PE-poly process method and application thereof, and TOPCon solar cell

Abstract

The invention discloses a PE-poly process method and application thereof, and a TOPCon solar cell, and relates to the technical field of solar cells. According to the invention, in a TOPcon mass production battery line, after alkali polishing treatment is switched from HF cleaning end to HCl cleaning end, the problem of PE-poly water mark printing and film explosion in a mass production process route can be effectively solved by optimizing a PE-poly process film layer structure and phosphorane doping amount; according to the method, the flow rate of phosphorane is set to be 5-20% of the maximum range when the phosphorus lightly-doped amorphous silicon layer is prepared, the problem of water mark printing and film explosion on a TOPcon mass production line is greatly solved through the two adjustments, and the production efficiency and the yield are both improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, and particularly relates to a PE-poly process method and application thereof and a TOPCon solar cell. BACKGROUND

[0002] A tunnel oxide passivated contact solar cell (TOPCon solar cell) is a type of cell with a passivated contact composed of a tunnel oxide and a heavily doped polysilicon. A PE-poly process is a core process technology that integrates a tunnel layer, a poly layer, and a doped layer into one, is an important process in the production of a TOPCon solar cell at present, and uses a selective tunnel oxide to pass through electrons and block holes, and then a doped polysilicon layer to form a passivated contact structure, thereby effectively reducing surface recombination and metal contact recombination.

[0003] In the production process of an N-type TOPCon solar cell, a PECVD technology is currently used to prepare a PE-poly in a production line. The PECVD technology has the advantages of low deposition temperature, fast growth rate, and high film density, and in particular, has a small impact on the substrate structure during the deposition process, which can avoid adverse effects caused by high-temperature film formation, and the use of photo-injection annealing in the later stage improves the quality of the cell. In the production cell line, an N-type silicon substrate cell is first prepared, a tunnel layer and a doped amorphous silicon are prepared on the back of the cell, and then an annealing process is performed to convert the amorphous silicon into polysilicon, activate phosphorus atoms, and form an energy barrier through a doping gradient.

[0004] In the PECVD technology, the raw gas is input into the reaction chamber under vacuum environment, and the gas molecules are ionized to form plasma by plasma source excitation. The active particles in the plasma will chemically react on the surface of the substrate material to form a thin film, which is suitable for temperature-sensitive substrate materials. In the control process, the surface of the substrate material needs to be cleaned, and the cleaning degree will affect the material adhesion and film formation quality. In the PE-poly process route, the ultra-thin tunnel oxide layer plays a key role, and at the same time, it is complementary with the natural oxide layer generated by the previous alkali etching process to form a tunnel channel. However, the cleaning process ended with hydrofluoric acid (HF acid) will remove the natural oxide layer, and the natural oxide layer which is greatly affected by the environment will also make the efficiency unstable, therefore, the alkali etching process ended with HF acid has a great impact on PE-poly. Based on the premise of improving efficiency and yield, the alkali etching process ended with hydrochloric acid (HCl) is adopted. However, on the TOPcon mass production battery line, the matching difference between the cleaning process ended with HCl and the PE-poly process in the alkali etching process will cause the PE-poly process to appear film explosion, affecting the film formation quality of the battery.

[0005] Therefore, it is of great significance to develop a PE-poly process without film explosion to solve the problem that the current TOPcon mass production battery line causes the PE-poly process to appear film explosion due to the matching difference between the cleaning process and the PE-poly process. SUMMARY

[0006] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application proposes a PE-poly process method and its application, and a TOPCon solar cell, aiming to solve the problem that the current TOPcon mass production battery line causes the PE-poly process to appear film explosion due to the matching difference between the cleaning process and the PE-poly process.

[0007] Embodiments of the first aspect of the present application provide a PE-poly process method, comprising the steps of:

[0008] S100, loading a silicon substrate treated by alkali etching into a graphite boat and sending it into a quartz tube;

[0009] S200, vacuumizing and preheating the quartz tube to a constant temperature;

[0010] S300, preparing a first layer of tunnel oxide layer on the silicon substrate;

[0011] S400, preparing a phosphorus light-doped amorphous silicon layer on the first layer of tunnel oxide layer, and the flow of phosphine introduced during the preparation process is 5-20% of the maximum range;

[0012] S500, preparing a second layer of a tunneling oxide layer on the phosphorus lightly doped amorphous silicon layer;

[0013] S600, preparing a phosphorus heavily doped amorphous silicon layer on the second layer of the tunneling oxide layer;

[0014] S700, preparing a mask layer on the phosphorus heavily doped amorphous silicon layer;

[0015] S800, after the preparation of the mask layer is completed, the silicon substrate is subjected to nitrogen blowing and vacuumizing, and then nitrogen is filled to press out the boat.

[0016] The PE-poly process method according to the first aspect of the present application has at least the following beneficial effects: the PE-poly process method provided by the present application solves the problem of water mark and blown film in the TOPcon mass production process by optimizing the process of the PE-poly process, and improves the production efficiency and yield. Based on the TOPcon mass production process route, the present application analyzes and studies the data of the electrical performance data and microscopic images of the finished battery, and finds that after the alkali etching treatment is switched from HF cleaning end to HCl cleaning end in the TOPcon mass production battery line, the PE-poly water mark and blown film problem in the mass production process route can be effectively solved by optimizing the film layer structure of the PE-poly process and the amount of phosphine doping. The present application removes the intrinsic layer of the PE-poly process, and sets the flow of phosphine to be 5-20% of the maximum range when preparing the phosphorus lightly doped amorphous silicon layer. Through the above two adjustments, the water mark and blown film problem in the TOPcon production line is greatly improved, and the production efficiency and yield are also improved.

