LPCVD furnace, TOPCon battery, preparation method of TOPCon battery and photovoltaic module

Abstract

The invention discloses an LPCVD furnace, a TOPCon battery, a preparation method of the TOPCon battery and a photovoltaic module, and relates to the technical field of photovoltaic batteries. The LPCVD furnace comprises a furnace body, a furnace cavity is formed in the furnace body, the furnace body is provided with a furnace opening and a furnace tail which are oppositely arranged, and the furnace opening is provided with an air inlet device for feeding air into the furnace cavity; the air supply assembly is arranged in the furnace chamber, is parallel to the axial direction of the furnace body, extends from the furnace tail to the furnace opening, and comprises a first air inlet pipe and a second air inlet pipe; the first air inlet pipe is longer than the second air inlet pipe. According to the LPCVD furnace, the air inlet structure is composed of the furnace mouth air inlet assembly and the air supply assembly, and the air supply assembly extends from the furnace tail to the furnace mouth and can compensate for consumption of furnace mouth airflow when a boat enters from the furnace mouth; furthermore, the furnace tail is provided with a long air inlet pipe and a short air inlet pipe, so that the airflow difference between the furnace mouth and the furnace tail can be effectively reduced; therefore, the difference of the film thickness is effectively reduced, and the uniformity of the film thickness of the amorphous silicon layer is effectively improved.

Description

Technical Field

[0001] This application relates to the technical field of photovoltaic cells, and particularly to an LPCVD furnace, a TOPCon cell and its manufacturing method, and a photovoltaic module. Background Art

[0002] The TOPCon cell structure requires the preparation of a passivation layer formed by a tunneling oxide layer and a doped polysilicon layer. The passivation layer is mainly prepared by depositing an amorphous silicon layer using an LPCVD furnace. The uniformity of the film thickness of the amorphous silicon layer will directly affect the performance of the subsequent cell.

[0003] The inlet pipe of the LPCVD furnace is generally located at one end of the furnace mouth. The gas is uniformly injected into the furnace chamber through a quartz nozzle or distributed small holes. Since the distance of each boat from the furnace mouth is different, as the distance from the furnace mouth to the furnace tail increases, the gas flow rate in the temperature zone not close to the inlet position is less, resulting in a large difference in film thickness and poor uniformity.

[0004] Therefore, there is an urgent need for a new LPCVD furnace deposition device. Summary of the Invention

[0005] The purpose of this application is to provide an LPCVD furnace, a TOPCon cell and its manufacturing method, and a photovoltaic module. The LPCVD furnace provided by this application effectively improves the uniformity of the film thickness and further improves the efficiency of the TOPCon cell.

[0006] The first aspect of this application provides an LPCVD furnace, including: a furnace body, the furnace body forms a furnace chamber and has a furnace mouth and a furnace tail arranged oppositely, and an air inlet device for introducing gas into the furnace chamber is arranged at the furnace mouth; a gas supplementing component, the gas supplementing component is arranged in the furnace chamber, parallel to the axial direction of the furnace body, and extends from the furnace tail to the furnace mouth, and the gas supplementing component includes a first inlet pipe and a second inlet pipe; the length of the first inlet pipe is greater than that of the second inlet pipe.

[0007] In an optional manner, the furnace body is set as a front furnace area, a middle furnace area and a rear furnace area from the furnace mouth to the furnace tail, the first inlet pipe extends from the rear furnace area to the middle furnace area, and the second inlet pipe is arranged in the rear furnace area; c

[0008] Preferably, the outlet end of the first inlet pipe is arranged at 1 / 3 - 1 / 2 of the middle furnace area close to the front furnace area; and / or, the outlet end of the second inlet pipe is arranged at 1 / 4 - 1 / 3 of the rear furnace area close to the middle furnace area.

[0009] In an optional manner, the furnace body includes at least 3 temperature zones, and the temperature of at least one temperature zone where the middle furnace area is located and / or the temperature of at least one temperature zone where the rear furnace area is located is greater than the temperature of the temperature zone where the front furnace area is located;

[0010] Preferably, the furnace body is composed of 6 temperature zones, the front furnace zone is composed of 2 temperature zones, the middle furnace zone is composed of 2 temperature zones, and the rear furnace zone is composed of 2 temperature zones;

[0011] More preferably, the temperatures of the 2 temperature zones in the front furnace zone are equal, the temperatures of the 2 temperature zones in the middle furnace zone gradually decrease, and the temperatures of the 2 temperature zones in the rear furnace zone gradually increase; and the temperature of the maximum temperature zone in the middle furnace zone is greater than the temperature of the maximum temperature zone in the front furnace zone, and the temperature of the maximum temperature zone in the rear furnace zone is greater than the temperature of the maximum temperature zone in the front furnace zone and / or the maximum temperature zone in the middle furnace zone.

[0012] More preferably, the temperature of the temperature zone is 590 - 630 °C; and / or, the temperature of the maximum temperature zone in the middle furnace zone is 1 - 10 °C higher than the temperature of the maximum temperature zone in the front furnace zone; and / or, the temperature of the maximum temperature zone in the rear furnace zone is 1 - 12 °C higher than the temperature of the maximum temperature zone in the front furnace zone; and / or, the temperature of the maximum temperature zone in the rear furnace zone is 1 - 5 °C higher than the temperature of the maximum temperature zone in the middle furnace zone.

