Single-cavity coating method, device and system for passivation of N layer of heterojunction cell
By using a single cavity coating method in the N-layer passivation process of heterojunction batteries, setting the power supply phase angle and using electromagnetic field control, the problem of excessive H2 loss is solved, and the effect of rapid passivation of N-layer and cost saving is achieved.
Patent Information
- Application Number
- CN202411545548.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-31
- Publication Date
- 2025-02-14
AI Technical Summary
The H2 loss in the N-layer passivation process of existing heterojunction batteries is too large, resulting in an increase in equipment costs and gas costs.
The single-cavity coating method is adopted, and the phase angles of the first power supply, the second power supply and the third power supply are set, and the electromagnetic field is used for control, so as to achieve rapid passivation of N-layers, avoiding excessive H2 loss under high-frequency power supply.
While achieving rapid passivation of N-layers, it reduces H2 losses, saves time and cost, and improves coating efficiency.
Smart Images
Figure CN119451273A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of SHJ cell microcrystalline coating, and in particular to a single-cavity coating method, device and system for passivation of an N layer of a heterojunction cell. Background Art
[0002] The traditional HJT cell structure first deposits a very thin intrinsic amorphous silicon film (ia-Si:H) and an N-type amorphous silicon film (na-Si:H) on the front of an N-type single crystal silicon wafer (c-Si), and then deposits a very thin intrinsic amorphous silicon film (ia-Si:H) and a P-type amorphous silicon film (pa-Si:H) on the back of the silicon wafer to form a back surface field; then a transparent oxide conductive film (TCO) is deposited on both sides of the cell, and finally a metal electrode is made on the TCO.
[0003] As the efficiency of heterojunction increases gradually, mainly due to the adoption of microcrystalline technology, the N-side microcrystalline technology of SHJ cells can improve efficiency by about 0.3%. The main reason is that the bandgap width of microcrystalline is larger than that of amorphous, and more light can penetrate the film layer into the silicon base, thereby improving efficiency. In addition, microcrystalline has lower resistivity and good conductivity, which can reduce film resistance and improve efficiency. Usually, microcrystalline characterization tests include crystallization rate, ECV concentration, resistivity, etc.
[0004] The industry currently uses VHF (40-60MHz) power supply, which increases the excitation frequency of the power supply, increases the gas decomposition rate and coating rate, and introduces a large amount of H2. The H2 flow rate is about 100 times that of silane for microcrystal processing, resulting in increased equipment and gas costs.
[0005] Therefore, how to overcome the H2 loss caused by increasing the coating rate during the passivation of the N layer of the heterojunction battery is a technical problem that needs to be solved urgently in this field. Summary of the invention
[0006] The present invention provides a single-chamber coating method, device and system for N-layer passivation of heterojunction batteries, so as to solve the problem of excessive H2 loss in the existing N-layer passivation process.
[0007] In order to solve the above technical problems, the present invention provides a single-chamber coating method for passivation of the N layer of a heterojunction battery, comprising the following steps: step S1, presetting the temperature of the PECVD chamber to 200-260°C, and feeding the N-type single crystal silicon wafer into the PECVD chamber; step S2, setting the phase angle between the first power supply and the second power supply to 0°-180°, and setting the phase angle between the second power supply and the third power supply to 180°-0°; step S3, starting the first power supply, introducing 1000-3000sccm of H2, 100-300sccm of SiH4 and 100-300sccm of PH3, setting the power of the electromagnetic field to 500-2000W, obtaining an N1 layer on the surface of the N-type single crystal silicon wafer, and setting the terminal pressure of the PECVD chamber to 60-90P a; Step S4, start the second power supply, pass 500-2000sccm of H2, 100-300sccm of SiH4 and 100-300sccm of PH3, set the power of the electromagnetic field to 500-2000W, obtain the N2 layer on the surface of the N1 layer, and set the terminal pressure of the PECVD chamber to 60-90Pa; Step S5, start the third power supply, pass 500-1000sccm of H2, 100-200sccm of SiH4 and 100-500sccm of PH3, set the power of the electromagnetic field to 500-2000W, obtain the N3 layer on the surface of the N2 layer, and set the terminal pressure of the PECVD chamber to 60-90Pa; Step S6, send the N-type single crystal silicon wafer with N layer passivated out of the PECVD chamber.
[0008] Furthermore, the method further comprises: step S7, performing a crystallization rate test to screen out N-type single crystal silicon wafers with N-layer passivation and a crystallization rate lower than 50%.
[0009] Furthermore, the method further comprises: step S8, performing a doping concentration test to screen out the ECV concentration lower than 1×10 21 cm -3 N-type single crystal silicon wafer with N layer passivation.
[0010] Furthermore, the thickness of the N1 layer is 4-10 nm.
