TW201925551A - Method for manufacturing polysilicon layer, heterojunction solar cell and manufacturing method thereof - Google Patents

Abstract

A method for manufacturing a polysilicon layer including following steps is provided. A substrate is provided. A microcrystalline silicon seed layer is formed on a substrate, wherein the microcrystalline silicon seed layer includes microcrystalline silicon seeds. An amorphous silicon layer is formed on the microcrystalline silicon seed layer. The amorphous silicon layer is melted, and the molten amorphous silicon layer recrystallizes on the microcrystalline silicon seeds to form a polysilicon layer.

Description

Method for manufacturing polycrystalline germanium layer, heterojunction solar cell and manufacturing method thereof

The present invention relates to a method of fabricating a semiconductor layer, a solar cell structure, and a method of fabricating the same, and more particularly to a method of fabricating a polysilicon layer, a heterojunction solar cell, and a method of fabricating the same.

At present, since the grain size of low-temperature polycrystalline germanium cannot be greatly improved, in order to form a preferred low-temperature polycrystalline germanium structure, a sequential lateral solidification (SLS), a phase shift mask (Phase Shift Mask) and a non- Process such as floating alpha-Si layer. However, the use of these methods requires additional equipment, which increases the cost of equipment for the process and is less likely to be integrated into existing processes.

The invention provides a method for manufacturing a polycrystalline germanium layer, which can reduce equipment investment cost and is easy to integrate with existing processes.

The present invention provides a heterojunction solar cell and a method of fabricating the same that can have better photoelectric conversion efficiency.

The present invention provides a method of manufacturing a polycrystalline germanium layer comprising the following steps. A substrate is provided. Forming a microcrystalline germanium seed layer on the substrate, wherein the microcrystalline germanium seed layer comprises a plurality of microcrystalline germanium seed crystals. An amorphous germanium layer is formed on the microcrystalline germanium seed layer. The amorphous germanium layer is melted, and the molten amorphous germanium layer is recrystallized on the microcrystalline germanium seed crystal to form a polycrystalline germanium layer.

According to an embodiment of the present invention, in the method of manufacturing the polysilicon layer, the substrate is, for example, a semiconductor substrate, a glass substrate, a plastic substrate, or a stainless steel substrate.

According to an embodiment of the present invention, in the method for fabricating the polysilicon layer, the method for forming the microcrystalline germanium seed layer is, for example, a plasma enhanced chemical vapor deposition (PECVD) method in which multi-point electromagnetic wave is fed.

According to an embodiment of the present invention, in the method for fabricating the polysilicon layer, the method of forming the amorphous germanium layer is, for example, a plasma enhanced chemical vapor deposition method.

According to an embodiment of the present invention, in the method for fabricating the polysilicon layer, the method of melting the amorphous germanium layer is, for example, an annealing process.

According to an embodiment of the present invention, in the method for fabricating the polysilicon layer, the annealing process is, for example, a laser annealing process.

The present invention provides a heterojunction solar cell comprising a first doped substrate, a first intrinsic semiconductor layer, at least one polysilicon layer, a second doped semiconductor layer, a first doped semiconductor layer, and a first transparent electrode. a film, a second transparent electrode film, a first electrode and a second electrode. The first doped substrate has opposing first and second surfaces. The first intrinsic semiconductor layer is disposed on the first surface. The polysilicon layer is disposed on the first intrinsic semiconductor layer. The second doped semiconductor layer is disposed on the polysilicon layer. The first doped semiconductor layer is disposed on the second surface. The first transparent electrode film is disposed on the second doped semiconductor layer. The second transparent electrode film is disposed on the first doped semiconductor layer. The first electrode is disposed on the first transparent electrode film. The second electrode is disposed on the second transparent electrode film.

According to an embodiment of the present invention, in the heterojunction solar cell, the polysilicon layer may be a first doped polysilicon layer, a second doped polysilicon layer, or a combination thereof.

According to an embodiment of the present invention, in the heterojunction solar cell, a second intrinsic semiconductor layer is further included. The second intrinsic semiconductor layer is disposed between the first doped substrate and the first doped semiconductor layer.

The invention provides a method for manufacturing a heterojunction solar cell, comprising the following steps. A first doped substrate is provided. The first doped substrate has opposing first and second surfaces. A first intrinsic semiconductor layer is formed on the first surface. At least one polysilicon layer is formed on the first intrinsic semiconductor layer. A second doped semiconductor layer is formed on the polysilicon layer. A first doped semiconductor layer is formed on the second surface. A first transparent electrode film is formed on the second doped semiconductor layer. A second transparent electrode film is formed on the first doped semiconductor layer. A first electrode is formed on the first transparent electrode film. A second electrode is formed on the second transparent electrode film.

