A PECVD device for field effect passivation of crystalline silicon cells

Abstract

The present invention discloses a PECVD device for field-effect passivation of crystalline silicon cells, relating to the technical field of crystalline silicon photovoltaic cell production. The polycrystalline silicon (Poly-Si) thin film structure comprises two low-concentration doped regions and two high-concentration doped regions, which are stacked layer by layer. By stacking the low-concentration doped regions and the high-concentration doped regions layer by layer, the present invention allows free carriers in the high-concentration doped regions to diffuse into the low-concentration doped regions, leaving behind charged fixed ions, thus transforming the high-concentration doped regions into high-net-charge regions. The low-concentration doped regions have high crystallinity and high carrier mobility, and suppress the diffusion of impurity atoms. By providing the high-net-charge regions, enhanced field-effect passivation is achieved, thereby improving the efficiency of crystalline silicon photovoltaic cells.

Description

Technical Field

[0001] The present invention relates to the technical field of crystalline silicon photovoltaic cell production, in particular to a PECVD device for field effect passivation of crystalline silicon cells. Background Art

[0002] Tunneling oxide passivated contact (TOPCon) crystalline silicon photovoltaic cells have already captured a significant portion of the photovoltaic market, and back-contact crystalline silicon photovoltaic cells based on TOPCon technology are also a mainstream research and development direction. The core of TOPCon technology is the bonding of silicon oxide to the silicon wafer surface, followed by the attraction of opposite-sign free carriers by the silicon oxide and the net charge in the doped polysilicon, a process known as field-effect passivation. The essential method for enhancing TOPCon technology is to increase the net charge concentration in the doped polysilicon. The PECVD route offers advantages over LPCVD in the flexible design of polysilicon thin film doping structures. A doping structure refers to a structure in which the electrical properties of a semiconductor material are altered by the intentional introduction of impurity atoms (called dopants). PECVD technology is able to adjust the dopant dosage in real time during the deposition of the polysilicon film. This means that PECVD technology can deposit novel polysilicon (Poly-Si) structures with periodic doping concentration increases and decreases, thereby creating a Poly-Si layer with unique structural properties.

[0003] The patent publication number of the existing patent application is: CN111575680B, and the publication date is May 3, 2022. The name of the patent is "A plasma chemical vapor deposition device". Since there are multiple electrode areas with different wear rates on the lower electrode, this patent divides the insulating layer of the lower electrode into multiple insulating areas. The multiple insulating areas correspond to the multiple electrode areas with different wear rates and the insulation properties of the multiple insulating areas are different. That is, insulating areas with corresponding insulation properties are set according to the wear rates of the multiple electrode areas to minimize the difference in wear degree of the multiple electrode areas of the lower electrode, thereby improving the wear consistency of the lower electrode and avoiding the occurrence of spots and other defects caused by excessive local wear. At the same time, it can also effectively extend the service life of the lower electrode and avoid the cost increase brought about by frequent replacement of new lower electrodes.

[0004] The above application has shortcomings. In traditional crystalline silicon photovoltaic cells, due to the limitations of the doping process, a gradient distribution of carrier concentration is often formed inside the cell. This uneven distribution will lead to increased recombination losses of carriers during transmission, thereby reducing the photoelectric conversion efficiency of the cell. At the same time, when using the equipment, in order to ensure the stability of the chip process results, the tray needs to rotate at high speed through the support shaft to uniform the airflow field, and at the same time use the heating element to heat the tray. However, due to the presence of the support shaft, the center of the tray will cause uneven heating, and the center point temperature is lower than other parts. At this time, it is generally achieved by setting multiple layers of heating elements in the inner circle to increase the support shaft temperature, thereby indirectly increasing the center temperature of the tray. However, this method will cause the tray temperature above the inner circle heating element to be too high, and the overall temperature cannot be uniformed. Summary of the Invention

[0005] The purpose of the present invention is to provide a PECVD device for field effect passivation of crystalline silicon cells to solve the deficiencies in the above-mentioned prior art.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A novel polysilicon thin film structure for field effect passivation of a crystalline silicon cell. The polysilicon (Poly-Si) thin film structure comprises two low-concentration doping regions and two high-concentration doping regions.

