JP2010192870A - Method for manufacturing silicon nano-wire, solar cell including the same, and method for manufacturing the solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a silicon nano-wire, a solar cell including the silicon nano-wire, and a method for manufacturing the solar cell. <P>SOLUTION: The solar cell is provided which includes: a substrate; a first<SP>++</SP>type polycrystalline silicon layer equipped on the substrate; a first type silicon nano-wire layer including a first type silicon nano-wire grown from the first<SP>++</SP>type polycrystalline silicon layer; an intrinsic layer provided on the substrate having the first type silicon nano-wire layer; and a second type doping layer equipped on the intrinsic layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing silicon nanowires, a solar cell including silicon nanowires, and a method for producing solar cells.

  At present, there is a growing demand for participation in greenhouse gas reduction obligations under the Framework Convention on Climate Change, which has led to the activation of the carbon dioxide market and increased interest in the field of new and renewable energy.

  Solar cells, which are a typical new and renewable energy field, are systems that produce electricity using sunlight, an infinite and clean energy source, with solar cells that directly convert light into electricity at the center. .

  Currently, more than 90% of solar cells in commercial use are bulk-based silicon solar cells, which are affected by the balance between supply and demand for silicon. However, there is a problem that thinning or low temperature process is not easy.

  An object of the present invention is to provide a method for producing silicon nanowires.

  Another object of the present invention is to provide a method of manufacturing silicon nanowires from a seed layer using a low-temperature high-density plasma.

  Still another object of the present invention is to provide a method of manufacturing a solar cell including a method of manufacturing silicon nanowires.

To achieve the above object, according to one aspect of the present invention, a substrate, a first ⁺⁺ type polycrystalline silicon layer provided on the substrate, and a first ⁺⁺ type polycrystalline silicon layer grown from the first ⁺⁺ type polycrystalline silicon layer are provided. A first type silicon nanowire layer including a type 1 silicon nanowire; an intrinsic layer provided on a substrate provided with the first type silicon nanowire layer; a second type doping layer provided on the intrinsic layer; A solar cell is provided.

  The solar cell includes a TCO layer provided on the second type doping layer, an antireflection film provided on the TCO layer and exposing a predetermined region of the TCO layer, and a predetermined region of the exposed TCO layer. And a front electrode provided in a patterned form.

The solar cell includes a TCO layer provided between the substrate and a first ⁺⁺ type polysilicon layer, and a back electrode provided on the second type doping layer.

  The intrinsic layer is a top cell intrinsic layer, the second type doping layer is a top cell second type doping layer, and the solar cell includes a buffer layer provided on the top cell second type doping layer, and the buffer A bottom cell first type doping layer provided on a layer; a bottom cell intrinsic layer provided on the bottom cell first type doping layer; a bottom cell second type doping layer provided on the bottom cell intrinsic layer; and the bottom cell. And a back electrode provided on the second type doping layer.

  The first type silicon nanowire has a length of 2 to 5 μm and a diameter of 1 to 5 nm.

To achieve the above object, according to another aspect of the present invention, a first ^{++ -} type poly-Si layer formation step of forming a first ^{++ -} type poly-Si layer on a substrate, the first ⁺⁺ - type poly A metal thin film layer forming step for forming a metal thin film layer on the crystalline silicon layer, a metal nanoparticle forming step for forming the metal thin film layer on metal nanoparticles, and the first ⁺⁺ type using the metal nanoparticles as a seed There is provided a silicon nanowire forming method including a first type silicon nanowire growth step of growing a first type silicon nanowire from a polycrystalline silicon layer.

To achieve the above object, According to yet another aspect, in the method for manufacturing the solar cell, the first ^{++ -} type poly-Si layer formation step of forming a first ^{++ -} type poly-Si layer on a substrate of the present invention A metal thin film layer forming step of forming a metal thin film layer on the first ^++- type polycrystalline silicon layer, a metal nanoparticle forming step of forming the metal thin film layer on metal nanoparticles, and seeding the metal nanoparticles And a first-type silicon nanowire growth step for growing a first-type silicon nanowire from the first ^++- type polycrystalline silicon layer.

  After the first-type silicon nanowire growth step, an intrinsic layer forming step of forming an intrinsic layer on the substrate on which the first-type silicon nanowire has grown, and a second type of forming a second-type doping layer on the intrinsic layer A doping layer forming step, a TCO layer forming step for forming a TCO layer on the second type doping layer, an antireflection film forming step for forming an antireflection film on the TCO layer, and a front surface on the antireflection film Forming a front electrode to form an electrode.

A TCO layer forming step of forming a TCO layer on the substrate before the first ⁺⁺ type polycrystalline silicon layer forming step, and the first type silicon nanowire grows after the first type silicon nanowire growth step; An intrinsic layer forming step for forming an intrinsic layer on the substrate, a second type doping layer forming step for forming a second type doping layer on the intrinsic layer, and a back electrode on the second type doping layer. A back electrode forming step.

A TCO layer forming step of forming a TCO layer on the substrate before the first ⁺⁺ type polycrystalline silicon layer forming step, and the first type silicon nanowire grows after the first type silicon nanowire growth step; A top cell intrinsic layer forming step for forming a top cell intrinsic layer on the substrate, a top cell second type doping layer forming step for forming a top cell second type doping layer on the top cell intrinsic layer, and the top cell A buffer layer forming step for forming a buffer layer on the second type doping layer, a bottom cell first type doping layer forming step for forming a bottom cell first type doping layer on the buffer layer, and a bottom cell first type doping layer A bottom cell intrinsic layer forming step for forming a bottom cell intrinsic layer on the bottom cell intrinsic layer; A bottom cell second type doping layer forming step of forming a bottom cell second type doping layer; and a back electrode forming step of forming a back electrode on the bottom cell second type doping layer.

  The metal thin film layer forming step is a step of depositing a metal to a thickness of 100 to 150 nm by using a sputtering method or an evaporation method.

  The metal nanoparticle formation step and the first-type silicon nanowire growth step may be performed using an inductively coupled plasma CVD apparatus or a VHF plasma CVD apparatus (very high frequency-chemical vapor).

  The metal nanoparticle formation step and the first type silicon nanowire growth step proceed continuously using an inductively coupled plasma CVD apparatus or a VHF plasma CVD apparatus.

The metal nanoparticle forming step includes a process temperature of 200 to 400 ° C., a process pressure of 80 to 150 mTorr, a hydrogen (H ₂ ) gas flow rate of 100 to 300 sccm, a plasma power of 500 to 700 W, a susceptor power of 30 to 50 W, and The metal thin film layer is formed on the metal nanoparticles using the inductively coupled plasma CVD apparatus under process conditions including a process time of 30 to 90 minutes.

  The metal nanoparticle formation step includes the VHF plasma under process conditions including a process temperature of 200 to 400 ° C., a process pressure of 0.05 to 0.2 Torr, a plasma power of 40 to 60 W, and a process time of 30 to 60 minutes. It is a step of forming the metal thin film layer on metal nanoparticles using a CVD apparatus.

The first-type silicon nanowire growth step includes a process temperature of 200 to 400 ° C., a process pressure of 70 to 80 mTorr, a silane gas ratio of 0.1 to 0.2, a plasma power of 500 to 700 W, a susceptor power of 30 to 50 W, And using the inductively coupled plasma CVD apparatus under process conditions including a process time of 1 to 20 minutes, and the silane gas ratio is a ratio of the silane gas in a mixed gas of silane (SiH ₄ ) gas and hydrogen gas. .

