at the bottom surface.

In step Sp8, the upper electrode 42 is formed from a predetermined formation target position on the upper surface of the transparent electrode 41 to the inside of the groove portion P2. For example, the upper electrode 42 is applied so that the conductive paste has a predetermined linear pattern from a predetermined formation target position on the upper surface of the transparent electrode 41 to the inside of the groove portion P2, and the conductive paste after application is dried. It can be formed by solidifying. As a result, the upper electrode 42 is connected to the first lower electrode 2 as shown in FIG.
The first transparent electrode 41a located on a is electrically connected to the second lower electrode 2b through the groove P2 from the first transparent electrode 41a. The connecting portion 5 disposed in the groove portion P2 corresponds to a part of the upper electrode 42. The upper electrode 42 and the connection portion 5 can be formed by applying a conductive paste, for example, by screen printing or the like. This conductive paste is, for example, a metal or alloy filler such as gold, silver, palladium, copper, or nickel kneaded in an epoxy resin or an acrylic resin. Thus, by forming the upper electrode 42, the resistance component is reduced as compared with a mode in which the transparent electrode 41 extends to the groove portion P <b> 2 and the adjacent photoelectric conversion cells are electrically connected.

  In the next step Sp9, a groove P3 (see FIGS. 1 and 2) is formed in a region extending from the upper surface of the light receiving surface side electrode portion 4 to the upper surface of the lower electrode 2. Thereby, the photoelectric conversion apparatus 100 in which a plurality of photoelectric conversion cells 10 are arranged on the substrate 1 is obtained.

  Specifically, in Step Sp9, at least a portion of the stacked body 234 located on the + X direction side as the first direction with respect to the stacked body 234 is cut linearly along the Y direction. The linear groove portion P3 extends from the upper surface of the light receiving surface side electrode portion 4 of the multilayer body 234 to the upper surface of the lower electrode 2. Thereby, the 1st lamination part 34a and the 2nd lamination part 34b which are located in a line with the + X direction are formed. The first stacked portion 34a is disposed, for example, in a region extending over the substrate 1 from the first lower electrode 2a through at least the groove portion P2 as a gap portion between the first lower electrode 2a and the second lower electrode 2b. It ’s fine. Moreover, the 2nd laminated part 34b should just be distribute | arranged on the 2nd lower electrode 2b, for example. Moreover, the groove part P3 is formed using the above-mentioned mechanical scribing method, for example.

  Through the above steps Sp1 to Sp8, the plurality of lower electrodes 2, the first semiconductor layer 31, the second semiconductor layer 32, and the light receiving surface side electrode portion 4 are sequentially stacked on the substrate 1 in the + Z direction as the second direction. A stacked body 234 is formed (see FIG. 13). In addition, the light receiving surface side electrode portion 4 that is electrically connected to the lower electrode 2 through the connection portion 5 located in the groove portion P2 disposed in the second semiconductor layer 32 and the first semiconductor layer 31 is formed.

<(2) Modification>
<(2-1) Modification 1>
Another embodiment of the present invention will be described with reference to FIG. In the present embodiment, the transparent electrode forming step is different from the transparent electrode forming step of the above-described embodiment. First, a film forming apparatus used in the manufacturing method according to this embodiment will be described.

  A film forming apparatus 50A for forming the transparent electrode 41 has a plurality of chambers as shown in FIG. Specifically, the film forming apparatus 50A includes a first chamber 51a, a second chamber 51b, and a third chamber 51c. In addition, mounting tables 52a, 52b, and 52c are provided inside each chamber. Furthermore, each chamber is provided with vacuum pumps 53a, 53b, 53c and exhaust pipes 54a, 54b, 54c. In addition, gate valves 57 (57a to 57b) are provided on both sides of each chamber. The first chamber 51a and the third chamber 51c are provided with air supply pipes 58 (58a and 58b) for supplying nitrogen or the like in order to return the pressure in the chamber to about atmospheric pressure. The second chamber 51b is provided with introduction pipes 55 and 56 into which the source gas is introduced. Therefore, in the film forming apparatus 50A, the second chamber 51b functions as a film forming chamber. In the film forming apparatus 50A, the substrate 1 has a structure that can be moved between the chambers by a chain drive, for example.

