Monocrystalline silicon cleaning and texturing method, silicon wafer and solar cell
Through the single crystal silicon cleaning and fleece making method, a tiny concave and convex structure is formed and heavy metal ions are removed, which solves the problem of incomplete removal of impurities on the surface of silicon wafers in the prior art and improves the performance of solar cells.
Patent Information
- Application Number
- CN202510527851.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-25
- Publication Date
- 2025-08-08
AI Technical Summary
In the prior art, the wet velvet making process cannot effectively remove metal impurities on the surface of the silicon wafer, and the microtexture of the surface is not conducive to forming an effective suede structure, affecting the performance of the solar cell.
A single crystal silicon cleaning and velvet making method is adopted, including pre-cleaning, pre-picking, velvet making, post-cleaning and post-picking steps. The silicon wafer is processed using a mixed solution of a specific concentration and temperature to form a tiny concave and convex structure and remove heavy metal ions to form a uniform suede structure.
The open circuit voltage, short circuit current and filling factor of solar cells are improved, and the conversion efficiency of solar cells is improved.
Smart Images
Figure CN120456640A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of solar cells, and in particular to a method for cleaning and texturing single-crystal silicon, a silicon wafer obtained by the method, and a solar cell made from the silicon wafer. Background Art
[0002] In the production of solar cells, a good silicon wafer substrate, especially an effective textured surface structure, is essential for achieving high-performance solar cells. The texturing process directly impacts various cell defects, such as surface texture, light trapping, and passivation. Currently, wet texturing cannot effectively remove metallic impurities from the surface of cleaned silicon wafers. Furthermore, the surface microtexture of the silicon wafer is not conducive to texturing, hindering the formation of an effective textured surface structure during subsequent texturing. Summary of the Invention
[0003] In order to improve the cleaning effect and enhance the surface microstructure of silicon wafers, the present disclosure provides a method for cleaning and texturing single crystal silicon, comprising the following steps: a pre-cleaning step, in which the silicon wafer is pre-cleaned by a pre-cleaning mixed solution; a pre-pickling step, in which the silicon wafer is pre-pickled by a pre-pickling mixed solution; a texturing step, in which the silicon wafer is texturized by a texturing mixed solution; a post-cleaning step, in which the silicon wafer is post-cleaned by a post-cleaning mixed solution; and a post-pickling step, in which the silicon wafer is post-pickled by a post-pickling mixed solution.
[0004] In the method for cleaning and texturing single crystal silicon, the pre-acid cleaning step is to use a mixed solution of HCL and H2O2 as a pre-acid cleaning mixed solution to pre-acid clean the silicon wafer.
[0005] In the method for cleaning and texturing single crystal silicon, the concentration of HCL in the mixed solution of HCL and H2O2 is 1-10 wt %, and the concentration of H2O2 is 1-10 wt %.
[0006] In the method for cleaning and texturing single crystal silicon, the pre-acid cleaning step is to pre-acid clean the silicon wafer at a temperature of 15° C.-70° C.
[0007] In the single crystal silicon cleaning and texturing method, the pre-cleaning step is an alkaline cleaning step, in which a mixed solution of KOH and H2O2 is used as a pre-cleaning mixed solution to clean the silicon wafer, the concentration of the KOH solution is 0.05-0.1wt%, and the concentration of the H2O2 is 1-5wt%.
[0008] In the method for cleaning and texturing single crystal silicon, the texturing step is to texturize the silicon wafer using a mixed solution of a texturing additive and KOH as a texturing mixed solution, wherein the concentration of the texturing additive in the mixed solution of the texturing additive and KOH is 1.0-1.5wt%, and the concentration of KOH is 0.03-0.5wt%.
[0009] In the single crystal silicon cleaning and texturing method, the post-cleaning step is to use a mixed solution of KOH and H2O2 as a post-cleaning mixed solution to post-clean the silicon wafer, and the KOH concentration in the mixed solution of KOH and H2O2 is 0.05-0.1wt%, and the H2O2 concentration is 1-5wt%.
[0010] In the monocrystalline silicon cleaning and texturing method, the post-pickling step uses a mixed solution of HF and HCl as a post-pickling mixed solution to pickle the silicon wafer; the concentration of HF in the mixed solution of HF and HCl is 7-9wt%, and the concentration of HCl is 2-5wt%.