[0017] TOPCon solar cells adopt a tunneling oxide passivation carrier selective contact structure, as shown in Figure 1 The tunneling layer can allow the passage of electrons (majority carriers) and block holes (minority carriers); the heavily doped a-Si film or poly-Si is used to contact the c-Si to make the Fermi level of the silicon wafer differ greatly, causing band bending at the interface, promoting the separation of electron-hole pairs, and achieving a certain passivation effect. Due to the unique tunneling oxide layer in the TOPCon battery, a large number of free electrons are allowed to pass through and accumulate on the surface of the metal electrode without the need for opening holes, while the drifting holes are prevented from passing through, and the band working principle is as shown in Figure 2As shown in the figure. In the route dominated by PE-poly process, the ultra-thin tunneling oxide layer plays a key role, and at the same time, the natural oxide layer generated by the previous alkali etching process is complementary, and together they form a tunneling channel. However, the cleaning method ending with HF acid will remove the natural oxide layer, and the natural oxide layer which is greatly affected by the environment will also make the efficiency unstable, therefore, the alkali etching process ending with HF has a greater impact on PE-poly. Based on the premise of efficiency and yield improvement, therefore, the alkali etching process ending with HCl is adopted. However, for the TOPCon cell line in mass production, when the acid used for the end cleaning of the alkali etching process is switched from HF acid to HCl acid, a large number of water mark blisters appear in the production line, resulting in low efficiency and EL yield.

[0018] Based on this, the appearance, electrical performance data, microscopic image, etc. of the finished battery are analyzed and studied, and it is found that: observing the appearance of the water mark blister, as shown in the figure, it is found that there are obvious white marks on the appearance, which cannot be wiped off, and are not caused by surface dirt; at the same time, tracking to the screen, observing the EL, as shown in the figure, there are obvious strip-shaped black marks, and they are not in the position of the belt, and are not belt marks; further observing the microscopic image of the water mark blister under the microscope, as shown in the figure, the microscopic image of the water mark blister corresponds to many more white bright spots than the microscopic image of the normal battery, and for this reason, the flow of battery pieces through the alkali etching, PE-poly machine and annealing machine are all observed under the microscope, and finally it is determined that it is generated in the PE-poly machine. Figure 3 Figure 4 Figures 5-6

[0019] At the same time, collecting the water mark blister battery pieces tracked to the screen, the corresponding electrical performance data is shown in Table 1, from the electrical performance parameters of the water mark, compared with the high-efficiency battery, the open-circuit voltage (Uoc) loss is about 1.25mv, the short-circuit current (Isc) loss is up to 97mA, and the fill factor (FF) is low by 0.57.

[0020] Table 1 Electrical performance data table of normal and water mark TOPCon battery

[0021] Type Eta Uoc Isc FF Rs Rsh Irev2 Normal 26.247％ 0.7277 13.815 86.20 0.00137 2168 0.091 Water mark 1 25.880％ 0.7260 13.704 85.56 0.04627 3554 0.222 Water mark 2 25 986％ 0.7269 13.731 85.71 0.00150 3503 0.235

[0022] ​​​In summary, there are obvious white marks on the appearance; there are obvious black strip marks on the EL diagram; and there are many white bright spots under the microscope corresponding to the water mark explosion film. This shows that such water mark explosion film is caused by the change of the acid cleaning formula of the alkali etching tank, which leads to the mismatch with the PE-poly process. The PE-poly explosion film causes the appearance and EL to be poor, and has a significant negative impact on the electrical performance, which is one of the reasons for the low efficiency of the battery and the increase of the defective rate of the finished product. The root cause of the explosion film is that the dehydration of the alkali etching tank with HCl at the end is worse than that of the alkali etching tank with HF at the end, so there are water mark marks caused by the basket bottom rod, and the morphology of the water mark mark is different from that of other areas, so it contains more H than other areas, and the difference in the diffusion coefficient of H leads to the fact that H cannot enter the silicon matrix in time or escape in time, which causes the explosion film. For the doped a-Si:H and intrinsic a-Si:H deposited in the subsequent poly process, the escape speed of H is also different, and the escape speed of H in the doped a-Si:H is much greater than that in the intrinsic a-Si:H, so under the action of high temperature, the H in the doped amorphous silicon can escape in time, while the H in the intrinsic amorphous silicon cannot escape in time, which leads to the explosion film.

[0023] Based on this, the present application mainly starts from the PE-poly process, and sets different experimental conditions by changing the process parameters, aiming at the film layer structure and gas flow, verifies the influence on the EL water mark, and determines the improvement measures. Finally, the present application finds that by removing the intrinsic layer of the PE-poly process and setting the flow of phosphine introduced during the preparation of the phosphorus lightly doped amorphous silicon layer to be 5-20% of the maximum range, the above two adjustments can effectively solve the problem of PE-poly water mark explosion film in the TOPcon mass production process route, the water mark explosion film is greatly improved on the mass production line, and the production efficiency and yield are also improved.

[0024] In some embodiments of the present application, when preparing the phosphorus lightly doped amorphous silicon layer, the flow of phosphine introduced is 100-400 sccm, preferably 250-350 sccm, and more preferably about 300 sccm.

[0025] In some embodiments of the present application, the range of the maximum range is 2-5 L / min, and preferably 2 L / min. At present, the maximum range of the equipment used for introducing phosphine is generally 2 L / min, and accordingly, 5-20% of the maximum range is about 100-400 sccm (standard cubic centimeter per minute).

[0026] In some embodiments of the present application, in step S100, the silicon substrate treated by alkali etching is loaded into a graphite boat and placed on a silicon carbide paddle to be sent into a quartz tube.

[0027] In some embodiments of the present application, in step S200, the preheating constant temperature is specifically set as follows: the temperatures of temperature zones 1-9 are respectively 440℃, 430℃, 430℃, 430℃, 430℃, 430℃, 430℃, 430℃, 440℃, the constant temperature time is 1130s, the auxiliary heating time is 600s, and the auxiliary heating temperature is set as 440℃.

[0028] In some embodiments of the present application, the preparation of the first layer of tunneling oxide layer comprises at least one of (a1)-(a7):

[0029] (a1) the first layer of tunneling oxide layer is a silicon oxide layer;

[0030] (a2) the thickness of the first layer of tunneling oxide layer is 1-1.5nm;

[0031] (a3) the gas introduced during the reaction is nitrous oxide;

[0032] (a4) the gas flow introduced during the reaction is 7000-15000sccm;

[0033] (a5) the reaction temperature is 430-440℃;

[0034] (a6) the reaction time is 95-115s;

[0035] (a7) the reaction pressure is 1500-2000mtorr, the radio frequency power source frequency is 40KHz, the radio frequency power is 10000-15000W, and the duty cycle is 1:80-1:110.

