Diffusion method, diffusion device and solar cell
During the diffusion process, diffusion gas is introduced inward with the first flow rate from the furnace of the diffusion furnace tube, and diffusion gas is introduced inward with the second flow rate at one of the furnace opening and the furnace tail, the problem of poor square resistance uniformity of pn junction in the prior art is solved, and a more efficient diffusion effect and better square resistance uniformity are achieved.
Patent Information
- Application Number
- CN202311016001.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-11
- Publication Date
- 2025-02-25
AI Technical Summary
The square resistance uniformity of the pn junction formed by the existing diffusion methods is poor, especially in larger-sized diffusion furnace tubes, resulting in low production capacity and uneven square resistance.
During the diffusion process, diffusion gas is inwardly introduced from the furnace of the diffusion furnace tube with a first flow rate, and diffusion gas is inwardly introduced at one of the furnace opening and the furnace tail, ensuring that the first flow rate is greater than the second flow rate, thereby improving the uniformity of square resistance.
This method effectively improves the square resistance uniformity of the pn junction, especially in larger-sized diffusion furnace tubes, which improves production capacity and enhances the uniformity of the square resistance.
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Figure CN119517736A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of photovoltaic technology, in particular to a diffusion method and a diffusion device and a solar cell. Background Art
[0002] Solar cells can convert light energy into electrical energy, making full use of renewable clean energy. Therefore, they have broad application prospects.
[0003] The core of solar cells is the pn junction, and diffusion is an important process in the preparation of the pn junction. However, the pn junction formed by the existing diffusion method has poor uniformity of square resistance. Summary of the invention
[0004] The present application aims to provide a diffusion method, a diffusion device and a solar cell, which at least solve the problem of poor uniformity of square resistance of a pn junction formed by an existing diffusion method.
[0005] In order to solve the above technical problems, this application is implemented as follows:
[0006] In a first aspect, an embodiment of the present application proposes a diffusion method, comprising:
[0007] In the diffusion process, a diffusion gas is introduced into the diffusion furnace tube from the furnace of the diffusion furnace tube at a first flow rate, and the diffusion gas is introduced into the diffusion furnace tube at a second flow rate at one of the furnace mouth and the furnace tail of the diffusion furnace tube;
[0008] Wherein, the first flow rate is greater than the second flow rate.
[0009] Optionally, along the first direction from the furnace mouth to the furnace tail, the size of the diffusion furnace tube is d;
[0010] The furnace of the diffusion furnace tube includes: a portion in the diffusion furnace tube, along the first direction, from a position 45% of d from the furnace opening to a position 55% of d from the furnace opening, and a portion therebetween.
[0011] Optionally, the diffusion is boron diffusion.
[0012] Optionally, a ratio of the first flow rate to the second flow rate is 6:1 to 6:3.
[0013] Optionally, the diffusion gas includes nitrogen, oxygen and boron trichloride.
[0014] In a second aspect, an embodiment of the present application proposes a diffusion device for implementing any of the aforementioned diffusion methods.
[0015] Optionally, the diffusion device is characterized by comprising: an air supply pipe, a first air intake pipe, a second air intake pipe, a three-way valve, a throttle valve and the diffusion furnace pipe;
[0016] The air inlet of the air supply pipe is used for the diffusion gas to flow in;
[0017] The air outlet of the air supply pipe is connected to the inlet of the three-way valve;
[0018] An outlet of the three-way valve is connected to the air inlet of the first air inlet pipe;
[0019] The other outlet of the three-way valve is connected to the air inlet of the second air inlet pipe through the throttle valve;
[0020] The gas outlet of the first gas inlet pipe is located in the furnace of the diffusion furnace tube;
[0021] The gas outlet of the second gas inlet pipe is located at one of the furnace mouth and the furnace tail of the diffusion furnace tube;
[0022] The first air inlet pipe is used to introduce the diffusion gas from the furnace of the diffusion furnace tube into the diffusion furnace tube at the first flow rate during the diffusion process;
[0023] The second air inlet pipe is used to introduce the diffusion gas into the diffusion furnace tube at the second flow rate from one of the furnace mouth and the furnace tail of the diffusion furnace tube during the diffusion process.
[0024] Optionally, the first air inlet pipe and the second air inlet pipe are both quartz tubes.
[0025] In a third aspect, an embodiment of the present application proposes a solar cell, comprising: a pn junction; the pn junction is formed by a p-type semiconductor and an n-type semiconductor; at least one of the p-type semiconductor and the n-type semiconductor is prepared by any of the aforementioned diffusion methods.
