JP2013105869A - Manufacturing method of photoelectric conversion element, photoelectric conversion element, and photoelectric conversion element module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a photoelectric conversion element, capable of manufacturing at low cost a large area photoelectric conversion element using a nitride semiconductor, and to provide a photoelectric conversion element and a photoelectric conversion element module.SOLUTION: The manufacturing method of a photoelectric conversion element, comprising processes of: forming a first buffer layer 2, a second buffer layer 600, an i-type nitride semiconductor layer 500, and an n-type nitride semiconductor layer 400 on a first substrate 1; and removing the first substrate 1 using a cutting tool 4, the photoelectric conversion element, and the photoelectric conversion element module are provided.

Description

  The present invention relates to a method for manufacturing a photoelectric conversion element, a photoelectric conversion element, and a photoelectric conversion element module.

  A photoelectric conversion element made of a silicon-based material has a band gap of 1.1 to 1.8 eV, and therefore has a low sensitivity to light having a high energy in a short wavelength region of 0.5 μm or less, and the entire solar spectrum. There is a problem peculiar to materials that the wavelength region of the material cannot be effectively used.

On the other hand, the band gap of the nitride semiconductor represented by Al _x In _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 <x + y ≦ 1) corresponds to the compositions x and y. Thus, it changes within a very wide range of 0.7 eV to 6.0 eV. Such nitride semiconductors have been actively developed as materials for light-emitting elements such as light-emitting diodes (LEDs) and laser diodes (LDs), but nitride semiconductors having the above composition are used as photoelectric conversion elements. When used, such a nitride semiconductor can be used as a material for next-generation photoelectric conversion elements because it can be sensitive to light in a short wavelength region of 0.5 μm or less. It is attracting a lot of attention.

A conventional photoelectric conversion element using a nitride semiconductor has an Al _x In _y Ga _(1-xy) N (0 ₎ as a light absorption layer under a p-type impurity-doped GaN layer from the light incident side. ≦ x ≦ 1, 0 ≦ y ≦ 1, and 0 <x + y ≦ 1) are provided. An i-type nitride semiconductor layer made of InGaN, AlGaN, AlInGaN, or the like, and a GaN layer doped with an n-type impurity are provided. It has a configuration.

  For example, in Patent Document 1 (Japanese Patent Laid-Open No. 2003-318434), a nitride semiconductor buffer layer (not shown) is formed on the [0001] surface of the sapphire substrate 1000, as shown in the schematic cross-sectional view of FIG. After p-type nitride semiconductor layer 6000, i-type nitride semiconductor layer 5000, and n-type nitride semiconductor layer 4000 are stacked in this order, element isolation is performed to form protective film 8000, and then n-type nitride semiconductor layer is formed. The photoelectric conversion element produced by forming the pad electrode 3000 and the support substrate 2000 in 4000, and irradiating the excimer laser beam 60 from the sapphire substrate 1000 side and removing the sapphire substrate 1000 is disclosed.

  In the photoelectric conversion element having such a configuration, by making the stacking direction from the n-type nitride semiconductor layer to the p-type nitride semiconductor coincide with the [000-1] direction, the piezoelectric electric field generated from the difference in lattice constant is In order to promote the separation of electron-hole pairs generated by absorbing light in the vicinity of the pi interface and to lower the conduction barrier hetero barrier in the vicinity of the ni interface, Has been.

  However, since it is difficult to manufacture a photoelectric conversion element having a large area, a large number of photoelectric conversion elements having a relatively small area are mounted to manufacture a photoelectric conversion element module such as a solar cell module. There was a need to do.

  Further, for example, in Patent Document 2 (Japanese Patent No. 4672753), after a nitride semiconductor layer is stacked on a sapphire substrate, the temperature of the sapphire substrate is returned to room temperature, whereby the nitride semiconductor layer is naturally separated from the sapphire substrate. A technique for peeling is disclosed.

Further, for example, in Patent Document 3 (Japanese Patent No. 4599442), a first buffer layer made of AlN, a second buffer made of Al _x Ga _1-x N (0.8 ≦ s <1) on a sapphire substrate. A buffer layer, a semiconductor layer made of a GaN layer or an AlGaInN layer, and a p-type semiconductor layer are formed in this order, and then irradiated with laser light having a wavelength shorter than the wavelength having energy corresponding to the forbidden band width of GaN. Discloses a technique for peeling a sapphire substrate.