[0008] Preferably, the low-concentration doping region and the high-concentration doping region are stacked layer by layer and prepared by a plasma enhanced chemical vapor deposition (PECVD) method, comprising the following steps:

[0009] S1, placing the processed silicon wafer in the reaction chamber 1, and introducing boron or phosphorus dopant and reaction gas through the inlet pipe 8;

[0010] S2. Plasma is formed by activating a high-frequency electric field, causing a chemical reaction between the dopant and the reaction gas. During the deposition process, the flow rate and partial pressure of the dopant are controlled to complete a low-high-low-high change cycle, thereby forming a polysilicon film with a periodic gradient of doping concentration;

[0011] S3. Annealing the deposited doped polysilicon film.

[0012] Preferably, the free carriers in the high-concentration doping region will diffuse to the low-concentration doping region, leaving charged fixed ions, making the high-concentration doping region a high net charge region. The low-concentration doping region has high crystallinity, high carrier mobility, and inhibits the diffusion of impurity atoms.

[0013] Preferably, when the deposited doped polysilicon film is annealed, a method of gradually increasing the temperature and then gradually decreasing the temperature is adopted, and an inert gas is introduced as a protective gas.

[0014] The PECVD equipment for preparing the above-mentioned crystalline silicon cell field effect passivation includes a reaction chamber and a sleeve, which is inserted into the bottom of the reaction chamber, a rotating column is installed in the sleeve, a lower electrode plate is installed on the top of the rotating column, a shielding cover covering the lower electrode plate is installed on the top of the sleeve, and a plurality of annular heating elements centered on the rotating column are installed below the shielding cover. A flow suppression ring is installed between the sleeve and the rotating column, and the interior of the sleeve is divided into a heat storage chamber for storing coolant and a heat dissipation chamber by the flow suppression ring. A turbulent opening and closing piece that cooperates with the flow suppression ring is rotatably installed in the heat storage chamber. While the shielding cover disperses the heat of the annular heating element, the rotating column drives the turbulent opening and closing piece to rotate, so that the coolant in the heat storage chamber and the heat dissipation chamber are intermittently mixed.

[0015] Preferably, an upper electrode plate is installed above the lower electrode plate inside the reaction chamber, an air inlet pipe connected to the outside of the reaction chamber is fixedly connected to the top of the upper electrode plate, and a spray plate is embedded in the bottom of the upper electrode plate.

[0016] Preferably, a guide ring is installed at the exhaust end of the air intake pipe, an annular groove is formed between the guide ring and the air intake pipe, and a circle of inclined air discharge holes connected to the annular groove is provided at the bottom of the air intake pipe.

[0017] Preferably, the spoiler opening and closing member includes a cover ring rotatably connected to the inner wall of the heat storage chamber, an upper through hole is provided on the cover ring, a lower through hole corresponding to the upper through hole is provided on the flow suppression ring, and a plurality of spoiler paddles are distributed in a ring on the top of the cover ring.

[0018] Preferably, a reflective dish is installed outside the sleeve, the reflective dish is located below the annular heating element, and the diameter of the reflective dish is larger than the outer diameter of any of the annular heating elements. A plurality of heat-conducting fins are distributed in an annular manner on the outer wall of the sleeve, and the upper and lower ends of the heat-conducting fins are in contact with the shielding cover and the reflective dish respectively.

[0019] Preferably, the bottom of the lower pole plate is fixedly connected to a plug rod, the top of the rotating column is fixedly connected to a docking joint for inserting the plug rod, the outer side wall of the docking joint is fixedly connected to a push plate, and the push plate is in abutment with the spoiler paddle.

[0020] Preferably, a heat distribution net is placed inside the shielding cover, and a gap is reserved between the heat distribution net and the lower electrode plate.