[0036] In some embodiments of the present application, in step S300, the first layer of tunneling oxide layer is a silicon oxide (SiO x ) layer with a thickness of 1-1.5nm.

[0037] In some embodiments of the present application, in step S300, the gas introduced during the reaction is nitrous oxide (N2O, also known as laughing gas), and the gas flow introduced is 7000-15000sccm, preferably 9000-11000sccm, and more preferably about 10000sccm.

[0038] In some embodiments of the present application, in step S300, the reaction time is 95-115s, and preferably about 105s.

[0039] In some embodiments of the present application, in step S300, the reaction pressure is 1500-2000mtorr, preferably 1700-1900mtorr, and more preferably about 1800mtorr.

[0040] In some embodiments of the present application, the radio frequency power source frequency in step S300 is about 40 KHz.

[0041] In some embodiments of the present application, the radio frequency power in step S300 is 10000-15000 W, preferably about 10000 W.

[0042] In some embodiments of the present application, the duty cycle in step S300 is 1:80-1:110, preferably about 1:80.

[0043] In some embodiments of the present application, the preparation of the phosphorous lightly doped amorphous silicon layer comprises at least one of (b1)-(b7):

[0044] (b1) the thickness of the phosphorous lightly doped amorphous silicon layer is 5-25 nm;

[0045] (b2) the phosphorous doping concentration of the phosphorous lightly doped amorphous silicon layer is 1.0x1018-3.0x1018cm-3; 20 20 -3

[0046] (b3) the gas introduced during the reaction is silane, hydrogen, and phosphine;

[0047] (b4) when (b3) is included, the volume flow rate ratio of the silane, hydrogen, and phosphine is (25-35):(100-120):(1-4);

[0048] (b5) the reaction temperature is 430-440℃;

[0049] (b6) the reaction time is 120-240 s;

[0050] (b7) the reaction pressure is 2700-3500 mtorr, the radio frequency power source frequency is 40 KHz, the radio frequency power is 15000-15500 W, and the duty cycle is 1:13-1:18.

[0051] In some embodiments of the present application, the gas introduced during the reaction in step S400 is silane (SiH4), hydrogen (H2), and phosphine (PH3).

[0052] In some embodiments of the present application, the volume flow rate ratio of the silane, hydrogen, and phosphine is (25-35):(100-120):(1-4), preferably about 35:111:1.

[0053] In some embodiments of the present application, the flow rate of the phosphine introduced during the reaction is controlled to be between 5-20% of the maximum flow rate range thereof. Within this range, the phosphine in this layer structure can ensure that the tunneling is not pushed through. ​​​

[0054] In some embodiments of the present application, the reaction time in step S400 is 120-240 s, preferably 160-200 s, and more preferably about 180 s.

[0055] In some embodiments of the present application, the reaction pressure in step S400 is 2700-3500 mtorr, preferably 3300-3500 mtorr, and more preferably about 3400 mtorr.

[0056] In some embodiments of the present application, the radio frequency power source frequency in step S400 is about 40 KHz.

[0057] In some embodiments of the present application, the duty cycle in step S400 is 1:13-1:18, and preferably about 1:16. The duty cycle is mainly affected by the film thickness uniformity and the length of the process time, and can be adjusted within this range.

[0058] In some embodiments of the present application, the preparation of the second layer of tunneling oxide layer comprises at least one of (c1)-(c7):

[0059] (c1) the second layer of tunneling oxide layer is a silicon oxide layer;

[0060] (c2) the thickness of the second layer of tunneling oxide layer is 1-1.5 nm;

[0061] (c3) the gas introduced during the reaction is nitrous oxide;

[0062] (c4) the gas flow introduced during the reaction is 7000-15000 sccm;

[0063] (c5) the reaction temperature is 430-440℃;

[0064] (c6) the reaction time is 50-85 s;

[0065] (c7) the reaction pressure is 1500-2000 mtorr, the radio frequency power source frequency is 40 KHz, the radio frequency power is 10000-15000 W, and the duty cycle is 1:80-1:110.

[0066] In some embodiments of the present application, the second layer of tunneling oxide layer in step S500 is a silicon oxide (SiO x ) layer with a thickness of 1-1.5 nm.

[0067] In some embodiments of the present application, the gas introduced during the reaction in step S500 is nitrous oxide (N2O, also known as laughing gas), and the gas flow introduced is 7000-15000 sccm, preferably 9000-11000 sccm, and more preferably about 10000 sccm.

[0068] In some embodiments of the present application, the reaction time in step S500 is 50-85 s, preferably about 85 s.

[0069] In some embodiments of the present application, the reaction pressure in step S500 is 1500-2000 mtorr, preferably 1700-1900 mtorr, more preferably about 1800 mtorr.

[0070] In some embodiments of the present application, the radio frequency power source frequency in step S500 is about 40 KHz.

[0071] In some embodiments of the present application, the radio frequency power in step S500 is 10000-15000 W, preferably about 10000 W.

[0072] In some embodiments of the present application, the duty cycle in step S300 is 1:80-1:110, preferably about 1:80.

[0073] In some embodiments of the present application, the preparation of the phosphorus heavily doped amorphous silicon layer comprises at least one of (d1)-(d7):

[0074] (d1) the thickness of the phosphorus heavily doped amorphous silicon layer is 70-100 nm;

[0075] (d2) the phosphorus doping concentration of the phosphorus heavily doped amorphous silicon layer is 3.0x1019-7.0x1019cm-3; 20 20 -3

[0076] (d3) the phosphorus heavily doped amorphous silicon layer is prepared by twice phosphorus doping;

[0077] (d4) when (d3) is included, the gas introduced in the first phosphorus doping reaction is silane, hydrogen, and phosphine, the volume flow ratio of the silane, hydrogen, and phosphine is (4.75-5):(15-20):1, the reaction time is 300-400 s, the reaction temperature is 430-440℃, the reaction pressure is 2700-3500 mtorr, the radio frequency power source frequency is 40 KHz, the radio frequency power is 10000-15000 W, and the duty cycle is 1:8-1:13;

[0078] ​​​(d5) when (d3) is included, the gas introduced in the second phosphorus doping reaction is silane, hydrogen, and phosphine, the volume flow ratio of the silane, hydrogen, and phosphine is (4.75-7):(15-20):1, the reaction time is 70-110 s, the reaction temperature is 430-440 °C, the reaction pressure is 2700-3500 mtorr, the radio frequency power source frequency is 40 KHz, the radio frequency power is 10000-15000 W, and the duty cycle is 1:8-1:130.