[0013] In an alternative embodiment, the length of the first inlet pipe is 1.4 - 2 times the length of the second inlet pipe;

[0014] In an alternative embodiment, the length of the first inlet pipe is 0.30 - 0.5 times the length of the furnace body;

[0015] In an alternative embodiment, the length of the second inlet pipe is 0.15 - 0.40 times the length of the furnace body;

[0016] In an alternative embodiment, the length of the furnace body is 3 - 6 meters;

[0017] In an alternative embodiment, the length of the first inlet pipe is 1.5 - 2.2 meters;

[0018] In an alternative embodiment, the length of the second inlet pipe is 1 - 1.8 meters;

[0019] In an alternative embodiment, the material of the first inlet pipe and / or the second inlet pipe is silicon carbide;

[0020] In an alternative embodiment, the first inlet pipe and / or the second inlet pipe is a straight-through pipe;

[0021] In an alternative embodiment, the outlet ends of the first inlet pipe and / or the second inlet pipe are flush structures;

[0022] In an alternative embodiment, the first inlet pipe and / or the second inlet pipe are arranged at the bottom of the furnace body;

[0023] In an alternative embodiment, the inner diameter of the first intake pipe and / or the second intake pipe is 8 to 16 mm;

[0024] In an alternative embodiment, the outer diameter of the first intake pipe and / or the second intake pipe is 12 to 24 mm;

[0025] In an alternative embodiment, the first intake pipe and / or the second intake pipe are respectively provided with flow meters.

[0026] In an alternative embodiment, the intake device includes an annular intake pipe provided at the end of the furnace mouth and air outlet holes facing the furnace cavity;

[0027] Preferably, the annular intake pipe is provided inside the end of the furnace mouth, and a plurality of air outlet holes are evenly distributed on the inner side surface of the annular intake pipe 201 facing the furnace cavity;

[0028] More preferably, the number of the air outlet holes is 4 - 20;

[0029] More preferably, the diameter of the air outlet holes is 1 - 3 mm.

[0030] The second aspect of the present application provides a method for preparing a TOPCon solar cell, which is prepared by using the LPCVD furnace of the first aspect of the present application; wherein, the intake device introduces oxygen and silane gas into the furnace cavity; the air supplement component introduces silane gas into the furnace cavity.

[0031] In an alternative embodiment, the flow rate of silane in the first intake pipe is greater than the flow rate of silane in the second intake pipe;

[0032] Preferably, the flow rate of silane in the first intake pipe is greater than the flow rate of silane in the second intake pipe by 0 - 50 SCCM;

[0033] Preferably, the flow rate of silane in the first intake pipe is 350 SCCM - 500 SCCM; and / or, the flow rate of silane in the second intake pipe is 300 SCCM - 450 SCCM;

[0034] Preferably, in the intake device, the flow rate of oxygen is 30000 - 50000 SCCM; and / or, the flow rate of silane is 100 - 1000 SCCM.

[0035] In an alternative embodiment, the deposition pressure of the LPCVD furnace is 20 - 30 Pa.

[0036] The third aspect of the present application provides a TOPCon photovoltaic cell, which is prepared by using the method for preparing a TOPCon photovoltaic cell of the second aspect of the present application.

[0037] The fourth aspect of the present application provides a photovoltaic module, which includes the TOPCon photovoltaic cell of the third aspect of the present application.

[0038] Compared with the prior art, the present application:

[0039] (1) For the LPCVD furnace provided by the present application, the air intake structure is composed of a furnace mouth air intake device and a gas supplement component. The furnace mouth air intake device is arranged at the furnace mouth position, and the gas supplement component extends from the furnace tail to the furnace mouth, which can compensate for the consumption of the furnace mouth air flow caused by the boat entering from the furnace mouth; further, two intake pipes with different lengths are arranged at the furnace tail, which can effectively reduce the air flow difference between the furnace mouth and the furnace tail; thus, the difference in film thickness is effectively reduced, and the uniformity of the film thickness of the amorphous silicon layer is effectively improved.

[0040] (2) For the deposition method of LPCVD of the present application, the first intake pipe and the second intake pipe adopt different air flow rates, which can not only effectively reduce the difference in film thickness, but also effectively improve the utilization rate of gas and effectively save the preparation cost of the battery wafers. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings described herein are used to provide a further understanding of the present application and form a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0042] Figure 1 A front schematic view of an embodiment of the LPCVD furnace of the present application is shown.

[0043] Figure 2 A side sectional schematic view of an embodiment of the LPCVD furnace of the present application is shown.

[0044] REFERENCE SIGNS:

[0045] 10 - furnace body; 101 - front furnace area; 102 - middle furnace area; 103 - rear furnace area; 20 - furnace mouth; 201 - annular intake pipe; 202 - air outlet hole; 30 - furnace tail; 40 - gas supplement component; 401 - first intake pipe; 402 - second intake pipe; 50 - boat DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present disclosure.

[0047] In addition, the terms "first" and "second" are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, "a plurality" means two or more, unless otherwise specifically defined. "Several" means one or more, unless otherwise specifically defined.

