TW201637225A - Solar cell and method for manufacturing thereof - Google Patents

Abstract

The present disclosure provides a solar cell including a photoelectric conversion substrate, an isolation layer, a passivation layer, a covering layer and a bottom electrode layer. The photoelectric conversion substrate has a bottom surface. The isolation layer is disposed underlying the bottom surface of the photoelectric conversion substrate. The passivation layer is disposed underlying the isolation layer. The covering layer is disposed underlying the passivation layer. The bottom electrode layer is disposed in the isolation layer, the passivation layer and the covering layer, and electrically connected the bottom surface of the photoelectric conversion substrate. A method for manufacturing the solar cell is also provided herein.

Description

Solar cell and method of manufacturing same

The present invention relates to a solar cell, and more particularly to a solar cell having an oxide layer formed by using an atmospheric-pressure plasma (AP-plasma) and a method of manufacturing the same.

At present, solar cells are mostly back-treated using passivated emitter and rear cell (PERC) technology to improve the stability and performance of solar cells. The so-called passivated emitter contact (PERC) technique forms a tantalum nitride (SiN _x ) layer or an aluminum oxide (A ₂ O ₃ ) layer on the back side of the solar cell to passivate the backside contact of the passivation layer as a passivation layer, thereby increasing The absorption of long-wavelength light, while at the same time maximizing the voltage difference between the PN contacts, to improve the photoelectric conversion efficiency of the solar cell.

However, the aluminum oxide layer in the passivated emitter contact technology forms an electric field passivation for the back side of the solar cell, which does not have any passivation effect on the dangling bonds of the tantalum substrate surface of the solar cell. The dangling bonds on the surface of the tantalum substrate of the above solar cell react with outside air and organic matter to form a highly active surface. This highly active surface causes the aluminum oxide layer to peel off from the surface of the tantalum substrate, and The back electric field of the solar substrate is disabled, thereby causing a decrease in the photoelectric conversion efficiency of the solar cell.

There is a need for a novel solar cell structure and method of fabricating the same that solves the problems associated with the structure of conventional solar cells.

In view of the problems faced by the prior art, the present invention discloses a novel solar cell and a method of fabricating the same that can improve the durability and photoelectric conversion efficiency of the solar cell.

One aspect of the present invention is to provide a solar cell. The solar cell includes a photoelectric conversion substrate, an isolation layer, a passivation layer, a cover layer, and a lower electrode layer. The photoelectric conversion substrate has a lower surface. The isolation layer is disposed under the lower surface of the photoelectric conversion substrate. The passivation layer is disposed under the isolation layer. The cover layer is disposed under the passivation layer. The lower electrode layer is disposed in the isolation layer, the passivation layer and the cover layer, and is electrically connected to the lower surface of the photoelectric conversion substrate.

According to an embodiment of the present invention, the photoelectric conversion substrate includes an N-type semiconductor layer and a P-type semiconductor layer.

According to an embodiment of the present invention, the P-type semiconductor layer is interposed between the N-type semiconductor layer and the isolation layer.

According to an embodiment of the invention, the photoelectric conversion substrate is a germanium substrate.

According to an embodiment of the invention, the isolation layer is an oxide layer.

According to an embodiment of the present invention, the above oxide layer is a cerium oxide (SiO _x ) layer.

According to an embodiment of the invention, the spacer layer has a thickness of about 1 to 2 nm.

According to an embodiment of the invention, the material of the passivation layer comprises aluminum oxide (Al ₂ O ₃ ).

According to an embodiment of the invention, the material of the cover layer comprises tantalum nitride (SiN _x ).

Another aspect of the present invention is to provide a method of fabricating a solar cell. The manufacturing method includes: forming a first type semiconductor layer on the second type semiconductor substrate; removing the first type semiconductor layer covering the edge of the second type semiconductor substrate, and exposing an edge of the second type semiconductor substrate; forming an isolation layer on Under the second type semiconductor substrate; forming a passivation layer under the isolation layer; and forming a cap layer under the passivation layer.