  The first-type silicon nanowire growth step includes a process temperature of 200 to 400 ° C., a process pressure of 0.05 to 0.2 Torr, a silane gas ratio of 0.4 to 0.6, a plasma power of 40 to 60 W, and 30 to In this step, the VHF plasma CVD apparatus is used under process conditions including a process time of 60 minutes, and the silane gas ratio is a ratio of the silane gas in a mixed gas of silane gas and hydrogen gas.

  The silicon nanowire has a length of 2 to 5 μm and a diameter of 1 to 5 nm.

  After the first type silicon nanowire growth step, a residual metal removal step of removing metal remaining on the substrate is included.

  According to the configuration of the present invention, all the objects of the present invention described above can be achieved. Specifically, according to the present invention, there is an effect of providing a method for manufacturing silicon nanowires.

  In addition, according to the present invention, there is an effect of providing a method of forming a seed layer using low-temperature and high-density plasma and manufacturing silicon nanowires using the seed layer.

  Furthermore, according to this invention, there exists an effect which provides the method of manufacturing a solar cell including the method of manufacturing a silicon nanowire.

1 is a cross-sectional view illustrating a solar cell according to an embodiment of the present invention. FIG. 5 is a cross-sectional view illustrating a solar cell according to another embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating a solar cell according to still another embodiment of the present invention. 3 is a flowchart illustrating a method for manufacturing a first-type silicon nanowire according to an embodiment of the present invention. It is a flowchart which shows the manufacturing method of the solar cell by one embodiment of this invention. 5 is a flowchart showing a method for manufacturing a solar cell according to another embodiment of the present invention. 5 is a flowchart showing a method for manufacturing a solar cell according to still another embodiment of the present invention.

  Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view illustrating a solar cell according to an embodiment of the present invention.

Referring to FIG. 1, a solar cell 100 according to an embodiment of the present invention includes a substrate 110, a first ⁺⁺ type polycrystalline silicon layer 120, a first type silicon nanowire layer 130, an intrinsic layer 140, a second type. A doping layer 150, a TCO layer 160, an antireflection film 170, and a front electrode 180 are included.

  At this time, the first type is a P type and the second type is an N type. In contrast, the first type may be an N type and the second type may be a P type.

  On the other hand, “++” in the first type or the second type displayed with “++” indicates the degree of doping with a P-type or N-type impurity, and the first type without “+” or Compared to the second type, it means that more impurities are doped in the first type or the second type indicated with “+”, and the first type indicated with “++”. Or, it means that more impurities are doped as compared with the first type or the second type indicated with “+” in the second type.

  The substrate 110 may be an opaque substrate such as a transparent insulating substrate or a metal foil substrate through which sunlight can be transmitted.

  When the substrate 110 is made of a transparent insulating substrate, the substrate 110 can be made of a glass substrate or plastic.

For the case where the substrate 110 comprises a metal foil substrate is insulating and the first ^{++ -} type poly-Si layer 120 which is provided on the substrate 110, the first ^{++ -} type poly-Si layer and the substrate 110 120 may be provided with an insulating layer.

The first ⁺⁺ type polycrystalline silicon layer 120 is provided on one side surface of the substrate 110.

The first ⁺⁺ type polycrystalline silicon layer 120 is provided as a polycrystalline silicon layer doped with a first type at a high concentration.

The first ⁺⁺ type polycrystalline silicon layer 120 is made of polycrystalline silicon doped with a high concentration of the first type and serves as a back electrode.

The first ⁺⁺ type polycrystalline silicon layer 120 serves as a seed layer on which the first type silicon nanowires of the first type silicon nanowire layer 130 are grown.

The first type silicon nanowire layer 130 is a first type silicon nanowire grown in a predetermined region of the first ⁺⁺ type polycrystalline silicon layer 120. That is, the first-type silicon nanowire layer 130 is grown on a predetermined region of the first ^++- type polycrystalline silicon layer 120 by a metal induced crystallization method or a laser crystallization method. It consists of type 1 silicon nanowires.

  The first type silicon nanowires constituting the first type silicon nanowire layer 130 may have a length of 2 to 5 μm and a diameter of 1 to 5 nm. This is because the first type silicon nanowire of the first type silicon nanowire layer 130 serves to absorb light when sunlight is incident. That is, the first-type silicon nanowires are preferably formed to have a length and a diameter of 2 to 5 μm and 1 to 5 nm that can absorb most sunlight.

The intrinsic layer 140 is formed by the first-type silicon nanowire layer 130 and the surface of the first ^++- type polycrystalline silicon layer 120 where the first-type silicon nanowire is not grown, that is, the first-type silicon nanowire layer 130 is formed. The substrate 110 is provided.

  The intrinsic layer 140 is made of intrinsic silicon that is not doped with a first-type or second-type impurity.

  The intrinsic layer 140 may be made of various forms of intrinsic silicon, but is preferably made of a hydrogenated amorphous silicon layer, that is, an α-Si: H layer.

  The intrinsic layer 140 also serves to passivate the first type silicon nanowire layer 130.

  The intrinsic layer 140 may be formed using a chemical vapor deposition apparatus or a physical vapor deposition apparatus. Preferably, the intrinsic layer 140 may be formed by an inductively coupled plasma enhanced chemical vapor deposition apparatus.

  When the intrinsic layer 140 is deposited by the inductively coupled plasma enhanced chemical vapor deposition apparatus, a mixed gas containing hydrogen gas and silane gas is used. The ratio of the silane gas to the hydrogen gas is 8 to 10, and the process pressure is It is preferably formed by vapor deposition under process conditions of 70 to 90 mtorr, process power of 200 to 300 W, and process temperature of 250 to 350 ° C.

  When the intrinsic layer 140 is formed by the inductively coupled plasma enhanced chemical vapor deposition apparatus, interface characteristics between the layer in contact with the intrinsic layer 140, particularly the first-type silicon nanowire layer 130, are excellent.

  The second type doping layer 150 is provided on the intrinsic layer 140.

  The second type doping layer 150 includes a silicon layer doped with the second type.

The second-type doping layer 150 may include a 2 ⁺ -type doping layer, and may include a second-type doping layer having a second-type impurity concentration lower than that of the 2 ⁺ -type doping layer.

  The second type doping layer 150 may be formed using a chemical vapor deposition apparatus such as a plasma enhanced chemical vapor deposition apparatus or a physical vapor deposition apparatus.

  The TCO (Transparent Conducting Oxide) layer 160 is provided on the second type doping layer 150.

  The TCO layer 160 may be a transparent conductive oxide such as ZnO (zinc oxide), aluminum-doped ZnO film AZO (aluminum zinc oxide), ITO (indium tin oxide), and SnO2: F. It can consist of a substance.

  The TCO layer 160 is preferably formed to a thickness of at least 5 μm, and may be a physical vapor deposition apparatus such as a sputtering apparatus or a metal organic chemical vapor deposition apparatus (MOCVD). It can be formed using a chemical vapor deposition apparatus or the like.

  The antireflection film 170 is provided on the TCO layer 160, and a part of the TCO layer 160 is exposed.

  The antireflection film 170 is a component that prevents incident sunlight from being reflected and emitted to the outside, and serves to increase the efficiency of photoelectric conversion of the solar cell 100.