[0026] In an embodiment of the present application, a diffusion gas is introduced into the diffusion furnace tube from the furnace of the diffusion furnace tube at a first flow rate, and a diffusion gas is introduced into the diffusion furnace tube at a second flow rate at one of the furnace mouth and the furnace tail of the diffusion furnace tube, and the first flow rate is greater than the second flow rate, that is, the diffusion gas entering the furnace in the furnace is used as the main intake air, and the diffusion gas entering the furnace at one of the furnace mouth and the furnace tail is used as the auxiliary intake air, and the distance between the furnace and the furnace mouth and the furnace tail is roughly equal, so the diffusion degree of the furnace mouth is basically the same as the diffusion degree of the furnace tail, thereby improving the uniformity of the square resistance, especially for the diffusion furnace tube of larger size, not only the production capacity is high, but also the uniformity of the square resistance is better. Moreover, the flow rate of the diffusion gas entering the furnace at one of the furnace mouth and the furnace tail is small, and the turbulence caused by the airflow in the furnace is small, which can further improve the uniformity of the square resistance. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.
[0028] Figure 1 A partial structural schematic diagram of a diffusion device in an embodiment of the present application is shown;
[0029] Figure 2 A comparison chart of the results of the embodiments and comparative examples in the examples of the present application is shown.
[0030] Figure numerals: 11 - diffusion furnace tube, 12 - air supply pipe, 13 - first air inlet pipe, 14 - second air inlet pipe, 15 - three-way valve, 16 - throttle valve, 111 - furnace mouth of the diffusion furnace tube, 112 - furnace tail of the diffusion furnace tube. DETAILED DESCRIPTION
[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0032] The inventors have found that the problem of poor uniformity of square resistance of pn junction formed by existing diffusion methods lies mainly in that in the existing diffusion methods, diffusion gas is introduced into the diffusion furnace tube from one of the furnace mouth and the furnace tail of the diffusion furnace tube as the main air inlet at a relatively large flow rate, and diffusion gas is introduced into the diffusion furnace tube from the furnace of the diffusion furnace tube as the auxiliary air inlet at a relatively small flow rate. The distance between the furnace mouth and the furnace tail is relatively far, especially as the production capacity continues to increase and the diffusion furnace tube continues to become larger, the distance between the furnace mouth and the furnace tail is even farther. The diffusion gas at the one of the furnace mouth and the furnace tail that is not used as the air vent is relatively small, and normal diffusion cannot be guaranteed, resulting in poor uniformity of square resistance of the formed pn junction. Moreover, in the existing diffusion method, diffusion gas is introduced into the diffusion furnace tube at a larger flow rate from one of the furnace mouth and the furnace tail of the diffusion furnace tube. The airflow at the furnace mouth is greater than the airflow in the furnace, which will cause turbulence to the airflow in the furnace, further resulting in less diffusion gas in the one of the furnace mouth and the furnace tail that is not used as a vent, and normal diffusion cannot be guaranteed, which further leads to poor uniformity of square resistance of the formed pn junction.
[0033] In view of the above technical problems, in the present invention, during the diffusion process, diffusion gas is introduced into the diffusion furnace tube from the furnace of the diffusion furnace tube at a first flow rate, and diffusion gas is introduced into the diffusion furnace tube at a second flow rate at one of the furnace mouth and the furnace tail of the diffusion furnace tube, and the first flow rate is greater than the second flow rate, that is, the diffusion gas entering the furnace in the furnace is used as the main air intake, and the diffusion gas entering the furnace at one of the furnace mouth and the furnace tail is used as the auxiliary air intake, and the distance between the furnace and the furnace mouth and the furnace tail is roughly equal, so the diffusion degree of the furnace mouth is basically the same as the diffusion degree of the furnace tail, thereby improving the uniformity of the square resistance, especially for the diffusion furnace tube of larger size, not only the production capacity is high, but also the uniformity of the square resistance is better. At the same time, the flow rate of the diffusion gas entering the furnace at one of the furnace mouth and the furnace tail is small, and the turbulence caused by the air flow in the furnace is small, which can further improve the uniformity of the square resistance.
[0034] It should be noted that the first flow rate is greater than the second flow rate, and the difference between the two may not be specifically limited. One of the furnace mouth and the furnace tail is used as an auxiliary air inlet, and the other is used as an air outlet. It is not specifically limited here whether it is for p-type diffusion or n-type diffusion. The aforementioned diffusion gas is selected according to whether p-type diffusion or n-type diffusion is required.