[0011] The present disclosure also provides a silicon wafer having a velvet surface prepared according to the method for cleaning and texturing single crystal silicon described in the present disclosure, wherein the average size of the pyramids in the velvet surface is 1.0-1.5 μm.
[0012] The present disclosure also provides a solar cell, which includes a silicon wafer prepared according to the single crystal silicon cleaning and texturing method described in the present disclosure.
[0013] The single crystal silicon cleaning and texturing method disclosed in the present invention can form some tiny concave-convex structures or textures on the surface of the silicon wafer through a pre-acid pickling step, thereby improving the light trapping effect of the silicon wafer and removing heavy metal ions on the surface of the silicon wafer. It can also form a more uniform and effective texturing structure, thereby improving the open circuit voltage, short circuit current and fill factor of the solar cell finally produced, and further improving the conversion efficiency of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 It is a schematic flow chart of a method for cleaning and texturing single crystal silicon in an embodiment of the present disclosure.
[0015] Figure 2 The velvet surface obtained in the embodiment was observed under a 3000X scanning electron microscope. DETAILED DESCRIPTION
[0016] In order to enable those skilled in the art to better understand the technical solution of the present disclosure, the technical solution of the present disclosure is described in detail below with reference to the accompanying drawings.
[0017] Example embodiments will be described more fully hereinafter with reference to the accompanying drawings, but the example embodiments may be embodied in 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 scope of this disclosure to those skilled in the art.
[0018] In the absence of conflict, the various embodiments of the present disclosure and the various features therein may be combined with each other.
[0019] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.
[0020] The terms used herein are used only to describe specific embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "a," "an," and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It will also be understood that when the terms "comprising" and / or "made of" are used in this specification, the presence of the features, wholes, steps, operations, elements, and / or components is specified, but the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or groups thereof is not excluded.
[0021] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted as having an idealized or overly formal meaning unless expressly defined as such herein.
[0022] Unless otherwise specified, the term "concentration" herein refers to mass concentration. The concentration of each substance in a mixed solution refers to the mass concentration of each substance based on the total amount of the mixed solution.
[0023] The present disclosure provides a method for cleaning and texturing single crystal silicon, such as Figure 1 As shown, it includes the following steps:
[0024] S1-pre-cleaning step, pre-cleaning the silicon wafer with a pre-cleaning mixed solution;
[0025] S2-pre-pickling step, pre-pickling the silicon wafer with a pre-pickling mixed solution;
[0026] S3-texturing step, texturing the silicon wafer using a texturing mixed solution;
[0027] S4—post-cleaning step, performing post-cleaning on the silicon wafer using a post-cleaning mixed solution; and
[0028] S5—post-acid cleaning step, wherein the silicon wafer is post-acid cleaned using a post-acid cleaning mixed solution.
[0029] In the monocrystalline silicon cleaning and texturing method, the pre-cleaning step is an alkaline cleaning step, in which a mixed solution of KOH and H2O2 is used as a pre-cleaning mixed solution to clean the silicon wafer. The concentration of the KOH solution is 0.05-0.1wt%, and the concentration of the H2O2 is 1-5wt%. The pre-cleaning step removes dirt from the surface of the silicon wafer and causes micro-etching of the silicon wafer surface.
[0030] In the monocrystalline silicon cleaning and texturing method, a pre-pickling step uses a mixed solution of HCl and H₂O₂ as the pre-pickling mixed solution to pre-pick the silicon wafer. The HCl concentration in the mixed solution is 1-10wt%, and the H₂O₂ concentration is 1-10wt%. The pre-pickling temperature is 15°C-70°C, and the time is 100s-500s. This pre-pickling step forms microscopic concave-convex structures or textures on the surface of the silicon wafer, and removes heavy metal ions from the surface of the silicon wafer.
[0031] In the monocrystalline silicon cleaning and texturing method, the texturing step is to texturize the silicon wafer using a mixed solution of a texturing additive and KOH as the texturing mixed solution. The concentration of the texturing additive in the mixed solution of the texturing additive and KOH is 1.0-1.5wt%, and the concentration of KOH is 0.03-0.5wt%.