  However, none of the techniques described in Patent Document 2 and Patent Document 3 can be applied to manufacture of a large-area photoelectric conversion element necessary for a photoelectric conversion element module such as a solar cell module.

JP 2003-318434 A Japanese Patent No. 4672753 Japanese Patent No. 4599442

  In view of the above circumstances, an object of the present invention is to provide a method for manufacturing a photoelectric conversion element, a photoelectric conversion element, and a photoelectric conversion element module capable of manufacturing a large-area photoelectric conversion element using a nitride semiconductor at low cost. Is to provide.

  The present invention includes a step of forming a first buffer layer on a first substrate, a step of forming a second buffer layer on the first buffer layer, and an i-type nitride on the second buffer layer. A step of forming a semiconductor layer, a step of forming an n-type nitride semiconductor layer on the i-type nitride semiconductor layer, a step of forming a metal layer on the n-type nitride semiconductor layer, and cutting the first substrate Removing using a tool, attaching the second substrate to the metal layer, removing the first buffer layer, and p-type nitriding in the second buffer layer after removing the first buffer layer And a step of forming a physical semiconductor layer.

  Here, in the method for manufacturing a photoelectric conversion element of the present invention, the step of removing the first substrate preferably includes a step of cutting the vicinity of the interface between the first substrate and the first buffer layer with a cutting tool. .

  In the method for manufacturing a photoelectric conversion element of the present invention, it is preferable that the cutting tool has a hardness higher than that of the first buffer layer and a hardness lower than that of the first substrate.

  In the method for manufacturing a photoelectric conversion element of the present invention, it is preferable that the first buffer layer has a lower hardness than each of the second buffer layer and the first substrate.

  In the method for manufacturing a photoelectric conversion element of the present invention, the first buffer layer is preferably GaAs or AlGaAs.

  In the method for manufacturing a photoelectric conversion element of the present invention, the step of forming the p-type nitride semiconductor layer preferably includes a step of injecting p-type impurities into a region other than the peripheral region of the second buffer layer.

In the method for manufacturing a photoelectric conversion element of the present invention, the i-type nitride semiconductor layer may be Al _x1 In _{y1 Gaz1} N (0 ≦ x1 ≦ 1, 0 ≦ y1 ≦ 1, 0 ≦ z1 ≦ 1, x1 + y1 + z1 ≠ 0. ), And the n-type nitride semiconductor layer includes Al _x2 In _{y2 Gaz2} N (0 ≦ x2 ≦ 1, 0 ≦ y2 ≦ 1, 0 ≦ z2 ≦ 1, x2 + y2 + z2 ≠ 0). It is preferable that a nitride semiconductor crystal represented by the formula

  Moreover, it is preferable that the manufacturing method of the photoelectric conversion element of this invention further includes the process of forming the metal film containing Ag on the surface of a 2nd board | substrate.

  The present invention also provides a metal layer provided on the second substrate, an n-type nitride semiconductor layer provided on the metal layer, and an i-type nitride semiconductor provided on the n-type nitride semiconductor layer. And a second buffer layer and a p-type nitride semiconductor layer provided on the i-type nitride semiconductor layer, and the p-type nitride semiconductor layer is provided in a region other than the peripheral region of the second buffer layer. It is the provided photoelectric conversion element.

  Here, in the photoelectric conversion element of the present invention, the second substrate preferably has flexibility.

  Furthermore, this invention is a photoelectric conversion element module containing said photoelectric conversion element.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of a photoelectric conversion element, a photoelectric conversion element, and a photoelectric conversion element module which can manufacture the large area photoelectric conversion element using a nitride semiconductor at low cost can be provided.

