Method for manufacturing solar cell
By controlling the flow rate of oxygen and phosphorus source in the phosphorus diffusion process of solar cells, and using laser to improve its density, the problem of insufficient density of the phosphorus silicon glass layer in the prior art is solved, and the overall efficiency and productivity of the solar cell are improved.
Patent Information
- Application Number
- CN202510232964.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-28
- Publication Date
- 2025-05-30
AI Technical Summary
The prior art has problems of insufficient density and poor stability in terms of phosphorus diffusion and improvement of phosphorus silicon glass (PSG) protective layer, which leads to the surface of the silicon wafer being easily eroded in the wet process, affecting the overall efficiency and productivity of the solar cell.
During the cooling process of the phosphorus diffusion process, oxygen and phosphorus sources are introduced into the diffusion chamber, and the flow rate of the oxygen and phosphorus sources is controlled, a phosphorus silicon glass layer is formed, and then laser is used to irradiate the phosphorus silicon glass layer in at least part of the area to improve its density and stability.
The density and stability of the phosphorus silicon glass layer are improved, its corrosion resistance is enhanced, and the stability in subsequent wet processes is ensured, thereby improving the overall efficiency and productivity of solar cells.
Smart Images
Figure CN120076459A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of photovoltaic technology, and in particular to a method for manufacturing a solar cell. Background Art
[0002] As a mainstream product in the photovoltaic industry, the production process of crystalline silicon solar cells includes steps such as texturing, diffusion, etching, coating, and electrode preparation. Among them, the phosphorus diffusion process is an important link to achieve the N-type doping layer. By diffusing the phosphorus source onto the surface of the silicon wafer / intrinsic polysilicon, an N-type doping layer / N+ polysilicon doping layer can be formed, and at the same time, a phosphorus silicate glass (PSG) protective layer is generated.
[0003] With the rapid development of photovoltaic technology, the improvement of the efficiency and the reduction of the cost of crystalline silicon solar cells have become the focus of the industry. In recent years, advanced surface passivation technology, the thinning process of polysilicon, and the development of high-efficiency cell structures have promoted the continuous progress of the technical field. However, in terms of the improvement of phosphorus diffusion and the PSG protective layer, the limitations of the existing technology still need to be further broken through to meet the market demand for high-efficiency and stable photovoltaic products. Summary of the Invention
[0004] In view of this, this application provides a method for manufacturing a solar cell to improve the overall efficiency and production yield of the solar cell.
[0005] In a first aspect, this application provides a method for manufacturing a solar cell, including:
[0006] Placing a solar cell intermediate in a diffusion chamber;
[0007] Forming a phosphorus silicate glass layer on the surface of the solar cell intermediate;
[0008] Introducing oxygen and a phosphorus source into the diffusion chamber, controlling the flow rate of the oxygen to be 500 - 1500 sscm, the flow rate of the phosphorus source to be 100 - 1000 sscm, and performing a cooling treatment on the solar cell intermediate formed with the phosphorus silicate glass layer;
[0009] Irradiating at least a part of the region of the phosphorus silicate glass layer with a laser.
[0010] In a possible implementation, the wavelength of the laser is 200 - 600 nm, and the pulse width of the laser is 20 - 100 ns.
[0011] In a possible implementation, the single-pulse energy of the laser is 90 - 110 mJ.
[0012] In a possible implementation, after irradiating at least a part of the region of the phosphorus silicate glass layer with a laser, it further includes:
[0013] Place the solar cell intermediate in a process chamber;
[0014] Control the temperature in the process chamber to be 800 - 900 °C.
[0015] In one possible implementation, it further includes:
[0016] Introduce nitrogen into the process chamber, control the flow rate of the nitrogen to be 3000 - 5000 sscm, and the time for introducing the nitrogen is greater than or equal to 5 min.
[0017] In one possible implementation, during the cooling process, the time for introducing oxygen and a phosphorus source is 100 - 400 s.