[0021] In the above technical solution, free carriers in the high-concentration doping region diffuse to the low-concentration doping region, leaving behind charged fixed ions, making the high-concentration doping region a high net charge region. Through the provision of the high net charge region, an enhanced field effect passivation effect is achieved, thereby improving the efficiency of the crystalline silicon photovoltaic cell. The low-concentration doping region has high crystallinity, high carrier mobility, and inhibits the diffusion of impurity atoms.

[0022] A shielding cover is provided to disperse the heat of the annular heating element, thereby achieving uniform heating of the lower electrode plate and the substrate above it, and improving the uniformity of the deposited layer. At the same time, when the rotating column drives the lower electrode plate to rotate and uniformize the air flow field, it drives the turbulent opening and closing parts in the heat storage chamber to rotate together, so that the coolant in the heat storage chamber and the heat dissipation chamber are intermittently mixed, which not only prevents the heat in the heat storage chamber from being lost too quickly, but also uses the heat storage chamber to heat the end of the rotating column to increase the center temperature of the upper electrode plate, preventing the temperature difference between the edge and the center of the tray on the upper plate from being too large. At the same time, the turbulent opening and closing parts can be used to regularly exchange the coolant in the heat storage chamber and the heat dissipation chamber, promoting the mixing and flow of the coolant, thereby ensuring that the temperature of the rotating column itself will not continue to rise after absorbing heat, avoiding excessive heating of the lower electrode plate above the rotating column, ensuring the uniformity of the overall temperature above the lower plate, and avoiding the problem of uneven tray temperature caused by setting multiple layers of heating elements in the inner ring in the traditional method, thereby ensuring the stability of the deposition process results.

[0023] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

[0024] This application document provides an overview of various implementations or examples of the technology described in this disclosure, and is not a comprehensive disclosure of the full scope or all features of the disclosed technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments described in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0026] Figure 1 Schematic diagram of the new Poly-Si structure deposited by PECVD before annealing;

[0027] Figure 2 Schematic diagram of the new Poly-Si structure deposited by PECVD after annealing;

[0028] Figure 3 This is a schematic diagram of the overall structure of a PECVD device of the present invention;

[0029] Figure 4 This is an overall cross-sectional view of a PECVD device according to the present invention;

[0030] Figure 5 For the present invention Figure 4 A magnified view of the structure at point A;

[0031] Figure 6This is a schematic diagram of the internal structure of a reaction chamber in a PECVD device of the present invention;

[0032] Figure 7 A top view of a shielding cover in a PECVD device according to the present invention;

[0033] Figure 8 A partial cross-sectional view of a sleeve in a PECVD device of the present invention;

[0034] Figure 9 A schematic diagram of the connection between the lower electrode plate and the rotating column in a PECVD device of the present invention;

[0035] Figure 10 A top view of a sleeve in a PECVD device according to the present invention;

[0036] Figure 11 This is a partial cross-sectional view of an air inlet pipe in a PECVD device of the present invention.

[0037] Description of reference numerals:

[0038] 1. Reaction chamber; 2. Sleeve; 201. Shielding cover; 202. Annular heating element; 203. Heat storage chamber; 204. Heat dissipation chamber; 205. Reflecting disk; 206. Heat-conducting fins; 3. Rotating column; 301. Connector; 302. Push plate; 4. Lower electrode; 401. Insert rod; 5. Flow suppression ring; 501. Lower through hole; 6. Turbine opening and closing member; 601. Cover ring; 602. Upper through hole; 603. Turbine paddle; 7. Upper electrode; 8. Inlet pipe; 801. Guide ring; 802. Annular groove; 803. Air discharge inclined hole; 9. Spray plate; 10. Heat distribution network. DETAILED DESCRIPTION

[0039] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0040] Example 1: Please refer to Figure 1-2 In an embodiment of the present invention, a novel polysilicon thin film structure for field effect passivation of a crystalline silicon cell is provided. The polysilicon (Poly-Si) thin film structure includes two low-concentration doping regions and two high-concentration doping regions.