[0048] The first aspect of this application provides an LPCVD furnace. As Figure 1-2 shown, the LPCVD furnace is a horizontally placed cylindrical quartz tube. The silicon wafers are vertically placed in the quartz boat dishes and are processed continuously or batchwise through the furnace tube. The LPCVD furnace includes a furnace body 10. The furnace body 10 forms a furnace cavity. Both ends of the furnace body 10 are provided with a furnace inlet 20 and a furnace tail 30. The dish 50 enters from the furnace inlet 20. An air inlet device for introducing gas into the furnace cavity is provided at the end of the furnace inlet 20. The gas flows through the dish 50 and flows from front to back. A gas supplement component 40 is installed in the furnace cavity. The gas supplement component 40 is arranged in the furnace cavity and is parallel to the axial direction of the furnace body 10. The gas supplement component 40 extends from the furnace tail 30 towards the furnace inlet 20. The gas supplement component 40 will introduce gas so that the gas flows through the dish 50. The gas supplement component 40 extends from the furnace tail 30 towards the furnace inlet 20, so that the gas flows from back to front, thereby effectively compensating for the shortage of the gas flow rate at the furnace tail 30 of the gas introduced by the air inlet device at the furnace inlet 20. The gas supplement component 40 includes a first inlet pipe 401 and a second inlet pipe 402; and the length of the first inlet pipe 401 is greater than that of the second inlet pipe 402. Thus, the difference in the gas flow in the furnace can be further improved, thereby effectively reducing the difference in the film thickness and effectively improving the uniformity of the film thickness of the amorphous silicon layer.

[0049] In an alternative manner, as Figure 1 shown, the furnace body 10 is set as a front furnace area 101, a middle furnace area 102, and a rear furnace area 103 from the furnace inlet 20 to the furnace tail 30. The first inlet pipe 401 is arranged to extend from the rear furnace area 103 into the middle furnace area 102; the first inlet pipe 401 starts to extend from the furnace tail 30 of the rear furnace area 103 into the middle furnace area 102. The outlet end of the first inlet pipe 401 can be set at the start position of the middle furnace area 102, or can be set in the middle of the middle furnace area 102, or can be set at the last position of the middle furnace area 102; the second inlet pipe 402 is arranged in the rear furnace area 103 and starts to be arranged at the furnace tail 30 of the rear furnace area 103 and extends towards a position in the rear furnace area 103 close to the middle furnace area 102. The outlet end of the second inlet pipe 402 can be set at the start position of the rear furnace area 103, or can be set in the middle of the rear furnace area 103, or can be set at the rear position of the middle furnace area 102.

[0050] In a preferred manner, as Figure 1As shown, the outlet end of the first intake pipe 401 is disposed at the position of 1 / 3 to 1 / 2 of the middle furnace zone 102 close to the front furnace zone 101. The outlet end of the first intake pipe extends from the furnace tail 30 of the rear furnace zone 103 towards the front furnace zone 101 in the middle furnace zone 102, and its outlet end is disposed at the position of 1 / 3 to 1 / 2 of the middle furnace zone 102 close to the front furnace zone 101; for example, it can be 1 / 3, 1 / 2 or any range between 1 / 3 and 1 / 2.

[0051] In a preferred embodiment, as Figure 1 shown, the outlet end of the second intake pipe 402 is disposed at the position of 1 / 4 to 1 / 3 of the rear furnace zone 103 close to the middle furnace zone 102. The second intake pipe 402 is disposed in the rear furnace zone 103 and extends from the furnace tail 30 of the rear furnace zone 103 towards the position of the rear furnace zone 103 close to the middle furnace zone 102. The outlet end of the second intake pipe 402 can be disposed at the position of 1 / 4 to 1 / 3 of the rear furnace zone 103 close to the middle furnace zone 102 in the rear furnace zone 103, for example, it can be 1 / 4, 1 / 3 or any range between 1 / 4 and 1 / 3.

[0052] In an alternative embodiment, as Figure 1 shown, the furnace body 10 is set as the front furnace zone 101, the middle furnace zone 102 and the rear furnace zone 103 from the furnace mouth 20 to the furnace tail 30; there are 6 temperature zones in the furnace body 10. The temperature zones of the LPCVD furnace are mainly realized by 6 independent temperature control heaters. The resistance wire heaters can be evenly distributed around the outer wall of the quartz tube and set to independent temperatures, and the temperature can be fed back in real time through the internal metal tubular thermocouple and the power can be adjusted to ensure the axial temperature uniformity. Each of the front furnace zone 101, the middle furnace zone 102 and the rear furnace zone 103 includes at least one temperature zone. Since the exhaust structure at the furnace mouth 20 is disposed at the furnace mouth 20, the temperature zones of the front furnace zone 101 are mainly affected by the airflow of the exhaust structure at the furnace mouth 20; the first intake pipe 401 is disposed in the middle furnace zone 102 extending from the rear furnace zone 103, so the temperature zones of the middle furnace zone 102 are mainly affected by the airflow of the first intake pipe 401; the second intake pipe 402 is disposed in the rear furnace zone 103; therefore, the temperature zones of the rear furnace zone 103 are mainly affected by the airflow of the second intake pipe 402; thus, the three furnace zones are regulated and controlled by three intake structures, which can further reduce the difference in film thickness and improve the uniformity of the film thickness of the amorphous silicon layer.

[0053] In some specific embodiments, the furnace body 10 is composed of 6 temperature zones, the front furnace zone 101 is composed of 2 temperature zones, the middle furnace zone 102 is composed of 2 temperature zones, and the rear furnace zone 103 is composed of 2 temperature zones; in some specific embodiments, the temperatures of the 2 temperature zones in the front furnace zone 101 are equal, the temperature of the middle furnace zone 102 is greater than the temperature of the front furnace zone 101, and the temperatures of the 3 temperature zones in the rear furnace zone 103 gradually increase. Thus, by controlling the temperature zones in the furnace zone, the difference in film thickness can be further reduced and the uniformity of the film thickness of the amorphous silicon layer can be improved.