  The anti-reflection layer 170 may be a material such as a silicon nitride layer (SiN).

  The front electrode 180 is disposed on a part of the TCO layer 160 exposed by the antireflection film 170 so as to be in contact with the TCO layer 160.

  The front electrode 180 is made of a conductive material such as aluminum (Al) or silver (Ag).

  The front electrode 180 has a thickness of 0.2 to 1 μm, preferably 0.5 μm.

  The front electrode 180 is provided in a patterned form.

  FIG. 2 is a cross-sectional view illustrating a solar cell according to another embodiment of the present invention.

Referring to FIG. 2, a solar cell 200 according to another embodiment of the present invention includes a substrate 210, a TCO layer 220, a first ⁺⁺ type polycrystalline silicon layer 230, a first type silicon nanowire layer 240, and an intrinsic layer 250. , The second type doping layer 260, and the back electrode 270.

  The substrate 210 may be a transparent insulating substrate through which sunlight can be transmitted.

  The substrate 210 may be made of a glass substrate or plastic.

  The TCO layer 220 is provided on one surface of the substrate 210.

  The TCO layer 220 may be made of a transparent conductive oxide such as ZnO, AZO, ITO, and SnO 2: F.

  The TCO layer 220 may be formed using a physical vapor deposition apparatus such as a sputtering apparatus or a chemical vapor deposition apparatus such as a metal organic chemical vapor deposition apparatus.

The first ⁺⁺ type polycrystalline silicon layer 230 is provided on the TCO layer 220.

The first ⁺⁺ type polycrystalline silicon layer 230 is provided as a polycrystalline silicon layer doped with a high concentration of the first type.

In addition, the first ⁺⁺ type polycrystalline silicon layer 230 serves as a seed layer on which the first type silicon nanowires of the first type silicon nanowire layer 240 are grown.

The first type silicon nanowire layer 240 is formed of a first type silicon nanowire grown in a predetermined region of the first ⁺⁺ type polycrystalline silicon layer 230. That is, the first type silicon nanowire layer 240 is formed of a first type silicon nanowire grown in a predetermined region of the first ⁺⁺ type polycrystalline silicon layer 230 by a metal induced crystallization method or a laser crystallization method.

  The first type silicon nanowire constituting the first type silicon nanowire layer 240 may have a length of 2 to 5 μm and a diameter of 1 to 5 nm. This is because the first type silicon nanowire of the first type silicon nanowire layer 240 functions to absorb light when sunlight is incident. That is, the first-type silicon nanowires are preferably formed to have a length and a diameter of 2 to 5 μm and 1 to 5 nm that can absorb most sunlight.

The intrinsic layer 250 is provided on the surface of the first type silicon nanowire layer 240 and the first ⁺⁺ type polycrystalline silicon layer 240 on which the first type silicon nanowire is not grown.

  The intrinsic layer 250 is made of intrinsic silicon that is not doped with a first-type or second-type impurity.

  The intrinsic layer 250 may be made of various forms of intrinsic silicon, but is preferably made of a hydrogenated amorphous silicon layer, that is, an α-Si: H layer.

  The intrinsic layer 250 has a thickness of 400 to 600 μm, preferably 500 μm.

  The intrinsic layer 250 also serves to passivate the first type silicon nanowire layer 240.

  The intrinsic layer 250 may be formed using a chemical vapor deposition apparatus or a physical vapor deposition apparatus. Preferably, the intrinsic layer 250 can be formed by an inductively coupled plasma enhanced chemical vapor deposition apparatus.

  When the intrinsic layer 250 is deposited by the inductively coupled plasma chemical vapor deposition apparatus, a mixed gas containing hydrogen gas and silane gas is used, and the ratio of silane gas to hydrogen gas is 8 to 10, and the process pressure is It is preferably formed by vapor deposition under process conditions of 70 to 90 mtorr, process power of 200 to 300 W, and process temperature of 250 to 350 ° C.

  When the intrinsic layer 250 is formed by the inductively coupled plasma enhanced chemical vapor deposition apparatus, the interface characteristics between the layer in contact with the intrinsic layer 250, particularly the first-type silicon nanowire layer 240, are excellent.

  The second type doping layer 260 is provided on the intrinsic layer 250.

  The second type doping layer 260 comprises a silicon layer doped with the second type.

The second type doping layer 260 may include a second ⁺ type doping layer, and may include a second type doping layer having a second type impurity concentration lower than that of the second ⁺ type doping layer.

  The second type doping layer 260 may be formed by a chemical vapor deposition apparatus such as a plasma chemical vapor deposition apparatus or a physical vapor deposition apparatus.

  The second type doping layer 260 has a thickness of 10 to 15 nm, preferably 12 nm.

  The back electrode 270 is provided on the second type doping layer 260.

  The back electrode 270 is made of a conductive material such as aluminum or silver.

  The back electrode 270 is provided on the entire surface of the second type doping layer 260.

  The back electrode 270 also functions as an antireflection film for preventing incident sunlight from being reflected and emitted to the outside.

  When the back electrode 270 is formed of aluminum, it has a thickness of 200 to 400 nm, preferably 300 nm.

  FIG. 3 is a cross-sectional view illustrating a solar cell according to another embodiment of the present invention.

  Referring to FIG. 3, a solar cell 300 according to another embodiment of the present invention includes a substrate 310, a TCO layer 320, a top cell 330, a buffer layer 340, a bottom cell 350, and a back electrode 360.

The top cell 330 includes a first ⁺⁺ type polysilicon layer 332, a first type silicon nanowire layer 334, a top cell intrinsic layer 336, and a top cell second type doping layer 338.

  The bottom cell 350 includes a bottom cell first type doping layer 352, a bottom cell intrinsic layer 354, and a bottom cell second type doping layer 356.

  The substrate 310 may be a transparent insulating substrate through which sunlight can be transmitted.

  The substrate 310 may be made of a glass substrate or plastic.

  The TCO layer 320 is provided on one surface of the substrate 310.

  The TCO layer 320 may be made of a transparent conductive oxide such as ZnO, AZO, ITO, and SnO 2: F.

The first ⁺⁺ type polysilicon layer 332 is provided on the TCO layer 320.

The first ⁺⁺ type polycrystalline silicon layer 332 is provided as a polycrystalline silicon layer doped with the first type at a high concentration.

The first ⁺⁺ type polysilicon layer 332 serves as a seed layer on which the first type silicon nanowires of the first type silicon nanowire layer 334 are grown.

The first type silicon nanowire layer 334 includes a first type silicon nanowire grown in a predetermined region of the first ⁺⁺ type polycrystalline silicon layer 332. That is, the first type silicon nanowire layer 332 is formed of a first type silicon nanowire grown in a predetermined region of the first ⁺⁺ type polycrystalline silicon layer 332 by a metal induced crystallization method or a laser crystallization method.

  The first type silicon nanowire constituting the first type silicon nanowire layer 334 may have a length of 2 to 5 μm and a diameter of 1 to 5 nm. This is because the first type silicon nanowire of the first type silicon nanowire layer 334 serves to absorb light when sunlight is incident. That is, the first-type silicon nanowires are preferably formed to have a length and a diameter of 2 to 5 μm and 1 to 5 nm that can absorb most sunlight.

The top cell intrinsic layer 336 is provided on the surface of the first type silicon nanowire layer 334 and the first ⁺⁺ type polycrystalline silicon layer 332 on which the first type silicon nanowire is not grown.