[0035] Specifically, during the diffusion process, the diffusion gas is introduced into the diffusion furnace tube from the furnace of the diffusion furnace tube at a first flow rate, and the diffusion gas is introduced into the diffusion furnace tube at a second flow rate at the furnace mouth of the diffusion furnace tube. Alternatively, during the diffusion process, the diffusion gas is introduced into the diffusion furnace tube from the furnace of the diffusion furnace tube at a first flow rate, and the diffusion gas is introduced into the diffusion furnace tube at a second flow rate at the furnace tail of the diffusion furnace tube.
[0036] The diffusion furnace tube has a furnace door. The furnace mouth refers to the area near the furnace door and its vicinity. In the diffusion furnace tube, the furnace mouth and the furnace tail are relatively distributed, or in other words, the furnace tail is far away from the furnace door.
[0037] Figure 1 FIG. 1 is a schematic diagram showing a partial structure of a diffusion device in an embodiment of the present application. Figure 1 , the diffusion device includes the aforementioned diffusion furnace tube 11, and L1 refers to the first direction along the furnace mouth 111 to the furnace tail 112. One end of the diffusion furnace tube 11 is the furnace mouth 111, and the other end is the furnace tail 112. Along the first direction L1, the size of the diffusion furnace tube 11 is d. The furnace of the diffusion furnace tube 11 includes: the part inside the diffusion furnace tube 11, along the first direction L1, from a position of 45% of d from the furnace mouth 111 to a position of 55% of d from the furnace mouth 111, and the part between the two. The furnace of the diffusion furnace tube 11 is precisely defined here, and the control of the main air intake position can be more accurate, which can further improve the uniformity of the square resistance.
[0038] Optionally, the aforementioned diffusion is boron diffusion, which can improve the square resistance uniformity of the boron diffusion.
[0039] Optionally, the aforementioned diffusion is boron diffusion, and the ratio of the aforementioned first flow rate to the second flow rate is 6:1 to 6:3. Within this range, the diffusion degree to the furnace mouth is closer to the diffusion degree to the furnace tail, which can further improve the uniformity of the square resistance, especially for larger-sized diffusion furnace tubes, which not only has high production capacity, but also better uniformity of square resistance. Moreover, at one of the furnace mouth and the furnace tail, the flow rate of the diffusion gas entering the furnace is smaller and more appropriate, and the turbulence caused by the airflow in the furnace is smaller, which can further improve the uniformity of the square resistance.
[0040] For example, the ratio of the first flow rate to the second flow rate may be 6:1, or 5:1, or 4:1, or 3:1, or 5:2, or 6:3, etc.
[0041] Optionally, the aforementioned diffusion is boron diffusion, and the aforementioned diffusion gas includes: nitrogen (N2), oxygen (O2) and boron trichloride (BCl3). The aforementioned gases are used as diffusion gases for boron diffusion, and a p-type semiconductor with better quality can be obtained.
[0042] Reference Figure 1 As shown, the present invention further provides a diffusion device, which may include: an air supply pipe 12, a first air intake pipe 13, a second air intake pipe 14, a three-way valve 15, a throttle valve 16 and the aforementioned diffusion furnace tube 11.
[0043] The air inlet of the air supply pipe 12 is Figure 1 The right port of the air supply pipe 12 is the position indicated by the large arrow. The air inlet of the air supply pipe 12 is used for the aforementioned diffusion gas to flow in. The air outlet of the air supply pipe 12 is the left port of the air supply pipe 12, and the air outlet of the air supply pipe 12 is connected to the inlet of the three-way valve 15. One outlet of the three-way valve 15 is connected to the air inlet of the first air intake pipe 13, and the other outlet of the three-way valve 15 is connected to the air inlet of the second air intake pipe 14 through the throttle valve 16. The main function of the three-way valve 15 is to divert the diffusion gas entering from the air supply pipe 12, and the main function of the throttle valve 16 is to reduce the flow rate of the diffusion gas entering the second air intake pipe 14. The flow rate of the diffusion gas entering the second air intake pipe 14 can be reduced by rotating the valve of the throttle valve 16, etc.
[0044] The gas outlet of the first air inlet pipe 13 is located in the furnace of the diffusion furnace tube 11. The gas outlet of the second air inlet pipe 14 is located at one of the furnace mouth 111 and the furnace tail 112 of the diffusion furnace tube 11. Figure 1 In the embodiment, the gas outlet of the second gas inlet pipe 14 is located at the furnace tail 112 of the diffusion furnace tube 11 .