[0079] In some embodiments of the present application, in step S600, the phosphorus heavily doped amorphous silicon layer is prepared by twice phosphorus doping, and the gas introduced in the first phosphorus doping reaction is silane, hydrogen, and phosphine, the volume flow ratio of the silane, hydrogen, and phosphine is (4.75-5):(15-20):1, preferably about 5:16:1; the reaction time is 300-400 s, preferably 340-350 s, more preferably about 345 s.

[0080] Specifically, in the first phosphorus doping reaction, the reaction temperature is 430-440 °C; the reaction pressure is 2700-3500 mtorr, preferably 3400-3500 mtorr, more preferably about 3450 mtorr; the radio frequency power source frequency is about 40 KHz; the radio frequency power is 10000-15000 W, preferably 11000-13000 W, more preferably about 12000 W; and the duty cycle is 1:8-1:13, preferably about 1:8.

[0081] In some embodiments of the present application, in step S600, the phosphorus heavily doped amorphous silicon layer is prepared by twice phosphorus doping, and the gas introduced in the second phosphorus doping reaction is silane, hydrogen, and phosphine, the volume flow ratio of the silane, hydrogen, and phosphine is (4.75-7):(15-20):1, preferably about 7:20:1; the reaction time is 70-110 s, preferably 80-100 s, more preferably about 90 s.

[0082] Specifically, in the second phosphorus doping reaction, the reaction temperature is 430-440 °C; the reaction pressure is 2700-3500 mtorr, preferably 3400-3500 mtorr, more preferably about 3450 mtorr; the radio frequency power source frequency is about 40 KHz; the radio frequency power is 10000-15000 W, preferably 11000-13000 W, more preferably about 12000 W; and the duty cycle is 1:8-1:13, preferably about 1:10.

[0083] In some embodiments of the present application, in step S700, the thickness of the mask layer is 10-20 nm, preferably about 15 nm.

[0084] In some embodiments of the present application, in step S700, the gases introduced during the reaction are silane (SiH4) and nitrogen dioxide (NO2), and the volume flow ratio of the silane and nitrogen dioxide is 1:4-1:5, preferably about 1:4.3.

[0085] In some embodiments of the present application, in step S700, the reaction temperature is 430-440℃.

[0086] In some embodiments of the present application, in step S700, the reaction time is 60-100s, preferably about 80s.

[0087] In some embodiments of the present application, in step S700, the reaction pressure is 1500-2000mtorr, preferably 1700-1800mtorr, more preferably about 1750mtorr.

[0088] In some embodiments of the present application, in step S700, the radio frequency power source frequency is about 40KHz.

[0089] In some embodiments of the present application, in step S700, the radio frequency power is 15000-15500W.

[0090] In some embodiments of the present application, in step S700, the duty cycle is 1:20.

[0091] In some embodiments of the present application, in step S800, after the film coating is completed, the silicon substrate is subjected to nitrogen blowing, vacuum pumping after blowing, and then nitrogen back pressure to discharge the boat.

[0092] The second aspect of the embodiments of the present application provides an application of the above-mentioned PE-poly process method in the preparation of a TOPCon solar cell.

[0093] The third aspect of the embodiments of the present application provides a preparation method of a TOPCon solar cell, comprising the steps of:

[0094] S1000, providing an N-type silicon substrate;

[0095] S2000, sequentially performing texturing, boron diffusion, SE, oxidation, BSG removal, and alkali etching treatment on the N-type silicon substrate;

[0096] S3000, performing Poly-Si deposition on the N-type silicon substrate subjected to the alkali etching treatment, wherein the Poly-Si deposition adopts the above-mentioned PE-poly process method;

[0097] S4000, the N-type silicon substrate after poly-Si deposition is sequentially subjected to annealing, PSG removal, RCA cleaning, MAD machine, back film plating, screen printing, sintering, light injection, laser sintering and test processing to obtain the TOPCon solar cell.

[0098] According to the preparation method of the TOPCon solar cell provided in the third aspect of the present application, the PE-poly water mark and film explosion problem in the TOPcon mass production process is solved by optimizing the process of the PE-poly process, and the production efficiency and yield are improved. Based on the TOPcon mass production process route, the electrical performance data and microscopic image data of the finished product battery are analyzed and studied, and it is found that after the alkali etching treatment is switched from HF cleaning to HCl cleaning, the PE-poly water mark and film explosion problem in the TOPcon mass production process route can be effectively solved by optimizing the film layer structure of the PE-poly process and the phosphine doping amount. The intrinsic layer of the PE-poly process is removed, and the flow of phosphine is set to 5-20% of the maximum range when preparing the phosphorus light doping amorphous silicon layer. Through the above two adjustments, the water mark and film explosion problem in the TOPcon mass production line is greatly improved, and the production efficiency and yield are improved.

[0099] In some embodiments of the present application, the alkali etching treatment is acid washing with hydrochloric acid (HCl).

