Front side anti-reflective film of perc solar cell, preparation method and solar cell
By stacking and depositing films of specific thickness and refractive index on the front side of PERC solar cells, the problem of poor refractive index gradient in existing technologies is solved, thereby improving light absorption and cell efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TIANJIN AIKO SOLAR ENERGY TECH CO LTD
- Filing Date
- 2022-12-30
- Publication Date
- 2026-05-22
Smart Images
Figure CN116259673B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of solar cell technology, specifically relating to a front anti-reflective film for a PERC solar cell, its preparation method, and the solar cell itself. Background Technology
[0002] Currently, the antireflective coating structure on the front of solar cells consists of two layers of silicon nitride and one layer of silicon oxide. This three-layer film exhibits poor reflection loss across the wavelength range and has limited light absorption capacity. Specifically, this is due to the poor refractive index gradient between the layers; the refractive index difference between adjacent layers is significant, failing to form a good gradient, resulting in poor light absorption and low utilization.
[0003] Therefore, a new technology is needed to solve the problem of poor refractive index gradient in existing antireflective coatings. Summary of the Invention
[0004] This invention provides a front antireflective coating for a PERC solar cell, a preparation method thereof, and the solar cell itself, aiming to improve the refractive index gradient of the front antireflective coating and enhance light utilization.
[0005] The embodiments of the present invention are implemented as follows:
[0006] An anti-reflective coating for the front side of a PERC solar cell includes a first silicon nitride layer, a first silicon oxynitride layer, a second silicon nitride layer, and a second silicon oxynitride layer sequentially deposited on the front side of the cell.
[0007] The refractive indices of the first silicon nitride layer, the first silicon oxynitride layer, the second silicon nitride layer, and the second silicon oxynitride layer decrease sequentially, and the difference in refractive index between two adjacent layers is no greater than 0.22. The thickness of the first silicon nitride layer is 5 nm to 15 nm, and the refractive index is 2.30 to 2.35. The thicknesses of the first silicon oxynitride layer, the second silicon nitride layer, and the second silicon oxynitride layer are all greater than the thickness of the first silicon nitride layer.
[0008] Furthermore, the thickness of the first silicon oxynitride layer is 15 nm to 25 nm, and the refractive index is 2.15 to 2.20.
[0009] Furthermore, the thickness of the second silicon nitride layer is 15 nm to 25 nm, and the refractive index is 2.07 to 2.12.
[0010] Furthermore, the thickness of the second silicon oxynitride layer is 15 nm to 25 nm, and the refractive index is 1.85 to 2.1.
[0011] The present invention also provides a method for preparing a front anti-reflection film, used to prepare a front anti-reflection film for a PERC solar cell as described in any of the preceding claims, the method comprising the following steps:
[0012] A first silicon nitride layer is deposited on the front side of the silicon wafer, with an ammonia flow rate of 9000 sccm to 14000 sccm and a silane flow rate of 500 sccm to 2100 sccm.
[0013] A first silicon oxynitride layer is deposited on the first silicon nitride layer, with a nitrous oxide flow rate of 5000 sccm to 14000 sccm, an ammonia flow rate of 4000 sccm to 11000 sccm, and a silane flow rate of 500 sccm to 2100 sccm.
[0014] A second silicon nitride layer is deposited on the first silicon oxynitride layer, with an ammonia flow rate of 7000 sccm to 15000 sccm and a silane flow rate of 500 sccm to 2100 sccm.
[0015] A second silicon oxynitride layer is deposited on the second silicon nitride layer, with a nitrous oxide flow rate of 3500 sccm to 14000 sccm, an ammonia flow rate of 5000 sccm to 21000 sccm, and a silane flow rate of 400 sccm to 2800 sccm.
[0016] Furthermore, in the step of depositing a first silicon nitride layer on the front side of the silicon wafer, with an ammonia flow rate of 9000 sccm to 14000 sccm and a silane flow rate of 500 sccm to 2100 sccm,
[0017] The deposition temperature was 300℃~600℃, the deposition pressure was 800~1500mTor, the deposition power was 8000W~15000W, the deposition time was 70s~150s, and the deposition duty cycle was 5 / 120ms~5 / 200ms.