[0032] In the single crystal silicon cleaning and texturing method, the post-cleaning step is to use a mixed solution of KOH and H2O2 as a post-cleaning mixed solution to post-clean the silicon wafer, and the KOH concentration in the mixed solution of KOH and H2O2 is 0.05-0.1wt%, and the H2O2 concentration is 1-5wt%.
[0033] In the monocrystalline silicon cleaning and texturing method, the post-pickling step is to use a mixed solution of HF and HCl as the post-pickling mixed solution to pickle the silicon wafer; the concentration of HF in the mixed solution of HF and HCl is 7-9wt%, and the concentration of HCl is 2-5wt%.
[0034] Specifically, according to one embodiment of the present disclosure, the method for cleaning and texturing single crystal silicon includes:
[0035] Pre-cleaning the silicon wafer using a mixed solution of KOH with a concentration of 0.05-0.1 wt% and H2O2 with a concentration of 1-5 wt% at a temperature range of 15-25°C;
[0036] Pre-acid washing the silicon wafer using a mixed solution of 1-10 wt% HCL and 1-10 wt% H2O2 at a temperature range of 15-70°C;
[0037] The silicon wafer is textured using a mixed solution having a KOH concentration of 0.03-0.5 wt% and a texturing additive concentration of 1.0-1.5 wt% at a temperature range of 70-90°C;
[0038] Post-cleaning the silicon wafer using a mixed solution of 0.05-0.1 wt% KOH and 1-5 wt% H2O2 at a temperature range of 55-75°C;
[0039] The silicon wafer is post-acid washed at room temperature using a mixed solution having an HF concentration of 7-9 wt % and an HCL concentration of 2-5 wt %.
[0040] According to another embodiment of the present disclosure, the method for cleaning and texturing single crystal silicon includes:
[0041] Pre-clean the silicon wafer using a mixed solution of 0.05-0.1 wt% KOH and 1-5 wt% H2O2 at a temperature range of 15-25°C for 100-200 seconds.
[0042] Pre-acid washing the silicon wafer using a mixed solution of 1-10 wt% HCL and 1-10 wt% H2O2 at a temperature range of 15-70°C for 100-500 seconds;
[0043] The silicon wafer is textured using a mixed solution of 0.03-0.5 wt% KOH and 1.0-1.5 wt% texturing additive at a temperature range of 70-90°C for 250-350 seconds.
[0044] Post-cleaning the silicon wafer using a mixed solution of 0.05-0.1 wt% KOH and 1-5 wt% H2O2 at a temperature range of 55-75°C for 200-300 seconds.
[0045] The silicon wafer is post-acid washed at room temperature using a mixed solution of HF with a concentration of 7-9 wt% and HCL with a concentration of 2-5 wt% for 60-120 seconds.
[0046] In the method for cleaning and texturing single crystal silicon disclosed herein, those skilled in the art can customize the texturing additives according to needs and combine different specific substances as long as the expected process parameters are achieved.
[0047] The texturing additives mainly play the following roles:
[0048] 1) Cleaning effect: The cleaning tank may not be able to completely remove the impurities remaining on the original silicon wafer, especially organic pollutants such as glue or oil. These pollutants will reduce the speed of texturing or even cause no reaction, resulting in uneven velvet surface and color difference. Therefore, they must be cleaned as soon as possible at the beginning of the texturing process.
[0049] 2) Degassing: A large amount of hydrogen is generated during the texturing process. The generated hydrogen is easily adsorbed on the surface of the silicon wafer, preventing further corrosion of the silicon wafer by the alkaline solution, thereby producing raindrop marks. Therefore, surfactants are usually included in the additives to reduce the surface tension of the solution to help the hydrogen leave the silicon wafer surface.
[0050] 3) Nucleation: The nucleation point is generally the apex of a cone. While hydrogen bubbles in the reaction product can help with nucleation, fewer nucleation points result in a larger and uneven velvet surface. A velvet catalyst in the additive can help with nucleation, resulting in denser and more uniform nucleation points and a smaller, more uniform velvet surface.