[0011] Furthermore, the thickness of the N2 layer is 4-10 nm.
[0012] Furthermore, the thickness of the N3 layer is 12-30 nm.
[0013] Furthermore, the frequency of the first power supply, the second power supply and the third power supply is 13.56 MHz.
[0014] On the other hand, the present invention also provides a single-chamber coating device, which is used in the coating of heterojunction solar cells by PECVD coating equipment using the continuous coating method as described above, and the coating device includes: a coating module, which is arranged above the inside of the PECVD chamber, and performs PECVD deposition according to at least three power sources in sequence while performing electromagnetic field guidance, wherein the phase angle between the first power source and the second power source is set to 0°-180°, and the phase angle between the second power source and the third power source is set to 180°-0°; a transmission module, which is arranged below the inside of the PECVD chamber, and is used to transmit a carrier loaded with N-type single crystal silicon wafers through the PECVD chamber by rollers.
[0015] Furthermore, at least one process pump is provided at the end of the coating module.
[0016] In a third aspect, the present invention further provides a single-chamber coating system, comprising the single-chamber coating device as described above, and a heterojunction cell, wherein the single-chamber coating device is used to deposit N layers of passivation film on the heterojunction cell.
[0017] The beneficial effects of the present invention are that the single-chamber coating method, device and system for heterojunction battery N-layer passivation of the present invention have the following advantages:
[0018] 1. Use the phase angle between two adjacent power supplies, without using VHF power supply, and cooperate with electromagnetic field for control. When the phase angle is set to 0°-180°, the coating rate is the fastest, and the setting of the electromagnetic field can fix the range of each layer of the N passivation layer. Based on the above cooperation, the N layer is quickly passivated while avoiding excessive H2 loss under high-frequency power supply;
[0019] 2. Single-chamber coating is adopted, and the carrier does not need to be still on the roller. Unlike the current process in which each independent chamber needs to evacuate the gas and open the gate valve after coating, the coating method of the present invention saves a lot of time. At the same time, only a process pump needs to be set at the end of the coating module to control the direction and pressure of the airflow.
[0020] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description and the drawings.
[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0023] Figure 1 A schematic diagram of the structure of a heterojunction battery involved in an embodiment of the present disclosure;
[0024] Figure 2 It is a schematic diagram of the structure of a single-chamber coating device involved in an embodiment of the present disclosure.
[0025] In the figure:
[0026] 1. PECVD chamber; 21. first power supply; 22. second power supply; 23. third power supply; 31. first gas inlet; 32. second gas inlet; 33. third gas inlet; 4. roller; 5. carrier plate; 6. gate valve; 7. process pump. DETAILED DESCRIPTION
[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. 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.
[0028] VHF power supply refers to power supply equipment working in the very high frequency (VHF) band, and its frequency range is usually 30MHz to 300MHz.
[0029] PECVD refers to plasma enhanced chemical vapor deposition.
[0030] like Figure 1As shown, the current technical solution for N-face microcrystals on the market is: after the carrier enters the chamber, the temperature is raised to about 200 degrees, and a gas with a ratio of H2 / SiH4 of about 100 is introduced, and then a certain ratio of doping gas PH3 is introduced, and the appropriate VHF power is turned on for deposition. During the coating process, the carrier is stationary, because the doped microcrystals need gradient doping. After N1 is deposited, the chamber gas is evacuated (to prevent the gas from entering the next chamber), the chamber valve is opened, and the carrier enters the next chamber to continue to deposit N2, N3, etc. in the same way. Because the N layer needs gradient doping, multiple chambers are required for the process, which increases the equipment cost and coating time. The existing N-layer passivation equipment cannot realize the entire N-layer gradient doping process in the same chamber. This is because a static single chamber can only use one power supply, and using multiple power supplies for coating will interfere with each other. If you want high-quality microcrystals, you can only use VHF power supply, relying on increasing the excitation frequency of the power supply to increase the gas decomposition rate and coating rate, but it will also increase the loss of H2.
[0031] The defects existing in the above solutions are the results obtained by the inventor after practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed by the present disclosure for the above problems below should be the contributions made by the inventor to the present disclosure during the disclosure process.