[0100] In some embodiments of the present application, the specific steps of the alkali etching treatment include:

[0101] Step one: put the silicon substrate into the alkali etching special basket, and enter the alkali etching machine for pretreatment: 1.6L of potassium hydroxide (KOH), 18L of hydrogen peroxide (H2O2), 670L of pure water (60% hot water ratio), under the condition of 45℃, react for 80s, remove the organic matter residues on the surface;

[0102] Step two: water washing: use overflow water to clean the mixed liquid brought by the pretreatment tank, for 100s;

[0103] Step three: alkali etching: 12.5L of potassium hydroxide, 3L of alkali etching additive, 678L of pure water, according to 85% hot water ratio, under the condition of 64.5℃, react for 160s, for back polishing;

[0104] Step four: water washing: use overflow water to clean the mixed liquid brought by the polishing tank, for 100s;

[0105] Step five: post-cleaning: 3L of potassium hydroxide 25L of hydrogen peroxide, 670L of pure water, 80% hot water ratio, under the condition of 62 DEG C, reaction 100s, for removing the surface organic matter residue;

[0106] Step six: water washing: using overflow water to clean the mixed liquid brought by the polishing tank, the time is 100s;

[0107] Step seven: acid washing: using 10L of hydrochloric acid (HCl), 680L of pure water, removing the borosilicate glass and metal ions on the surface of the silicon wafer, the time is 100s;

[0108] Step eight: water washing: using overflow water to remove the surface organic matter residue, the time is 100s;

[0109] Step nine: slow lifting: using slow lifting to pre-dehydrate the silicon substrate, the temperature is 45 DEG C, the time is 20s;

[0110] Step ten: drying: using high temperature to dry the silicon substrate completely, the temperature is set to 95 DEG C, the time is 1000s.

[0111] The embodiment of the fourth aspect of the application provides a TOPCon solar cell prepared by the preparation method of the TOPCon solar cell.

[0112] The embodiment of the fifth aspect of the application provides application of the TOPCon solar cell in a photovoltaic device.

[0113] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application can be achieved and obtained by the structure particularly pointed out in the specification, claims and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0114] Figure 1 The structure schematic diagram of the TOPcon solar cell provided by the application is shown in the figure;

[0115] Figure 2 The energy band working principle schematic diagram of the TOPcon solar cell provided by the application is shown in the figure;

[0116] Figure 3 The water mark print appearance picture of the cell prepared by the comparative example 1 of the application is shown in the figure;

[0117] Figure 4 The water mark print EL picture of the cell prepared by the comparative example 1 of the application is shown in the figure;

[0118] Figure 5Microscopic picture of the water mark explosion film of the battery prepared for the present application comparative example 1;

[0119] Figure 6 Microscopic picture of the battery prepared for the present application example 1. DETAILED DESCRIPTION

[0120] The concept and the technical effects of the present application will be described in detail below in combination with the examples, so as to fully understand the purpose, features and effects of the present application. Obviously, the described examples are only some of the examples of the present application, but not all the examples. Based on the examples of the present application, other examples obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0121] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are contained in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0122] In the description of the present application, unless otherwise specified, the numerical range "a~b" represents a shorthand representation of any real combination between a and b, where a and b are real numbers. Unless otherwise specified, each reaction or operation step can be carried out in sequence or not in sequence. Preferably, the reaction method in the present application is carried out in sequence.

[0123] The experimental methods in the following examples not noted specific conditions are usually carried out according to the conventional conditions, or according to the conditions suggested by the manufacturers. The materials, reagents, etc. used in the present examples, if not specifically mentioned, are the reagents and materials obtained from commercial channels.

[0124] Example 1

[0125] The N-type commercial Cz silicon wafer with a thickness of about 130±10 μm and an area of about 182 mm×182 mm was selected.

[0126] 1. Texturing: the N-type monocrystalline silicon wafer was reacted in 675 L pure water, 8 L KOH and 3 L additive liquid, the reaction process time was 420 s, and the double-sided pyramid structure with uniform size was formed, and the temperature was controlled at 82℃;

[0127] 2. Boron diffusion: BCl3 is used as diffusion source to diffuse on the front side of the silicon wafer; the diffusion temperature is 880°C, and the diffusion sheet resistance is controlled at 110 (Ω / sq);

[0128] 3. SE: the metal gate line position is highly doped by laser reduction, and the sheet resistance is reduced to 33 (Ω / sq);

[0129] 4. Oxidation: the silicon wafer after SE is oxidized, the oxidation temperature is 1040°C, and the time is 70 min;

[0130] 5. BSG removal: 380L of HF acid and 270L of pure water are used to control the conductivity at 315±5 us / cm, and the oxide layer on the back side of the silicon wafer is removed;

[0131] 6. Alkaline polishing:

[0132] a. The silicon substrate is loaded into a special basket for alkaline polishing, and pretreatment is performed in the alkaline polishing machine: 1.6L of potassium hydroxide (KOH), 18L of hydrogen peroxide (H2O2), and 670L of pure water (60% hot water ratio), under the condition of 45°C, for 80s, to remove the surface organic residue;

[0133] b. Water washing: overflow water is used to clean the mixed liquid brought by the pretreatment tank, for 100s;

[0134] c. Alkaline polishing: 12.5L of potassium hydroxide, 3L of alkaline polishing additive, and 678L of pure water, according to 85% hot water ratio, under the condition of 64.5°C, for 160s, for backside polishing;

[0135] d. Water washing: overflow water is used to clean the mixed liquid brought by the polishing tank, for 100s;

[0136] e. Post-cleaning: 3L of potassium hydroxide, 25L of hydrogen peroxide, and 670L of pure water, 80% hot water ratio, under the condition of 62°C, for 100s, to remove the surface organic residue;

[0137] f. Water washing: overflow water is used to clean the mixed liquid brought by the polishing tank, for 100s;

[0138] g. Acid washing: 10L of hydrochloric acid (HCl) and 680L of pure water are used to remove the borosilicate glass and metal ions on the surface of the silicon wafer, for 100s;

[0139] h. Water washing: overflow water is used to remove the surface organic residue, for 100s;

[0140] i. Slow lifting: slow lifting is used to pre-dehydrate the silicon substrate, at a temperature of 45°C for 20s;

[0141] j. Drying: The silicon substrate is dried completely using high temperature, the temperature is set to 95℃, and the time is 1000s.

[0142] 7. Poly-Si deposition:

[0143] a. The cleaned silicon wafer after the alkali etching process is placed in a graphite boat on a silicon carbide paddle and sent into a quartz tube.