[0051] 4) Corrosion inhibition: Controlling the reaction rate of texturing is crucial for texturing, as it is the basis for obtaining a better texture and improving battery efficiency. Corrosion inhibition does not mean that the texturing time will be longer. On the contrary, it helps to reduce the texturing time and complete the texturing at a low weight loss. Corrosion inhibition helps to reduce the initial reaction rate, which can reduce the impact of silicon wafer surface roughness on texture uniformity and further reduce the corrosion rate in the direction of the anisotropy factor (111) crystal plane.
[0052] The main components of additives include surfactants, velvet catalysts, or velvet corrosion inhibitors. These additives generally use carboxylates, low-foaming surfactants, etc. as cleaning ingredients. Surfactants can reduce the surface tension of the solution, increase the wetting properties of silicon wafers, dissolve and remove organic pollutants, and reduce their impact on velvet production. The cleaning effect is particularly outstanding under high-temperature alkaline conditions. Velvet catalysts slow down the reaction rate of Si and -OH, increase the density of pyramidal cores, and form a large number of small-sized pyramids. Velvet corrosion inhibitors increase various factors, with the 100 face reaction rate being fast and the 111 face reaction rate being slow, ultimately completing the pyramid growth. Usually, some polymer velvet corrosion inhibitors may also be added to the additives.
[0053] For example, the texturing additive may include the following components: water <80.0%; potassium sorbate 1.0-2.0%; sodium acetate 2.0-4.0%; defoaming agent 5.0-7.0%; surfactant 5.0-10.0%; and others <6.0%.
[0054] The single crystal silicon cleaning and texturing method disclosed in the present invention can form some tiny concave-convex structures or textures on the surface of the silicon wafer through a pre-acid pickling step, thereby improving the light trapping effect of the silicon wafer and removing heavy metal ions on the surface of the silicon wafer. It can also form a more uniform and effective texturing structure, thereby improving the open circuit voltage, short circuit current and filling of the solar cell finally produced, and further improving the conversion efficiency of the solar cell.
[0055] The present disclosure also provides a silicon wafer, such as Figure 2 As shown, the silicon wafer has a velvet surface prepared according to the single crystal silicon cleaning and velvet making method disclosed in the present invention, and the average size of the pyramids in the velvet surface is 1.0-1.5 μm.
[0056] The present disclosure also provides a solar cell, which includes a silicon wafer prepared according to the single crystal silicon cleaning and texturing method described in the present disclosure.
[0057] In order to enable those skilled in the art to more clearly understand the technical solution of the present disclosure, the technical solution of the present disclosure is described in detail below through specific embodiments.
[0058] Example 1
[0059] Using G12 rectangular half-chip silicon wafers, after the completion of automatic wafer loading, the whole texturing adopts a full-tank processing method, 4 baskets / tank, 240 pieces / basket, the flower basket is loaded to the loading position; the flower basket is placed in the pre-cleaning tank by a robot, and kept at 25°C for 100s in a mixed solution of KOH concentration of 0.1wt% and H2O2 concentration of 5wt%; the flower basket is placed in the water tank by a robot, and kept at room temperature for 120s; the flower basket is placed in the pre-pickling tank by a robot, and kept at 15°C for 300s in a mixed solution of HCl concentration of 10wt% and H2O2 concentration of 10wt%; the flower basket is placed in the water tank by a robot, and kept at room temperature for 120s; the flower basket is placed in the texturing tank by a robot, and kept at 15°C for 150s in a mixed solution of HCl concentration of 10wt% and H2O2 concentration of 10wt%; wt% mixed solution at 70°C for 250 seconds; the flower basket is placed in a water tank by a robot and kept at room temperature for 120 seconds; the flower basket is placed in a post-cleaning tank by a robot and kept at 55°C for 200 seconds in a mixed solution of KOH concentration of 0.1wt% and H2O2 concentration of 5wt%; the flower basket is placed in a water tank by a robot and kept at room temperature for 120 seconds; the flower basket is placed in a post-pickling tank by a robot and kept at room temperature for 60 seconds in a mixed solution of HF concentration of 9wt% and HCl concentration of 5wt%; the flower basket is placed in a water tank by a robot and kept at room temperature for 120 seconds; the flower basket is placed in a slow pulling tank by a robot and kept at room temperature for 100 seconds; the flower basket is placed in a drying tank by a robot and kept at 95°C for 600 seconds; and finally, the flower basket is unloaded by the robot.