According to an embodiment of the present invention, in the method for fabricating a heterojunction solar cell, the polysilicon layer may be a first doped polysilicon layer, a second doped polysilicon layer, or a combination thereof.

According to an embodiment of the present invention, in the method of fabricating a heterojunction solar cell, the method of forming a polysilicon layer includes the following steps. A microcrystalline germanium seed layer is formed. The microcrystalline germanium seed layer includes a plurality of microcrystalline germanium seed crystals. An amorphous germanium layer is formed on the microcrystalline germanium seed layer. The amorphous germanium layer is melted, and the molten amorphous germanium layer is recrystallized on the microcrystalline germanium seed crystal to form a polycrystalline germanium layer.

According to an embodiment of the present invention, in the method of manufacturing a heterojunction solar cell, the method further includes forming a second intrinsic semiconductor layer between the first doped substrate and the first doped semiconductor layer.

Based on the above, in the method for producing a polycrystalline germanium layer proposed by the present invention, after the amorphous germanium layer is melted, a temperature gradient is generated between the molten amorphous germanium layer and the microcrystalline germanium crystal seed, thereby making the molten amorphous The tantalum layer is recrystallized on the lower temperature microcrystalline seed crystals, whereby the polycrystalline germanium layer can be formed at lower process temperatures. In addition, since the molten amorphous germanium layer has sufficient time for directional crystallization, a polycrystalline germanium layer having a preferable crystal structure can be formed, so that the polycrystalline germanium layer can have better electrical properties and stability. In addition, since the polycrystalline germanium layer manufacturing method proposed by the present invention can produce a polycrystalline germanium layer having a better crystal structure without adding additional equipment, the equipment investment cost can be reduced, and integration with an existing process can be easily performed.

On the other hand, in the heterojunction solar cell and the method of manufacturing the same according to the present invention, since the polysilicon layer disposed between the first intrinsic semiconductor layer and the second doped semiconductor layer can function as a light absorbing layer, It can effectively increase the open circuit voltage (Voc) and short circuit current (Jsc), thereby improving the photoelectric conversion efficiency of the heterojunction solar cell.

The above described features and advantages of the invention will be apparent from the following description.

1 is a flow chart showing the manufacture of a polysilicon layer according to an embodiment of the present invention. 2A to 2B are cross-sectional views showing a manufacturing process of a polysilicon layer according to an embodiment of the present invention.

Referring to FIG. 1 and FIG. 2A, step S100 is performed to provide the substrate 100. The substrate 100 is, for example, a semiconductor substrate, a glass substrate, a plastic substrate, or a stainless steel substrate. In addition, a desired film layer may be formed on the substrate 100 depending on the product requirements.

Next, in step S102, a microcrystalline germanium seed layer 102 is formed on the substrate 100, wherein the microcrystalline germanium seed layer 102 includes a plurality of microcrystalline germanium seed crystals 102a. In addition, the microcrystalline germanium seed layer 102 may further include an amorphous germanium material 102b. The amorphous germanium material 102b covers the microcrystalline germanium seed crystal 102a. The method of forming the microcrystalline germanium seed layer 102 is, for example, a plasma enhanced chemical vapor deposition method in which multi-point electromagnetic waves are fed, whereby a regular microcrystalline twin seed crystal 102a can be formed.

Then, in step S104, an amorphous germanium layer 104 is formed on the microcrystalline germanium seed layer 102. The method of forming the amorphous germanium layer 104 is, for example, a chemical vapor deposition method such as a plasma enhanced chemical vapor deposition method.

Referring to FIG. 1 and FIG. 2B, step S106 is performed to melt the amorphous germanium layer 104, and the molten amorphous germanium layer 104 is recrystallized on the microcrystalline germanium seed crystal 102a to form a polycrystalline germanium layer 106. In step S106, the amorphous germanium material 102b may be simultaneously melted and recrystallized on the microcrystalline seed crystal 102a in accordance with actual process conditions and desired characteristics to form a polycrystalline germanium layer 106. Thereby, the polysilicon layer 106 can be formed at a lower process temperature, and thus the polysilicon layer 106 can be a low temperature polysilicon layer. The method of melting the amorphous germanium layer 104 is, for example, an annealing process such as a laser annealing process. The laser beam used in the laser annealing process is, for example, a quasi-molecular laser beam such as a xenon chloride (XeCl) laser beam or krypton fluoride (KrF).