  The top cell intrinsic layer 336 is made of intrinsic silicon that is not doped with a first-type or second-type impurity.

  The top cell intrinsic layer 336 may be formed of various forms of intrinsic silicon, but is preferably formed of a hydrogenated amorphous silicon layer, that is, an α-Si: H layer.

  At this time, the top cell intrinsic layer 336 may have the same form as the intrinsic layer 250 described with reference to FIG.

  The top cell intrinsic layer 336 also serves to passivate the first type silicon nanowire layer 334.

  The top cell intrinsic layer 336 may be formed by a chemical vapor deposition apparatus or a physical vapor deposition apparatus. Preferably, the top cell intrinsic layer 336 can be formed by an inductively coupled plasma enhanced chemical vapor deposition apparatus.

  When the top cell intrinsic layer 336 is deposited by the inductively coupled plasma enhanced chemical vapor deposition apparatus, a mixed gas containing hydrogen gas and silane gas is used, but the ratio of silane gas to hydrogen gas is 8 to 10, Preferably, the pressure is 70 to 90 mtorr, the process power is 200 to 300 W, and the process temperature is 250 to 350.degree.

  When the top cell intrinsic layer 336 is formed by the inductively coupled plasma enhanced chemical vapor deposition apparatus, the interface property between the layer in contact with the top cell intrinsic layer 336, particularly the first type silicon nanowire layer 334 is Become excellent.

  The top cell intrinsic layer 336 has a thickness of 400 to 600 μm, preferably 500 μm.

  The top cell second type doping layer 338 is provided on the top cell intrinsic layer 336.

  The top cell second type doping layer 338 includes a silicon layer doped with a second type impurity.

  At this time, the top cell second type doping layer 338 may have the same form as the second type doping layer 260 described with reference to FIG.

The top cell second type doping layer 338 may be formed of a second ⁺ type doping layer, and may be formed of a second type doping layer having a second type impurity concentration lower than that of the second + type doping layer. .

  The top cell second type doping layer 338 may be formed by a chemical vapor deposition apparatus such as a plasma chemical vapor deposition apparatus or a physical vapor deposition apparatus.

  The buffer layer 340 is provided on the top cell second type doping layer 338.

  The buffer layer 340 serves to electrically connect the top cell 330 and the bottom cell 350.

  In the buffer layer 340, the top cell 330 and the bottom cell 350, in particular, the top cell second type doping layer 338 of the top cell 330 and the bottom first type doping layer 352 of the bottom cell 350 form a tunnel junction. To play a role.

  The buffer layer 340 also serves to adjust the band gap between the top cell 330 and the bottom cell 350.

  The buffer layer 340 is preferably made of a transparent conductive material such as ZnO.

  The bottom cell first type doping layer 352 is provided on the buffer layer 340.

The bottom cell first type doping layer 352 may be formed of a first ⁺ type doping layer, and may be formed of a second type doping layer having a second type impurity concentration lower than that of the first ⁺ type doping layer. .

  The bottom cell first type doping layer 352 may be formed by a chemical vapor deposition apparatus such as a plasma chemical vapor deposition apparatus or a physical vapor deposition apparatus.

  The bottom cell intrinsic layer 354 is disposed on the bottom cell first type doping layer 352.

  The bottom cell intrinsic layer 354 is made of intrinsic silicon that is not doped with a first-type or second-type impurity.

  The bottom cell intrinsic layer 354 may be made of various forms of intrinsic silicon, but is preferably made of a hydrogenated fine crystalline silicon layer, that is, a μc-Si: H layer.

  The bottom cell intrinsic layer 354 can be formed by a chemical vapor deposition apparatus or a physical vapor deposition apparatus.

  The bottom cell intrinsic layer 354 has a thickness of 1 to 2 μm.

  The bottom cell second type doping layer 356 is provided on the bottom cell intrinsic layer 354.

  The bottom cell second type doping layer 356 includes a silicon layer doped with a second type impurity.

The bottom cell second type doping layer 356 may be formed of a second ⁺ type doping layer, and may be formed of a second type doping layer having a second type impurity concentration lower than that of the second ⁺ type doping layer. .

  The bottom cell second type doping layer 356 may be formed by a chemical vapor deposition apparatus such as a plasma chemical vapor deposition apparatus or a physical vapor deposition apparatus.

  The back electrode 360 is provided on the second type doping layer 356.

  The back electrode 360 is made of a conductive material such as aluminum or silver.

  FIG. 4 is a flowchart illustrating a method for manufacturing a first-type silicon nanowire according to an embodiment of the present invention.

Referring to FIG. 4, a method for manufacturing a first type silicon nanowire according to an embodiment of the present invention includes a first ⁺⁺ type polycrystalline silicon layer forming step (S110) and a metal thin film layer forming step (S120). A metal nanoparticle formation step (S130), a first-type silicon nanowire growth step (S140), and a residual metal removal step (S150).

The first ⁺⁺ type polycrystalline silicon layer forming step (S110) is a step of forming a first ⁺⁺ type polycrystalline silicon layer on the substrate.

In the first ⁺⁺ type polycrystalline silicon layer, a silicon layer doped with a high concentration of the first type is crystallized into polycrystalline.

The first ⁺⁺ type polycrystalline silicon layer forming step (S110) may form the first ⁺⁺ type polycrystalline silicon layer by various methods.

In this embodiment, one of the methods for forming the first ⁺⁺ type polycrystalline silicon layer is introduced.

The first ⁺⁺ type polycrystalline silicon layer is formed by forming a first ⁺⁺ type amorphous silicon layer on the substrate and performing a crystallization method such as a metal induced crystallization method or a laser crystallization method. The first ⁺⁺ type silicon layer may be used to form the first ⁺⁺ type polycrystalline silicon layer.

At this time, a general silicon layer forming method can be used to form the first ⁺⁺ type amorphous silicon layer. That is, the first ⁺⁺ type amorphous silicon layer can be formed on the substrate 110 using a chemical vapor deposition apparatus such as a plasma enhanced chemical vapor deposition apparatus or an inductively coupled plasma CVD apparatus.

After the first ⁺⁺ type polycrystalline silicon layer forming step (S110), the metal thin film layer forming step (S120) is performed.

The metal thin film layer forming step (S120) is a step of forming a metal layer by depositing a metal on the first ⁺⁺ type polycrystalline silicon layer using a sputtering method or a vapor deposition method.

  The metal thin film layer forming step (S120) deposits the metal layer to a thickness of 100 to 150 nm.

  The metal thin film layer forming step (S120) forms the metal layer, and is preferably a step of forming the metal layer so that the metal of the metal layer is deposited at a low density. This is because the metal layer can be easily changed to metal nanoparticles in the metal nanoparticle formation step (S130).

  The metal of the metal thin film layer includes at least one of Au, In, Ga, and Sn.

  After the metal thin film layer forming step (S120), the metal nanoparticle forming step (S130) is performed.

  The metal nanoparticle formation step (S130) is a step of changing the metal thin film layer into metal nanoparticles.

  In the metal nanoparticle formation step (S130), the metal nanoparticles are formed using an inductively coupled plasma CVD apparatus or a VHF plasma CVD apparatus.