[0060] Example 2
[0061] G12 rectangular half-wafer silicon wafers are used. After the automatic wafer loading is completed, the whole texturing adopts a full-tank processing method, 4 baskets / tank, 240 wafers / basket, and the flower basket is loaded to the loading position; the flower basket is placed in the pre-cleaning tank by a robot, and kept at 15°C for 200s in a mixed solution of KOH concentration of 0.05wt% and H2O2 concentration of 1wt%; the flower basket is placed in the water tank by a robot, and kept at room temperature for 120s; the flower basket is placed in the pre-pickling tank by a robot, and kept at 70°C for 100s in a mixed solution of HCl concentration of 1wt% and H2O2 concentration of 1wt%; the flower basket is placed in the water tank by a robot, and kept at room temperature for 120s; the flower basket is placed in the texturing tank by a robot, and kept at 1.0wt% for the texturing additive concentration and 0.03wt% for the KOH concentration. t% mixed solution at 70°C for 350 seconds; the flower basket is placed in a water tank by a robot and kept at room temperature for 120 seconds; the flower basket is placed in a post-cleaning tank by a robot and kept at 75°C for 200 seconds in a mixed solution of KOH concentration of 0.05wt% and H2O2 concentration of 1wt%; the flower basket is placed in a water tank by a robot and kept at room temperature for 120 seconds; the flower basket is placed in a post-pickling tank by a robot and kept at room temperature for 120 seconds in a mixed solution of HF concentration of 7wt% and HCl concentration of 2wt%; the flower basket is placed in a water tank by a robot and kept at room temperature for 120 seconds; the flower basket is placed in a slow pulling tank by a robot and kept at room temperature for 100 seconds; the flower basket is placed in a drying tank by a robot and kept at 95°C for 600 seconds; and finally, the flower basket is unloaded by the robot.
[0062] Example 3
[0063] G12 rectangular half-wafer silicon wafers are used. After the automatic wafer loading is completed, the whole texturing adopts a full-tank processing method, 4 baskets / tank, 240 wafers / basket, and the flower basket is loaded to the loading position; the flower basket is placed in the pre-cleaning tank by a robot, and kept at 20°C for 150s in a mixed solution of KOH concentration of 0.08wt% and H2O2 concentration of 3wt%; the flower basket is placed in the water tank by a robot, and kept at room temperature for 120s; the flower basket is placed in the pre-pickling tank by a robot, and kept at 45°C for 300s in a mixed solution of HCl concentration of 5wt% and H2O2 concentration of 5wt%; the flower basket is placed in the water tank by a robot, and kept at room temperature for 120s; the flower basket is placed in the texturing tank by a robot, and kept at 1.2wt% of the texturing additive concentration and 0.04wt% of the KOH concentration. t% mixed solution at 80°C for 300 seconds; the flower basket is placed in a water tank by a robot and kept at room temperature for 120 seconds; the flower basket is placed in a post-cleaning tank by a robot and kept at 65°C for 250 seconds in a mixed solution of KOH concentration of 0.08wt% and H2O2 concentration of 3wt%; the flower basket is placed in a water tank by a robot and kept at room temperature for 120 seconds; the flower basket is placed in a post-pickling tank by a robot and kept at room temperature for 100 seconds in a mixed solution of HF concentration of 8wt% and HCl concentration of 4wt%; the flower basket is placed in a water tank by a robot and kept at room temperature for 120 seconds; the flower basket is placed in a slow-lifting tank by a robot and kept at room temperature for 100 seconds; the flower basket is placed in a drying tank by a robot and kept at 95°C for 600 seconds; and finally, the flower basket is unloaded by the robot.