[0041] In a further embodiment of the present invention, the low-concentration doped region and the high-concentration doped region are stacked layer by layer and prepared by a plasma enhanced chemical vapor deposition (PECVD) method, comprising the following steps:

[0042] S1. Pre-treat the silicon wafer to be deposited to ensure that there are no impurities and oxide residues on the surface, and then form a silicon oxide film with a thickness of 1 to 2 nanometers on the surface of the silicon wafer;

[0043] S2, placing the pre-treated silicon wafer in the PECVD reaction chamber 1, and introducing phosphorus dopant and reaction gas through the gas inlet pipe 8;

[0044] S3, through the high frequency electric field activation to form plasma, the dopant and the reaction gas to chemically react, in the deposition process, by precisely controlling the dopant gas partial pressure, RF power and deposition time and other parameters, to form a polycrystalline silicon (Poly-Si) film with a periodic gradient of doping concentration, such as Figure 1 As shown;

[0045] S4, annealing the deposited doped polysilicon (Poly-Si) film;

[0046] S5. Phosphorus atoms doped in the polysilicon film ionize free electrons. The free electrons in the high-concentration doping area diffuse to the low-concentration doping area, leaving behind positively charged fixed phosphorus ions, making the high-concentration doping area a high net charge area. Figure 2 shown.

[0047] Specifically, such as Figure 1-2 As shown, Figure 1 and 2 The height of the black line in the figure indicates the doping concentration. Figure 2 The plus sign area in the middle represents a high net charge area. By precisely controlling the reaction conditions to grow a Poly-Si film with a periodic gradient of doping concentration, annealing treatment is performed to improve the crystal quality and activate the dopant, and the diffusion behavior of free electrons under the doping concentration gradient is utilized to prepare a Poly-Si film with a high net charge concentration for crystalline silicon photovoltaic cells. When a high-concentration doping area is adjacent to a low-concentration doping area, there is a concentration gradient for the free electrons ionized by the doped phosphorus atoms. The free electrons will spontaneously diffuse from the high-concentration area to the low-concentration area. This diffusion behavior causes the free electrons in the high-concentration doping area to decrease, which is insufficient to shield the phosphorus ions, thus forming a high net charge area (such as Figure 2As shown), that is, the charge density (or net charge) in this area is relatively high. Field effect passivation refers to the phenomenon of suppressing or weakening certain electrical effects by changing the charge distribution on the semiconductor surface. In the high net charge area, due to the increase in charge density, the electric field on the semiconductor surface is enhanced. This change can more effectively suppress or weaken undesirable electrical effects, such as leakage current, recombination current, etc. Therefore, the high net charge area created by PECVD technology helps to enhance the field effect passivation effect, thereby improving the performance and stability of crystalline silicon photovoltaic cells. Combined with Figure 2 Further description, wherein SiO x Region 1 blocks the diffusion of doped atoms into the single crystal silicon wafer, region 2 has a high doping concentration, and region 3 has a low doping concentration, so the free electrons in region 2 will diffuse into region 3, and the fixed phosphorus ions in region 2 lose the shielding of free electrons and become a net charge. Region 4 has a high doping concentration and can form an ohmic contact with the metal gate line. Figure 2 Region 2 is the high net charge region, which can enhance the field effect passivation effect. Region 3 is the high crystallinity region, which can achieve low resistivity by lower doping concentration and better prevent metal atoms from corroding inward.

[0048] Compared to existing technologies, the present invention stacks low-concentration doped regions and high-concentration doped regions layer by layer, allowing free carriers in the high-concentration doped regions to diffuse into the low-concentration doped regions, leaving behind charged fixed ions and transforming the high-concentration doped regions into high-net-charge regions. This high-net-charge region achieves enhanced field-effect passivation, thereby improving the efficiency of crystalline silicon photovoltaic cells. The low-concentration doped regions have high crystallinity, high carrier mobility, and inhibit the diffusion of impurity atoms.