[0032] Based on the above research, the embodiment of the present disclosure provides a single-chamber coating method for passivation of the N layer of a heterojunction battery, comprising the following steps: step S1, presetting the temperature of the PECVD chamber to 200-260°C, and feeding an N-type single crystal silicon wafer into the PECVD chamber; step S2, setting the phase angle between the first power supply and the second power supply to 0°-180°, and setting the phase angle between the second power supply and the third power supply to 180°-0°; step S3, starting the first power supply, introducing 1000-3000sccm of H2, 100-300sccm of SiH4 and 100-300sccm of PH3, setting the power of the electromagnetic field to 500-2000W, obtaining an N1 layer on the surface of the N-type single crystal silicon wafer, and setting the end pressure of the PECVD chamber to 60-90Pa; step S4, starting the second power supply, introducing 500-2000sccm of H2, 100-300sccm of SiH4 and 100-300sccm of PH3, the power of the electromagnetic field is set to 500-2000W, an N2 layer is obtained on the surface of the N1 layer, and the terminal pressure of the PECVD chamber is set to 60-90Pa; step S5, start the third power supply, pass 500-1000sccm of H2, 100-200sccm of SiH4 and 100-500sccm of PH3, the power of the electromagnetic field is set to 500-2000W, an N3 layer is obtained on the surface of the N2 layer, and the terminal pressure of the PECVD chamber is set to 60-90Pa; step S6, the N-type single crystal silicon wafer with N layer passivation is sent out of the PECVD chamber; step S7, perform a crystallization rate test, and screen out the N-type single crystal silicon wafer with N layer passivation whose crystallization rate is less than 50%; step S8, perform a doping concentration test, and screen out the N-type single crystal silicon wafer with ECV concentration less than 1×10 21 cm -3 N-type single crystal silicon wafer with N layer passivation.
[0033] In the embodiment of the present disclosure, specifically, the thickness of the N1 layer is 4-10 nm; the thickness of the N2 layer is 4-10 nm; and the thickness of the N3 layer is 12-30 nm.
[0034] In the embodiment of the present disclosure, specifically, the frequency of the first power supply, the second power supply and the third power supply is 13.56 MHz, but is not limited to 13.56 MHz. The frequency of 13.56 MHz is only used as a distinguishing frequency lower than the VHF power supply (30 MHz-300 MHz) used in the prior art.
[0035] In the embodiments of the present disclosure, specifically, in Embodiment 1, after the first power is turned on, the gas flow rate is set to 2500sccm of H2, 200sccm of SiH4 and 200sccm of PH3, after the second power is turned on, the gas flow rate is set to 1500sccm of H2, 150sccm of SiH4 and 200sccm of PH3, and after the third power is turned on, the gas flow rate is set to 500sccm of H2, 150sccm of SiH4 and 300sccm of PH3.
[0036] Specifically, the phase angle and the magnetic field in the method embodiment are adjusted to obtain the parameters and performances of Example 1 and Comparative Examples 1-2, as shown in Tables 1 and 2 below.
[0037] Table 1
[0038]
[0039] Table 2
[0040]
[0041] Specifically, it can be seen from Table 1 and Table 2 that in the absence of a magnetic field and a phase angle of 0°-180°, the coating speed will be slowed down, resulting in insufficient thickness, low crystallization rate and poor conductivity.
[0042] Specifically, the power in the method embodiment is adjusted to obtain the parameters and performances of Example 1 and Comparative Examples 3-4, as shown in Table 3 and Table 4 below.
[0043] Table 3
[0044]
[0045] Table 4
[0046]
[0047] Specifically, it can be seen from Table 3 and Table 4 that the thickness of the N layer can be thickened by increasing the power.
[0048] See also Figure 2 , Figure 2A single-chamber coating device is shown, which is used in the coating of heterojunction solar cells by a PECVD coating device using the continuous coating method as described above, and the coating device includes: a coating module, which is arranged above the inside of a PECVD chamber 1, and performs PECVD deposition in sequence according to at least three power sources while performing electromagnetic field guidance, wherein the phase angle between the first power source 21 and the second power source 22 is set to 0°-180°, and the phase angle between the second power source 22 and the third power source 23 is set to 180°-0°; a transmission module, which is arranged below the inside of the PECVD chamber 1, and is used to transmit a carrier 5 loaded with N-type single crystal silicon wafers through the PECVD chamber 1 via a roller 4.
[0049] In the disclosed embodiment, specifically, at least one process pump 7 is provided at the end of the coating module. Since only one chamber is provided, only one process pump at the tail end is required to control the direction and pressure of the airflow, and no gate valve is required in the middle, so the equipment cost is greatly reduced.
[0050] In the embodiments of the present disclosure, specifically, the first power supply is used to pass 1000-3000sccm of H2, 100-300sccm of SiH4 and 100-300sccm of PH3, and the power of the electromagnetic field is set to 500-2000W; the second power supply is used to pass 500-2000sccm of H2, 100-300sccm of SiH4 and 100-300sccm of PH3, and the power of the electromagnetic field is set to 500-2000W; the third power supply is used to pass 500-1000sccm of H2, 100-200sccm of SiH4 and 100-500sccm of PH3, and the power of the electromagnetic field is set to 500-2000W.