Based on the above embodiments, it is known that after the amorphous germanium layer 104 is melted, a temperature gradient is generated between the molten amorphous germanium layer 104 and the microcrystalline germanium seed crystal 102a, so that the molten amorphous germanium layer 104 is at a lower temperature. The microcrystalline germanium seed crystal 102a is recrystallized, whereby the polycrystalline germanium layer 106 can be formed at a lower process temperature. In addition, since the molten amorphous germanium layer 104 has sufficient time for directional crystallization, the polycrystalline germanium layer 106 having a preferred crystal structure can be formed, so that the polycrystalline germanium layer 106 can have better electrical properties and stability. In addition, since the above-described method for manufacturing the polysilicon layer 106 can produce the polycrystalline germanium layer 106 having a better crystal structure without adding additional equipment, the investment cost of the device can be reduced, and integration with an existing process can be easily performed.

3 is a perspective view of a heterojunction solar cell according to an embodiment of the present invention.

Hereinafter, a method of manufacturing the heterojunction solar cell 200 of the present embodiment will be described with reference to FIG.

A first doped substrate 202 is provided. The first doped substrate 202 has opposing first and second surfaces S1 and S2. The first doping type and the second doping type are different doping types, and may be one of the N type and the P type, respectively. In this embodiment, the first doping type is described by taking the N type as an example, and the second doping type is described by taking the P type as an example, but the invention is not limited thereto. In another embodiment, the first doping type may be a P type, and the second doping type may be an N type. The substrate 110 is, for example, a semiconductor substrate such as a germanium substrate. In this embodiment, the substrate 110 is described by taking an N-type single crystal germanium substrate as an example.

A first intrinsic semiconductor layer 204 is formed on the first surface S1. The material of the first intrinsic type semiconductor layer 204 is, for example, an amorphous germanium. The formation method of the first intrinsic type semiconductor layer 204 is, for example, a chemical vapor deposition method such as a plasma enhanced chemical vapor deposition method.

At least one polysilicon layer 206 is formed on the first intrinsic semiconductor layer 204. The polysilicon layer 206 can function as a light absorbing layer, so that the photoelectric conversion efficiency of the heterojunction solar cell 200 can be effectively improved. The polysilicon layer 206 can be a single layer structure or a multilayer structure. The polysilicon layer 206 may be a first doped polysilicon layer (eg, an N-type doped polysilicon layer), a second doped polysilicon layer (eg, a P-type doped polysilicon layer), or a combination thereof. In this embodiment, the polysilicon layer 206 is exemplified by a single layer structure of a second doped polysilicon layer (eg, a P-type doped polysilicon layer). In other embodiments, in the case where the polysilicon layer 206 is a multilayer structure, the polysilicon layer 206 may be an alternately arranged first doped polysilicon layer (eg, an N-type doped polysilicon layer) and a second doped polysilicon layer. A stacked structure of layers (eg, a P-type doped polysilicon layer) forms a battery cell in series in the heterojunction solar cell 200.

Additionally, the polysilicon layer 206 can be a low temperature polysilicon layer. The method of forming the polysilicon layer 206 may be carried out by the above-described method of forming the polysilicon layer 106 described in FIG. 1, FIG. 2A and FIG. 2B, and the description thereof will not be repeated. In addition, in the case where the polysilicon layer 206 has a multilayer structure, step S102 (forming a microcrystalline germanium seed layer), step S104 (forming an amorphous germanium layer), and step S106 (making an amorphous germanium layer) in FIG. 1 may be repeatedly performed. Melt and recrystallize on the microcrystalline seed crystal to form a polycrystalline germanium layer). In the method of forming the polysilicon layer 206, the doping profile of the polysilicon layer 206 can be determined by adjusting the deposition gas.

A second doped semiconductor layer 208 is formed on the polysilicon layer 206. The material of the second doped semiconductor layer 208 is, for example, an amorphous germanium. In this embodiment, the second doped semiconductor layer 208 is exemplified by a P-type amorphous germanium layer. The method of forming the second doped semiconductor layer 208 is, for example, a chemical vapor deposition method such as a plasma enhanced chemical vapor deposition method.