It is typical sectional drawing illustrating a part of manufacturing process of the manufacturing method of the photoelectric conversion element of embodiment. It is typical sectional drawing illustrating another part of manufacturing process of the manufacturing method of the photoelectric conversion element of embodiment. It is typical sectional drawing illustrating another part of manufacturing process of the manufacturing method of the photoelectric conversion element of embodiment. It is typical sectional drawing illustrating another part of manufacturing process of the manufacturing method of the photoelectric conversion element of embodiment. It is typical sectional drawing illustrating another part of manufacturing process of the manufacturing method of the photoelectric conversion element of embodiment. It is typical sectional drawing illustrating another part of manufacturing process of the manufacturing method of the photoelectric conversion element of embodiment. It is typical sectional drawing illustrating another part of manufacturing process of the manufacturing method of the photoelectric conversion element of embodiment. It is typical sectional drawing illustrating another part of manufacturing process of the manufacturing method of the photoelectric conversion element of embodiment. It is typical sectional drawing illustrating another part of manufacturing process of the manufacturing method of the photoelectric conversion element of embodiment. It is typical sectional drawing illustrating another part of manufacturing process of the manufacturing method of the photoelectric conversion element of embodiment. FIG. 3 is a schematic cross-sectional view illustrating an example of a process for forming a mask layer on the first buffer layer shown in FIG. 1. FIG. 6 is a schematic plan view of an example of a p-type nitride semiconductor layer formed in a second buffer layer. It is a typical block diagram of the photoelectric conversion element module of embodiment. 10 is a schematic cross-sectional view illustrating a method for manufacturing a photoelectric conversion element described in Patent Document 1. FIG.

  Hereinafter, the manufacturing method of the photoelectric conversion element of embodiment which is an example of the manufacturing method of the photoelectric conversion element of this invention is demonstrated. In the drawings of the present invention, the same reference numerals represent the same or corresponding parts.

  First, as shown in the schematic cross-sectional view of FIG. 1, a step of forming the first buffer layer 2 on the first substrate 1 is performed. The first buffer layer 2 can be formed on the surface of the first substrate 1 having a large area, for example, by metal organic chemical vapor deposition (MOCVD). In addition, as a surface of the 1st board | substrate 1 of a large area, the surface which has an area more than the surface of width 10mm x length 10mm can be mentioned, for example.

  Although the material of the 1st board | substrate 1 is not specifically limited, From a viewpoint of producing a photoelectric conversion element at low cost, it is preferable to use sapphire.

  Also, the first buffer layer 2 is not particularly limited, and for example, GaAs or AlGaAs can be used. Moreover, the 1st buffer layer 2 can be formed by the thickness of 1 micrometer or more and 2 micrometers or less on the [0001] plane of the sapphire substrate as the 1st board | substrate 1, for example.

  In addition, as shown in the schematic cross-sectional view of FIG. 11, for example, a mask layer 3 having a lattice-like opening may be formed on the surface of the first buffer layer 2. When the mask layer 3 having a lattice-shaped opening is formed on the surface of the first buffer layer 2, the crystallinity of the nitride semiconductor layer formed on the mask layer 3 tends to be improved. is there.

As the mask layer 3, for example, SiO ₂ or SiN can be used. Moreover, the thickness of the mask layer 3 can be 50 nm or more and 100 nm or less, for example.

  Next, as shown in the schematic cross-sectional view of FIG. 2, a step of forming the second buffer layer 600 on the first buffer layer 2 is performed. The second buffer layer 600 can be formed on the first substrate 1 by, for example, MOCVD (Metal Organic Chemical Vapor Deposition).

  As the second buffer layer 600, for example, GaN, InGaN, AlGaN, InN, or AlN can be used. In addition, the thickness of the second buffer layer 600 can be, for example, 30 nm or more and 50 nm or less.

  Next, as shown in the schematic cross-sectional view of FIG. 3, a step of forming an i-type nitride semiconductor layer 500 on the second buffer layer 600 is performed. The i-type nitride semiconductor layer 500 can be formed on the second buffer layer 600 by, for example, the MOCVD method.

The i-type nitride semiconductor layer 500 is, for example, a nitride semiconductor represented by the formula of Al _x1 In _y1 Ga _z1 N (0 ≦ x1 ≦ 1, 0 ≦ y1 ≦ 1, 0 ≦ z1 ≦ 1, x1 + y1 + z1 ≠ 0). Crystals can be used. The i-type nitride semiconductor layer 500 may have a nitride semiconductor crystal MQW (multiple quantum well) structure or SQW (single quantum well) structure.

  The thickness of the i-type nitride semiconductor layer 500 is preferably 20 nm or more and 400 nm or less. When the thickness of the i-type nitride semiconductor layer 500 is 20 nm or more, the i-type nitride semiconductor layer 500 can sufficiently absorb light such as sunlight and generate photocarriers sufficiently. When the thickness of the i-type nitride semiconductor layer 500 is 400 nm or less, the i-type nitride semiconductor layer 500 does not become too thick, so that an n-type nitride semiconductor layer and a p-type nitride semiconductor layer described later are used. The formed internal electric field tends to be sufficiently applied to the i-type nitride semiconductor layer 500.