[0051] In the embodiment of the present disclosure, specifically, the first gas inlet 31 is suitable for performing vapor deposition operations within the electromagnetic field range after the first power supply 21 is started, the second gas inlet 32 is suitable for performing vapor deposition operations within the electromagnetic field range after the second power supply 22 is started, and the third gas inlet 33 is suitable for performing vapor deposition operations within the electromagnetic field range after the third power supply 23 is started.
[0052] In the embodiment of the present disclosure, specifically, since only one PECVD chamber 1 is provided, only one pair of gate valves 6 is required, thus eliminating the need for multiple pairs of gate valves and process pumps in existing multiple chambers.
[0053] The disclosed embodiment also provides a single-chamber coating system, comprising the single-chamber coating device as described above, and a heterojunction cell, wherein the single-chamber coating device is used to deposit N layers of passivation film on the heterojunction cell.
[0054] In summary, the single-cavity coating method for passivation of the N layer of heterojunction batteries of the present invention utilizes a phase angle between two adjacent power sources, without the need to use a VHF power source, and is controlled by an electromagnetic field. When the phase angle is set to 0°-180°, the coating rate is the fastest, and the setting of the electromagnetic field can fix the range of each layer of the N passivation layer. Based on the above cooperation, while achieving rapid passivation of the N layer, excessive H2 loss under high-frequency power supply is avoided.
[0055] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.
[0056] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.
Claims
1. A single-chamber coating method for passivation of the N layer of a heterojunction battery, characterized in that: The steps include: Step S1, preset the temperature of the PECVD chamber to 200-260° C., and place an N-type single crystal silicon wafer into the PECVD chamber; Step S2, setting the phase angle between the first power supply and the second power supply to 0°-180°, and setting the phase angle between the second power supply and the third power supply to 180°-0°; Step S3, start the first power supply, introduce 1000-3000 sccm of H2, 100-300 sccm of SiH4 and 100-300 sccm of PH3, set the power of the electromagnetic field to 500-2000 W, obtain an N1 layer on the surface of the N-type single crystal silicon wafer, and set the terminal pressure of the PECVD chamber to 60-90 Pa; Step S4, start the second power supply, introduce 500-2000sccm of H2, 100-300sccm of SiH4 and 100-300sccm of PH3, set the power of the electromagnetic field to 500-2000W, obtain the N2 layer on the surface of the N1 layer, and set the terminal pressure of the PECVD chamber to 60-90Pa; Step S5, start the third power supply, introduce 500-1000 sccm of H2, 100-200 sccm of SiH4 and 100-500 sccm of PH3, set the power of the electromagnetic field to 500-2000 W, obtain the N3 layer on the surface of the N2 layer, and set the terminal pressure of the PECVD chamber to 60-90 Pa; Step S6, sending the N-type single crystal silicon wafer with N-layer passivation out of the PECVD chamber.
2. The single-chamber coating method for heterojunction battery N-layer passivation according to claim 1, characterized in that: Also includes: Step S7, performing a crystallization rate test to screen out N-layer passivated N-type single crystal silicon wafers with a crystallization rate lower than 50%.
3. The single-chamber coating method for heterojunction battery N-layer passivation according to claim 1, characterized in that: Also includes: Step S8: perform doping concentration test and screen out samples with ECV concentration lower than 1×10 21 cm -3 N-type single crystal silicon wafer with N layer passivation.
4. The single-chamber coating method for N-layer passivation of heterojunction batteries according to claim 1, characterized in that: The thickness of the N1 layer is 4-10 nm.
5. The single-chamber coating method for heterojunction battery N-layer passivation according to claim 1, characterized in that: The thickness of the N2 layer is 4-10 nm.
6. The single-chamber coating method for heterojunction battery N-layer passivation according to claim 1, characterized in that: The thickness of the N3 layer is 12-30 nm.
7. The single-chamber coating method for heterojunction battery N-layer passivation according to claim 1, characterized in that: The frequencies of the first power supply, the second power supply and the third power supply are 13.56 MHz.
8. A single-chamber coating device, characterized in that: Applicable to coating heterojunction solar cells with a PECVD coating device using the continuous coating method according to any one of claims 1 to 6, the coating device comprising: The coating module is arranged above the interior of the PECVD chamber, and sequentially performs PECVD deposition according to at least three power sources while performing electromagnetic field guidance, wherein The phase angle between the first power supply and the second power supply is set to 0°-180°, and the phase angle between the second power supply and the third power supply is set to 180°-0°; The transmission module is arranged at the lower part of the PECVD chamber and is used to transmit the carrier loaded with N-type single crystal silicon wafers through the PECVD chamber through rollers.
9. The single-chamber coating device according to claim 8, characterized in that: At least one process pump is arranged at the end of the coating module.
10. A single-chamber coating system, characterized in that: It comprises the single-chamber coating device as described in claims 8-9, and a heterojunction cell, wherein the single-chamber coating device is used to deposit N layers of passivation film on the heterojunction cell.