[0018] In one possible implementation, during the cooling process, when introducing oxygen and a phosphorus source into the diffusion chamber, control the temperature in the diffusion chamber to be 600 - 870 °C.
[0019] In one possible implementation, forming a phosphosilicate glass layer on the surface of the solar cell intermediate includes:
[0020] Control the temperature in the diffusion chamber to a preset temperature and keep it constant for a preset time;
[0021] Introduce oxygen into the diffusion chamber to oxidize the solar cell intermediate;
[0022] Introduce oxygen and a phosphorus source into the diffusion chamber, deposit the phosphorus source on the surface of the solar cell intermediate, thereby forming a phosphosilicate glass layer on the surface of the solar cell intermediate.
[0023] In one possible implementation, during the oxidation process, the flow rate of the introduced oxygen is 800 - 1800 sscm.
[0024] In one possible implementation, during the process of depositing the phosphorus source, the flow rate of the introduced oxygen is 400 - 1400 sscm, and the flow rate of the introduced phosphorus source is 1000 - 2000 sscm.
[0025] Compared with the prior art, the present application has the following advantages:
[0026] In the present application, by introducing oxygen and a phosphorus source into the diffusion chamber during the cooling process of the phosphorus diffusion process, and controlling the flow rate of the oxygen to be 500 - 1500 sscm and the flow rate of the phosphorus source to be 100 - 1000 sscm, and then using laser to irradiate at least part of the area of the phosphosilicate glass layer to improve the density and stability of the phosphosilicate glass layer in these areas, thereby improving the overall efficiency and production yield of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The accompanying drawings are provided to provide a further understanding of the present application, and they are incorporated and constitute a part of this application. The drawings illustrate embodiments of the present application and, together with the description herein, serve to explain the principles of the present application. In the drawings:
[0028] Figure 1 is a schematic flow chart of a method for manufacturing a solar cell provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some examples or embodiments of the present application. For those of ordinary skill in the art, without creative efforts, the present application can also be applied to other similar scenarios based on these drawings. Unless obvious from the language context or otherwise stated, the same reference numerals in the drawings represent the same structure or operation.
[0030] As shown in the present application, unless the context clearly indicates an exceptional situation, words such as "a", "an", "one", and / or "the" are not specifically singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of the clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.
[0031] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that for the sake of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant fields may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the description. In all the examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.
[0032] In addition, although the terms used in the present application are selected from well-known and commonly used terms, some of the terms mentioned in the description of the present application may be selected by the applicant according to his or her judgment, and their detailed meanings are described in the relevant parts of this description. In addition, it is required to understand the present application not only through the actual terms used, but also through the meaning implied by each term.
[0033] It should be understood that when a component is referred to as "on another component", "connected to another component", "coupled to another component", or "in contact with another component", it can be directly on, connected to, or coupled to, or in contact with the other component, or there may be an intervening component. In contrast, when a component is referred to as "directly on another component", "directly connected to", "directly coupled to", or "directly in contact with" another component, there is no intervening component.
[0034] In this application, flowcharts are used to illustrate the operations performed by the methods according to the embodiments of this application. It should be understood that the operations before or below do not necessarily need to be performed precisely in sequence. Instead, they can be performed in reverse order or simultaneously. Also, other operations can be added to these processes, or one or more operations can be removed from these processes.
[0035] In the manufacturing process of crystalline silicon solar cells, although the existing phosphorus diffusion technology can effectively form an N-type doping layer and generate a PSG protective layer, the PSG protective layer generated by the existing process has insufficient density on the silicon wafer surface and is easily eroded or damaged in subsequent wet processes (such as pickling and etching), resulting in an unsatisfactory protection effect. This affects the surface quality of the silicon wafer and the overall efficiency of the battery, reducing the production yield. In addition, the existing PSG protective layer generation process is restricted by the limitations of temperature control and the diffusion process, which may lead to uneven thickness of the PSG protective layer, thus affecting the performance consistency and stability of the battery.