[0054] In some more specific embodiments, the temperatures of the two temperature zones in the front furnace zone 101 are equal, the temperatures of the two temperature zones in the middle furnace zone 102 gradually decrease, and the temperatures of the two temperature zones in the rear furnace zone 103 gradually increase; and the temperature of the maximum temperature zone in the middle furnace zone 102 is greater than the temperature of the maximum temperature zone in the front furnace zone 101, and the temperature of the maximum temperature zone in the rear furnace zone 103 is greater than the temperature of the maximum temperature zone in the middle furnace zone 102. Thus, by controlling the temperature zones in the furnace, the difference in film thickness is further reduced, and the uniformity of the film thickness of the amorphous silicon layer is improved.

[0055] In some more specific embodiments, the temperature of the temperature zone is 590 - 630 °C; for example, it can be 590 °C, 600 °C, 610 °C, 620 °C or 630 °C.

[0056] In some more specific embodiments, the temperature of the maximum temperature zone in the middle furnace zone 102 is 1 - 10 °C higher than the temperature of the maximum temperature zone in the front furnace zone 101; for example, it can be 1 °C, 2 °C, 3 °C, 4 °C, 5 °C, 6 °C, 7 °C, 8 °C, 9 °C or 10 °C.

[0057] The temperature of the maximum temperature zone in the rear furnace zone 103 is 1 - 12 °C higher than the temperature of the maximum temperature zone in the front furnace zone 101; for example, it can be 1 °C, 2 °C, 3 °C, 4 °C, 5 °C, 6 °C, 7 °C, 8 °C, 9 °C, 10 °C, 11 °C or 12 °C.

[0058] The temperature of the maximum temperature zone in the rear furnace zone 103 is 1 - 5 °C higher than the temperature of the maximum temperature zone in the middle furnace zone 102; for example, it can be 1 °C, 2 °C, 3 °C, 4 °C or 5 °C.

[0059] In an alternative manner, as Figure 1 shown, the length of the first inlet pipe 401 is 1.4 - 2 times the length of the second inlet pipe 402; for example, it can be 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times or 2 times; within this range, the first inlet pipe 401 and the second inlet pipe 402 cooperate with each other to compensate for the air flow in the furnace body 10, thereby reducing the air flow difference from the furnace mouth 20 to the furnace tail 30, effectively reducing the difference in film thickness, and effectively improving the uniformity of the film thickness of the amorphous silicon layer.

[0060] In an alternative manner, the length of the first inlet pipe is 0.30 - 0.5 times the length of the furnace body; for example, it can be 0.3, 0.35, 0.4, 0.45 or 0.5 times;

[0061] In an alternative manner, the length of the second inlet pipe is 0.15 - 0.40 times the length of the furnace body; for example, it can be 0.15, 0.2, 0.25, 0.3, 0.35 or 0.4 times.

[0062] In some specific embodiments, the length of the furnace body is 3 - 6 meters; for example, it can be 3 meters, 3.1 meters, 3.2 meters, 3.3 meters, 3.4 meters, 3.5 meters, 3.6 meters, 3.7 meters, 3.8 meters, 3.9 meters, 4 meters, 4.1 meters, 4.2 meters, 4.3 meters, 4.4 meters, 4.5 meters, 4.6 meters, 4.7 meters, 4.8 meters, 4.9 meters, 5 meters, 5.1 meters, 5.2 meters, 5.3 meters, 5.4 meters, 5.5 meters, 5.6 meters, 5.7 meters, 5.8 meters, 5.9 meters, or 6 meters.

[0063] In some specific embodiments, the length of the first intake pipe 401 is 1.5 - 2.2 meters; for example, it can be 1.5 meters, 1.6 meters, 1.7 meters, 1.8 meters, 1.9 meters, 2 meters, 2.1 meters, or 2.2 meters. Within this range, the first intake pipe 401.

[0064] In some specific embodiments, the length of the second intake pipe 402 is 1 - 1.8 meters; for example, it can be 1 meter, 1.1 meters, 1.2 meters, 1.3 meters, 1.4 meters, 1.5 meters, 1.6 meters, 1.7 meters, 1.8 meters, 1.9 meters, or 2 meters.

[0065] In an alternative embodiment, the material of the first intake pipe 401 and / or the second intake pipe 402 is silicon carbide; the intake pipe made of silicon carbide can withstand high temperatures, and compared with the traditional metal intake pipe, it is not easy to deform and break, avoiding the pollution of the furnace tube and the blockage of the intake pipe.

[0066] In an alternative embodiment, the first intake pipe 401 and / or the second intake pipe 402 is a straight-through pipe; that is, there are no openings on the side of the pipe, and the gas flows from the tail of the intake pipe to the mouth of the intake pipe, without other air outlets in the middle. This avoids problems such as easy blockage, easy deformation, and low service life caused by multi-hole air outlet.

[0067] In an alternative embodiment, the outlet end of the first intake pipe 401 and / or the second intake pipe 402 is a flush structure; there is no slot at the pipe mouth, avoiding the dust in the furnace tube from falling back and accumulating at the slot position.