[0045] The first air inlet pipe 13 is used to introduce the aforementioned diffusion gas from the furnace of the diffusion furnace tube 11 at a first flow rate into the diffusion furnace tube 11 during the diffusion process. The second air inlet pipe 14 is used to introduce the aforementioned diffusion gas from one of the furnace mouth 111 and the furnace tail 112 of the diffusion furnace tube 11 at the aforementioned second flow rate into the diffusion furnace tube 11 during the diffusion process.
[0046] The device can conveniently adjust the second flow rate of the diffusion gas entering the second air intake pipe 14 , and can easily adjust the first flow rate of the diffusion gas entering the first air intake pipe 13 .
[0047] Optionally, the first air inlet pipe 13 and the second air inlet pipe 14 are both quartz tubes. During the diffusion process, the first air inlet pipe 13 and the second air inlet pipe 14 can withstand the diffusion temperature.
[0048] Optionally, the air supply pipe 12 may be a hose, and a hose may be provided between one outlet of the three-way valve 15 and the air inlet of the first air inlet pipe 13. A hose may be provided between the other outlet of the three-way valve 15 and the throttle valve 16, and a hose may be provided between the throttle valve 16 and the air inlet of the second air inlet pipe 14. It should be noted that the aforementioned hoses do not substantially extend into the diffusion furnace tube 11, so the diffusion temperature need not be considered, and the hoses here may be polytetrafluoroethylene hoses or the like.
[0049] The present application also provides a solar cell, which may include a pn junction; the pn junction is formed by a p-type semiconductor and an n-type semiconductor; at least one of the p-type semiconductor and the n-type semiconductor is prepared using any of the aforementioned diffusion methods, thereby improving the uniformity of square resistance in the solar cell, thereby improving the performance of the solar cell.
[0050] It should be noted that in the present application, the diffusion method, the diffusion device and the solar cell have the same or similar beneficial effects. In order to avoid repetition, the relevant parts are abbreviated or omitted.
[0051] The present application is further explained below in conjunction with specific embodiments.
[0052] Example
[0053] use Figure 1 The diffusion device shown in the figure performs boron diffusion. During the diffusion process, a diffusion gas is introduced into the diffusion furnace tube 11 from the furnace of the diffusion furnace tube 11 at a first flow rate, and the aforementioned diffusion gas is introduced into the diffusion furnace tube 11 at a second flow rate at the furnace tail 112 of the diffusion furnace tube 11. The aforementioned diffusion gases are nitrogen, oxygen and boron trichloride. Here, the ratio of the first flow rate to the second flow rate is 3:1. Here, along the first direction L1 from the furnace mouth 111 to the furnace tail 112, the size of the diffusion furnace tube is d, and the outlet of the first air inlet pipe 13 is located at: along the first direction L1 from the furnace mouth 111 to the furnace tail 112, at a position d that is 50% of the distance from the furnace mouth 111.
[0054] In the embodiment, there are 11 boats in the diffusion furnace tube 11 , and the boats are numbered from 1 to 11 and are distributed in sequence from the furnace mouth 111 to the furnace tail 112 .
[0055] Comparative Example
[0056] During the boron diffusion process, a diffusion gas is introduced into the diffusion furnace tube from the furnace tail of the diffusion furnace tube at a first flow rate, and in the furnace of the diffusion furnace tube, the aforementioned diffusion gas is introduced into the diffusion furnace tube at a second flow rate. The aforementioned diffusion gases are also nitrogen, oxygen and boron trichloride. Here, the ratio of the first flow rate to the second flow rate is also 3:1. The air outlet of the air inlet pipe of the furnace mouth in the comparative example is also located along the first direction from the furnace mouth to the furnace tail, at a position 50% of the total length of the furnace tube from the furnace mouth. The direction where the total length of the furnace tube is located here is along the first direction from the furnace mouth to the furnace tail.
[0057] In the comparative example, the diffusion furnace tube 11 has 11 boats in total, and the boats numbered from 1 to 11 are distributed in sequence from the furnace mouth to the furnace tail.