[0018] Furthermore, in the step of depositing a first silicon oxynitride layer on the first silicon nitride layer, with a nitrous oxide flow rate of 5000 sccm to 14000 sccm, an ammonia flow rate of 4000 sccm to 11000 sccm, and a silane flow rate of 500 sccm to 2100 sccm,
[0019] The deposition temperature was 320℃~580℃, the deposition pressure was 800~6500mTor, the deposition power was 6000W~18000W, the deposition time was 80s~400s, and the deposition duty cycle was 5 / 40ms~5 / 200ms.
[0020] Furthermore, in the step of depositing a second silicon nitride layer on the first silicon oxynitride layer, with an ammonia flow rate of 7000 sccm to 15000 sccm and a silane flow rate of 500 sccm to 2100 sccm,
[0021] The deposition temperature was 350℃~600℃, the deposition pressure was 500~8000mTor, the deposition power was 7000W~16000W, the deposition time was 70s~300s, and the deposition duty cycle was 5 / 40ms~5 / 120ms.
[0022] Furthermore, in the step of depositing a second silicon oxynitride layer on the second silicon nitride layer, with a nitrous oxide flow rate of 3500 sccm to 14000 sccm, an ammonia flow rate of 5000 sccm to 21000 sccm, and a silane flow rate of 400 sccm to 2800 sccm,
[0023] The deposition temperature was 400℃~600℃, the deposition pressure was 700~9000mTor, the deposition power was 8000W~18000W, the deposition time was 100s~350s, and the deposition duty cycle was 5 / 50ms~5 / 140ms.
[0024] The present invention also provides a solar cell, including a front anti-reflective coating of a PERC solar cell as described in any of the preceding claims.
[0025] The beneficial effects achieved by this invention are:
[0026] In the antireflective coating of the PERC solar cell of this invention, the refractive index of each layer decreases sequentially from bottom to top, and the difference in refractive index between adjacent layers is no greater than 0.22. The first silicon nitride layer has the highest refractive index, ranging from 2.30 to 2.35, with a thickness of 5 nm to 15 nm. The thickness of the remaining layers ranges from 15 nm to 25 nm. This creates a stacked film with different refractive index gradients, allowing light to pass through different refractive index gradients from air to the silicon wafer, thereby maximizing the absorption of sunlight. Under these constraints of refractive index difference and thickness, the overall refractive index of the front antireflective coating can be controlled to approach optimal reflection conditions, with an overall refractive index close to 2.387, which matches the refractive index of the encapsulated photovoltaic module (i.e., glass and silicon wafer), thereby improving current and cell efficiency. Attached Figure Description
[0027] Figure 1 This is a schematic diagram of the structure of the anti-reflective coating on the front side of the PERC solar cell provided in an embodiment of the present invention;
[0028] Figure 2 This is a step diagram of the preparation method of the front antireflective film of the present invention;
[0029] Figure 3 This is a comparison diagram of the reflection curves of the present invention and the original design of the prior art.
[0030] Icon labels:
[0031] 1. Silicon wafer; 2. First silicon nitride layer; 3. First silicon oxynitride layer; 4. Second silicon nitride layer; 5. Second silicon oxynitride layer. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the invention, and should not be construed as limiting the invention. Furthermore, it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
[0033] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.
[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0036] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0037] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.
[0038] The present invention creates a suitable refractive index difference and a suitable refractive index gradient between the various film layers on the front side, allowing light to pass through different refractive index gradients from air to silicon wafer 1, thereby maximizing the absorption of sunlight. Under the constraints of this refractive index difference and thickness, the overall refractive index of the front antireflective film can be controlled to approach optimal reflection conditions, with an overall refractive index close to 2.387, which matches the refractive index of the encapsulated photovoltaic module (i.e., glass and silicon wafer), thereby improving current and cell efficiency.
[0039] Example 1
[0040] Reference Figure 1 This embodiment provides an anti-reflective coating for the front side of a PERC solar cell, comprising a first silicon nitride layer 2, a first silicon oxynitride layer 3, a second silicon nitride layer 4, and a second silicon oxynitride layer 5 sequentially deposited on the front side of the cell.