According to an embodiment of the invention, the first type semiconductor layer is an N type semiconductor layer, and the second type semiconductor substrate is a P type semiconductor substrate.

According to an embodiment of the present invention, the method of forming the first type semiconductor layer on the second type semiconductor substrate includes an evaporation method, a sputtering method, a printing method, a chemical vapor deposition method, or a physical vapor deposition method.

According to an embodiment of the present invention, the above method of removing the first type semiconductor layer covering the edge of the second type semiconductor substrate comprises a wet etching method.

According to an embodiment of the invention, the forming the isolation layer under the second type semiconductor substrate forms a tantalum oxide layer under the second type semiconductor substrate.

According to an embodiment of the invention, the above-mentioned isolation layer is formed in the second The method under the type semiconductor substrate includes an Atmospheric-pressure plasma (AP-plasma).

According to an embodiment of the invention, after removing the first type semiconductor layer covering the edge of the second type semiconductor substrate, the isolation layer is formed under the second type semiconductor substrate by using the atmospheric plasma method.

According to an embodiment of the invention, the passivation layer is formed under the isolation layer to form an aluminum oxide (Al ₂ O ₃ ) layer under the isolation layer.

According to an embodiment of the present invention, the method of forming the passivation layer under the isolation layer includes an evaporation method, a sputtering method, a printing method, a chemical vapor deposition method, or a physical vapor deposition method.

According to an embodiment of the invention, the forming the cap layer is formed under the passivation layer to form a tantalum nitride layer under the passivation layer.

According to an embodiment of the present invention, the method of forming the cap layer under the passivation layer includes an evaporation method, a sputtering method, a printing method, a chemical vapor deposition method, or a physical vapor deposition method.

100, 200‧‧‧ solar cells

110‧‧‧Photoelectric conversion substrate

110a‧‧‧lower surface

112‧‧‧P type semiconductor layer

114‧‧‧N type semiconductor layer

120, 220‧‧‧ isolation layer

130, 230‧‧‧ Passivation layer

140, 240‧‧ ‧ overlay

150‧‧‧ lower electrode layer

212‧‧‧Second type semiconductor substrate

212a‧‧‧ edge

214‧‧‧First type semiconductor layer

1 is a cross-sectional view of a solar cell according to an embodiment of the present invention; and FIGS. 2A-2E are cross-sectional views of a method for fabricating a solar cell according to an embodiment of the present invention. Figure.

The invention will now be described in detail by way of embodiments with reference to the drawings. In the drawings or the description, similar or identical parts are given the same symbols or numbers. In the drawings, the shape or thickness of the embodiments may be expanded to simplify or facilitate the labeling, and the parts of the elements in the drawings will be described in the text. It will be appreciated that elements not shown or described may be in a variety of styles known to those skilled in the art.

The terminology used herein is for the purpose of describing particular embodiments and is not intended to The singular forms "a", "the", "the" and "the" It is to be understood that the term "comprises" and / or "comprising" when used in the specification is intended to mean the presence of the described features, integers, steps, operations, components and/or components, but does not exclude the presence or addition. One or more other features, integers, steps, operations, components, components, and/or groups thereof. Embodiments of the present invention are described herein with reference to cross-section illustrations of the schematic illustration of the preferred embodiments (and intermediate structures) of the invention. As such, it is contemplated that the shapes of the descriptions may be varied, for example, from variations in manufacturing techniques and/or tolerances. Therefore, the embodiments of the invention should not be construed as being limited to the particular shapes of the embodiments described herein. The shapes of the devices are not intended to limit the actual shape of the device and are not intended to limit the scope of the invention.

In order to solve the problems faced by the prior art, the present invention discloses a novel solar cell and a method of fabricating the same that can improve the ability to resist electrical decay without affecting solar cell efficiency.

Figure 1 is a diagram of an embodiment of the present invention. A cross-sectional view of solar cell 100. In FIG. 1, the solar cell 100 includes a photoelectric conversion substrate 110, an isolation layer 120, a passivation layer 130, a cover layer 140, and a lower electrode layer 150.