[0058] Figure 2 The table shows the results of the embodiment and the comparative example in the present application. After the diffusion is completed, the square resistance of 1 silicon wafer in each boat of the embodiment, a total of 11 silicon wafers, is measured, and the square resistance of 1 silicon wafer in each boat of the comparative example, a total of 11 silicon wafers, is measured, that is, a silicon wafer is randomly selected from each boat. The measurement results are shown in Figure 2 For a silicon wafer, square resistance 1 to square resistance 9 refer to the square resistance at each position measured by taking 9 different positions from the silicon wafer. The intra-wafer non-uniformity of a single wafer refers to the geometric mean of the 9 square resistances at the aforementioned 9 positions in a silicon wafer, the maximum square resistance minus the minimum square resistance, divided by twice the 9 square resistances. The intra-wafer non-uniformity of a single tube refers to the geometric mean of the intra-wafer non-uniformity of 11 silicon wafers.
[0059] Depend on Figure 2 It can be inferred that, compared with the comparative example, in the embodiment, the non-uniformity of the square resistance of the silicon wafers of the 11 boats is reduced, and for the non-uniformity within a single tube wafer, it is reduced by about 5%, and the uniformity is improved. The main reason is that in the embodiment, during the diffusion process, the diffusion gas entering the furnace in the furnace is used as the main intake gas, and the diffusion gas entering the furnace at the furnace tail 112 is used as the auxiliary intake gas. The distance between the furnace and the furnace mouth 111 and the furnace tail 112 is roughly equal. Therefore, the diffusion degree of the furnace mouth 111 is basically the same as the diffusion degree of the furnace tail 112, thereby improving the uniformity of the square resistance. Moreover, at the furnace tail 112, the flow rate of the diffusion gas entering the furnace is small, and the turbulence caused by the airflow in the furnace is small, which can further improve the uniformity of the square resistance.
[0060] It should be noted that the aforementioned solar cells and photovoltaic modules can refer to each other in their related parts and can achieve the same or similar effects. In order to avoid repetition, the related parts are briefly described.
[0061] It should be noted that, for the method embodiments, for the sake of simplicity of description, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the embodiments of the present application are not limited by the described order of actions, because according to the embodiments of the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of the present application.
[0062] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.
[0063] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for enabling a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present invention.
[0064] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.
Claims
1. A diffusion method, characterized in that: include: In the diffusion process, a diffusion gas is introduced into the diffusion furnace tube from the furnace of the diffusion furnace tube at a first flow rate, and the diffusion gas is introduced into the diffusion furnace tube at a second flow rate at one of the furnace mouth and the furnace tail of the diffusion furnace tube; Wherein, the first flow rate is greater than the second flow rate.
2. The diffusion method according to claim 1, characterized in that: Along the first direction from the furnace mouth to the furnace tail, the size of the diffusion furnace tube is d; The furnace of the diffusion furnace tube includes: a portion in the diffusion furnace tube, along the first direction, from a position 45% of d from the furnace opening to a position 55% of d from the furnace opening, and a portion therebetween.
3. The diffusion method according to claim 1, characterized in that: The diffusion is boron diffusion.
4. The diffusion method according to claim 3, characterized in that: The ratio of the first flow rate to the second flow rate is 6:1 to 6:
3.
5. The diffusion method according to claim 3 or 4, characterized in that: The diffusion gas includes nitrogen, oxygen and boron trichloride.
6. A diffusion device, characterized in that: Used to implement the diffusion method described in any one of claims 1 to 5.
7. The diffusion device according to claim 6, characterized in that include: An air supply pipe, a first air inlet pipe, a second air inlet pipe, a three-way valve, a throttle valve and the diffusion furnace pipe; The air inlet of the air supply pipe is used for the diffusion gas to flow in; The air outlet of the air supply pipe is connected to the inlet of the three-way valve; An outlet of the three-way valve is connected to the air inlet of the first air inlet pipe; The other outlet of the three-way valve is connected to the air inlet of the second air inlet pipe through the throttle valve; The gas outlet of the first gas inlet pipe is located in the furnace of the diffusion furnace tube; The gas outlet of the second gas inlet pipe is located at one of the furnace mouth and the furnace tail of the diffusion furnace tube; The first air inlet pipe is used to introduce the diffusion gas from the furnace of the diffusion furnace tube into the diffusion furnace tube at the first flow rate during the diffusion process; The second air inlet pipe is used to introduce the diffusion gas into the diffusion furnace tube at the second flow rate from one of the furnace mouth and the furnace tail of the diffusion furnace tube during the diffusion process.
8. The diffusion device according to claim 7, characterized in that The first air inlet pipe and the second air inlet pipe are both quartz tubes.
9. A solar cell, characterized in that: include: pn junction; The pn junction is formed by a p-type semiconductor and an n-type semiconductor; at least one of the p-type semiconductor and the n-type semiconductor is prepared by the diffusion method described in any one of claims 1 to 5.