The transparent electrode forming step in the present embodiment includes a low temperature heating step of heating the substrate 1 at a temperature lower than that of the heating step before the moisture supply step and the heating step. And this low-temperature heating process is performed in the 1st chamber 51a. On the other hand, the moisture supply process, the heating process, and the film forming process are performed in the second chamber 51b.

  Next, an example of the transparent electrode forming process according to this embodiment using the film forming apparatus 50A shown in FIG. 14 will be described. First, the gate valve 57a is opened, and the substrate 1 on which the photoelectric conversion layer 3 is formed is mounted on the mounting table 52a in the first chamber 51a. Next, after closing the gate valve 57a, the vacuum pump 54a is operated to exhaust excess gas from the exhaust pipe 53a, and the pressure inside the first chamber 51a is reduced to about several Pa. Next, the board | substrate 1 is heated with the heater provided in the mounting base 52a. The temperature of the substrate 1 at this time may be a room temperature or higher and 10 ° C. or lower than the temperature at the time of forming the transparent electrode 41. This process corresponds to the low-temperature heating process described above.

  Next, the vacuum pump 54b is operated to exhaust excess gas in the second chamber 51b from the exhaust pipe 53b. Thereby, the internal pressures of the first chamber 51a and the second chamber 51b become substantially equal. Next, the gate valve 57b is opened, and the substrate 1 is mounted on the mounting table 52b in the second chamber 51b. It mounts on the mounting base 52b inside the 2nd chamber 51b. Next, a heater (not shown) provided on the mounting table 52b is energized to heat the substrate 1 so as to raise the temperature to a predetermined temperature during film formation (heating process). During this heating step, water vapor is supplied onto the photoelectric conversion layer 3 of the substrate 1 using the introduction tube 56 (moisture supply step). In addition, you may perform this moisture supply process before the said heating process.

  Next, after the substrate 1 reaches the predetermined film-forming temperature T3 through the heating step, a mixed gas of the alkylzinc-containing compound gas and the dopant-containing compound gas is supplied from the introduction pipe 55 into the second chamber 51b. The transparent electrode 41 is formed by supplying water vapor from the introduction pipe 56 (film formation step).

  Further, after the film formation of the transparent electrode 41 with a predetermined thickness is completed, the supply of the source gas is stopped and the residual gas in the second chamber 51b is exhausted. Next, the vacuum pump 54c is operated to exhaust excess gas in the third chamber 51c from the exhaust pipe 53c. Thereby, the internal pressures of the second chamber 51b and the third chamber 51c become substantially equal. Next, the gate valve 57c is opened, and the substrate 1 is placed on the placing table 52c in the third chamber 51c. Next, the gate valve 57c is closed to stop the exhaust. Next, nitrogen or the like is supplied from the air supply pipe 58b to return the pressure inside the third chamber 51c to almost atmospheric pressure. Finally, after the substrate 1 is sufficiently cooled, the gate valve 57d is opened and the substrate 1 is taken out from the film forming apparatus 50A.

  Thus, in this embodiment, the low temperature heating process and the processes after the low temperature heating process (water supply, heating, and film formation) are performed in different chambers. Accordingly, in the present embodiment, when the transparent electrode 41 is continuously formed, the low temperature heating is performed in the first chamber 51a in parallel with the water supply, heating, and film forming steps in the second chamber 51b. The process can proceed. As a result, the tact time of the transparent electrode forming step can be shortened, so that the transparent electrode 41 can be formed efficiently. Further, in order to further improve the tact time, a plurality of second chambers 51b may be connected in series.

<(2-2) Modification 2>
In the present embodiment, the moisture supply process is performed in the first chamber 51a while heating the substrate 1 at a temperature lower than the temperature at the time of film formation of the transparent electrode 41, and the heating process and the film formation process are performed in the second chamber 51b. This is different from the above-described embodiment in that it is performed.

In the manufacturing method of the present embodiment, for example, the film forming apparatus 50B shown in FIG. 15 is used.
The film forming apparatus 50B has a structure in which an introduction pipe 56 for supplying water vapor to the first chamber 51a of the film forming apparatus 50A is provided.