[0068] In an alternative embodiment, the first intake pipe 401 and / or the second intake pipe 402 is arranged at the bottom of the furnace body 10; so that the gas flows upward to the corresponding boat 50, further reducing the thickness difference of the amorphous silicon film.

[0069] In an alternative embodiment, such as Figure 2As shown in the figure, the air inlet device at the furnace mouth includes an annular air inlet pipe 201 and air outlet holes 202 arranged facing the furnace cavity; thus, the air inlet at the furnace mouth can flow into the furnace cavity evenly through the air outlet holes. Specifically, the annular air inlet pipe 201 is arranged inside the end of the furnace mouth, and a plurality of air outlet holes 202 are evenly distributed on the inner side surface of the annular air inlet pipe 201 facing the furnace cavity; the inner diameter of the annular air inlet pipe 201 is 3 - 6 mm; for example, it can be 3 mm, 4 mm, 5 mm, or 6 mm; in a specific embodiment, the number of air outlet holes is 4 - 20, for example, it can be 4, 6, 8, 12, 16, or 20. In a more specific embodiment, the diameter of the air outlet holes is 1 - 3 mm; for example, it can be 1 mm, 1.5 mm, 2 mm, 2.5 mm, or 3 mm.

[0070] In an alternative manner, the inner diameter of the furnace body is 300 mm to 600 m; for example, it can be 300 mm, 350 mm, 400 mm, 450 mm, 500 mm, 550 mm, or 600 mm.

[0071] In an alternative manner, the inner diameter of the annular air inlet pipe 201 included in the air inlet device at the furnace mouth is 10 - 20 mm; for example, it can be 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, or 20 mm.

[0072] In an alternative manner, the inner diameter of the first air inlet pipe 401 and / or the second air inlet pipe 402 is 8 - 16 mm; for example, it can be 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, or 16 mm.

[0073] In an alternative manner, the outer diameter of the first air inlet pipe 401 and / or the second air inlet pipe 402 is 12 - 24 mm; for example, it can be 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, or 24 mm.

[0074] In an alternative manner, flow meters are respectively arranged on the first air inlet pipe 401 and / or the second air inlet pipe 402. Thus, the flow rates of the first air inlet pipe 401 and the second air inlet pipe 402 can be controlled separately.

[0075] The second aspect of the present application provides a method for preparing a TOPCon cell, which is prepared by using the LPCVD furnace provided in the first aspect of the present application.

[0076] LPCVD (Low Pressure Chemical Vapor Deposition) is a conventional method for depositing amorphous silicon in TOPCon solar cells. It mainly produces silicon oxide by reacting oxygen with silicon at high temperature under low pressure conditions to form an oxide layer. Then, silane is introduced at high temperature, and silane thermally decomposes into silicon and hydrogen to form an amorphous silicon layer on the surface of the silicon wafer.

[0077] Specifically, as Figure 1 shown, the working process of the LPCVD furnace is to push multiple boats 50 containing silicon wafers into the furnace cavity from the furnace opening 20 and arrange them at intervals inside the furnace. After evacuation, heating, leak detection, gas is introduced and deposition begins. Among them, the furnace opening 20 is provided with an air inlet device, and the air flow uniformly enters the furnace cavity through the air inlet device. The air inlet device introduces oxygen and silane gas into the furnace cavity.

[0078] The air supplement component 40 is arranged to extend from the furnace tail 30 to the furnace opening 20. The air supplement component 40 includes a first inlet pipe 401 and a second inlet pipe 402; and the length of the first inlet pipe 401 is greater than that of the second inlet pipe 402. The first inlet pipe 401 and the second inlet pipe 402 respectively introduce gas, and the gas flows from the back to the front, effectively compensating for the insufficient gas flow at the furnace tail 30 of the gas introduced by the air inlet device at the furnace opening 20. Among them, the air supplement component introduces silane gas into the furnace cavity. This can further improve the difference in air flow in the furnace, thereby effectively reducing the difference in film thickness and effectively improving the uniformity of the film thickness of the amorphous silicon layer.

[0079] In an optional manner, the flow rate of the first inlet pipe 401 is greater than that of the second inlet pipe 402; this can further improve the difference in air flow in the furnace and improve the uniformity of the film thickness of the amorphous silicon layer.

[0080] In an optional manner, in the air inlet device, the flow rate of oxygen is 30000 - 50000 SCCM; for example, it can be 30000 SCCM, 35000 SCCM, 40000 SCCM, 450000 SCCM or 50000 SCCM; the flow rate of silane is 100 - 1000 SCCM; for example, it can be 100 SCCM, 200 SCCM, 300 SCCM, 400 SCCM, 500 SCCM, 600 SCCM, 700 SCCM, 800 SCCM, 900 SCCM or 1000 SCCM.

