阅读说明：本技术 太阳能电池及其制作方法 (Solar cell and manufacturing method thereof ) 是由 梁建军 龙巍 郁操 刘霖 徐希翔 李沅民 于 2018-06-21 设计创作，主要内容包括：一种太阳能电池的制作方法,包括：在硅基底表面依次形成第一钝化层和第一掺杂层；在第一掺杂层表面形成第一电介质保护层；按预定图案利用激光刻蚀第一电介质保护层；以第一电介质保护层为掩模除去第一钝化层和第一掺杂层；在第一电介质保护层和露出的硅基底层上形成图案化的第二钝化层和第二掺杂层；在形成于硅基底层上的第二掺杂层上形成刻蚀阻挡层；除去形成于第一电介质保护层上的第二钝化层和第二掺杂层；除去第一电介质保护层和刻蚀阻挡层；形成第二电介质保护层；按预定图案利用激光刻蚀第二电介质保护层；最后形成透明导电层和电极。本发明的利用激光刻蚀结合第一电介质保护层替代光刻工艺,在不损失电池效率的前提下,简化工艺流程,具备低成本大规模生产的可行性。(A method of fabricating a solar cell, comprising: sequentially forming a first passivation layer and a first doping layer on the surface of the silicon substrate; forming a first dielectric protection layer on the surface of the first doped layer; etching the first dielectric protection layer by using laser according to a preset pattern; removing the first passivation layer and the first doping layer by using the first dielectric protection layer as a mask; forming a patterned second passivation layer and a second doping layer on the first dielectric protection layer and the exposed silicon base layer; forming an etching barrier layer on the second doping layer formed on the silicon substrate layer; removing the second passivation layer and the second doping layer formed on the first dielectric protection layer; removing the first dielectric protection layer and the etching barrier layer; forming a second dielectric protection layer; etching the second dielectric protection layer by using laser according to a preset pattern; and finally forming a transparent conductive layer and an electrode. The invention utilizes the combination of laser etching and the first dielectric protective layer to replace the photoetching process, simplifies the process flow on the premise of not losing the efficiency of the battery, and has the feasibility of low-cost large-scale production.)

1. A method of fabricating a solar cell, the method comprising:

sequentially forming a first passivation layer and a first doping layer on a first surface of a silicon substrate;

forming a first dielectric protection layer on the surface of the first doped layer;

etching the first dielectric protection layer by using laser according to a preset pattern;

removing the first passivation layer and the first doping layer by using the patterned first dielectric protection layer as a mask to expose the silicon substrate layer;

forming a patterned second passivation layer and a second doped layer on the patterned first dielectric protection layer and the exposed silicon base layer;

forming an etching barrier layer on the second doping layer formed on the silicon substrate layer;

removing the second passivation layer and the second doping layer formed on the patterned first dielectric protection layer;

removing the patterned first dielectric protection layer and the etch stop layer;

forming a second dielectric protection layer on the patterned first and second doped layers;

etching the second dielectric protection layer by using laser according to a preset pattern;

forming a transparent conductive layer by using the patterned second dielectric protection layer as a mask;

and forming an electrode on the transparent conductive layer.

2. A method of fabricating a solar cell, the method comprising:

sequentially forming a first passivation layer and a first doping layer on a first surface of a silicon substrate;

forming a first dielectric protection layer on the surface of the first doped layer;

etching the first dielectric protection layer by using laser according to a preset pattern;

removing the first doping layer by taking the patterned first dielectric protection layer as a mask to expose the first passivation layer;

forming a patterned second doped layer on the patterned first dielectric protection layer and the exposed first passivation layer;

forming an etching barrier layer on the second doping layer formed on the first passivation layer;

removing the second doped layer formed on the patterned first dielectric protection layer;

removing the patterned first dielectric protection layer and the etch stop layer;

forming a second dielectric protection layer on the patterned first and second doped layers;

etching the second dielectric protection layer by using laser according to a preset pattern;

forming a transparent conductive layer by using the patterned second dielectric protection layer as a mask;

and forming an electrode on the transparent conductive layer.

3. The method of claim 1 or 2, wherein the laser etching is picosecond or femtosecond laser etching.

4. The method of claim 1 or 2, wherein the method further comprises:

and forming a passivation antireflection layer on a second surface opposite to the first surface of the silicon substrate.