[0041] In this embodiment, a four-layer film structure is formed on the front side of the solar cell. These four film layers are formed by deposition. The first silicon nitride layer 2 is formed on the silicon surface of the front side of the cell, and the second silicon oxynitride layer 5 is formed on the first silicon nitride layer 2. Correspondingly, the second silicon nitride layer 4 is formed on the first silicon oxynitride layer 3, and the second silicon oxynitride layer 5 is formed on the second silicon nitride layer 4. These four film layers are stacked one on top of the underlying structure.
[0042] The refractive indices of the first silicon nitride layer 2, the first silicon oxynitride layer 3, the second silicon nitride layer 4, and the second silicon oxynitride layer 5 decrease sequentially, and the difference in refractive index between two adjacent layers is no greater than 0.22. The thickness of the first silicon nitride layer 2 is 5 nm to 15 nm, and the refractive index is 2.30 to 2.35. The thicknesses of the first silicon oxynitride layer 3, the second silicon nitride layer 4, and the second silicon oxynitride layer 5 are all greater than the thickness of the first silicon nitride layer 2.
[0043] Specifically, the thickness of the first silicon nitride layer 2 can be 8 nm, 9 nm, 10 nm, 11 nm, 13 nm, etc., and the refractive index can be 2.31, 2.32, 2.33, 2.34, etc. The difference in refractive index between two adjacent layers can be 0.05, 0.08, 0.10, 0.15, 0.21, etc. The thicknesses of the first silicon oxynitride layer 3, the second silicon nitride layer 4, and the second silicon oxynitride layer 5 are 16 nm, 18 nm, 20 nm, 22 nm, or 24 nm.
[0044] In this embodiment, the thickness of the first silicon nitride layer 2 is 10 nm and the refractive index is 2.32.
[0045] In this four-layer film structure, the first silicon nitride layer 2, located at the bottom, has the highest refractive index and the smallest thickness. The thickness of the three layers above it is approximately twice that of the first silicon nitride layer 2. By setting the difference in refractive index between adjacent layers to no more than 0.22, a good refractive index gradient can be formed among the four layers, allowing light to pass through different refractive index gradients from air to silicon wafer 1, thereby maximizing the absorption of sunlight.
[0046] Photovoltaic modules are encapsulated before use, with an outer layer of glass and an inner layer of silicon wafer 1. Therefore, the refractive index of the anti-reflective coating on its front side must meet the refractive index requirements of the encapsulated photovoltaic module. According to theoretical calculations, the refractive index has the following relationship:
[0047] n 2 =n0*n Si
[0048] In the formula, n is the refractive index of the antireflective coating, n0 is the refractive index of the glass, and n Si Let be the refractive index of silicon, then
[0049] The square of the refractive index of an antireflective coating is equal to the product of the refractive indices of glass and silicon. Where the refractive index of glass is n0 = 1.5, and the refractive index of silicon is n... Si =3.9, the refractive index of the best-matched antireflective film is about 2.387. Therefore, if you want to reduce light reflection, the refractive index of the antireflective film needs to be close to 2.387. The closer it is to 2.387, the less light is reflected. Correspondingly, the better the absorption effect of sunlight, and the higher the current and battery efficiency.
[0050] In this embodiment, under the limitation of this thickness and refractive index difference, the combined refractive index of these four film layers can be close to 2.387, thereby ensuring that the solar cell can absorb sunlight well and ensure the conversion efficiency of the cell.
[0051] Example 2
[0052] This embodiment provides a front anti-reflective coating for a PERC solar cell, which, based on Embodiment 1, also has the following design:
[0053] The thickness of the first silicon oxynitride layer 3 is 15nm to 25nm, and the refractive index is 2.15 to 2.20.
[0054] A first silicon oxynitride layer 3 covers the first silicon nitride layer 2, and its thickness is approximately twice that of the first silicon nitride layer 2. This thickness can be 16 nm, 18 nm, 20 nm, 21 nm, 22 nm, or 24 nm, etc. The refractive index of the first silicon oxynitride layer 3 is slightly smaller than that of the first silicon nitride layer 2, specifically 2.16, 2.17, 2.18, or 2.19. In this embodiment, the thickness of the first silicon oxynitride layer 3 is 21 nm, and its refractive index is 2.17.