[0049] In a further embodiment of the present invention, the free carriers in the high-concentration doping region will diffuse to the low-concentration doping region, leaving charged fixed ions, so that the high-concentration doping region becomes a high net charge region. The low-concentration doping region has high crystallinity, high carrier mobility, and inhibits the diffusion of impurity atoms. Specifically, the strong electric field generated by the high net charge region in the phosphorus-doped polycrystalline silicon film attracts free electrons and repels free holes, greatly reducing the recombination of free electrons and holes on the surface of the silicon wafer, reducing the recombination current, and thus improving the photoelectric conversion efficiency of the crystalline silicon photovoltaic cell.

[0050] In a further embodiment of the present invention, when the deposited doped Poly-Si film is annealed, a gradual heating and then gradual cooling method is adopted. By precisely controlling parameters such as the heating rate, annealing temperature, holding time and cooling rate during the annealing process, the annealing effect can be optimized, so that the stress and defects in the doped Poly-Si film can be more thoroughly eliminated, while improving the crystallization quality and stability of the film. Gradual heating helps the atoms in the film gradually adapt to temperature changes and avoid damage caused by thermal shock, while gradual cooling helps the atoms in the film gradually recover to a stable lattice structure, thereby further improving the quality of the film.

[0051] In a further embodiment of the present invention, an inert gas is introduced as a protective gas during the annealing process, which can create an oxygen-free and water vapor-free environment, effectively preventing the oxidation and hydrolysis of the film at high temperature, ensuring the positive impact of the annealing treatment on the film quality, and ultimately obtaining a doped Poly-Si film with more stable performance and higher quality, providing a key film quality guarantee for the manufacture of high-efficiency crystalline silicon photovoltaic cells.

[0052] Example 2: Please refer to Figure 3-11 A PECVD device for preparing field-effect passivation of crystalline silicon cells provided in an embodiment of the present invention comprises a reaction chamber 1 and a sleeve 2, which is inserted into the bottom of the reaction chamber 1, a rotating column 3 is installed in the sleeve 2, a lower electrode plate 4 is installed on the top of the rotating column 3, a shielding cover 201 covering the lower electrode plate 4 is installed on the top of the sleeve 2, and a plurality of annular heating elements 202 centered on the rotating column 3 are installed below the shielding cover 201. A suppression ring 5 is installed between the sleeve 2 and the rotating column 3. The interior of the sleeve 2 is divided into a heat storage chamber 203 for storing coolant and a heat dissipation chamber 204 by the suppression ring 5. A turbulent opening and closing member 6 that cooperates with the suppression ring 5 is rotatably installed in the heat storage chamber 203. While the shielding cover 201 disperses the heat of the annular heating element 202, the rotating column 3 drives the turbulent opening and closing member 6 to rotate, so that the coolant in the heat storage chamber 203 and the heat dissipation chamber 204 are intermittently mixed.

[0053] Specifically, the lower electrode plate 4 is a circular flat plate for placing a tray for carrying silicon wafer substrate materials, and is connected to the negative pole of the power supply through a wire to form an electric field during the plasma vapor deposition process. The shielding cover 201 is an annular structure with a diameter slightly larger than the lower electrode plate 4. It is fixed to the top of the sleeve 2 by bolts or welding to ensure that it stably covers the lower electrode plate 4. The material of the shielding cover 201 is a material that is resistant to high temperatures and has good thermal conductivity. The annular heating element 202 is an annular structure composed of several resistance wires or electric heating tubes, which are evenly distributed below the shielding cover 201. The heat generated by the annular heating element 202 is effectively dispersed through the dispersing effect of the shielding cover 201, and the heat is prevented from directly It is transferred to the lower electrode 4 to uniformly heat the gas in the reaction chamber 1 and provide the required temperature conditions for plasma vapor deposition. The heat storage chamber 203 and the heat dissipation chamber 204 are respectively located on the upper and lower sides of the flow suppression ring 5, and are both surrounded by the inner wall of the sleeve 2 and the outer wall of the rotating column 3. The heat storage chamber 203 is filled with a high heat capacity coolant for storing the heat generated by the annular heating element 202. The heat dissipation chamber 204 is also filled with a coolant, but is mainly used to conduct excess heat in the heat storage chamber 203 for external cooling. In the present invention, during the plasma vapor deposition process, the heat generated by the annular heating element 202 is dispersed by the shielding cover 201 to uniformly heat the gas in the reaction chamber 1. At the same time, when the rotating column 3 drives the rotating column 3 to drive the lower plate 4 to rotate and uniformize the airflow field, it will also drive the turbulence opening and closing part 6 to rotate, so that the coolant in the heat storage chamber 203 and the heat dissipation chamber 204 are intermittently mixed, thereby achieving uniform distribution and effective dissipation of heat. This design not only improves the thermal efficiency of the equipment, but also ensures the stability and reliability of the crystalline silicon photovoltaic cell production process.