[0036] Figure 1 It is a schematic flow diagram of a manufacturing method of a solar cell provided by an embodiment of this application. As Figure 1 shown, the manufacturing method of the solar cell includes the following steps:
[0037] Step S110: Place the solar cell intermediate in a diffusion chamber.
[0038] Certain pre-treatments can be performed on the silicon wafer to obtain the solar cell intermediate. The pre-treatments include but are not limited to cleaning, polishing, or forming a specific layer on the silicon wafer surface, such as a silicon dioxide layer, an intrinsic amorphous silicon layer, etc.
[0039] Step S120: Form a phosphosilicate glass layer on the surface of the solar cell intermediate.
[0040] After placing the solar cell intermediate in the diffusion chamber, introducing a phosphorus source into the diffusion chamber can form a phosphorus-silicon glass layer on the surface of the solar cell intermediate. Among them, the phosphorus source can be phosphorus oxychloride, etc. In some embodiments, forming a phosphorus-silicon glass layer on the surface of the solar cell intermediate includes the following steps: controlling the temperature in the diffusion chamber to a preset temperature and maintaining it at a constant temperature for a preset time; introducing oxygen into the diffusion chamber to oxidize the solar cell intermediate; introducing oxygen and a phosphorus source into the diffusion chamber to deposit the phosphorus source on the surface of the solar cell intermediate, thereby forming a phosphorus-silicon glass layer on the surface of the solar cell intermediate.
[0041] In one example, after placing the solar cell intermediate in the diffusion chamber, first preheat the diffusion chamber, control the temperature in the diffusion chamber to be heated to 830 - 860 °C, and maintain it at a constant temperature for 160 - 200 s. After preheating, introduce oxygen into the diffusion chamber to oxidize the solar cell intermediate. During the oxidation process, the flow rate of the introduced oxygen is 800 - 1800 sscm, and the oxidation time is 250 - 400 s. Then introduce oxygen and a phosphorus source into the diffusion chamber to deposit the phosphorus source on the surface of the solar cell intermediate, thereby forming a phosphorus-silicon glass layer on the surface of the solar cell intermediate. During the deposition of the phosphorus source, the flow rate of the introduced oxygen is 400 - 1400 sscm, the flow rate of the introduced phosphorus source is 1000 - 2000 sscm, and the deposition time is 1300 - 2000 s. In some embodiments, after depositing the phosphorus source, it further includes a phosphorus source pushing and annealing step, such as pushing the phosphorus source into the intrinsic amorphous silicon layer on the surface of the solar cell intermediate to form a doped polycrystalline silicon layer. An example of the process parameters during the phosphorus source pushing and annealing process is as follows: the temperature is 870 - 890 °C, the time is 1300 - 1700 s, and the pressure is 120 - 140 mbar. The pressure during the aforementioned preheating and deposition processes can also both be 120 - 140 mbar.
[0042] Step S130: Introduce oxygen and a phosphorus source into the diffusion chamber to cool down the solar cell intermediate with a phosphorus-silicon glass layer formed thereon.
[0043] In the embodiment of the present application, the post-oxidation step is cancelled after the phosphorus source pushing and annealing step in the phosphorus diffusion process, and the temperature of the solar cell intermediate with a phosphorus-silicon glass layer formed thereon is directly reduced. During the temperature reduction process, oxygen and a phosphorus source are introduced into the diffusion chamber. By controlling the flow rates of oxygen and the phosphorus source, they are attached to the surface of the solar cell intermediate to generate a phosphorus-rich layer. In one example, the flow rate of oxygen is controlled to be 500 - 1500 sscm, such as 500 sscm, 700 sscm, 900 sscm, 1100 sscm, 1300 sscm or 1500 sscm, to avoid excessive oxidation of the phosphorus-rich layer caused by too much oxygen, which may affect its physical properties. At the same time, the flow rate of the phosphorus source is controlled to be 100 - 1000 sscm, such as 100 sscm, 300 sscm, 500 sscm, 700 sscm, 900 sscm or 1000 sscm, to keep the flow rate of the phosphorus source at an appropriate level to ensure that the chemical composition of the phosphorus-rich layer meets the requirements.