  Next, an example of a transparent electrode forming process according to the present embodiment using the film forming apparatus 50B shown in FIG. 15 will be described. First, the gate valve 57a is opened, and the substrate 1 on which the photoelectric conversion layer 3 is formed is mounted on the mounting table 52a in the first chamber 51a. Next, the inside of the first chamber 51a is depressurized to a predetermined pressure. Next, the substrate 1 is heated to a temperature lower than the temperature at the time of forming the transparent electrode 41 and maintained at that temperature. The temperature of the substrate 1 at this time may be a temperature that is, for example, 5 ° C. or more and 30 ° C. or less lower than the temperature at which the transparent electrode 41 is formed. Then, water is supplied onto the photoelectric conversion layer 3 of the substrate 1 by supplying water vapor from the introduction tube 56 into the first chamber 51a when the substrate 1 is heated (moisture supply step).

  Next, the substrate 1 is moved from the first chamber 51a to the mounting table 52b of the second chamber 51b, and the temperature of the substrate 1 is raised to a predetermined temperature during film formation (heating step). Next, after reaching the temperature T3, which is the film formation temperature, water vapor is supplied from the introduction pipe 56 into the second chamber 51b, and a mixed gas of the alkylzinc-containing compound gas and the dopant-containing compound gas is supplied from the introduction pipe 55 to the first gas. The transparent electrode 41 is formed by supplying the gas into the two chamber 51b (film formation process).

  In addition, the said one Embodiment and various modifications are not limited to the above-mentioned description content, It can change suitably. For example, the method of vaporizing the alkylzinc-containing compound and moisture may be a method of directly vaporizing by heating or the like in addition to using a bubbler.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Lower electrode 2a 1st lower electrode 2b 2nd lower electrode 3 Photoelectric conversion layer 4 Light-receiving surface side electrode part 4a 1st light-receiving surface side electrode part 4b 2nd light-receiving surface side electrode part 5 Connection part 10 Photoelectric conversion cell 10a, 10b First and second photoelectric conversion cells 31, 31a, 31b First semiconductor layer 32, 32a, 32b Second semiconductor layer 34 Laminated portion 34a, 34b First, second laminated portion 41 Transparent electrodes 41a, 41b First, first 2 transparent electrode 42 upper electrode 42a, 42b first and second upper electrode 50, 50A, 50B film forming apparatus 51 chamber 51a first chamber 51b second chamber 51c third chamber 52, 52a-52c mounting table 53, 53a-53c Exhaust pipe 54, 54a to 54c Vacuum pump 55, 56 Inlet pipe 57, 57a to 57d Gate valve 58, 58a, 58b Supply Pipe 60 bubbler 61 main container 62 a thermostat 63 carrier gas inlet tube 64 mixed gas introduction pipe 100 the photoelectric conversion device 234 laminate 310 precursor layer P1~P3 groove

Claims (4)

A photoelectric conversion layer forming step of forming a photoelectric conversion layer mainly containing an I-III-VI group compound on the substrate;
A transparent electrode forming step of forming a transparent electrode on the photoelectric conversion layer,
The transparent electrode forming step includes a moisture supplying step for supplying moisture onto the photoelectric conversion layer, a heating step for raising the temperature of the substrate to a temperature during film formation of the transparent electrode, and an alkylzinc-containing compound after the heating step. A film forming step of reacting a gas, a dopant-containing compound gas, and water vapor to form the transparent electrode on the photoelectric conversion layer supplied with the moisture, and
The method for manufacturing a photoelectric conversion device, wherein the water supply step is performed before the film formation step. The transparent electrode forming step further includes a low-temperature heating step of heating the substrate at a temperature lower than the temperature at the time of film formation of the transparent electrode before the moisture supply step and the heating step,
The low temperature heating step is performed in the first chamber,
The method for manufacturing a photoelectric conversion device according to claim 1, wherein the moisture supply step, the heating step, and the film forming step are performed in a second chamber. The moisture supply step is performed in the first chamber while heating the substrate at a temperature lower than the temperature at the time of forming the transparent electrode,
The method for manufacturing a photoelectric conversion device according to claim 1, wherein the heating step and the film forming step are performed in a second chamber.   4. The method of manufacturing a photoelectric conversion device according to claim 1, wherein the film forming step is performed in an atmosphere in which the concentration of the water vapor is higher than that of the alkylzinc-containing compound gas and the dopant-containing compound gas.

Images