The photoelectric conversion substrate 110 has a lower surface 110a. According to an embodiment of the present invention, the photoelectric conversion substrate 110 includes an N-type semiconductor layer 114 and a P-type semiconductor layer 112. According to an embodiment of the present invention, the photoelectric conversion substrate 110 is a germanium substrate.

The isolation layer 120 is disposed under the lower surface 110a of the photoelectric conversion substrate 110. According to an embodiment of the present invention, the P-type semiconductor layer 112 is interposed between the N-type semiconductor layer 114 and the isolation layer 120. According to an embodiment of the invention, the isolation layer 120 is an oxide layer. According to an embodiment of the present invention, the oxide layer is a silicon oxide (SiO _x) layer. According to an embodiment of the invention, the spacer layer 120 has a thickness of about 1 to 2 nanometers.

The passivation layer 130 is disposed under the isolation layer 120. According to an embodiment of the invention, the material of the passivation layer 130 comprises aluminum oxide (Al ₂ O ₃ ).

The cover layer 140 is disposed under the passivation layer 140. According to an embodiment of the present invention, the material layer 140 comprising silicon nitride covering (SiN _x).

The lower electrode layer 150 is disposed in the isolation layer 120, the passivation layer 130, and the cover layer 140, and is electrically connected to the lower surface 110a of the photoelectric conversion substrate 110.

2A-2E are cross-sectional views of various stages of a method of fabricating a solar cell according to an embodiment of the present invention.

In FIG. 2A, the first type semiconductor layer 214 is formed on the second type semiconductor substrate 212. First type semiconductor according to an embodiment of the present invention The layer 214 is an N-type semiconductor layer, and the second type semiconductor substrate 212 is a P-type semiconductor substrate. According to an embodiment of the present invention, the method of forming the first type semiconductor layer 214 on the second type semiconductor substrate 212 includes an evaporation method, a sputtering method, a printing method, a chemical vapor deposition method, or a physical vapor deposition method.

In FIG. 2B, the first type semiconductor layer 214 covering the edge 212a of the second type semiconductor substrate 212 in FIG. 2A is removed, and the edge 212a of the second type semiconductor substrate 212 is exposed. In accordance with an embodiment of the present invention, a method of removing a first type semiconductor layer 214 overlying an edge 212a of a second type semiconductor substrate 212 includes a wet etch process.

In FIG. 2C, the isolation layer 220 is formed under the second type semiconductor substrate 212. According to an embodiment of the present invention, the isolation layer 220 is formed under the second type semiconductor substrate 212 to form a tantalum oxide layer under the second type semiconductor substrate 212. According to an embodiment of the present invention, a method of forming the isolation layer 220 under the second type semiconductor substrate 212 includes an Atmospheric-pressure plasma (AP-plasma).

According to an embodiment of the present invention, after the first type semiconductor layer 214 covering the edge 212a of the second type semiconductor substrate 212 is removed, the isolation layer 220 is formed under the second type semiconductor substrate 212 by the atmospheric plasma method. According to an embodiment of the present invention, the upper surface of the first type semiconductor layer 214 is modified by atmospheric plasma method to reform the lower surface of the originally hydrophobic second type semiconductor substrate 212 into a hydrophilic cerium oxide. Layer (ie, isolation layer 220). According to an embodiment of the invention, the contact layer 220 has a contact angle of less than 10 degrees.

In FIG. 2D, a passivation layer 230 is formed under the isolation layer 220. According to an embodiment of the present invention, the passivation layer 230 is formed under the isolation layer 220 to form an aluminum oxide (Al ₂ O ₃ ) layer under the isolation layer 220. According to an embodiment of the present invention, the method of forming the passivation layer 230 under the isolation layer 220 includes an evaporation method, a sputtering method, a printing method, a chemical vapor deposition method, or a physical vapor deposition method.

In FIG. 2E, a capping layer 240 is formed under the passivation layer 230. According to an embodiment of the present invention, the cap layer 240 is formed under the passivation layer 230 to form a tantalum nitride layer under the passivation layer 230. According to an embodiment of the present invention, the method of forming the cap layer 240 under the passivation layer 230 includes an evaporation method, a sputtering method, a printing method, a chemical vapor deposition method, or a physical vapor deposition method.