[0081] In some specific embodiments, silane gas is introduced into the first intake pipe 401 and the second intake pipe 402, and the flow rate of the first intake pipe 401 is greater than that of the second intake pipe 402 by 0 to 50 SCCM; for example, it can be greater than 0.1 SCCM, 1 SCCM, 5 SCCM, 10 SCCM, 15 SCCM, 20 SCCM, 25 SCCM, 30 SCCM, 35 SCCM, 40 SCCM, 45 SCCM or 50 SCCM;

[0082] In some more specific embodiments, the flow rate of the first intake pipe 401 is 350 SCCM to 500 SCCM; for example, it can be 350 SCCM, 360 SCCM, 370 SCCM, 380 SCCM, 390 SCCM, 400 SCCM, 410 SCCM, 420 SCCM, 430 SCCM, 440 SCCM, 450 SCCM, 460 SCCM, 470 SCCM, 480 SCCM, 490 SCCM or 500 SCCM;

[0083] In some more specific embodiments, the flow rate of the second intake pipe 401 is 300 SCCM to 450 SCCM, for example, it can be 300 SCCM, 310 SCCM, 320 SCCM, 330 SCCM, 340 SCCM, 350 SCCM, 360 SCCM, 370 SCCM, 380 SCCM, 390 SCCM, 400 SCCM, 410 SCCM, 420 SCCM, 430 SCCM, 440 SCCM or 450 SCCM.

[0084] In an alternative manner, in an alternative manner, the deposition pressure in the LPCVD furnace is 20 to 30 Pa; for example, it can be 20 Pa, 21 Pa, 22 Pa, 23 Pa, 24 Pa, 25 Pa, 25 Pa, 26 Pa, 27 Pa, 28 Pa, 29 Pa or 30 Pa. The deposition time in the LPCVD furnace is 110 - 200 minutes.

[0085] The third aspect of the present application provides a TOPCon photovoltaic cell, which is prepared by using the preparation method of the TOPCon photovoltaic cell in the second aspect of the present application.

[0086] For the photovoltaic cell provided in the third aspect of the present application, under the condition of the film thickness difference of the amorphous silicon layer, the uniformity of the film thickness of the amorphous silicon layer is good, and thus the efficiency of the TOPCon photovoltaic cell can be effectively improved.

[0087] The fourth aspect of the present application provides a photovoltaic module, which includes the TOPCon photovoltaic cell in the third aspect of the present application.

[0088] For the photovoltaic cell provided in the third aspect of the present application, the power of its photovoltaic module is higher.

[0089] The following describes in detail, with several specific embodiments, the TOPCon photovoltaic cell provided in the second aspect of the present application prepared by the LPCVD furnace according to the first aspect. It should be understood that the following description is only an exemplary illustration and not a specific limitation of the invention.

[0090] Example 1

[0091] In Example 1, N-type monocrystalline silicon wafers were selected for the preparation of TOPCon cell wafers. The wafers were processed through texturing, boron diffusion, alkaline polishing, LPCVD tunneling and amorphous silicon layer deposition, phosphorus diffusion doping, RCA cleaning, front-side alumina, front and back film silicon nitride passivation and metallization, and finally a TOPCon cell was formed. The TOPCon cell uses an N-type monocrystalline silicon wafer as the substrate. On the front side of the substrate, there are alumina passivation, antireflection film thickness, and a front electrode; on the back side of the substrate, there are a tunneling oxide layer, a phosphorus-doped polysilicon layer, a silicon nitride passivation film thickness, and a back electrode.

[0092] Among them, during the process of depositing the amorphous silicon layer by LPCVD, the LPCVD furnace is a horizontally placed cylindrical quartz tube, and the silicon wafers are vertically placed in a quartz boat; there are 12 boats in the furnace; the first 4 boats form the front furnace zone 101, the middle 4 boats form the middle furnace zone 102, and the last 4 boats form the back furnace zone 103; there are 2 temperature zones set on each furnace zone, for a total of 6 temperature zones. The temperatures of the 6 temperature zones are 601 °C, 601 °C, 609 °C, 601 °C, 603 °C, and 612 °C respectively. The deposition pressure of the LPCVD furnace is 25 pa.

[0093] There is an annular inlet pipe at the end face of the furnace mouth. There are 16 evenly distributed air outlet holes on the annular inlet pipe, and the air outlet holes face the cavity to introduce gas; the inner diameter of the furnace body is 480 mm, the inner diameter of the annular inlet pipe is 12 mm, and the diameter of the air outlet holes is 1 mm;

[0094] There is a gas supplementing component from the furnace mouth to the furnace tail. The gas supplementing component consists of a first inlet pipe and a second inlet pipe. The materials of the first inlet pipe and the second inlet pipe are silicon carbide. The diameter of the first inlet pipe is 12 mm, the diameter of the second inlet pipe is 12 mm, the length of the first inlet pipe is 2.1 m, and the length of the second inlet pipe is 1.3 m. Thus, the first inlet pipe is located at the 1 / 2 position of the middle furnace zone 102 close to the front furnace zone 101; the second inlet pipe is located at the 1 / 2 position of the back furnace zone 103 close to the middle furnace zone 102.

[0095] The oxygen flow rate introduced by the furnace mouth inlet device is 35000 SCCM, and the silane gas flow rate introduced is 300 SCCM; SCCM, the gas flow rate of silane introduced through the first inlet pipe is 400 SCCM; the gas flow rate of silane introduced through the second inlet pipe is 420 SCCM.

[0096] Example 2

[0097] Different from Example 1, the gas flow rate of silane introduced into the first intake pipe is 410 SCCM; the gas flow rate of silane introduced into the second intake pipe is 410 SCCM.

[0098] Example 3

[0099] Different from Example 1, the gas flow rate of silane introduced into the first intake pipe is 420 SCCM; the gas flow rate of silane introduced into the second intake pipe is 400 SCCM.

[0100] Example 4

[0101] Different from Example 1, the gas flow rate of silane introduced into the first intake pipe is 430 SCCM; the gas flow rate of silane introduced into the second intake pipe is 390 SCCM.