[0044] In some embodiments, during the temperature reduction process, the time for introducing oxygen and the phosphorus source is 100 - 400 s, such as 100 s, 150 s, 200 s, 250 s, 300 s, 350 s or 400 s. During the temperature reduction process, when introducing oxygen and the phosphorus source into the diffusion chamber, the temperature in the diffusion chamber can also be controlled to be 600 - 870 °C, such as 600 °C, 700 °C, 800 °C or 870 °C, to ensure the effective formation of the phosphorus-rich layer.
[0045] Step S140: Use a laser to irradiate at least a partial area of the phosphorus-silicon glass layer.
[0046] If the diffusion chamber has the condition to use a laser, step S140 can be performed in the diffusion chamber. The solar intermediate can also be taken out of the diffusion chamber and step S140 can be performed in other environments. The embodiment of the present application does not limit this.
[0047] In one example, the laser used is a nanosecond ultraviolet laser, the wavelength of the laser is 200 - 600 nm, such as 200 nm, 300 nm, 400 nm, 500 nm or 600 nm. The pulse width of the laser is 20 - 100 ns, such as 20 ns, 40 ns, 60 ns, 80 ns or 100 ns. The single-pulse energy of the laser is 90 - 110 mJ, such as 90 mJ, 95 mJ, 100 mJ, 105 mJ or 110 mJ.
[0048] After step S130, the phosphosilicate glass layer in the target area is irradiated with a laser of a specific wavelength. Without damaging the surface of the solar intermediate, energy input promotes the rearrangement and densification of the phosphorus-rich layer, thereby forming a denser phosphosilicate glass layer, enhancing the erosion resistance of the PSG protective layer, ensuring stability in subsequent wet processes, and thus improving the overall efficiency and production yield of the battery. In addition, the laser processing technology can precisely control the energy distribution, making the PSG protective layer more uniformly generated on the surface of the solar intermediate, thereby improving the consistency of battery performance and also enhancing the stability of the products during the production process. It can be understood that the target area is the area where the densification of the phosphosilicate glass layer needs to be improved, such as the grid line area of the solar cell or the entire phosphosilicate glass layer.
[0049] After the formation of the PSG protective layer, subsequent processes such as wet etching, cleaning, and electrode preparation can be carried out. During the wet etching process, due to its densification and uniformity, the PSG protective layer can better resist chemical erosion, ensuring the integrity and optoelectronic performance of the surface of the solar cell intermediate. Finally, through coating and electrode preparation, the manufacturing of the solar cell is completed.
[0050] In some embodiments, after step S140, the solar cell intermediate is further placed in a process chamber, and the temperature in the process chamber is controlled to be 800 - 900 °C, such as 800 °C, 850 °C, or 900 °C, to further ensure the effective formation of the PSG protective layer. It should be noted that the process chamber can be the diffusion chamber in the above steps or a processing chamber different from the diffusion chamber. When the process chamber is the diffusion chamber in the above steps, if the solar cell intermediate is not taken out of the diffusion chamber in step S140, then the solar cell intermediate is already in the process chamber, and only the temperature in the process chamber needs to be controlled.
[0051] In some embodiments, nitrogen can also be introduced into the process chamber, and the flow rate of nitrogen is controlled to be 3000 - 5000 sscm, and the time for introducing nitrogen is greater than or equal to 5 min, such as 10 - 30 min, to make the temperature distribution in the process chamber more uniform and improve the formation quality of the PSG protective layer.
[0052] The basic concepts have been described above. Obviously, for those skilled in the art, the above invention disclosure is only an example and does not constitute a limitation to this application. Although not explicitly stated here, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are proposed in this application, so such modifications, improvements, and corrections still fall within the spirit and scope of the exemplary embodiments of this application.
[0053] Meanwhile, this application uses specific terms to describe the embodiments of this application. For example, "one embodiment", "an embodiment", and / or "some embodiments" mean a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more at different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application can be appropriately combined.