  When the inductively coupled plasma CVD apparatus is used in the metal nanoparticle formation step (S130), a process temperature of 200 to 400 ° C., a process pressure of 80 to 150 mTorr, a hydrogen gas flow rate of 100 to 300 sccm, a plasma power of 500 to 700 W, The metal nanoparticles may be formed under process conditions including a susceptor power of 30 to 50 W and a process time of 30 to 90 minutes.

  In the metal nanoparticle formation step (S130), when the VHF plasma CVD apparatus is used, a process temperature of 200 to 400 ° C., a process pressure of 0.05 to 0.2 Torr, a plasma power of 40 to 60 W, and 30 to 30 are used. It may be a step of forming the metal nanoparticles under process conditions including a process time of 60 minutes.

  After the metal nanoparticle formation step (S130), the first-type silicon nanowire growth step (S140) is performed.

  The first type silicon nanowire growth step (S140) is a step of growing the first type silicon nanowire, more precisely the first type silicon nanowire, using an inductively coupled plasma CVD apparatus or a VHF plasma CVD apparatus.

In the first type silicon nanowire growth step (S140), the first type silicon nanowire is formed using the first ⁺⁺ type polycrystalline silicon layer on which the metal nanoparticles are formed in the metal nanoparticle formation step (S130) as a seed layer. Is a step to grow.

That is, metal nanoparticles formed on the first ⁺⁺ type polycrystalline silicon layer act as a seed for crystal growth, and the first type silicon nanowire is grown from the first ⁺⁺ type polycrystalline silicon layer. The

  In the first type silicon nanowire growth step (S140), when the inductively coupled plasma CVD apparatus is used, a process temperature of 200 to 400 ° C., a process pressure of 70 to 80 mTorr, a silane gas ratio of 0.1 to 0.2, and 500 to The step of growing the first-type silicon nanowires under process conditions including a plasma power of 700 W, a susceptor power of 30 to 50 W, and a process time of 1 to 20 minutes.

  The first-type silicon nanowire growth step (S140) may be performed at a process temperature of 200 to 400 ° C., a process pressure of 0.05 to 0.2 Torr, and a pressure of 0.4 to 0.6 when using the VHF plasma CVD apparatus. In this step, the first-type silicon nanowires are grown under process conditions including a silane gas ratio, a plasma power of 40 to 60 W, and a process time of 30 to 60 minutes.

At this time, the silane gas ratio in the step of growing the first-type silicon nanowires using the inductively coupled plasma CVD apparatus and the VHF plasma CVD apparatus is the ratio of the silane gas to the mixed gas of silane gas and hydrogen gas (SiH ₄ / (SiH ₄ + H ₂ )).

The metal nanoparticle formation step (S130) and the first type silicon nanowire growth step (S140) may be continuously performed using the inductively coupled plasma CVD apparatus and the VHF plasma CVD apparatus. That is, the metal thin film layer provided on the first ⁺⁺ type polycrystalline silicon layer is changed to metal nanoparticles, and the first type silicon nanowire is changed from the first ⁺⁺ type polycrystalline silicon layer using the metal nanoparticles. The process of growing can be performed as a continuous process in the inductively coupled plasma CVD apparatus or the VHF plasma CVD apparatus.

  At this time, the first type silicon nanowire grown in the first type silicon nanowire growth step (S140) has a length of 2 to 5 μm and a diameter of 1 to 5 nm.

  After the first-type silicon nanowire growth step (S140), the residual metal removal step (S150) is performed.

  In the residual metal removal step (S150), after the first-type silicon nanowire growth step (S140), the metal remaining on the substrate, particularly the first-type silicon nanowire layer made of the first-type silicon nanowire is etched. This is a step of removing by a wet process.

  At this time, the remaining metal may be a part of the metal thin film layer or a part of the metal nanoparticles.

  FIG. 5 is a flowchart showing a method for manufacturing a solar cell according to an embodiment of the present invention.

Referring to FIG. 5, a method for manufacturing a solar cell according to an embodiment of the present invention includes a first ⁺⁺ type polycrystalline silicon layer forming step (S210), a first type silicon nanowire layer forming step (S220), and an intrinsic property. It includes a layer forming step (S230), a second doping layer forming step (S240), a TCO layer forming step (S250), an antireflection film forming step (S260), and a front electrode forming step (S270).

  The method for manufacturing the solar cell according to the present embodiment will be described focusing on the method for manufacturing the solar cell 100 described with reference to FIG.

The first ⁺⁺ type polycrystalline silicon layer forming step (S <b> 210) is a step of forming the first ⁺⁺ type polycrystalline silicon layer 120 on the substrate 110.

First, before forming the first ⁺⁺ type polycrystalline silicon layer 120 on the substrate 110, the substrate 110 is prepared by cleaning. At this time, the process of cleaning the substrate 110 may be a process of removing organic substances, metals, oxides, and the like remaining on the substrate 110. A process used in a general semiconductor manufacturing process can be used as a process of removing organic substances, metals, oxides, and the like remaining on the substrate 110.

Next, the first ⁺⁺ type polycrystalline silicon layer 120 is formed on the substrate 110.

The first ⁺⁺ type polycrystalline silicon layer 120 is formed on the substrate 110 by using the same method as the first ⁺⁺ type polycrystalline silicon layer forming step (S110) described with reference to FIG. Detailed description will be omitted.

After the first ⁺⁺ type polycrystalline silicon layer forming step (S210), the first type silicon nanowire layer forming step (S220) is performed.

The first-type silicon nanowire layer forming step (S220) is a step of forming the first-type silicon nanowire layer 130 by growing the first-type silicon nanowire on the first ^++- type polycrystalline silicon layer 120.

The first type silicon nanowire layer forming step (S220) includes the metal thin film layer forming step (S120), the metal nanoparticle forming step (S130), and the first type silicon nanowire growth step (S140) described with reference to FIG. , And the residual metal removal step (S150) are sequentially performed to grow the first type silicon nanowire from the first ⁺⁺ type polycrystalline silicon layer 120 to form the first type silicon nanowire layer 130. Detailed description is omitted.

  After the first-type silicon nanowire layer forming step (S220), the intrinsic layer forming step (S230) is performed.

In the intrinsic layer forming step (S230), the intrinsic layer 140 is formed on the surface of the first type silicon nanowire layer 130 and the first ⁺⁺ type polycrystalline silicon layer 120 where the first type silicon nanowire is not grown. It is.

  In the intrinsic layer forming step (S230), the intrinsic layer 140 made of various types of intrinsic silicon that is not doped with the first-type or second-type impurities can be formed. Preferably, the hydrogenated amorphous silicon layer is formed. That is, it is preferable to form an intrinsic layer 140 made of an α-Si: H layer.

  The intrinsic layer forming step (S230) may be a step of forming the intrinsic layer 140 using a chemical vapor deposition apparatus or a physical vapor deposition apparatus, preferably an inductively coupled plasma chemical vapor deposition apparatus.

  In the intrinsic layer forming step (S230), when the inductively coupled plasma enhanced chemical vapor deposition apparatus is used, a mixed gas containing hydrogen gas and silane gas is used, but the ratio of silane gas to hydrogen gas is 8 to 10, The intrinsic layer 140 is preferably formed under process conditions of a process pressure of 70 to 90 mtorr, a process power of 200 to 300 W, and a process temperature of 250 to 350 ° C.

  After the intrinsic layer forming step (S230), the second doping layer forming step (S240) is performed.