[0144] b. The quartz tube is preheated and kept at a constant temperature, the temperature of temperature zones 1 to 9 is set to 440℃, 430℃, 430℃, 430℃, 430℃, 430℃, 430℃, 430℃, 440℃ respectively, the constant temperature time is 1130s, the auxiliary heating time is 600s, and the auxiliary heating temperature is set to 440℃;

[0145] c. First layer of tunneling oxide layer (SiOx): the reaction temperature is the same as above, controlled at 430℃-440℃, N2O is introduced at a volume flow rate of 10000sccm, the pressure is set to 1800mtorr, the radio frequency power source frequency is 40KHz, the radio frequency power is 10000W, the reaction time is 115s, and the duty cycle is 1:80, to obtain a 1-1.5nm thick tunneling oxide layer (SiOx);

[0146] d. Lightly doped amorphous silicon layer: the reaction temperature is the same as above, controlled at 430℃-440℃, SiH4 and H2 and PH3 are introduced at a volume flow rate ratio of 35:111:1, wherein the PH3 gas flow rate is 300sccm; the pressure is set to 3400mtorr, the radio frequency power source frequency is 40KHz, the radio frequency power is 15000W-15500W, the reaction time is 180s, and the duty cycle is 1:16, to obtain a lightly doped amorphous silicon layer;

[0147] e. Second layer of tunneling oxide layer (SiOx): the reaction temperature is the same as above, controlled at 430℃-440℃, N2O is introduced at a volume flow rate of 10000sccm, the pressure is set to 1800mtorr, the radio frequency power source frequency is 40KHz, the radio frequency power is 10000W, the reaction time is 85s, and the duty cycle is 1:80, to obtain a 1-1.5nm thick tunneling oxide layer (SiOx);

[0148] f. Heavy doped amorphous silicon layer: the reaction temperature is the same as above, controlled at 430-440°C, the pressure is set at 3450mtorr, the radio frequency power frequency is 40KHz, the radio frequency power is 12000W, the preparation of the heavy doped layer is divided into two steps: in the first step, SiH4, H2 and PH3 with a volume flow ratio of 5:16:1 are introduced, the flow rate of phosphine PH3 is 700sccm, the reaction time is 345s, and the duty cycle is 1:8; in the second step, SiH4, H2 and PH3 with a volume flow ratio of 7:20:1 are introduced, the flow rate of phosphine PH3 is 500sccm, the reaction time is 90s, and the duty cycle is 1:10, to obtain a heavy doped amorphous silicon layer;

[0149] g. Mask layer: the reaction temperature is the same as above, controlled at 430-440°C, SiH4 and NO2 with a volume flow ratio of 1:4.3 are introduced, the pressure is set at 1750mtorr, the radio frequency power frequency is 40KHz, the radio frequency power is 15000-15500W, the reaction time is 80s, and the duty cycle is 1:20, to obtain a mask layer;

[0150] h. Nitrogen blowing after the film plating is completed;

[0151] i. Vacuum pumping after the blowing;

[0152] j. Nitrogen back pressure out of the boat.

[0153] 8. Annealing: high temperature crystallization is performed at a temperature of 900°C for 2500s to convert amorphous silicon into polycrystalline silicon;

[0154] 9. PSG removal: 150L of HF and 500L of pure water are used to configure the conductivity to be 120±5us / cm, and the borosilicate glass layer and the phosphosilicate glass layer on the front side and the edge are removed;

[0155] 10. RCA cleaning: divided into alkali etching and acid etching, 27L of KOH and 5.8L of additives are used to perform etching in 655L of pure water, the reaction time is 380s, and the edge etching of the silicon wafer is performed; 530L of HF and 170 pure water are used, the reaction time is 150s, and the borosilicate glass and the mask layer of the poly on the front side are removed;

[0156] 11. MAD machine: the same machine for aluminum oxide and positive film, the aluminum oxide is at 240°C, the process is cycled for 30 times, and 4.5nm of aluminum oxide is deposited to form a film; positive film plating: the reaction temperature is 520°C, 73nm of anti-reflection film is deposited in a PECVD machine, which is silicon nitride, silicon oxynitride and silicon oxide respectively;

[0157] 12: Back film plating: the reaction temperature is about 500°C, 80nm of anti-reflection film is deposited in a PECVD machine;

[0158] 13. Screen printing, sintering, photo-injection, laser sintering, testing: make the metal paste form a good ohmic contact with the silicon wafer, realize metallization, and make finished battery pieces.

[0159] Example 2

[0160] The difference between this example and Example 1 is that in step 7, the flow rate of PH3 gas introduced in step d is 100 sccm.

[0161] Example 3

[0162] The difference between this example and Example 1 is that in step 7, the flow rate of PH3 gas introduced in step d is 500 sccm.

[0163] Comparative Example 1

[0164] The difference between this example and Example 1 is that:

[0165] Step 7 is Poly-Si deposition:

[0166] a. After the alkali throwing process, the cleaned silicon wafer is loaded into a graphite boat and placed on a silicon carbide paddle and sent into a quartz tube;

[0167] b. Preheat and constant temperature are performed in the quartz tube, the temperature of temperature zones 1 to 9 is set to 440℃, 430℃, 430℃, 430℃, 430℃, 430℃, 430℃, 430℃, 440℃ respectively, the constant temperature time is 1130s, the auxiliary heating time is 600s, and the auxiliary heating temperature is set to 440℃;

[0168] c. First layer of tunneling oxide layer (SiOx): the reaction temperature is the same as above, controlled at 430℃-440℃, N2O is introduced at a volume flow rate of 10000sccm, the pressure is set to 1800mtorr, the radio frequency power source frequency is 40KHz, the radio frequency power is 10000W, the reaction time is 115s, and the duty cycle is 1:80, to obtain a 1-1.5nm thick tunneling oxide layer (SiOx);

[0169] d. Intrinsic layer: the reaction temperature is the same as above, controlled at 430℃-440℃, SiH4 and H2 are introduced at a volume flow rate ratio of 1:2.95, the pressure is set to 3400mtorr, the radio frequency power source frequency is 40KHz, the radio frequency power is 10000W, the reaction time is 90s, and the duty cycle is 1:16, to obtain an intrinsic layer;

[0170] e. Lightly doped amorphous silicon layer: the reaction temperature is the same as above, controlled at 430-440°C, and SiH4, H2 and PH3 with a volume flow ratio of 38:111:1 are introduced, wherein the flow rate of PH3 gas is 300 seem; the pressure is set at 3400mtorr, the radio frequency power is 40KHz, the radio frequency power is 15000-15500W, the reaction time is 180s, and the duty cycle is 1:16, to obtain a lightly doped amorphous silicon layer;