A more specific example of the i-type nitride semiconductor layer 500 is, for example, a non-doped In _0.1 Ga _0.9 N film having a thickness of 45 nm. The non-doped In _0.1 Ga _0.9 N film is formed, for example, by supplying 10 μmol of TMG (trimethylgallium), 54 μmol of TMI (trimethylindium), and 420 mmol of NH ₃ (ammonia) to the reactor of the MOCVD apparatus. can do.

As another more specific example of the i-type nitride semiconductor layer 500, for example, a quantum well layer made of In _0.2 Ga _0.8 N having a thickness of 3.5 nm and a thickness of 6 nm are formed on the second buffer layer 600. An MQW structure in which six barrier layers made of GaN are alternately stacked. In this case, it goes without saying that the number of alternately stacked quantum well layers and barrier layers is not limited to six.

The i-type nitride semiconductor layer 500 may have a buffer layer for relaxing lattice mismatch with an n-type nitride semiconductor layer described later. As the buffer layer, for example, 20 quantum well layers made of In _s Ga _1-s N (s <0.1) with a thickness of less than 2 nm and 20 barrier layers made of GaN with a thickness of less than 2 nm are stacked alternately. An MQW structure is used.

  Next, as shown in the schematic cross-sectional view of FIG. 4, a step of forming an n-type nitride semiconductor layer 400 on the i-type nitride semiconductor layer 500 is performed. N-type nitride semiconductor layer 400 can be formed on i-type nitride semiconductor layer 500 by, for example, MOCVD.

The n-type nitride semiconductor layer 400 is, for example, a nitride semiconductor represented by the formula of Al _x2 In _y2 Ga _z2 N (0 ≦ x2 ≦ 1, 0 ≦ y2 ≦ 1, 0 ≦ z2 ≦ 1, x2 + y2 + z2 ≠ 0). A crystal doped with an n-type impurity can be used. Examples of the n-type impurity include Si, P, As, or Sb. Needless to say, the n-type nitride semiconductor layer 400 and the i-type nitride semiconductor layer 500 may use nitride semiconductor crystals having the same composition or nitride semiconductor crystals having different compositions.

  As the n-type nitride semiconductor layer 400, it is particularly preferable to use an n-type GaN layer in which Si is doped in a GaN crystal.

  The n-type nitride semiconductor layer 400 preferably has a larger band gap energy than the i-type nitride semiconductor layer 500. In this case, a decrease in the light intensity absorbed by the n-type nitride semiconductor layer 400 can be minimized, and the light intensity of light incident on the i-type nitride semiconductor layer 500 is increased. There is a tendency to generate photo carriers.

The n-type impurity concentration in the n-type nitride semiconductor layer 400 is not particularly limited, but is preferably 1 × 10 ¹⁸ / cm ³ or more and 1 × 10 ²⁰ / cm ³ or less. In this case, the conductivity of n-type nitride semiconductor layer 400 can be increased, and the crystallinity of i-type nitride semiconductor layer 500 is improved without the surface of n-type nitride semiconductor layer 400 being roughened. Tend to be able to.

  Next, as shown in the schematic cross-sectional view of FIG. 5, a step of forming a metal layer 300 on the n-type nitride semiconductor layer 400 is performed. Metal layer 300 can be formed on n-type nitride semiconductor layer 400 by, for example, sputtering or plating. In the present embodiment, the metal layer 300 includes not only the upper surface of the n-type nitride semiconductor layer 400 but also the n-type nitride semiconductor layer 400, the i-type nitride semiconductor layer 500, the second buffer layer 600, and It is also formed on each side surface of the first buffer layer 2.

  A specific example of such a metal layer 300 includes a structure in which a Ni layer having a thickness of 40 nm, a Pt layer and an Au layer having a thickness of 200 nm, and an Ag layer having a thickness of 80 nm are stacked in this order.

  Next, as shown in the schematic cross-sectional view of FIG. 6, a step of removing the first substrate 1 using a cutting tool 4 is performed. The removal of the first substrate 1 can be performed, for example, by pressing the cutting tool 4 near the interface between the first substrate 1 and the first buffer layer 2 and cutting the vicinity of the interface with the cutting tool 4. it can. As the cutting tool 4, for example, a cutting tool made of tungsten carbide or the like can be used.