[0055] Example 3
[0056] This embodiment provides a front anti-reflective coating for a PERC solar cell, which, based on Embodiment 1, also has the following design:
[0057] The second silicon nitride layer 4 has a thickness of 15nm to 25nm and a refractive index of 2.07 to 2.12.
[0058] A second silicon nitride layer 4 covers the first silicon oxynitride layer 3, and its thickness is approximately the same as that of the first silicon oxynitride layer 3, such as 16 nm, 18 nm, 20 nm, 21 nm, 22 nm, or 24 nm. The refractive index of the second silicon nitride layer 4 is slightly smaller than that of the first silicon oxynitride layer 3, specifically 2.08, 2.09, 2.10, or 2.11. In this embodiment, the thickness of the second silicon nitride layer 4 is 22 nm, and the refractive index is 2.09.
[0059] Example 4
[0060] This embodiment provides a front anti-reflective coating for a PERC solar cell, which, based on Embodiment 1, also has the following design:
[0061] The second silicon oxynitride layer 5 has a thickness of 15 nm to 25 nm and a refractive index of 1.85 to 2.1.
[0062] The second silicon oxynitride layer 5 covers the second silicon nitride layer 4, and its thickness is approximately equal to that of the second silicon nitride layer 4, and can be 16nm, 18nm, 20nm, 21nm, 22nm, or 24nm, etc. The refractive index of the second silicon oxynitride layer 5 is slightly smaller than that of the second silicon nitride layer 4, specifically 1.86, 1.88, 1.89, or 2.0. In this embodiment, the thickness of the second silicon oxynitride layer 5 is 20nm, and the refractive index is 1.88.
[0063] Example 5
[0064] This embodiment provides a method for preparing a front anti-reflection film, used to prepare a front anti-reflection film for a PERC solar cell as described in any one of Examples 1 to 4, referring to... Figure 2 The method includes the following steps:
[0065] S1. A first silicon nitride layer 2 is deposited on the front side of silicon wafer 1, with an ammonia flow rate of 9000 sccm to 14000 sccm and a silane flow rate of 500 sccm to 2100 sccm.
[0066] Ammonia and silane are introduced into a reactor, where they decompose and react, depositing on the front side of silicon wafer 1 to form a first silicon nitride layer 2. By controlling the flow rate ratio of ammonia and silane and the deposition time, first silicon nitride layers 2 of different thicknesses can be obtained, and the refractive index of the first silicon nitride layer 2 also varies with this ratio; the higher the ratio of silane to silane, the higher the refractive index. Through control of the ratio and thickness, the refractive index of the first silicon nitride layer 2 is achieved to be 2.30–2.35, preferably 2.32.
[0067] In this step, the deposition temperature in the reactor is 300℃~600℃, the deposition pressure is 800~1500mTor, the deposition power is 8000W~15000W, the deposition time is 70s~150s, and the deposition duty cycle is 5 / 120ms~5 / 200ms.
[0068] S2. Deposit a first silicon oxynitride layer 3 on the first silicon nitride layer 2, with a nitrous oxide flow rate of 5000 sccm to 14000 sccm, an ammonia flow rate of 4000 sccm to 11000 sccm, and a silane flow rate of 500 sccm to 2100 sccm.
[0069] After the deposition of the first silicon nitride layer 2 is completed, the deposition of the first silicon oxynitride layer 3 is performed. Laughable gas is added to the mixture of ammonia and silane, thus transforming the film during reaction deposition into the first silicon oxynitride layer 3. Similarly, by adjusting the deposition time, different thicknesses of the first silicon oxynitride layer 3 can be obtained, and by adjusting the ratio of ammonia to silane, different refractive indices can also be obtained.
[0070] In this step, the deposition temperature is 320℃~580℃, the deposition pressure is 800~6500mTor, the deposition power is 6000W~18000W, the deposition time is 80s~400s, and the deposition duty cycle is 5 / 40ms~5 / 200ms.