[0171] f. Intrinsic layer: the reaction temperature is the same as above, controlled at 430-440°C, and SiH4 and H2 with a volume flow ratio of 1:2.95 are introduced, the pressure is set at 3400mtorr, the radio frequency power is 40KHz, the radio frequency power is 10000W, the reaction time is 90s, and the duty cycle is 1:16, to obtain an intrinsic layer;

[0172] g. Second layer of tunneling oxide layer (SiOx): the reaction temperature is the same as above, controlled at 430-440°C, and N2O with a volume flow rate of 10000 seem is introduced, the pressure is set at 1800mtorr, the radio frequency power is 40KHz, the radio frequency power is 10000W, the reaction time is 85s, and the duty cycle is 1:80, to obtain a 1-1.5nm thick tunneling oxide layer (SiOx);

[0173] h. Heavily doped amorphous silicon layer: the reaction temperature is the same as above, controlled at 430-440°C, the pressure is set at 3450mtorr, the radio frequency power is 40KHz, and the radio frequency power is 12000W; the preparation of the heavily doped layer is divided into two steps: in the first step, SiH4, H2 and PH3 with a volume flow ratio of 5:16:1 are introduced, the flow rate of phosphine PH3 is 700 seem, the reaction time is 345s, and the duty cycle is 1:8; in the second step, SiH4, H2 and PH3 with a volume flow ratio of 7:20:1 are introduced, the flow rate of phosphine PH3 is 500 seem, the reaction time is 90s, and the duty cycle is 1:10, to obtain a heavily doped amorphous silicon layer;

[0174] i. Mask layer: the reaction temperature is the same as above, controlled at 430-440°C, SiH4 and NO2 with a volume flow ratio of 1:4.3 are introduced, the pressure is set at 1750mtorr, the radio frequency power is 40KHz, the radio frequency power is 15000-15500W, the reaction time is 80s, and the duty cycle is 1:20, to obtain a mask layer;

[0175] j. Nitrogen blowing after film plating is completed;

[0176] k. Vacuum pumping after blowing;

[0177] l. Nitrogen back pressure out of the boat.

[0178] Comparative Example 2

[0179] The difference between the present comparative example and Comparative Example 1 is that in Step 7, the reaction time of step c is 80 s, and the reaction time of step g is 35 s.

[0180] Comparative Example 3

[0181] The difference between the present comparative example and Comparative Example 1 is that in Step 7, the reaction time of step c is 80 s, and the reaction time of step g is 35 s.

[0182] Comparative Example 4

[0183] The difference between the present comparative example and Comparative Example 3 is that in Step 7, the flow rate of PH3 gas in step e is 250 sccm;

[0184] Comparative Example 5

[0185] The difference between the present comparative example and Comparative Example 3 is that in Step 7, the flow rate of PH3 gas in step e is 200 sccm;

[0186] Comparative Example 6

[0187] The difference between the present comparative example and Comparative Example 3 is that in Step 7, the flow rate of PH3 gas in step e is 100 sccm;

[0188] Comparative Example 7

[0189] The difference between the present comparative example and Comparative Example 6 is that in Step 6, step g is: pickling: using 5.7 L of hydrofluoric acid (HF acid), 675 L of pure water, removing borosilicate glass and metal ions on the surface of the silicon wafer, and the time is 100 s.

[0190] Test Example

[0191] First, the appearance and microscopic image of the finished battery prepared by the examples and comparative examples were observed, and the EL water mark explosion film ratio was detected. Figure 3 The water mark appearance picture of the battery prepared for Comparative Example 1, Figure 4 The EL picture of the water mark of the battery prepared for Comparative Example 1, Figure 5 The microscopic picture of the corresponding water mark explosion film of the microscope. It can be found that Comparative Example 1 has obvious white marks in appearance, obvious strip-shaped black marks on the EL map, and many white bright spots under the microscope corresponding to the water mark explosion film. Figure 6 The microscopic picture of the microscope of the battery prepared for Comparative Example 1 can be found that the explosion film problem has been completely improved.

[0192] Afterwards, the electrical performance data of the battery is detected: the complete battery prepared by the example and the comparative example is detected, a solar simulator conforming to the standard is used to ensure that the spectrum is highly matched with the standard solar spectrum (such as AM1.5G), and an electronic load, a constant temperature and humidity box device and the like are prepared. The solar cell prepared by the example and the comparative example is placed on the test platform of the simulator, the light intensity of the simulator is set to 1000W / m 2 , the spectrum is AM1.5G, and the temperature is controlled at 25℃±1℃. The solar cell is connected with the electronic load, the voltage and the current of the solar cell under different load conditions are measured, and the current-voltage (I-V) curve is drawn. The open circuit voltage (Voc), the short circuit current (Isc), the maximum power point voltage (Vmpp), the maximum power point current (Impp) and the like of the solar cell can be determined through the I-V curve. The photoelectric conversion efficiency of the solar cell is calculated according to the formula η=(Vmpp×Impp) / (1000×S)×100%, wherein S is the area of the solar cell. Whether the adjusted parameters have an influence on the battery performance is determined.

[0193] The EL water trace printing explosion film ratio and the electrical performance data of examples 1-3 and comparative examples 1-7 are shown in table 2:

[0194] Table 2

[0195] Group EL water mark burst membrane ratio Eta Uoc Isc FF Rs Rsh Irev2 Example 1 0.00 26.400％ 0.7303 13.926 86.54 0.00261 4429 0.156 Example 2 7.16％ 26.342％ 0.7300 13.823 86.19 0.00140 5028 0.096 Example 3 0.00 26.270％ 0.7302 13.979 85.80 0.00138 2594 0.122 Comparative Example 1 10.12％ 26.325％ 0.7303 13.949 86.15 0.00144 1873 0.108 Comparative Example 2 18.50％ 26.256％ 0.7303 13.944 85.95 0.00137 1933 0.046 Comparative Example 3 15.80％ 26.319％ 0.7309 13.947 86.08 0.00138 1856 0.106 Comparative Example 4 19.30％ 26.307％ 0.7306 13.949 86.06 0.00136 2093 0.040 Comparative Example 5 20.51％ 26.29％ 0.7292 13.975 86.00 0.00145 2030 0.097 Comparative Example 6 27.61％ 26.287％ 0.7280 13.882 85.88 0.00151 3195 0.138 Comparative Example 7 0.00 26.223％ 0.7271 13.803 86.18 0.00148 4252 0.121