[0054] Compared with the prior art, the embodiment of the present invention disperses the heat of the annular heating element 202 by setting a shielding cover 201, thereby achieving uniform heating of the lower plate 4 and the substrate above it, and improving the uniformity of the deposition layer. At the same time, when the rotating column 3 drives the lower plate 4 to rotate and uniformize the airflow field, it drives the turbulent opening and closing member 6 in the heat storage chamber 203 to rotate together, so that the coolant in the heat storage chamber 203 and the heat dissipation chamber 204 are intermittently mixed, which not only avoids the heat loss in the heat storage chamber 203 too quickly, but also uses the heat storage chamber 203 to heat the end of the rotating column 3 to achieve the heat dissipation in the upper plate 7. The core temperature is increased to prevent the temperature difference between the edge and the center of the tray on the upper plate from being too large, and the coolant in the heat storage chamber 203 and the heat dissipation chamber 204 can be regularly exchanged through the turbulent opening and closing part 6, which promotes the mixing and flow of the coolant, thereby ensuring that the temperature of the rotating column 3 itself will not continue to rise after absorbing heat, avoiding excessive heating of the lower plate 4 above the rotating column 3, ensuring the uniformity of the overall temperature above the lower plate, and avoiding the problem of uneven tray temperature caused by setting multiple layers of heating elements in the inner ring in the traditional method, thereby ensuring the stability of the chip process results.

[0055] In a further embodiment of the present invention, an upper electrode plate 7 is installed above the lower electrode plate 4 inside the reaction chamber 1, and an air inlet pipe 8 connected to the outside of the reaction chamber 1 is fixedly connected to the top of the upper electrode plate 7, and a spray plate 9 is embedded at the bottom of the upper electrode plate 7. Specifically, during the vapor deposition process, the upper electrode plate 7 and the lower electrode plate 4 are energized by a radio frequency power supply (RF power supply). The high-frequency alternating current generated by the RF power supply forms an electric field between the upper electrode plate 7 and the lower electrode plate 4, thereby exciting the raw material gas to generate plasma. This electric field effect not only ionizes and excites the raw material gas molecules, but also promotes the progress of chemical reactions and the deposition of thin films. At the same time, the air inlet pipe 8 on the upper electrode plate 7 is connected to the outside of the reaction chamber 1. , used to introduce process gas into the reaction chamber. The design of the air inlet pipe 8 takes into account the uniform distribution and flow control of the gas to ensure that a stable and uniform gas atmosphere can be formed in the reaction chamber during the plasma vapor deposition process. A spray plate 9 is embedded at the bottom of the upper electrode plate 7. This spray plate 9 is composed of a plurality of tiny nozzles, which are evenly distributed at the bottom of the upper electrode plate 7 to form a spray surface. During the plasma vapor deposition process, after the process gas enters the reaction chamber 1 through the air inlet pipe 8, it will be evenly sprayed through the nozzles of the spray plate 9. This design not only improves the utilization rate of the process gas, but also enables a more uniform and stable plasma environment to be formed in the reaction chamber.

[0056] In a further embodiment of the present invention, a guide ring 801 is installed at the exhaust end of the air inlet pipe 8, and an annular groove 802 is formed between the guide ring 801 and the air inlet pipe 8. A circle of gas discharge inclined holes 803 connected to the annular groove 802 is provided at the bottom of the air inlet pipe 8. Specifically, during the plasma vapor deposition process, the raw gas enters the reaction chamber 1 through the air inlet pipe 8. When reaching the exhaust end of the air inlet pipe 8, part of the gas will be guided by the guide ring 801 and distributed in the annular groove 802. Subsequently, these process gases enter the reaction chamber 1 in a more uniform and dispersed manner through a circle of gas discharge inclined holes 803. Under the spraying action of the spray plate 9, these process gases can accurately cover the silicon wafer base material on the lower electrode 4 and react with the base material.