[0102] Example 5

[0103] Different from Example 1, the gas flow rate of silane introduced into the first intake pipe is 440 SCCM; the gas flow rate of silane introduced into the second intake pipe is 380 SCCM.

[0104] Example 6

[0105] Different from Example 3,

[0106] A quartz nozzle is provided at the furnace mouth to introduce gas into the furnace cavity. A gas supplementing component is provided at the furnace tail starting from the furnace mouth. The gas supplementing component is composed of a first intake pipe and a second intake pipe. The materials of the first intake pipe and the second intake pipe are silicon carbide. The length of the first intake pipe is 1.9 m, and the length of the second intake pipe is 1.0 m. Thus, the first intake pipe is located at 1 / 4 of the middle furnace zone 102 close to the front furnace zone 101; the second intake pipe is located at 1 / 4 of the rear furnace zone 103 close to the middle furnace zone 102.

[0107] Comparative Example 1

[0108] Different from Example 3, the LPCVD furnace is not provided with a gas supplementing component.

[0109] Comparative Example 2

[0110] Different from Example 3, the gas supplementing component only has a first intake pipe. The material of the first intake pipe is silicon carbide, and the length of the first intake pipe is 2.1 m. Thus, the first intake pipe is located at 1 / 2 of the middle furnace zone 102 close to the front furnace zone 101.

[0111] The gas flow rate of silane introduced at the furnace mouth is 300 SCCM, and the gas flow rate of silane introduced into the first intake pipe is 430 SCCM.

[0112] Comparative Example 3

[0113] Different from Example 3, the air supplement component only has a second intake pipe. The material of the first intake pipe is silicon carbide. The length of the second intake pipe is 1.0 mm, and the second intake pipe is located at 1 / 4 of the rear furnace zone 103 close to the middle furnace zone 102.

[0114] The gas flow rate at the furnace mouth is 300 SCCM, and the gas flow rate of the silicon tetrahydride introduced into the first intake pipe is 390 SCCM.

[0115] Comparative Example 4

[0116] Different from Example 3, the air supplement component includes two first intake pipes of the same length. The material of the first intake pipe is silicon carbide. The length of the first intake pipe is 2.1 m, so that the first intake pipe is located at 1 / 2 of the middle furnace zone 102 close to the front furnace zone 101.

[0117] The gas flow rate at the furnace mouth is 300 SCCM, and the gas flow rate of the silicon tetrahydride introduced into the two first intake pipes is 430 SCCM.

[0118] Comparative Example 5

[0119] Different from Example 3, the air supplement component includes two second intake pipes of the same length. The material of the first intake pipe is silicon carbide. The length of the second intake pipe is 1.0 mm, and the second intake pipe is located at 1 / 4 of the rear furnace zone 103 close to the middle furnace zone 102. The gas flow rate at the furnace mouth is 300 SCCM, and the gas flow rate of the silicon tetrahydride introduced into the two first intake pipes is 390 SCCM.

[0120] Table 1 below shows the film thickness and film thickness uniformity of different boats in Examples 1-6 and Comparative Examples 1-5. The film thickness uniformity is the range uniformity; Range uniformity = (maximum film thickness value - minimum film thickness value -) × 100% / (maximum film thickness value + minimum film thickness value). The smaller the range uniformity value, the better the film thickness uniformity.

[0121] As can be seen from the table, (1) Compared with Comparative Examples 1-5, after Examples 1-6 adopted the intake results of the present application, their film thickness uniformity was significantly higher. (2) Compared with Examples 1-2, Examples 3-5 adopted a larger gas flow rate in the first intake pipe than in the second intake pipe, resulting in higher film thickness uniformity. (3) Compared with Example 3, when the difference between the gas flow rates of the first intake pipe and the second intake pipe in Example 5 was greater than 50 SCCM, the film thickness uniformity effect became worse. (4) Compared with Example 3, in Example 6, the positions of the first intake pipe and the second intake pipe were too close to the furnace mouth, and the film thickness uniformity effect became slightly worse.

[0122] Table 1 Film thickness and film thickness uniformity of different boats in Examples 1-6 and Comparative Examples 1-5

[0123]

[0124]

[0125]

[0126] In addition, a battery efficiency tester was used to test the electrical performance data of the battery chips in Example 3 and Comparative Example 1. Table 2 shows the electrical performance data of the battery chips prepared in Example 3 and Comparative Example 1. As can be seen from the table, as the film thickness uniformity becomes better, the battery efficiency of Example 3 increases, and the proportion of low-efficiency batteries decreases significantly.

[0127] Table 2 Electrical performance data of the battery chips prepared in Example 3 and Comparative Example 1

[0128]

[0129] Although the present application has been described in connection with various embodiments, however, in the process of implementing the claimed present application, those skilled in the art can understand and achieve other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "one" does not exclude a plurality. A single processor or other unit can implement several functions recited in the claims. Certain measures are recited in mutually different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0130] Although the present application has been described in connection with specific features and their embodiments, it is obvious that various modifications and combinations can be made without departing from the spirit and scope of the present application. Accordingly, the present specification and the drawings are merely exemplary illustrations of the present application defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of the present application. Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these changes and modifications.