The second intrinsic semiconductor layer 210 may be selectively formed on the second surface S2. The material of the second intrinsic semiconductor layer 210 is, for example, an amorphous germanium. The method of forming the second intrinsic type semiconductor layer 210 is, for example, a chemical vapor deposition method such as a plasma enhanced chemical vapor deposition method.

A first doped semiconductor layer 212 is formed on the second intrinsic semiconductor layer 210. The material of the first doped semiconductor layer 212 is, for example, amorphous germanium. In this embodiment, the first doped semiconductor layer 212 is exemplified by an N-type amorphous germanium layer. The formation method of the first doped semiconductor layer 212 is, for example, a chemical vapor deposition method such as a plasma enhanced chemical vapor deposition method.

A first transparent electrode film 214 may be formed on the second doped semiconductor layer 208, and a second transparent electrode film 216 may be formed on the first doped semiconductor layer 212. The first transparent electrode film 214 and the second transparent electrode film 216, respectively, can be used to increase the collection efficiency of current. The material of the first transparent electrode film 214 and the second transparent electrode film 216 may be a transparent conductive oxide (TCO), for example, a metal oxide such as indium tin oxide (ITO). The method of forming the first transparent electrode film 214 and the second transparent electrode film 216 is, for example, a sputtering method or a vapor deposition method.

A first electrode 218 may be formed on the first transparent electrode film 214, and a second electrode 220 may be formed on the second transparent electrode film 216. The first electrode 218 and the second electrode 220 can be used to take out electric power generated by the heterojunction solar cell 200. The material of the first electrode 218 and the second electrode 220 is, for example, a metal such as aluminum, copper, gold or silver. In this embodiment, the first electrode 218 and the second electrode 220 are described by taking a grid electrode as an example, but the invention is not limited thereto. In another embodiment, in a case where the first surface S1 is a light incident surface, the second electrode 220 may also be a whole electrode structure covering the second transparent electrode film 216.

Hereinafter, the structure of the heterojunction solar cell 200 of the present embodiment will be described with reference to FIG.

Referring to FIG. 3, the heterojunction solar cell 200 includes a first doped substrate 202, a first intrinsic semiconductor layer 204, at least one polysilicon layer 206, a second doped semiconductor layer 208, and a first doped semiconductor layer. 212, and further comprising at least one of the second intrinsic semiconductor layer 210, the first transparent electrode film 214, the second transparent electrode film 216, the first electrode 218, and the second electrode 220. The first doped substrate 202 has an opposite first surface S1 and a first surface S2. The first intrinsic semiconductor layer 204 is disposed on the first surface S1. The polysilicon layer 206 is disposed on the first intrinsic semiconductor layer 204. The second doped semiconductor layer 208 is disposed on the polysilicon layer 206. The first doped semiconductor layer 212 is disposed on the first surface S2. The second intrinsic semiconductor layer 210 is disposed between the first doped substrate 202 and the first doped semiconductor layer 212. The first transparent electrode film 214 is disposed on the second doped semiconductor layer 208. The second transparent electrode film 216 is disposed on the first doped semiconductor layer 212. The first electrode 218 is disposed on the first transparent electrode film 214. The second electrode 220 is disposed on the second transparent electrode film 216.

In addition, the materials, aspects, formation methods, and effects of the members in the heterojunction solar cell 200 have been described in detail in the above embodiments, and the description thereof will not be repeated.

Based on the above embodiments, in the heterojunction solar cell 200 and the method of fabricating the same, the polysilicon layer 206 disposed between the first intrinsic semiconductor layer 204 and the second doped semiconductor layer 208 can function as a light absorbing layer. Therefore, the open circuit voltage and the short circuit current can be effectively improved, thereby improving the photoelectric conversion efficiency of the heterojunction solar cell 200.

In summary, the method for fabricating the polysilicon layer of the above embodiment can form a polycrystalline germanium layer having a better crystal structure at a lower process temperature, so that the polycrystalline germanium layer can have better electrical properties and stability. In addition, the method for manufacturing the polysilicon layer of the above embodiment can produce a polycrystalline germanium layer having a better crystal structure without adding additional equipment, thereby reducing equipment investment cost and easily integrating with existing processes.