5. A solar cell, characterized by being manufactured by the method of any one of claims 1 to 4.

6. The solar cell of claim 5, wherein the first doped layer is a P-doped amorphous silicon or microcrystalline silicon layer and the second doped layer is an N-doped amorphous silicon or microcrystalline silicon layer.

7. The solar cell of claim 5, wherein the first doped layer is an N-doped amorphous silicon or microcrystalline silicon layer and the second doped layer is a P-doped amorphous silicon or microcrystalline silicon layer.

8. The solar cell of claim 5, wherein the thickness of the first doped layer and the second doped layer is 5nm to 100 nm.

9. The solar cell of claim 5, wherein the first and second dielectric caps comprise at least one of silicon nitride, silicon oxide.

10. The solar cell of claim 5, wherein the thickness of the first and second dielectric caps is between 100nm and 500 nm.

11. The method of claim 5, wherein the transparent conductive layer comprises at least one of ITO, AZO, or BZO.

12. The method of claim 5, wherein the metal electrode comprises at least one of silver and aluminum.

Technical Field

The invention belongs to the technical field of solar photovoltaics, and particularly relates to a back contact heterojunction monocrystalline silicon solar cell and a manufacturing method thereof.

Background

The back contact electrode structure is one of the main technical development directions of a photovoltaic solar cell with higher efficiency, and an HBC cell technology combined with a heterojunction process is a key technology for ensuring the high efficiency of the cell. The difficulty of the HBC battery process is the realization of back process integration, and how to arrange the positive and negative electrodes adjacently on the same side of a silicon wafer. The existing known method is realized by adopting a very complicated photoetching process, and is difficult to realize large-scale production along with the problems of multiple process steps, high requirements on equipment and environment, high cost and the like.

Disclosure of Invention

In order to overcome the existing defects, the invention provides a manufacturing method of a solar cell and the solar cell manufactured by the method.

In one aspect, the present invention provides a method for manufacturing a solar cell, including: sequentially forming a first passivation layer and a first doping layer on a first surface of a silicon substrate; forming a first dielectric protection layer on the surface of the first doped layer; etching the first dielectric protection layer by using laser according to a preset pattern; removing the first passivation layer and the first doping layer by using the patterned first dielectric protection layer as a mask to expose the silicon substrate layer; forming a patterned second passivation layer and a second doped layer on the patterned first dielectric protection layer and the exposed silicon base layer; forming an etching barrier layer on the second doping layer formed on the silicon substrate layer; removing the second passivation layer and the second doping layer formed on the patterned first dielectric protection layer; removing the patterned first dielectric protection layer and the etch stop layer; forming a second dielectric protection layer on the patterned first and second doped layers; etching the second dielectric protection layer by using laser according to a preset pattern; forming a transparent conductive layer by using the patterned second dielectric protection layer as a mask; and forming an electrode on the transparent conductive layer.

In another aspect of the present invention, a method for fabricating a solar cell includes: sequentially forming a first passivation layer and a first doping layer on a first surface of a silicon substrate; forming a first dielectric protection layer on the surface of the first doped layer; etching the first dielectric protection layer by using laser according to a preset pattern; removing the first doping layer by taking the patterned first dielectric protection layer as a mask to expose the first passivation layer; forming a patterned second doped layer on the patterned first dielectric protection layer and the exposed first passivation layer; forming an etching barrier layer on the second doping layer formed on the silicon substrate layer; removing the second doped layer formed on the patterned first dielectric protection layer; removing the patterned first dielectric protection layer and the etch stop layer; forming a second dielectric protection layer on the patterned first and second doped layers; etching the second dielectric protection layer by using laser according to a preset pattern; forming a transparent conductive layer by using the patterned second dielectric protection layer as a mask; and forming an electrode on the transparent conductive layer.

According to an embodiment of the invention, the laser etching is picosecond or femtosecond laser etching.

According to another embodiment of the invention, the method further comprises: and forming a passivation antireflection layer on a second surface opposite to the first surface of the silicon substrate.

Another aspect of the present invention provides a solar cell fabricated by the above method.

According to an embodiment of the present invention, the first doped layer is a P-type doped amorphous silicon or microcrystalline silicon layer, and the second doped layer is an N-type doped amorphous silicon or microcrystalline silicon layer.