Claims

1. An LPCVD furnace, characterized in that, Comprising: A furnace body, which forms a furnace cavity and has a furnace mouth and a furnace tail arranged oppositely, and an air inlet device for introducing air into the furnace cavity is arranged at the furnace mouth; A gas supplement component, which is arranged in the furnace cavity, is parallel to the axial direction of the furnace body, and extends from the furnace tail to the furnace mouth. The gas supplement component includes a first inlet pipe and a second inlet pipe; the length of the first inlet pipe is greater than that of the second inlet pipe.

2. The LPCVD furnace according to claim 1, wherein The furnace body is arranged as a front furnace area, a middle furnace area and a rear furnace area from the furnace mouth to the furnace tail. The first inlet pipe extends from the rear furnace area to the middle furnace area, and the second inlet pipe is arranged in the rear furnace area; Preferably, the air outlet end of the first inlet pipe is arranged at 1 / 3 - 1 / 2 of the middle furnace area close to the front furnace area; and / or, the air outlet end of the second inlet pipe is arranged at 1 / 4 - 1 / 3 of the rear furnace area close to the middle furnace area.

3. The LPCVD furnace according to claim 2, characterized in that The furnace body includes at least 3 temperature zones, and the temperature of at least one temperature zone where the middle furnace area is located and / or the temperature of at least one temperature zone where the rear furnace area is located are greater than the temperature of the temperature zone where the front furnace area is located; Preferably, the furnace body is composed of 6 temperature zones, the front furnace area is composed of 2 temperature zones, the middle furnace area is composed of 2 temperature zones, and the rear furnace area is composed of 2 temperature zones; More preferably, the temperatures of the 2 temperature zones in the front furnace area are equal, the temperatures of the 2 temperature zones in the middle furnace area gradually decrease, and the temperatures of the 2 temperature zones in the rear furnace area gradually increase; and the temperature of the maximum temperature zone in the middle furnace area is greater than the temperature of the maximum temperature zone in the front furnace area, and the temperature of the maximum temperature zone in the rear furnace area is greater than the temperature of the maximum temperature zone in the front furnace area and / or the middle furnace area.

4. The LPCVD furnace according to claim 3, characterized in that, The temperature of the temperature zone is 590 - 630 °C; and / or, the temperature of the maximum temperature zone in the middle furnace area is 1 - 10 °C greater than the temperature of the maximum temperature zone in the front furnace area; and / or, the temperature of the maximum temperature zone in the rear furnace area is 1 - 12 °C greater than the temperature of the maximum temperature zone in the front furnace area; and / or, the temperature of the maximum temperature zone in the rear furnace area is 1 - 5 °C greater than the temperature of the maximum temperature zone in the middle furnace area.

5. The LPCVD furnace according to claim 1, wherein The length of the first inlet pipe is 1.4 - 2 times the length of the second inlet pipe; and / or, The length of the first inlet pipe is 0.30 - 0.5 times the length of the furnace body; and / or, the length of the second inlet pipe is 0.15 - 0.40 times the length of the furnace body; and / or, The length of the furnace body is 3 - 6 meters; and / or, The length of the first inlet pipe is 1.5 - 2.2 meters; and / or, The length of the second inlet pipe is 1 - 1.8 meters; and / or, The material of the first inlet pipe and / or the second inlet pipe is silicon carbide; and / or, The first inlet pipe and / or the second inlet pipe is a straight-through pipe; and / or, The air outlet ends of the first inlet pipe and / or the second inlet pipe are of a flush structure; and / or, The first inlet pipe and / or the second inlet pipe are arranged at the bottom of the furnace body; and / or, The inner diameter of the first inlet pipe and / or the second inlet pipe is 8 - 16 mm; and / or, The outer diameter of the first intake pipe and / or the second intake pipe is 12 to 24 mm; and / or, The first intake pipe and / or the second intake pipe are respectively provided with flow meters.

6. The LPCVD furnace according to claim 1, characterized in that, The intake device includes an annular intake pipe provided at the end of the furnace opening and air outlet holes facing the furnace cavity; Preferably, the annular intake pipe is provided inside the end of the furnace opening, and a plurality of the air outlet holes are uniformly distributed on the inner side surface of the annular intake pipe facing the furnace cavity; More preferably, the number of the air outlet holes is 4 - 20; More preferably, the diameter of the air outlet holes is 1 - 3 mm.

7. A preparation method of a TOPCon solar cell chip, characterized in that, Prepared by using the LPCVD furnace described in claims 1 - 6; Wherein, the intake device introduces oxygen and silane gas into the furnace cavity; the air supplement component introduces silane gas into the furnace cavity; Preferably, the flow rate of silane in the first intake pipe is greater than the flow rate of silane in the second intake pipe; More preferably, the flow rate of silane in the first intake pipe is greater than the flow rate of silane in the second intake pipe by 0 - 50 SCCM; More preferably, the flow rate of silane in the first intake pipe is 350 SCCM to 500 SCCM; and / or, the flow rate of silane in the second intake pipe is 300 SCCM to 450 SCCM; More preferably, in the intake device, the flow rate of oxygen is 30000 - 50000 SCCM; and / or, the flow rate of silane is 100 - 1000 SCCM.

8. The method for preparing a battery chip according to claim 7, wherein the deposition pressure of the LPCVD furnace is 20 - 30 Pa.

9. A TOPCon photovoltaic cell, characterized in that, Prepared by using the preparation method described in any one of claims 1 - 8.

10. A photovoltaic module, characterized in that, Including the TOPCon photovoltaic cell described in claim 9.

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