[0057] In a further embodiment of the present invention, the spoiler opening and closing member 6 includes a cover ring 601 rotatably connected to the inner wall of the heat storage chamber 203, the inner wall of the heat storage chamber 203 is provided with a limiting ring groove matching the edge of the cover ring 601, an upper through hole 602 is provided on the cover ring 601, and a lower through hole 501 corresponding to the upper through hole 602 is provided on the flow suppression ring 5, a plurality of spoiler paddles 603 are distributed in an annular manner on the top of the cover ring 601, and the bottom of the cover ring 601 is in contact with the flow suppression ring 5. Specifically, the upper through hole 602 on the cover ring 601 corresponds to the lower through hole 501 on the flow suppression ring 5. When the rotating column 3 drives the cover ring 601 to rotate to a specific position, the upper through hole 602 and the lower through hole 501 will completely overlap, thereby allowing The coolant in the heat storage chamber 203 and the coolant in the heat dissipation chamber 204 are mixed to reduce the continuously rising heat in the heat storage chamber 203. When the cover ring 601 rotates to other positions, the upper through hole 602 and the lower through hole 501 will be partially or completely staggered, thereby reducing or completely preventing the coolant in the heat storage chamber 203 from flowing into the heat dissipation chamber 204, so as to ensure that the heat storage chamber 203 can continuously absorb the heat generated by the annular heating element 202, and transfer it to the central area of the lower electrode 4 through the rotating column 3 by absorbing sufficient heat, thereby ensuring the consistency of its overall temperature. At the same time, the coolant in the heat dissipation chamber 204 can also play a cooling role at an appropriate time to prevent the rotating column 3 from being continuously heated.

[0058] In a further embodiment of the present invention, a reflective disk 205 is installed on the outside of the sleeve 2. The reflective disk 205 is located below the annular heating element 202, and the diameter of the reflective disk 205 is larger than the outer diameter of any of the annular heating elements 202. A plurality of heat-conducting fins 206 are distributed in an annular manner on the outer wall of the sleeve 2. The upper and lower ends of the heat-conducting fins 206 are in contact with the shielding cover 201 and the reflective disk 205, respectively. Specifically, these annular heating elements 202 are arranged in a concentric circle and are connected to an external power supply through wires. The reflective disk 205 installed on the outer wall can ensure that all generated heat can be effectively reflected and concentrated on the shielding cover 201. In addition, the multiple heat-conducting fins 206 distributed in an annular manner on the outer wall of the sleeve 2 extend in the vertical direction, with the upper part in contact with the bottom of the shielding cover 201 and the lower part tightly fitting with the top of the reflective disk 205, forming an efficient heat conduction path, which can more comprehensively absorb excess heat and enter the heat storage chamber 203, thereby further ensuring that the heat in the middle of the lower plate 4 is within the corresponding value.

[0059] When the upper end of the upper plate 7 is lowered to the bottom, the upper end of the lower plate 7 is rotated to a predetermined temperature, and the upper and lower ends of the upper and lower plates 303 are in a state of contact with each other, so that the upper and lower plates 303 are in a state of contact with each other, so that the upper and lower plates 303 are in a state of contact with each other, so that the upper and lower plates 303 are in a state of contact with each other, so that the upper and lower plates 303 are in a state of contact with each other, so that the upper and lower plates 303 are in a state of contact with each other, so that the upper and lower plates 303 are in a state of contact with each other,