On the other hand, in the heterojunction solar cell of the above embodiment and the method of manufacturing the same, the photoelectric conversion efficiency of the heterojunction solar cell can be effectively improved by using the polysilicon layer as the light absorbing layer.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧Substrate

102‧‧‧Microcrystalline germanium seed layer

102a‧‧‧Microcrystalline seed crystal

102b‧‧‧Amorphous material

104‧‧‧Amorphous layer

106‧‧‧Polysilicon layer

200‧‧‧Hexual junction solar cells

202‧‧‧First doped substrate

204‧‧‧First Intrinsic Semiconductor Layer

206‧‧‧Polysilicon layer

208‧‧‧Second doped semiconductor layer

210‧‧‧Second essential semiconductor layer

212‧‧‧First doped semiconductor layer

214‧‧‧First transparent electrode film

216‧‧‧Second transparent electrode film

218‧‧‧First electrode

220‧‧‧second electrode

S1‧‧‧ first surface

S2‧‧‧ second surface

S100, S102, S104, S106‧‧‧ steps

1 is a flow chart showing the manufacture of a polysilicon layer according to an embodiment of the present invention. 2A to 2B are cross-sectional views showing a manufacturing process of a polysilicon layer according to an embodiment of the present invention. 3 is a perspective view of a heterojunction solar cell according to an embodiment of the present invention.

Claims (13)

A method for manufacturing a polycrystalline germanium layer, comprising: providing a substrate; forming a microcrystalline germanium seed layer on the substrate, wherein the microcrystalline germanium seed layer comprises a plurality of microcrystalline germanium seed crystals; Forming an amorphous germanium layer on the seed layer; and melting the amorphous germanium layer, and the molten amorphous germanium layer is recrystallized on the plurality of microcrystalline germanium crystal seeds to form a polycrystalline germanium layer. The method for producing a polysilicon layer according to claim 1, wherein the substrate comprises a semiconductor substrate, a glass substrate, a plastic substrate or a stainless steel substrate. The method for producing a polycrystalline germanium layer according to claim 1, wherein the method for forming the microcrystalline germanium seed layer comprises a plasma enhanced chemical vapor deposition method in which a plurality of electromagnetic waves are fed. The method for producing a polycrystalline germanium layer according to claim 1, wherein the method for forming the amorphous germanium layer comprises a plasma enhanced chemical vapor deposition method. The method for producing a polycrystalline germanium layer according to claim 1, wherein the method of melting the amorphous germanium layer comprises performing an annealing process. The method for producing a polysilicon layer according to claim 5, wherein the annealing process comprises a laser annealing process. A heterojunction solar cell comprising: a first doped substrate having opposite first and second surfaces; a first intrinsic semiconductor layer disposed on the first surface; at least one polysilicon layer disposed on a first doped semiconductor layer; a second doped semiconductor layer disposed on the at least one polysilicon layer; a first doped semiconductor layer disposed on the second surface; a first transparent electrode film And disposed on the second doped semiconductor layer; a second transparent electrode film disposed on the first doped semiconductor layer; a first electrode disposed on the first transparent electrode film; Two electrodes are disposed on the second transparent electrode film. The heterojunction solar cell of claim 7, wherein the at least one polysilicon layer comprises a first doped polysilicon layer, a second doped polysilicon layer, or a combination thereof. The heterojunction solar cell according to claim 7, further comprising a second intrinsic semiconductor layer disposed between the first doped substrate and the first doped semiconductor layer. A method of manufacturing a heterojunction solar cell, comprising: providing a first doped substrate, wherein the first doped substrate has opposing first and second surfaces; forming a first on the first surface An intrinsic semiconductor layer; forming at least one polysilicon layer on the first intrinsic semiconductor layer; forming a second doped semiconductor layer on the at least one polysilicon layer; forming a first doping on the second surface Forming a first transparent electrode film on the second doped semiconductor layer; forming a second transparent electrode film on the first doped semiconductor layer; forming on the first transparent electrode film a first electrode; and a second electrode formed on the second transparent electrode film. The method of manufacturing a heterojunction solar cell according to claim 10, wherein the at least one polysilicon layer comprises a first doped polysilicon layer, a second doped polysilicon layer, or a combination thereof. The method for fabricating a heterojunction solar cell according to claim 10, wherein the method for forming the at least one polysilicon layer comprises: forming a microcrystalline germanium seed layer, wherein the microcrystalline germanium seed layer comprises a microcrystalline germanium seed crystal; forming an amorphous germanium layer on the microcrystalline germanium seed layer; and melting the amorphous germanium layer, and melting the amorphous germanium layer in the plurality of microcrystalline germanium The seed crystals are recrystallized to form a polycrystalline germanium layer. The method for manufacturing a heterojunction solar cell according to claim 10, further comprising forming a second intrinsic semiconductor layer between the first doped substrate and the first doped semiconductor layer.