[0071] S3. Deposit a second silicon nitride layer 4 on the first silicon oxynitride layer 3, with an ammonia flow rate of 7000 sccm to 15000 sccm and a silane flow rate of 500 sccm to 2100 sccm.
[0072] After the deposition of the first silicon oxynitride layer 3 is completed, the second silicon nitride layer 4 is deposited. Similar to step S1, ammonia and silane are used. Likewise, by adjusting the deposition time, different thicknesses of the second silicon nitride layer 4 can be obtained, and by adjusting the ratio of ammonia to silane, different refractive indices can also be obtained.
[0073] In this step, the deposition temperature is 350℃~600℃, the deposition pressure is 500~8000mTor, the deposition power is 7000W~16000W, the deposition time is 70s~300s, and the deposition duty cycle is 5 / 40ms~5 / 120ms.
[0074] S4. Deposit a second silicon oxynitride layer 5 on the second silicon nitride layer 4, with a nitrous oxide flow rate of 3500 sccm to 14000 sccm, an ammonia flow rate of 5000 sccm to 21000 sccm, and a silane flow rate of 400 sccm to 2800 sccm.
[0075] After the deposition of the second silicon nitride layer 4 is completed, the deposition of the second silicon oxynitride layer 5 is performed. Similar to step S2, nitrous oxide, ammonia, and silane are used. Likewise, by adjusting the deposition time, different thicknesses of the second silicon oxynitride layer 5 can be obtained, and by adjusting the ratio of ammonia to silane, different refractive indices can also be obtained.
[0076] In this step, the deposition temperature is 400℃~600℃, the deposition pressure is 700~9000mTor, the deposition power is 8000W~18000W, the deposition time is 100s~350s, and the deposition duty cycle is 5 / 50ms~5 / 140ms.
[0077] Example 6
[0078] This embodiment provides a solar cell, including the front anti-reflective film of the PERC solar cell as described in any one of Embodiments 1 to 4.
[0079] Reference Figures 1 to 3In a preferred embodiment, the first silicon nitride layer 2 has a thickness of 10 nm and a refractive index of 2.32; the first silicon oxynitride layer 3 has a thickness of 21 nm and a refractive index of 2.17; the second silicon nitride layer 4 has a thickness of 22 nm and a refractive index of 2.09; and the second silicon oxynitride layer 5 has a thickness of 20 nm and a refractive index of 1.88.
[0080] The electrical performance of 2500 PCS batteries produced using the original process and the design of this invention were compared. The specific electrical performance data is shown in Table 1 below.
[0081] line labels Uoc Isc FF Eta M3_Eta Double surface rate Original design 0.6911 18.362 80.58 23.187 18.2 78.49％ This invention 0.691 18.386 80.6 23.221 18.26 78.63％ Difference -0.0001 0.024 0.02 0.034 0.06 0.14％
[0082] Table 1
[0083] The electrical performance shows a 0.035% efficiency improvement, mainly due to improvements in short-circuit current and fill power. The gradual change in refractive index increases the absorption of sunlight by the PERC solar cell. The more fully the sunlight is absorbed, the greater the short-circuit current density, which is the main reason for the increase in short-circuit current.
[0084] like Figure 3 The diagram shows a comparison of the reflection curves of the present invention and the original design of the prior art. It can be seen that the present invention reflects less light and has a stronger ability to absorb sunlight compared to the original design.
[0085] In the description of this specification, references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with the described embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0086] Furthermore, the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A front anti-reflective coating for a PERC solar cell, characterized in that, It includes a first silicon nitride layer, a first silicon oxynitride layer, a second silicon nitride layer, and a second silicon oxynitride layer deposited sequentially on the front side of the battery; The refractive indices of the first silicon nitride layer, the first silicon oxynitride layer, the second silicon nitride layer, and the second silicon oxynitride layer decrease sequentially, and the difference in refractive index between two adjacent layers is no greater than 0.
22. The thickness of the first silicon nitride layer is 5 nm to 15 nm, and its refractive index is 2.30 to 2.
35. The thicknesses of the first silicon oxynitride layer, the second silicon nitride layer, and the second silicon oxynitride layer are all greater than the thickness of the first silicon nitride layer. The thickness of the first silicon oxynitride layer is 15 nm to 25 nm. The thickness of the second silicon nitride layer is 15 nm to 25 nm.