Although the embodiments of the present invention have been disclosed as above, it is not intended to limit the present invention, and any person skilled in the art can make some modifications and retouchings without departing from the spirit and scope of the present invention. The scope is defined as defined in the scope of the patent application.

100‧‧‧ solar cells

110‧‧‧Photoelectric conversion substrate

110a‧‧‧lower surface

112‧‧‧P type semiconductor layer

114‧‧‧N type semiconductor layer

120‧‧‧Isolation

130‧‧‧ Passivation layer

140‧‧‧ Coverage

150‧‧‧ lower electrode layer

Claims (20)

A solar cell comprising: a photoelectric conversion substrate having a lower surface; an isolation layer disposed under the lower surface of the photoelectric conversion substrate; a passivation layer disposed under the isolation layer; a cover layer disposed on the passivation layer And a lower electrode layer disposed in the isolation layer, the passivation layer and the cover layer, and electrically connected to the lower surface of the photoelectric conversion substrate. The solar cell of claim 1, wherein the photoelectric conversion substrate comprises an N-type semiconductor layer and a P-type semiconductor layer. The solar cell of claim 2, wherein the P-type semiconductor layer is interposed between the N-type semiconductor layer and the isolation layer. The solar cell of claim 1, wherein the photoelectric conversion substrate is a germanium substrate. The solar cell of claim 1, wherein the separator is an oxide layer. The solar cell of claim 5, wherein the oxide layer is a tantalum oxide (SiO _x ) layer. The solar cell of claim 1, wherein the separator has a thickness of about 1 to 2 nm. The solar cell of claim 1, wherein the material of the passivation layer comprises aluminum oxide (Al ₂ O ₃ ). The solar cell of claim 1, wherein the material of the cover layer comprises tantalum nitride (SiN _x ). A method of manufacturing a solar cell, comprising: forming a first type semiconductor layer on a second type semiconductor substrate; removing the first type semiconductor layer covering an edge of the second type semiconductor substrate, and exposing the second The edge of the semiconductor substrate; forming an isolation layer under the second type semiconductor substrate; forming a passivation layer under the isolation layer; and forming a cap layer under the passivation layer. The manufacturing method according to claim 10, wherein the first type semiconductor layer is an N type semiconductor layer, and the second type semiconductor substrate is a P type semiconductor substrate. The manufacturing method according to claim 10, wherein the method of forming the first type semiconductor layer on the second type semiconductor substrate comprises an evaporation method, a sputtering method, a printing method, a chemical vapor deposition method, or a physical vapor deposition method. law. The manufacturing method of claim 10, wherein the method of removing the first type semiconductor layer covering the edge of the second type semiconductor substrate comprises a wet etching method. The method of claim 10, wherein forming the isolation layer under the second type semiconductor substrate forms a tantalum oxide layer under the second type semiconductor substrate. The method of claim 10, wherein the method of forming the isolation layer under the second type semiconductor substrate comprises an Atmospheric-pressure plasma (AP-plasma). The manufacturing method of claim 15, wherein after the first type semiconductor layer covering the edge of the second type semiconductor substrate is removed, the isolation layer is formed directly on the second type semiconductor by using an atmospheric plasma method Under the substrate. The method of claim 10, wherein the passivation layer is formed under the isolation layer to form an aluminum oxide (Al ₂ O ₃ ) layer under the isolation layer. The manufacturing method according to claim 10, wherein the method of forming the passivation layer under the spacer layer comprises an evaporation method, a sputtering method, a printing method, a chemical vapor deposition method, or a physical vapor deposition method. The manufacturing method of claim 10, wherein the covering layer is formed under the passivation layer to form a tantalum nitride layer under the passivation layer. The manufacturing method according to claim 10, wherein the method of forming the overcoat layer under the passivation layer comprises an evaporation method, a sputtering method, a printing method, a chemical vapor deposition method, or a physical vapor deposition method.