  The cutting tool 4 is preferably harder than the first buffer layer 2 and lower in hardness than the first substrate 1. In this case, since the first buffer layer 2 can be easily scraped off by the cutting tool 4, it tends to be easily removed by peeling off the first substrate 1.

  Further, the first buffer layer 2 preferably has a lower hardness than each of the second buffer layer 600 and the first substrate 1. In this case, since only the first buffer layer 2 can be easily scraped off by the cutting tool 4, it tends to be easily removed by peeling off the first substrate 1.

GaN, GaAs, AlGaAs, sapphire Knoop hardness, ^{respectively, 850kg / mm 2, 730kg /} mm 2, 430~520kg / mm 2, and a 1500~1800kg / mm ^2. Therefore, for example, when the first buffer layer 2 is made of GaAs or AlGaAs and the first substrate 1 is made of sapphire, tungsten carbide is provided near the interface between the first buffer layer 2 and the first substrate 1. The first buffer layer 2 can be scraped off by pressing a cutting tool 4 made of

  More specifically, the first buffer layer 2 is cut into a size of 5 mm wide by 5 mm long using a cutting tool having a width of 5 mm with a SAICAS (surface and interface cutting machine) manufactured by Daipura Wintes. Can do. When a wider cutting tool is used, the first buffer layer 2 having a width of 5 mm or more can be scraped off.

  Next, as shown in the schematic cross-sectional view of FIG. 7, a step of attaching the second substrate 200 to the metal layer 300 is performed. Second substrate 200 can be attached to metal layer 300 using, for example, silver paste.

  The material of the second substrate 200 is not particularly limited. For example, alumina-based or titanium oxide-based ceramics, mica that is lighter than ceramics, and the like can be used. It is preferable to use a substrate having In this case, a flexible photoelectric conversion element can be manufactured.

  It is preferable to further include a step of forming a metal film containing Ag on the surface of the second substrate 200. In this case, a metal film can be used as a protective film for the second substrate 200 when the first buffer layer 2 is removed with aqua regia in a process described later. For example, when an Ag film is formed on the surface of the second substrate 200, a protective film of AgCl is formed by aqua regia, and the second substrate 200 tends to remain without being removed. Further, when a metal film containing Ag is formed on the surface of the second substrate 200, as described later, when the photoelectric conversion element is modularized, the metal film may be used as a wiring connection portion. it can.

  Next, as shown in the schematic cross-sectional view of FIG. 8, a step of removing the first buffer layer 2 is performed. The first buffer layer 2 can be removed by aqua regia or plasma etching, for example. In addition, as shown in FIG. 11, when the mask layer 3 is formed on the 1st buffer layer 2, it is preferable to remove the 1st buffer layer 2 by plasma etching.

  Next, as shown in the schematic cross-sectional view of FIG. 9, after removing the first buffer layer 2, a step of forming a p-type nitride semiconductor layer 602 in the second buffer layer 600 is performed. Here, the p-type nitride semiconductor layer 602 uses, for example, the mask 5 having a pattern for masking the peripheral region of the second buffer layer 600 as an ion implantation mask, and the ions 6 of the p-type impurity are used as the second buffer layer 600. Then, the second buffer layer 600 can be formed by annealing. Thereby, for example, as shown in the schematic plan view of FIG. 12, the p-type nitride semiconductor layer 602 can be formed in a region other than the peripheral region of the second buffer layer 600.

As the p-type impurity ions 6, for example, magnesium ions can be used. The acceleration energy of the p-type impurity ions 6 can be set to, for example, 30 keV. In addition, the p-type impurity concentration in the p-type nitride semiconductor layer 602 is not particularly limited, but is preferably, for example, from 1 × 10 ¹⁷ / cm ^{3 to} 2 × 10 ¹⁹ / cm ³ .

  The annealing of the second buffer layer 600 is preferably performed for 5 minutes in a nitrogen atmosphere at 800 ° C., for example.

More specifically, magnesium ions as p-type impurity ions 6 are implanted into regions other than the peripheral region of the second buffer layer 600 at an acceleration energy of about 30 keV, and are performed at 800 ° C. for 5 minutes in a nitrogen atmosphere. By performing annealing, a p-type nitride semiconductor layer 602 having a magnesium concentration of p-type impurities of about 1 × 10 ¹⁹ pieces / cm ³ can be formed.