2. The anti-reflective coating on the front side of the PERC solar cell according to claim 1, characterized in that, The refractive index of the first silicon oxynitride layer is 2.15 to 2.
20.
3. The anti-reflective coating on the front side of the PERC solar cell according to claim 1, characterized in that, The refractive index of the second silicon nitride layer is 2.07 to 2.
12.
4. The anti-reflective coating on the front side of the PERC solar cell according to claim 1, characterized in that, The refractive index of the second silicon oxynitride layer is 1.85 to 2.
1.
5. A method for preparing a front antireflective film, used to prepare a front antireflective film for a PERC solar cell as described in any one of claims 1 to 4, characterized in that, The method includes the following steps: A first silicon nitride layer is deposited on the front side of the silicon wafer, with an ammonia flow rate of 9000 sccm to 14000 sccm and a silane flow rate of 500 sccm to 2100 sccm. A first silicon oxynitride layer is deposited on the first silicon nitride layer, with a nitrous oxide flow rate of 5000 sccm to 14000 sccm, an ammonia flow rate of 4000 sccm to 11000 sccm, and a silane flow rate of 500 sccm to 2100 sccm. A second silicon nitride layer is deposited on the first silicon oxynitride layer, with an ammonia flow rate of 7000 sccm to 15000 sccm and a silane flow rate of 500 sccm to 2100 sccm. A second silicon oxynitride layer is deposited on the second silicon nitride layer, with a nitrous oxide flow rate of 3500 sccm to 14000 sccm, an ammonia flow rate of 5000 sccm to 21000 sccm, and a silane flow rate of 400 sccm to 2800 sccm.
6. The method for preparing the front antireflective film according to claim 5, characterized in that, In the step of depositing a first silicon nitride layer on the front side of the silicon wafer, with an ammonia flow rate of 9000 sccm to 14000 sccm and a silane flow rate of 500 sccm to 2100 sccm, The deposition temperature was 300℃~600℃, the deposition pressure was 800~1500mTor, the deposition power was 8000W~15000W, the deposition time was 70s~150s, and the deposition duty cycle was 5 / 120ms~5 / 200ms.
7. The method for preparing the front antireflective film according to claim 5, characterized in that, In the step of depositing a first silicon oxynitride layer on the first silicon nitride layer, the flow rate of nitrous oxide is 5000 sccm to 14000 sccm, the flow rate of ammonia is 4000 sccm to 11000 sccm, and the flow rate of silane is 500 sccm to 2100 sccm. The deposition temperature was 320℃~580℃, the deposition pressure was 800~6500mTor, the deposition power was 6000W~18000W, the deposition time was 80s~400s, and the deposition duty cycle was 5 / 40ms~5 / 200ms.
8. The method for preparing the front antireflective film according to claim 5, characterized in that, In the step of depositing a second silicon nitride layer on the first silicon oxynitride layer, with an ammonia flow rate of 7000 sccm to 15000 sccm and a silane flow rate of 500 sccm to 2100 sccm... The deposition temperature was 350℃~600℃, the deposition pressure was 500~8000mTor, the deposition power was 7000W~16000W, the deposition time was 70s~300s, and the deposition duty cycle was 5 / 40ms~5 / 120ms.
9. The method for preparing the front antireflective film according to claim 5, characterized in that, In the step of depositing a second silicon oxynitride layer on the second silicon nitride layer, the flow rate of nitrous oxide is 3500 sccm to 14000 sccm, the flow rate of ammonia is 5000 sccm to 21000 sccm, and the flow rate of silane is 400 sccm to 2800 sccm. The deposition temperature was 400℃~600℃, the deposition pressure was 700~9000mTor, the deposition power was 8000W~18000W, the deposition time was 100s~350s, and the deposition duty cycle was 5 / 50ms~5 / 140ms.
10. A solar cell, characterized in that, Includes the front antireflective coating of the PERC solar cell as described in any one of claims 1 to 4.