[0060] In a further embodiment of the present invention, a heat distribution net 10 is placed inside the shielding cover 201, and a gap is reserved between the heat distribution net 10 and the lower electrode plate 4. Specifically, the heat distribution net 10 is made of a material that is resistant to high temperatures and has good thermal conductivity. Its shape and size can fit tightly against the inner wall of the shielding cover 201, and a certain gap is reserved between it and the lower electrode plate 4. The gap is to ensure that the heat distribution net 10 can evenly distribute heat and avoid excessive concentration of heat on the lower electrode plate 4, thereby improving the uniformity and efficiency of heating. In addition, the introduction of the heat distribution net 10 also increases the path and area of heat transfer, so that the heat generated by the annular heating element 202 can be transferred to the air inside the shielding cover 201 and the lower electrode plate 4 more quickly. At the same time, since a gap is reserved between the heat distribution net 10 and the lower electrode plate 4, this gap can also serve as a buffer zone to reduce the direct impact of heat on the lower electrode plate 4, thereby extending the service life of the lower electrode plate 4.

[0061] The above description is merely illustrative of certain exemplary embodiments of the present invention. It goes without saying that those skilled in the art will be able to modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and description are illustrative in nature and should not be construed as limiting the scope of protection of the claims.

Claims

1. A PECVD device for field effect passivation of crystalline silicon cells, comprising a reaction chamber (1), characterized in that: Also includes: A sleeve (2) is inserted into the bottom of the reaction chamber (1), a rotating column (3) is installed in the sleeve (2), a lower electrode plate (4) is installed on the top of the rotating column (3), a shielding cover (201) covering the lower electrode plate (4) is installed on the top of the sleeve (2), a plurality of annular heating elements (202) centered on the rotating column (3) are installed below the shielding cover (201), a heat distribution net (10) is placed inside the shielding cover (201), and a gap is reserved between the heat distribution net (10) and the lower electrode plate (4); A flow suppression ring (5) is installed between the sleeve (2) and the rotating column (3); the interior of the sleeve (2) is divided into a heat storage chamber (203) for storing coolant and a heat dissipation chamber (204) by the flow suppression ring (5); a flow turbulence opening and closing member (6) that cooperates with the flow suppression ring (5) is rotatably installed in the heat storage chamber (203); The spoiler opening and closing member (6) comprises a cover ring (601) rotatably connected to the inner wall of the heat storage chamber (203), an upper through hole (602) is provided on the cover ring (601), a lower through hole (501) corresponding to the upper through hole (602) is provided on the flow suppression ring (5), and a plurality of spoiler paddles (603) are distributed in an annular manner on the top of the cover ring (601); The bottom of the lower pole plate (4) is fixedly connected to an insertion rod (401), the top of the rotating column (3) is fixedly connected to a docking joint (301) for inserting the insertion rod (401), the outer side wall of the docking joint (301) is fixedly connected to a push plate (302), and the push plate (302) is in abutment with the spoiler paddle (603); An upper electrode plate (7) is installed above the lower electrode plate (4) inside the reaction chamber (1); an air intake pipe (8) communicating with the outside of the reaction chamber (1) is fixedly connected to the top of the upper electrode plate (7); a spray plate (9) is embedded in the bottom of the upper electrode plate (7); a guide ring (801) is installed at the exhaust end of the air intake pipe (8); an annular groove (802) is formed between the guide ring (801) and the air intake pipe (8); and a circle of air discharge inclined holes (803) communicating with the annular groove (802) is provided at the bottom of the air intake pipe (8); While the shielding cover (201) disperses the heat of the annular heating element (202), the rotating column (3) drives the turbulent opening and closing member (6) to rotate, so that the coolant in the heat storage chamber (203) and the heat dissipation chamber (204) are intermittently mixed.

2. The PECVD device for field effect passivation of a crystalline silicon cell according to claim 1, characterized in that: A reflective disk (205) is installed on the outside of the sleeve (2), and the reflective disk (205) is located below the annular heating elements (202). The diameter of the reflective disk (205) is larger than the outer diameter of any of the annular heating elements (202). A plurality of heat-conducting fins (206) are distributed in an annular pattern on the outer wall of the sleeve (2), and the upper and lower ends of the heat-conducting fins (206) are in contact with the shielding cover (201) and the reflective disk (205), respectively.

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