  The p-type nitride semiconductor layer 602 is preferably formed in a region other than the peripheral region of the second buffer layer 600. In this case, current leakage at the end face of the photoelectric conversion element can be avoided.

  Next, as shown in the schematic cross-sectional view of FIG. 10, a step of forming a transparent electrode layer 700 on the p-type nitride semiconductor layer 602 is performed. Transparent electrode layer 700 can be formed on p-type nitride semiconductor layer 602 by, for example, magnetron sputtering or ion plating.

  The material of the transparent electrode layer 700 is not particularly limited, but it is preferable to use a single-layer or multi-layer stack made of an oxide of at least one metal selected from the group consisting of zinc, indium, tin and magnesium. .

  A specific example of the transparent electrode layer 700 is zinc oxide doped with 2% aluminum having a thickness of 320 nm.

  Note that a collecting electrode may be formed on the transparent electrode layer 700. As the collector electrode, for example, a comb-shaped collector electrode made of at least one selected from the group consisting of nickel, platinum, gold and silver can be formed.

  As described above, the large-area photoelectric conversion element 100 according to the embodiment which is an example of the photoelectric conversion element of the present invention can be manufactured.

  As illustrated in FIG. 10, the photoelectric conversion element 100 includes a second substrate 200, a metal layer 300 provided on the second substrate 200, and an n-type nitride semiconductor layer 400 provided on the metal layer 300. An i-type nitride semiconductor layer 500 provided on the n-type nitride semiconductor layer 400, a second buffer layer 600 and a p-type nitride semiconductor layer 602 provided on the i-type nitride semiconductor layer 500, And a transparent electrode layer 700 provided on the p-type nitride semiconductor layer 602. A p-type nitride semiconductor layer 602 is provided in a region other than the peripheral region of the second buffer layer 600.

  In the photoelectric conversion element 100, light that enters from the transparent electrode layer 700 side, passes through the transparent electrode layer 700 and the p-type nitride semiconductor layer 602, and reaches the i-type nitride semiconductor layer 500 is used as a light absorption layer. The i-type nitride semiconductor layer 500 is absorbed. The carriers generated in the i-type nitride semiconductor layer 500 can be taken out of the photoelectric conversion element 100 from the metal layer 300 and the transparent electrode layer 700. The metal layer 300 can function as a reflective layer that reflects light transmitted through the n-type nitride semiconductor layer 400 toward the i-type nitride semiconductor layer 500.

  For example, as shown in the schematic configuration diagram of FIG. 13, the photoelectric conversion element module 101 can be manufactured by electrically connecting a plurality of large-area photoelectric conversion elements 100 manufactured as described above. .

  A photoelectric conversion element module 101 illustrated in FIG. 13 includes a frame 10 provided with a back plate 11, a plurality of photoelectric conversion elements 100 arranged in an array in the frame 10, and the photoelectric conversion elements 100 in electrical series. Or the wiring 12 connected in parallel is provided. In addition, the frame 10 includes a sealing material 13 and a protective material 14 for protecting the photoelectric conversion element 100 and the wiring 12 from the external environment and external impact.

  In addition, the serial number and the parallel number of the photoelectric conversion elements 100 can be determined according to the rated voltage and the rated current of the photoelectric conversion element module 101.

  Moreover, the shape of the frame 10 is not specifically limited, For example, shapes other than said square shape may be polygonal shape, circular shape, elliptical shape, etc.

  Further, in the case where a flexible material is used for the second substrate 200, the photoelectric conversion element module 101 that is lightened by mounting the photoelectric conversion element 100 on a curved surface of a vehicle body or the like can be configured.

  In the production of the photoelectric conversion element 100 and the photoelectric conversion element module 101 described above, the removal of the first substrate 1 having a large area used for the growth of the i-type nitride semiconductor layer 500 and the n-type nitride semiconductor layer 400 is conventionally performed. As described above, the cutting tool 4 is used instead of laser irradiation or substrate temperature change. Therefore, even when a large-area substrate is used as the first substrate 1, the removal of the first substrate 1 can be performed more easily and at a lower cost than in the past. The photoelectric conversion element module 101 using it can be manufactured at low cost.

  Further, when the first substrate 1 is not an expensive nitride semiconductor substrate but a reusable and relatively inexpensive sapphire substrate, a large-area photoelectric conversion element 100 can be manufactured at a lower cost. can do.