[0064] Comparative Example 1
[0065] Using G12 rectangular half-piece silicon wafers, after the completion of automatic wafer loading, the whole texturing adopts a full-tank processing method, 4 baskets / tank, 240 wafers / basket, the flower basket is loaded to the loading position; the flower basket is placed in the pre-cleaning tank by a robot, and kept at 25℃ for 100s in a mixed solution of KOH concentration of 0.1wt% and H2O2 concentration of 5wt%; the flower basket is placed in the water tank by a robot, and kept at room temperature for 120s; the flower basket is placed in the texturing tank by a robot, and kept at 70℃ for 250s in a mixed solution of texturing additive concentration of 1.5wt% and KOH concentration of 0.5wt%; the flower basket is placed in the water tank by a robot, and kept at room temperature for 120s s; the flower basket is placed in the post-cleaning tank by a robot and maintained at 55°C for 200 seconds in a mixed solution of KOH with a concentration of 0.1wt% and H2O2 with a concentration of 5wt%; the flower basket is placed in the water tank by a robot and maintained at room temperature for 120 seconds; the flower basket is placed in the post-pickling tank by a robot and maintained at room temperature for 60 seconds in a mixed solution of HF with a concentration of 9wt% and HCl with a concentration of 5wt%; the flower basket is placed in the water tank by a robot and maintained at room temperature for 120 seconds; the flower basket is placed in the slow-drawing tank by a robot and maintained at room temperature for 100 seconds; the flower basket is placed in the drying tank by a robot and maintained at 95°C for 600 seconds; and finally, the flower basket is unloaded by the robot.
[0066] Comparative Example 2
[0067] Using G12 rectangular half-piece silicon wafers, after the completion of automatic wafer loading, the whole texturing adopts a full-tank processing method, 4 baskets / tank, 240 pieces / basket, the flower basket is loaded to the loading position; the flower basket is placed in the pre-cleaning tank by a robot, and kept at 15℃ for 200s in a mixed solution of KOH concentration of 0.05wt% and H2O2 concentration of 1wt%; the flower basket is placed in the water tank by a robot, and kept at room temperature for 120s; the flower basket is placed in the texturing tank by a robot, and kept at 70℃ for 350s in a mixed solution of texturing additive concentration of 1.0wt% and KOH concentration of 0.03wt%; the flower basket is placed in the water tank by a robot, and kept at room temperature for 120s s; the flower basket is placed in the post-cleaning tank by a robot and maintained at 75°C for 200 seconds in a mixed solution of KOH with a concentration of 0.05wt% and H2O2 with a concentration of 1wt%; the flower basket is placed in the water tank by a robot and maintained at room temperature for 120 seconds; the flower basket is placed in the post-pickling tank by a robot and maintained at room temperature for 120 seconds in a mixed solution of HF with a concentration of 7wt% and HCl with a concentration of 2wt%; the flower basket is placed in the water tank by a robot and maintained at room temperature for 120 seconds; the flower basket is placed in the slow pulling tank by a robot and maintained at room temperature for 100 seconds; the flower basket is placed in the drying tank by a robot and maintained at 95°C for 600 seconds; and finally, the flower basket is unloaded by the robot.
[0068] Comparative Example 3
[0069] Using G12 rectangular half-piece silicon wafers, after the completion of automatic wafer loading, the whole texturing adopts a full-tank processing method, 4 baskets / tank, 240 pieces / basket, the flower basket is loaded to the loading position; the flower basket is placed in the pre-cleaning tank by a robot, and kept at 20℃ for 150s in a mixed solution of KOH concentration of 0.08wt% and H2O2 concentration of 3wt%; the flower basket is placed in the water tank by a robot, and kept at room temperature for 120s; the flower basket is placed in the texturing tank by a robot, and kept at 80℃ for 300s in a mixed solution of texturing additive concentration of 1.2wt% and KOH concentration of 0.04wt%; the flower basket is placed in the water tank by a robot, and kept at room temperature for 120s s; the flower basket is placed in the post-cleaning tank by a robot and maintained at 65°C for 250 seconds in a mixed solution of KOH with a concentration of 0.08wt% and H2O2 with a concentration of 3wt%; the flower basket is placed in the water tank by a robot and maintained at room temperature for 120 seconds; the flower basket is placed in the post-pickling tank by a robot and maintained at room temperature for 100 seconds in a mixed solution of HF with a concentration of 8wt% and HCl with a concentration of 4wt%; the flower basket is placed in the water tank by a robot and maintained at room temperature for 120 seconds; the flower basket is placed in the slow-drawing tank by a robot and maintained at room temperature for 100 seconds; the flower basket is placed in the drying tank by a robot and maintained at 95°C for 600 seconds; and finally, the flower basket is unloaded by the robot.