According to another embodiment of the present invention, the first doped layer is an N-type doped amorphous silicon or microcrystalline silicon layer and the second doped layer is a P-type doped amorphous silicon or microcrystalline silicon layer.

According to another embodiment of the present invention, the thickness of the first doped layer and the second doped layer is 5nm to 100 nm.

According to another embodiment of the present invention, the first dielectric cap layer and the second dielectric cap layer include at least one of silicon nitride and silicon oxide.

According to another embodiment of the present invention, the thickness of the first dielectric cap layer and the second dielectric cap layer is 100nm to 500 nm.

According to another embodiment of the present invention, the transparent conductive layer includes at least one of ITO, AZO, or BZO.

According to another embodiment of the present invention, the metal electrode includes at least one of silver and aluminum.

The conventional back contact cell needs at least 3 times of photoetching process, and the laser etching combined with the first dielectric protective layer replaces the photoetching process, so that the working procedure times are reduced, the process flow is simplified, and the feasibility of low-cost large-scale production is realized on the premise of not losing the cell efficiency.

Still further, the present invention employs picosecond or femtosecond lasers to act on dielectric materials, such as silicon dioxide, silicon nitride, silicon materials, and the like. Since the mechanism of picosecond or femtosecond laser interaction with a material is a "cold" process, the effect on the properties of the material itself is relatively small.

Drawings

The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

Fig. 1 to 8 are schematic views illustrating a method for manufacturing a solar cell according to the present invention.

Wherein the reference numerals are as follows:

1-a silicon substrate; 2-a first passivation layer; 3-a first doped layer; 4-a first dielectric cap layer; 5-a second passivation layer; 6-a second doped layer; 7-etching the barrier layer; 8-passivating the antireflective layer; 9-a second dielectric protection layer; 10-a transparent conductive layer; 11-a first electrode; 12-second electrode

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. In the drawings, the thickness of regions and layers are exaggerated for clarity. The same reference numerals denote the same or similar structures in the drawings, and thus detailed descriptions thereof will be omitted.

It should be noted that the terms "upper" and "lower" in the present invention are only relative concepts or reference to the normal use status of the product, and should not be considered as limiting.

As shown in fig. 1, a silicon substrate 1 after single-sided texturing (second surface texturing and first surface chemical polishing) is first chemically cleaned to remove organic substances, particles, metal ions and other contaminants on the surface of the silicon wafer. A passivating antireflective coating (not shown) such as a SiN layer or the like is deposited on the second surface of the silicon substrate 1 to a thickness of 5nm to 100 nm. Then, a first passivation layer 2 is formed on the first surface, and then a first doping layer 3 is formed on the first passivation layer 2. The first passivation layer 2 may be deposited on the silicon substrate 1 by PECVD or HWCVD, and the first passivation layer 2 may be an intrinsic amorphous silicon layer. The first doped layer 3 may be a P-type doped layer, such as a P-type doped amorphous silicon or microcrystalline silicon layer, or an N-type doped layer, such as an N-type doped amorphous silicon or microcrystalline silicon layer. The P-type doped layer can be formed by doping TMB or B₂H₆And growing to form. The N-type doped layer may be formed by doping with PH₃And growing to form. The layer has a thickness of between about 5nm and about 100 nm. After the first doping layer 3 is formed, a first dielectric protection layer 4 is formed thereon. The first dielectric cap layer 4 may be at least one of silicon nitride and silicon oxide. The thickness of the layer is between 100nm and 500 nm. The first dielectric cap layer 4 is then laser etched to form a patterned first dielectric cap layer 4. The laser etching is preferably picosecond or femtosecond laser etching. Fig. 2 shows the structure after laser etching.

After the laser etching, the first doping layer 3 and the first passivation layer 2 are removed using the first dielectric protection layer 4 as a mask to expose the base layer 1. Alternatively, only the first doping layer 3 is removed using the first dielectric protection layer 4 as a mask, exposing the first passivation layer 2. The first doped layer 3 and/or the first passivation layer 2 may be removed by chemical etching. The structure of removing the first doped layer 3 and the first passivation layer 2 is shown in fig. 3A. The structure of removing only the first doped layer 3 is shown in fig. 3B.