  The second doping layer forming step (S240) is a step of forming the second type doping layer 150 on the intrinsic layer 140.

In the second type doping layer forming step (S240), silicon doped with a second type impurity or a second ⁺ type impurity by a chemical vapor deposition apparatus such as a plasma chemical vapor deposition apparatus or a physical vapor deposition apparatus is used. It may be a step of forming the second type doping layer 150 as a layer.

  After the second-type doping layer forming step (S240), the TCO layer forming step (S250) is performed.

  The TCO layer forming step (S250) is a step of forming the TCO layer 160 on the second type doping layer 150.

In the TCO layer forming step (S250), at least the TCO layer 160 made of a material such as ZnO, AZO, ITO, and SnO ₂ : F is formed on the second-type doping layer 150. This is a step of forming a thickness of 5 μm or more.

  The TCO layer forming step (S250) is a step of forming the TCO layer 160 using a physical vapor deposition apparatus such as a sputtering apparatus or a chemical vapor deposition apparatus such as a metal organic chemical vapor deposition apparatus. possible.

  After the TCO layer forming step (S250), the antireflection film forming step (S260) is performed.

  The antireflection film forming step (S260) is a step of forming the antireflection film 170 on the TCO layer 160 using a material such as a silicon nitride film.

  The antireflection film forming step (S260) may be a step of forming the antireflection film 170 by two methods.

  The first method is a method of forming the antireflection film 170 on the entire surface of the TCO layer 160, and the second method is the method of forming the antireflection film 170 on the TCO layer 160. In this method, the antireflection film 170 is patterned so that a predetermined region of the layer 160 is exposed.

  After the antireflection film formation step (S270), the front electrode formation step (S270) is performed.

  In the front electrode forming step (S270), a conductive material such as aluminum or silver is formed in contact with the TCO layer 160, and the front electrode 180 is formed in a patterned form.

  The front electrode forming step (S270) may be a step of forming by two methods similar to the antireflection film forming step (S260).

  In the first method, when the antireflection film 170 is formed over the entire surface of the TCO layer 160, a paste for forming a front electrode is applied on a predetermined region of the antireflection film 170, that is, after a pattern shape is applied. Then, the front electrode 180 may be formed by firing and etching the antireflection film 170 to contact the TCO layer 160.

  At this time, the front electrode forming paste includes an etching material capable of etching the anti-reflection layer 170 as well as aluminum or silver as a material constituting the front electrode 280.

  A second method is to deposit the front electrode 180 in a patterned form on the exposed TCO layer 160 when the anti-reflective coating 170 is provided on the TCO layer 160 in a patterned form. It can be a method. That is, it may be a method of forming the patterned front electrode 180 using a pattern mask method or the like.

  At this time, the front electrode forming step (S270) is a step of forming the front electrode 180 to a thickness of 0.2 to 1 μm, preferably 0.5 μm.

  FIG. 6 is a flowchart illustrating a method of manufacturing a solar cell according to another embodiment of the present invention.

Referring to FIG. 6, a method for manufacturing a solar cell according to another embodiment of the present invention includes a TCO layer forming step (S310), a first ⁺⁺ type polycrystalline silicon layer forming step (S320), and a first type. A silicon nanowire layer forming step (S330), an intrinsic layer forming step (S340), a second type doping layer forming step (S350), and a back electrode forming step (S360) are included.

  The method for manufacturing the solar cell according to the present embodiment will be described focusing on the method for manufacturing the solar cell 200 described with reference to FIG.

  The TCO layer forming step (S310) is a step of forming the TCO layer 220 on the substrate 210.

  First, before forming the TCO layer 220 on the substrate 210, the substrate 210 is cleaned and prepared.

  At this time, the method for cleaning the substrate 210 may be the same as the method for cleaning the substrate 110 described with reference to FIG.

  Further, the TCO layer forming step (S310) can be formed on the substrate 210 by the same method as the TCO layer forming step (S250) described with reference to FIG. Is omitted.

After the TCO layer formation step (S310), a first ⁺⁺ type polycrystalline silicon layer formation step (S320) is performed.

The ^{first ++ -} type poly-Si layer formed step (S320) is a step of forming a ^{first ++ -} type poly-Si layer 230 on the TCO layer 220, a ^{first ++ -} type described with reference to FIG. 5 Since the same method as the polycrystalline silicon layer forming step (S220) can be used, detailed description thereof is omitted.

After the first ⁺⁺ type polycrystalline silicon layer forming step (S320), the first type silicon nanowire layer forming step (S330) is performed.

The first-type silicon nanowire layer forming step (S330) is a step of growing the first-type silicon nanowire from the first ^++- type polycrystalline silicon layer 230 to form the first-type silicon nanowire layer 240, Since the same method as the first-type silicon nanowire forming step (S220) described with reference to FIG. 5 can be used, detailed description thereof is omitted.

  After the first-type silicon nanowire layer forming step (S330), the intrinsic layer forming step (S340) is performed.

  The intrinsic layer forming step (S340) is a step of forming the intrinsic layer 250 on the substrate on which the first-type silicon nanowire layer 240 is grown to a thickness of 400 to 600 μm, preferably 500 μm, see FIG. However, since the same method can be used except that the thickness of the intrinsic layer 250 to be formed can be different from the intrinsic layer forming step (S230) described above, detailed description thereof will be omitted.

  After the intrinsic layer forming step (S340), the second type doping layer forming step (S350) is performed.

  The second type doping layer forming step (S350) is a step of forming a second type doping layer 260 on the intrinsic layer 250.

  The second type doping layer forming step (S350) is a step of forming the second type doping layer 260 to a thickness of 10 to 15 nm, preferably 12 nm. The second type doping layer described with reference to FIG. Since the same method can be used except that the thickness of the formed second type doping layer 260 can be different from that of the layer forming step (S240), detailed description is omitted.

  After the second-type doping layer forming step (S350), the back electrode forming step (S360) is performed.

  The back electrode forming step (S360) is a step of forming the back electrode 270 on the second type doping layer 260.

  The back electrode forming step (S360) is a step of forming the back electrode 270 to a thickness of 200 to 400 nm, preferably 300 nm, when the back electrode 270 is formed of aluminum.

  The back electrode forming step (S360) is a step of forming the back electrode 270 made of a conductive material such as aluminum or silver on the second type doping layer 260 by using a sputtering method or a vapor deposition method.

  FIG. 7 is a flowchart illustrating a method for manufacturing a solar cell according to another embodiment of the present invention.

Referring to FIG. 7, a method for manufacturing a solar cell according to another embodiment of the present invention includes a TCO layer forming step (S410), a first ⁺⁺ type polycrystalline silicon layer forming step (S422), and a first method. Type silicon nanowire layer formation step (S424), top cell intrinsic layer formation step (S426), top cell second type doping layer formation step (S428), buffer layer formation step (S430), bottom cell first type doping layer formation step ( S442), bottom cell intrinsic layer forming step (S444), bottom cell second type doping layer forming step (S446), and back electrode forming step (S450).

  The method for manufacturing the solar cell according to the present embodiment will be described focusing on the method for manufacturing the solar cell 300 described with reference to FIG.

  The TCO layer forming step (S410) is a step of forming a TCO layer 320 on the substrate 310.

  First, before forming the TCO layer 320 on the substrate 310, the substrate 310 is cleaned and prepared.

  At this time, the method for cleaning the substrate 310 may be the same as the method for cleaning the substrate 110 described with reference to FIG.