[0070] G12 silicon wafers were weighed before and after texturing using an electronic balance, and the weight loss was calculated. The reflectivity of the G12 silicon wafers after texturing was measured according to national standards, and the texturing surfaces were photographed using a 3000X scanning electron microscope. The measurement results are shown in Tables 1-2 below.
[0071] Table 1
[0072]
[0073] Table 2
[0074]
[0075] According to the data in Table 1-2, it can be seen that the silicon wafers obtained by cleaning and texturing using the method disclosed in this disclosure maintain a considerable level of weight loss and reflectivity, but the amount of texturing produced per unit area is greatly improved.
[0076] Example embodiments have been disclosed herein, and although specific terms are employed, they are used and should be interpreted only in a general illustrative sense and not for purposes of limitation. In some embodiments, it will be apparent to those skilled in the art that, unless otherwise expressly stated, features, characteristics, and / or elements described in conjunction with a particular embodiment may be used alone or in combination with features, characteristics, and / or elements described in conjunction with other embodiments. Therefore, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the scope of the present disclosure as set forth in the appended claims.
Claims
1. A method for cleaning and texturing single crystal silicon, characterized in that: The following steps are involved: Pre-cleaning step, pre-cleaning the silicon wafer with a pre-cleaning mixed solution; A pre-pickling step, wherein the silicon wafer is pre-pickled using a pre-pickling mixed solution; A texturing step, texturing the silicon wafer using a texturing mixed solution; a post-cleaning step, wherein the silicon wafer is post-cleaned using a post-cleaning mixed solution; In the post-pickling step, the silicon wafer is post-pickled using a post-pickling mixed solution.
2. The method for cleaning and texturing single crystal silicon according to claim 1, characterized in that: In the pre-acid cleaning step, a mixed solution of HCl and H2O2 is used as the pre-acid cleaning mixed solution to perform pre-acid cleaning on the silicon wafer.
3. The method for cleaning and texturing single crystal silicon according to claim 2, characterized in that: In the mixed solution of HCL and H2O2, the concentration of HCL is 1-10 wt %, and the concentration of H2O2 is 1-10 wt %.
4. The method for cleaning and texturing single crystal silicon according to claim 3, characterized in that: In the pre-acid cleaning step, the silicon wafer is pre-acid cleaned at a temperature of 15° C. to 70° C.
5. The method for cleaning and texturing single crystal silicon according to any one of claims 1 to 4, characterized in that: The pre-cleaning step is an alkaline cleaning step, in which a mixed solution of KOH and H2O2 is used as a pre-cleaning mixed solution to clean the silicon wafer, the concentration of the KOH solution is 0.05-0.1wt%, and the concentration of the H2O2 is 1-5wt%.
6. The method for cleaning and texturing single crystal silicon according to any one of claims 1 to 4, characterized in that: In the texturing step, a mixed solution of a texturing additive and KOH is used as a texturing mixed solution to texturing the silicon wafer. The concentration of the texturing additive in the mixed solution of the texturing additive and KOH is 1.0-1.5wt%, and the concentration of KOH is 0.03-0.5wt%.
7. The method for cleaning and texturing single crystal silicon according to any one of claims 1 to 4, characterized in that: In the post-cleaning step, a mixed solution of KOH and H2O2 is used as a post-cleaning mixed solution to post-clean the silicon wafer, wherein the KOH concentration in the mixed solution of KOH and H2O2 is 0.05-0.1 wt %, and the H2O2 concentration is 1-5 wt %.
8. The method for cleaning and texturing single crystal silicon according to any one of claims 1 to 4, characterized in that: In the post-pickling step, a mixed solution of HF and HCl is used as the post-pickling mixed solution to pickle the silicon wafer; the concentration of HF in the mixed solution of HF and HCl is 7-9wt%, and the concentration of HCl is 2-5wt%.
9. A silicon wafer, characterized in that: The silicon wafer has a textured surface prepared by the method for cleaning and texturing single crystal silicon according to any one of claims 1 to 8, and the average size of the pyramids in the textured surface is 1.0-1.5 μm.
10. A solar cell, characterized in that: The solar cell comprises a silicon wafer prepared by the method for cleaning and texturing single crystal silicon according to any one of claims 1 to 8.