  Furthermore, since the photoelectric conversion element 100 of the embodiment uses the i-type nitride semiconductor layer 500 made of a nitride semiconductor crystal as the light absorption layer, the light absorption rate is very high compared to Si and the like. The conversion element 100 can be formed thinner than before. Therefore, the degree of freedom in selecting the second substrate 200 is improved, and the flexible and lightweight photoelectric conversion element 100 and photoelectric conversion element module 101 can be formed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  INDUSTRIAL APPLICATION This invention can be utilized for the manufacturing method of a photoelectric conversion element, a photoelectric conversion element, and a photoelectric conversion element module, and can be utilized suitably especially for manufacture of a solar cell and a solar cell module.

  DESCRIPTION OF SYMBOLS 1 1st board | substrate, 2 1st buffer layer, 3 mask layer, 4 cutting tool, 5 mask, 6 ion of p-type impurity, 10 frame, 11 back plate, 12 wiring, 13 sealing material, 14 protective material 60 excimer laser light, 100 photoelectric conversion element, 101 photoelectric conversion element module, 200 second substrate, 300 metal layer, 400 n-type nitride semiconductor layer, 500 i-type nitride semiconductor layer, 600 second buffer layer, 602 p-type nitride semiconductor layer, 700 transparent electrode layer, 1000 sapphire substrate, 2000 support substrate, 3000 pad electrode, 4000 n-type nitride semiconductor layer, 5000 i-type nitride semiconductor layer, 6000 p-type nitride semiconductor layer, 8000 Protective film.

Claims (11)

Forming a first buffer layer on a first substrate;
Forming a second buffer layer on the first buffer layer;
Forming an i-type nitride semiconductor layer on the second buffer layer;
Forming an n-type nitride semiconductor layer on the i-type nitride semiconductor layer;
Forming a metal layer on the n-type nitride semiconductor layer;
Removing the first substrate using a cutting tool;
Attaching a second substrate to the metal layer;
Removing the first buffer layer;
Forming a p-type nitride semiconductor layer on the second buffer layer after removing the first buffer layer.   The method for manufacturing a photoelectric conversion element according to claim 1, wherein the step of removing the first substrate includes a step of cutting the vicinity of the interface between the first substrate and the first buffer layer with the cutting tool. .   The method for manufacturing a photoelectric conversion element according to claim 2, wherein the cutting tool has a hardness higher than that of the first buffer layer and a hardness lower than that of the first substrate.   4. The method for manufacturing a photoelectric conversion element according to claim 1, wherein the first buffer layer has a lower hardness than each of the second buffer layer and the first substrate. 5.   5. The method of manufacturing a photoelectric conversion element according to claim 1, wherein the first buffer layer is made of GaAs or AlGaAs.   The photoelectric conversion element according to claim 1, wherein the step of forming the p-type nitride semiconductor layer includes a step of injecting a p-type impurity into a region other than a peripheral region of the second buffer layer. Manufacturing method. The i-type nitride semiconductor layer includes a nitride semiconductor crystal represented by a formula of Al _x1 In _{y1 Gaz1} N (0 ≦ x1 ≦ 1, 0 ≦ y1 ≦ 1, 0 ≦ z1 ≦ 1, x1 + y1 + z1 ≠ 0). ,
The n-type nitride semiconductor layer includes a nitride semiconductor crystal represented by the formula of Al _x2 In _y2 Ga _z2 N (0 ≦ x2 ≦ 1, 0 ≦ y2 ≦ 1, 0 ≦ z2 ≦ 1, x2 + y2 + z2 ≠ 0). The manufacturing method of the photoelectric conversion element in any one of Claim 1 to 6.   The manufacturing method of the photoelectric conversion element in any one of Claim 1 to 7 which further includes the process of forming the metal film containing Ag on the surface of the said 2nd board | substrate. A metal layer provided on the second substrate;
An n-type nitride semiconductor layer provided on the metal layer;
An i-type nitride semiconductor layer provided on the n-type nitride semiconductor layer;
A second buffer layer and a p-type nitride semiconductor layer provided on the i-type nitride semiconductor layer,
A photoelectric conversion element, wherein the p-type nitride semiconductor layer is provided in a region other than a peripheral region of the second buffer layer.   The photoelectric conversion element according to claim 9, wherein the second substrate has flexibility.   A photoelectric conversion element module comprising the photoelectric conversion element according to claim 9.

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