  Further, the TCO layer forming step (S410) can be formed on the substrate 310 by the same method as the TCO layer forming step (S250) described with reference to FIG. .

After the TCO layer forming step (S410), the first ⁺⁺ type polycrystalline silicon layer forming step (S422), the first type silicon nanowire layer forming step (S424), the top cell intrinsic layer forming step (S426), and the top The cell second type doping layer forming step (S428) is sequentially performed.

The first ⁺⁺ type polycrystalline silicon layer forming step (S422), the first type silicon nanowire layer forming step (S424), the top cell intrinsic layer forming step (S426), and the top cell second type doping layer forming step (S428). each has, the TCO layer 320 forming the ^{first ++ -} type poly-Si layer 332 on the ^{first ++ -} type poly-Si layer 332 silicon nano said wire is grown first-type silicon nano wire layer 334 from Forming a bottom cell intrinsic layer 336 on the substrate on which the first-type silicon nanowire layer 334 is formed, and forming a bottom cell doping layer 338 on the bottom cell intrinsic layer 336, see FIG. The first ⁺⁺ type polycrystalline silicon layer forming step (S210) explained while Since it can be formed by the same method as the silicon nanowire layer forming step (S220), the intrinsic layer forming step (S230), and the second type doping layer forming step (S240), detailed description is omitted.

  After the top cell second-type doping layer forming step (S428), the buffer layer forming step (S430) is performed.

  The buffer layer forming step (S430) is a step of forming a buffer layer 340 that allows a tunnel junction to be formed between the top cell 330 formed in the above step and the bottom cell 350 formed thereafter.

  The buffer layer forming step (S430) is a step of forming the buffer layer 340 on the second-type doping layer 338 using a chemical vapor deposition apparatus or a physical vapor deposition apparatus.

  After the buffer layer forming step (S430), the bottom cell first type doping layer forming step (S442) is performed.

  The bottom cell first type doping layer forming step (S442) is a step of forming the bottom cell first type doping layer 352 on the buffer layer 340.

  The bottom cell first type doping layer forming step (S442) is a step of forming a silicon layer doped with the first type on the buffer layer 340.

At this time, the bottom cell first-type doping layer 352 may include a first ⁺ -type doping layer, and may include a first-type doping layer having a lower first-type impurity concentration than the first ⁺ -type doping layer. be able to.

  In the bottom cell first type doping layer forming step (S442), the bottom cell first type doping layer 352 is formed using a chemical vapor deposition apparatus such as a plasma chemical vapor deposition apparatus or a physical vapor deposition apparatus. It can be.

  After the bottom cell first type doping layer forming step (S442), the bottom cell intrinsic layer forming step (S444) is performed.

  In the bottom cell intrinsic layer forming step (S444), the bottom cell intrinsic layer 354 made of a hydrogenated fine crystalline silicon layer, that is, a μc-Si: H layer, is formed on the bottom cell first type doping layer 352 by 1 to 2 μm. This is a step of forming a thickness.

  The bottom cell intrinsic layer forming step (S444) may directly form the bottom cell intrinsic layer 354 including the hydrogenated fine crystalline silicon layer using an inductively coupled plasma enhanced chemical vapor deposition apparatus. Forming a hydrogenated amorphous silicon layer on the layer 352 and then microcrystallizing the hydrogenated amorphous silicon layer using a crystallization method to form a bottom cell intrinsic layer 354 composed of the hydrogenated microcrystalline silicon layer; It can be. At this time, the crystallization method may be performed by selecting any one of various methods such as a heat treatment crystallization method, a laser crystallization method, and a metal catalyst crystallization method.

  After the bottom cell intrinsic layer forming step (S444), the bottom cell second type doping layer forming step (S446) is performed.

  The bottom cell second type doping layer forming step (S446) is a step of forming the bottom cell second type doping layer 356 on the bottom cell intrinsic layer 354, and the second type doping layer forming step described with reference to FIG. Since it can be formed by the same method as (S230), detailed description is omitted.

  After the bottom cell second type doping layer forming step (S446), the back electrode forming step (S450) is performed.

  The back electrode forming step (S450) is a step of forming the back electrode 360 on the bottom cell second type doping layer 356, and is the same method as the back electrode forming step (S360) described with reference to FIG. Since it can be formed, detailed description is omitted.

  The present invention has been described above by taking the embodiment described above as an example, but the present invention is not limited to this. A person having ordinary knowledge in the technical field to which the present invention pertains can make corrections and changes without departing from the spirit and scope of the present invention. Such corrections and changes also belong to the present invention. You will understand that there is.

110, 210, 310 Substrate 120, 230, 332 First ⁺⁺ type polycrystalline silicon layer 130, 240, 334 First type silicon nanowire layer

Claims (30)