If the first doping layer 3 and the first passivation layer 2 are removed, a patterned second passivation layer 5 and a second doping layer 6 are formed on the patterned first dielectric protection layer 4 and the exposed silicon substrate 1. The first doped layer 3 is a different type of doping than the second doped layer 6. If the first doped layer 3 is a P-type doped layer, the second doped layer 6 is an N-type doped layer. If the first doped layer 3 is an N-type doped layer, the second doped layer 6 is a P-type doped layer. The second passivation layer 5 and the second doped layer 6 may be formed by PECVD or HWCVD deposition. The structure after deposition is shown in fig. 4A.

If only the first doping layer 3 is removed, a patterned second doping layer 6 is formed on the patterned first dielectric protection layer 4 and the exposed first passivation layer 2. The first doped layer 3 is a different type of doping than the second doped layer 6. If the first doped layer 3 is a P-type doped layer, the second doped layer 6 is an N-type doped layer. If the first doped layer is an N-type doped layer, the second doped layer 6 is a P-type doped layer. The second doped layer 6 may be formed by PECVD or HWCVD deposition. The structure after deposition is shown in fig. 4B.

Subsequently, an etch stopper 7 is formed on the second doping layer 6 formed on the silicon substrate 1. Thereafter, the second passivation layer 5 and the second doping layer 6 formed on the first dielectric protection layer 4 are removed (as shown in fig. 4A), or the second doping layer 6 is removed (as shown in fig. 4B). The etch stop layer 7 may be, but is not limited to, a polymer layer to protect the second passivation layer 5 and the second doped layer 6 formed on the base layer 1 during a subsequent etching process. The etch stop layer 7 may be formed by screen printing. The second passivation layer 5 and the second doped layer 6 may be removed by any means such as chemical etching. The structure after removal of the second passivation layer 5 and the second doped layer 6 is shown in fig. 5.

Then, the first dielectric cap layer 3 and the etch stopper layer 7 are removed. The first dielectric cap layer 7 may be removed by chemical etching. The etch stop layer 7 is then removed with a different chemical. The passivation formed on the second surface of the silicon substrate 1 may be damaged by chemical etchingThe antireflective film (not shown) and thus the passivated antireflective layer 8 may be reformed on the second surface after this step, as shown in fig. 6, which is illustrated as one layer, but it will be understood by those skilled in the art that the passivated antireflective layer 8 may be two layers, a passivation layer and an antireflective layer, and the antireflective layer may also be a double layer or a multilayer. The passivation anti-reflective layer 8 can be, but is not limited to, for example, a-Si, SiO₂SiN, etc., or double antireflection, etc. And a second dielectric protection layer 9 is formed on the first doped layer 3 and the second doped layer 6. The second dielectric cap layer 9 may be at least one of silicon nitride and silicon oxide.

Subsequently, the second dielectric cap layer 9 is etched by laser in a predetermined pattern, and the resulting structure is shown in fig. 7. Preferably picosecond or femtosecond laser etching.

Subsequently, the transparent conductive layer 10 is formed with the patterned second dielectric protection layer 9 as a mask. The transparent conductive layer 10 may be formed by screen printing. The transparent conductive layer 10 may be formed of at least one of ITO, AZO, BZO. Finally, the first electrode 11 and the second electrode 12 are formed on the transparent conductive layer 10. The first electrode 11 and the second electrode 12 are of opposite polarity. The first electrode 11 and the second electrode 12 may be metal electrodes, for example, at least one of Ag and Al. The resulting structure is shown in fig. 8.

The conventional back contact cell needs at least 3 times of photoetching process, but the invention utilizes the combination of the super laser etching and the first dielectric protective layer to replace the photoetching process, reduces the working procedure times, simplifies the process flow and has the feasibility of low-cost large-scale production on the premise of not losing the cell efficiency.

Still further, the present invention employs picosecond or femtosecond lasers to act on dielectric materials, such as silicon dioxide, silicon nitride, silicon materials, and the like. Since the mechanism of picosecond or femtosecond laser interaction with a material is a "cold" process, the impact on the properties of the material itself is relatively small.

The technical solution of the present invention has been disclosed above by the preferred embodiments. Those skilled in the art will recognize that changes and modifications can be made thereto without departing from the scope and spirit of the invention as disclosed in the appended claims.