[0054] Similarly, it should be noted that, in order to simplify the description of this application disclosure and thus help the understanding of one or more inventive embodiments, in the foregoing description of the embodiments of this application, sometimes multiple features are merged into one embodiment, drawing, or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned. In fact, the features of the embodiment are less than all the features of the single embodiment disclosed above.
[0055] In some embodiments, numbers are used to describe the components and the quantity of attributes. It should be understood that such numbers used for the description of embodiments are modified by the modifiers "about", "approximately", or "substantially" in some examples. Unless otherwise specified, "about", "approximately", or "substantially" indicate that the said numbers allow a variation of ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification are all approximate values, and this approximate value can be changed according to the characteristics required by individual embodiments. In some embodiments, the numerical parameters should consider the specified significant digits and adopt the method of retaining the general number of digits. Although the numerical ranges and parameters used to confirm the scope breadth in some embodiments of this application are approximate values, in specific embodiments, the setting of such numerical values is as precise as possible within the feasible range.
[0056] Although this application has been described with reference to the current specific embodiments, those of ordinary skill in the art in this technical field should recognize that the above embodiments are only used to illustrate this application, and various equivalent changes or substitutions can be made without departing from the spirit of this application. Therefore, as long as the changes and modifications to the above embodiments are within the scope of the substantial spirit of this application, they will fall within the scope of this application.
Claims
1. A method for manufacturing a solar cell, characterized in that: include: placing a solar cell intermediate in a diffusion chamber; forming a phosphorus-silicate glass layer on the surface of the solar cell intermediate; Introducing oxygen and a phosphorus source into the diffusion chamber, controlling the flow rate of the oxygen to be 500-1500sscm, and the flow rate of the phosphorus source to be 100-1000sscm, and performing a temperature reduction treatment on the solar cell intermediate formed with the phosphorus silicon glass layer; At least a partial area of the phosphosilicate glass layer is irradiated with laser.
2. The manufacturing method according to claim 1, characterized in that The wavelength of the laser is 200-600nm, and the pulse width of the laser is 20-100ns.
3. The manufacturing method according to claim 2, characterized in that: The single pulse energy of the laser is 90-110 mJ.
4. The manufacturing method according to claim 1, characterized in that: After the step of irradiating at least a partial area of the phosphosilicate glass layer with laser, the method further comprises: placing the solar cell intermediate in a process chamber; The temperature in the process chamber is controlled to be 800-900°C.
5. The manufacturing method according to claim 4, characterized in that: Also includes: Nitrogen gas is introduced into the process chamber, the flow rate of the nitrogen gas is controlled to be 3000-5000sscm, and the time for introducing the nitrogen gas is greater than or equal to 5 minutes.
6. The manufacturing method according to claim 1, characterized in that: During the temperature reduction treatment, the time for introducing oxygen and phosphorus source is 100-400 seconds.
7. The manufacturing method according to claim 1 or 6, characterized in that: During the temperature reduction treatment, when oxygen and phosphorus source are introduced into the diffusion chamber, the temperature in the diffusion chamber is controlled to be 600-870°C.
8. The manufacturing method according to claim 1, characterized in that: The forming of a phosphorus-silicate glass layer on the surface of the solar cell intermediate body comprises: Controlling the temperature in the diffusion chamber to a preset temperature and maintaining the constant temperature for a preset time; introducing oxygen into the diffusion chamber to oxidize the solar cell intermediate; Oxygen and a phosphorus source are introduced into the diffusion chamber to deposit the phosphorus source on the surface of the solar cell intermediate body, thereby forming a phosphorus-silicate glass layer on the surface of the solar cell intermediate body.
9. The manufacturing method according to claim 8, characterized in that: During the oxidation treatment, the oxygen flow rate is 800-1800sscm.
10. The manufacturing method according to claim 8 or 9, characterized in that: During the deposition of the phosphorus source, the flow rate of the introduced oxygen is 400-1400 sscm, and the flow rate of the introduced phosphorus source is 1000-2000 sscm.