A substrate,
A first ⁺⁺ type polycrystalline silicon layer provided on the substrate;
A first type silicon nanowire layer including a first type silicon nanowire grown from the first ⁺⁺ type polycrystalline silicon layer;
An intrinsic layer provided on a substrate provided with the first-type silicon nanowire layer;
And a second type doping layer provided on the intrinsic layer. The solar cell is
A TCO layer provided on the second type doping layer;
An antireflective film provided on the TCO layer and exposing a predetermined region of the TCO layer;
The solar cell according to claim 1, further comprising: a front electrode provided in a patterned form on a predetermined region of the exposed TCO layer. The solar cell is
A TCO layer provided between the substrate and a first ⁺⁺ type polysilicon layer;
The solar cell according to claim 1, further comprising a back electrode provided on the second type doping layer. The intrinsic layer is a top cell intrinsic layer;
The second type doping layer is a top cell second type doping layer;
The solar cell is
A buffer layer provided on the top cell second type doping layer;
A bottom cell first type doping layer provided on the buffer layer;
A bottom cell intrinsic layer provided on the bottom cell first type doping layer;
A bottom cell second type doping layer provided on the bottom cell intrinsic layer;
The solar cell according to claim 1, further comprising a back electrode provided on the bottom cell second type doping layer.   The solar cell of claim 1, wherein the first-type silicon nanowire has a length of 2 to 5 µm and a diameter of 1 to 5 nm. A first ^{++ -} type poly-Si layer formation step of forming a first ^{++ -} type poly-Si layer on a substrate,
A metal thin film layer forming step of forming a metal thin film layer on the first ⁺⁺ type polycrystalline silicon layer;
A metal nanoparticle forming step of forming the metal thin film layer into metal nanoparticles;
A first-type silicon nanowire growth step of growing a first-type silicon nanowire from the first ^++- type polycrystalline silicon layer using the metal nanoparticles as a seed.   The metal thin film layer forming step is a step of depositing a metal using a sputtering method or an evaporation method, and depositing the metal to a thickness of 100 to 150 nm. The silicon nanowire formation method as described.   The method according to claim 7, wherein the metal includes one or more of Au, In, Ga, and Sn.   The metal nanoparticle formation step and the first-type silicon nanowire growth step may be performed using an inductively coupled plasma chemical vapor deposition apparatus or a VHF plasma CVD apparatus (very high frequency-chemical vapor deposition). The method for forming silicon nanowires according to claim 6.   10. The method of forming a silicon nanowire according to claim 9, wherein the metal nanoparticle formation step and the first type silicon nanowire growth step proceed continuously using an inductively coupled plasma CVD apparatus or a VHF plasma CVD apparatus. The metal nanoparticle forming step includes a process temperature of 200 to 400 ° C., a process pressure of 80 to 150 mTorr, a hydrogen (H ₂ ) gas flow rate of 100 to 300 sccm, a plasma power of 500 to 700 W, a susceptor power of 30 to 50 W, and 10. The method of forming a silicon nanowire according to claim 9, wherein the metal thin film layer is formed on metal nanoparticles using the inductively coupled plasma CVD apparatus under process conditions including a process time of 30 to 90 minutes. .   The metal nanoparticle formation step includes the VHF plasma under process conditions including a process temperature of 200 to 400 ° C., a process pressure of 0.05 to 0.2 Torr, a plasma power of 40 to 60 W, and a process time of 30 to 60 minutes. The method of forming a silicon nanowire according to claim 9, wherein the metal thin film layer is formed on metal nanoparticles using a CVD apparatus. The first-type silicon nanowire growth step includes a process temperature of 200 to 400 ° C., a process pressure of 70 to 80 mTorr, a silane gas ratio of 0.1 to 0.2, a plasma power of 500 to 700 W, a susceptor power of 30 to 50 W, And using the inductively coupled plasma CVD apparatus under process conditions including a process time of 1 to 20 minutes,
The method of forming a silicon nanowire according to claim 9, wherein the silane gas ratio is a ratio of the silane gas in a mixed gas of silane (SiH ₄ ) gas and hydrogen gas. The first-type silicon nanowire growth step includes a process temperature of 200 to 400 ° C., a process pressure of 0.05 to 0.2 Torr, a silane gas ratio of 0.4 to 0.6, a plasma power of 40 to 60 W, and 30 to Using the VHF plasma CVD apparatus under process conditions including a process time of 60 minutes,
The method of forming a silicon nanowire according to claim 9, wherein the silane gas ratio is a ratio of the silane gas in a mixed gas of silane gas and hydrogen gas.   The method according to claim 6, wherein the silicon nanowire has a length of 2 to 5 μm and a diameter of 1 to 5 nm. After the first type silicon nanowire growth step,
The method of forming a silicon nanowire according to claim 6, further comprising a residual metal removing step of removing the metal remaining on the substrate. In the method for manufacturing a solar cell,
A first ^{++ -} type poly-Si layer formation step of forming a first ^{++ -} type poly-Si layer on a substrate,
A metal thin film layer forming step of forming a metal thin film layer on the first ⁺⁺ type polycrystalline silicon layer;
A metal nanoparticle forming step of forming the metal thin film layer into metal nanoparticles;
A first-type silicon nanowire growth step of growing a first-type silicon nanowire from the first ^++- type polycrystalline silicon layer using the metal nanoparticles as a seed. After the first type silicon nanowire growth step,
An intrinsic layer forming step of forming an intrinsic layer on the substrate on which the first-type silicon nanowires are grown;
A second type doping layer forming step of forming a second type doping layer on the intrinsic layer;
A TCO layer forming step of forming a TCO layer on the second type doping layer;
An antireflection film forming step of forming an antireflection film on the TCO layer;
The method for manufacturing a solar cell according to claim 17, further comprising: a front electrode forming step of forming a front electrode on the antireflection film. Before the first ⁺⁺ type polycrystalline silicon layer forming step,
Forming a TCO layer on the substrate;
After the first type silicon nanowire growth step,
An intrinsic layer forming step of forming an intrinsic layer on the substrate on which the first-type silicon nanowires are grown;
A second type doping layer forming step of forming a second type doping layer on the intrinsic layer;
The method for manufacturing a solar cell according to claim 17, further comprising a back electrode forming step of forming a back electrode on the second type doping layer. Before the first ⁺⁺ type polycrystalline silicon layer forming step,
Forming a TCO layer on the substrate;
After the first type silicon nanowire growth step,
A top cell intrinsic layer forming step of forming a top cell intrinsic layer on the substrate on which the first-type silicon nanowires are grown;
A top cell second type doping layer forming step of forming a top cell second type doping layer on the top cell intrinsic layer;
A buffer layer forming step of forming a buffer layer on the top cell second type doping layer;
A bottom cell first type doping layer forming step of forming a bottom cell first type doping layer on the buffer layer;
A bottom cell intrinsic layer forming step of forming a bottom cell intrinsic layer on the bottom cell first type doping layer;
A bottom cell second type doping layer forming step of forming a bottom cell second type doping layer on the bottom cell intrinsic layer;
The method for manufacturing a solar cell according to claim 17, further comprising: a back electrode forming step of forming a back electrode on the bottom cell second type doping layer.   18. The method of manufacturing a solar cell according to claim 17, wherein the metal thin film layer forming step is a step of depositing a metal using a sputtering method or a vapor deposition method to a thickness of 100 to 150 nm.   The method for manufacturing a solar cell according to claim 21, wherein the metal includes at least one of Au, In, Ga, and Sn.   18. The method of manufacturing a solar cell according to claim 17, wherein the metal nanoparticle formation step and the first type silicon nanowire growth step use an inductively coupled plasma CVD apparatus or a VHF plasma CVD apparatus.   24. The method of manufacturing a solar cell according to claim 23, wherein the metal nanoparticle formation step and the first type silicon nanowire growth step proceed continuously.   The metal nanoparticle formation step includes a process temperature of 200 to 400 ° C., a process pressure of 80 to 150 mTorr, a hydrogen gas flow rate of 100 to 300 sccm, a plasma power of 500 to 700 W, a susceptor power of 30 to 50 W, and a time of 30 to 90 minutes. 24. The method for manufacturing a solar cell according to claim 23, wherein the metal thin film layer is formed on the metal nanoparticles using the inductively coupled plasma CVD apparatus under process conditions including the following process time.   The metal nanoparticle formation step includes the VHF plasma under process conditions including a process temperature of 200 to 400 ° C., a process pressure of 0.05 to 0.2 Torr, a plasma power of 40 to 60 W, and a process time of 30 to 60 minutes. The method of manufacturing a solar cell according to claim 23, wherein the metal thin film layer is formed into metal nanoparticles using a CVD apparatus. The first-type silicon nanowire growth step includes a process temperature of 200 to 400 ° C., a process pressure of 70 to 80 mTorr, a silane gas ratio of 0.1 to 0.2, a plasma power of 500 to 700 W, a susceptor power of 30 to 50 W, And using the inductively coupled plasma CVD apparatus under process conditions including a process time of 1 to 20 minutes,
The method for manufacturing a solar cell according to claim 23, wherein the silane gas ratio is a ratio of the silane gas in a mixed gas of silane gas and hydrogen gas. The first-type silicon nanowire growth step includes a process temperature of 200 to 400 ° C., a process pressure of 0.05 to 0.2 Torr, a silane gas ratio of 0.4 to 0.6, a plasma power of 40 to 60 W, and 30 to Using the VHF plasma CVD apparatus under process conditions including a process time of 60 minutes,
The method for manufacturing a solar cell according to claim 23, wherein the silane gas ratio is a ratio of the silane gas in a mixed gas of silane gas and hydrogen gas.   The method of claim 17, wherein the first type silicon nanowire has a length of 2 to 5 μm and a diameter of 1 to 5 nm. After the first type silicon nanowire growth step,
The method for manufacturing a solar cell according to claim 17, further comprising a residual metal removing step of removing metal remaining on the substrate.

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