[0196] Result analysis

[0197] Comparative example 7 is HF before switching, which is matched with intrinsic layer PE-poly process; comparative example 6 is that the acid used for alkali etching is switched from HF to HCl, which is matched with intrinsic layer PE-poly process, comparative examples 3-5 are to adjust the light doping PH3 flow on this basis, to verify the influence of the difference of light doping flow on the explosion film; comparative examples 1-2 are to adjust the two-step tunneling time on the basis of comparative example 3, to observe the influence of tunneling time on the explosion film; example 1 is to remove the intrinsic layer on the basis of comparative example 1, to observe the influence of the existence of intrinsic layer on the explosion film; examples 2-3 are to adjust the light doping PH3 flow on the basis of example 1, to observe the influence of light doping flow on the explosion film.

[0198] From the EL water mark explosion film ratio results of Table 2, it can be seen that: only from the EL water mark explosion film ratio, the effects of Examples 1 and 3 are the best, which are consistent with the ratio of HF used in Comparative Example 7. Comparative Example 7 uses HF, and the PE-poly process does not appear to explode the film; after switching to HCl in Comparative Example 6, the PE-poly intrinsic process is no longer matched, and the water mark explosion film ratio is as high as 27.61%; with the increase of light doping layer flow in Comparative Examples 3-5, the film explosion is improved, but the ratio is still high; by increasing the two-step tunneling thickness in Comparative Example 1, the film explosion ratio also decreases; and the most important improvement is that after removing the intrinsic layer in the Examples, the water mark explosion film ratio is greatly reduced, which shows that the process direction of deleting the intrinsic layer is correct to improve the water mark explosion film ratio, and at the same time, the light doping amorphous silicon layer gas flow ratio is optimized, the water mark explosion film ratio is reduced to 0.00%, and the water mark explosion film problem has been completely solved.

[0199] From the electrical performance data in Table 2, it can be seen that: with the increase of light doping flow in Comparative Examples 3-5, the efficiency and FF are both obviously improved, and the film explosion ratio is gradually reduced; compared with Comparative Example 3, the efficiency of Comparative Example 1 is improved by 0.014%, and the FF is improved by 0.07% by increasing the two-step tunneling time; by removing the intrinsic layer, the efficiency of the Examples is improved compared with the Comparative Examples, and the film explosion ratio is obviously reduced; by increasing the light doping flow to 300sccm, the film explosion is completely improved, and the efficiency is also improved by 0.058% compared with 100sccm, mainly reflected in the FF improvement of 0.35%; the light doping flow of Example 3 is set to 500sccm, although the film explosion is completely improved, the efficiency is low. At the same time, the thickness of the tunneling layer and the excess of the light doping flow will also have a significant impact on the effect of the selective passivation contact, and the reason for the sharp decline in passivation effect is related to the increase of Auger recombination caused by phosphorus doping into the base silicon. The tunneling layer is easily pushed through, and the excess of light doping phosphine increases the phosphine on both sides of the tunneling, which easily aggravates the Auger recombination.

[0200] In summary, in the TOPCon solar cell mass production line, when the acid used for cleaning at the end of the alkali stripping process is switched from HF acid to HCl acid, the PE-poly intrinsic process is no longer matched, resulting in a large number of water mark explosion films. The present application optimizes the process from the direction of the film layer structure and gas flow ratio of the PE-poly process, solves the phenomenon of water mark explosion film in the production process, and improves the cell efficiency and yield.

[0201] The above is a specific description of the preferred embodiments of the present application, but the present application is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or replacements without departing from the spirit of the present application, and these equivalent modifications or replacements are all included in the scope defined by the claims of the present application.

Claims

1. A PE-poly process method, characterized by, The method comprises the steps of: putting the silicon substrate treated by alkali into a graphite boat and into a quartz tube; vacuumizing and preheating the quartz tube; preparing a first tunneling oxide layer on the silicon substrate; preparing a phosphorus lightly doped amorphous silicon layer on the first tunneling oxide layer, and the flow rate of phosphine during the preparation is 5-20% of the maximum range; preparing a second tunneling oxide layer on the phosphorus lightly doped amorphous silicon layer; preparing a phosphorus heavily doped amorphous silicon layer on the second tunneling oxide layer; preparing a mask layer on the phosphorus heavily doped amorphous silicon layer; after the preparation of the mask layer, the silicon substrate is purged by nitrogen and vacuumized, and then the boat is discharged after the nitrogen is filled back.

2. The PE-poly process method according to claim 1, characterized in that, The flow rate of phosphine during the preparation of the phosphorus lightly doped amorphous silicon layer is 100-400sccm. The maximum range is 2-5L / min.

3. The PE-poly process of claim 1, wherein, The preparation of the first tunneling oxide layer comprises at least one of (a1)-(a7): (a1) the first tunneling oxide layer is a silicon oxide layer; (a2) the thickness of the first tunneling oxide layer is 1-1.5nm; (a3) the gas during the reaction is nitrous oxide; (a4) the flow rate of the gas during the reaction is 7000-15000sccm; (a5) the reaction temperature is 430-440℃; (a6) the reaction time is 95-115s; (a7) the reaction pressure is 1500-2000mtorr, the frequency of the radio frequency power supply is 40KHz, the radio frequency power is 10000-15000W, and the duty cycle is 1:80-1:

110.

4. The PE-poly process of claim 1, wherein, The preparation of the phosphorus lightly doped amorphous silicon layer comprises at least one of (b1)-(b7): (b1) the thickness of the phosphorus lightly doped amorphous silicon layer is 5-25nm; (b2) the phosphorus-doped concentration of the phosphorus-doped amorphous silicon layer is 1.0 x 1010 20 ~ 3.0 x 1010 20 cm -3 -3 (b3) the gas during the reaction is silane, hydrogen and phosphine; (b4) when (b3) is included, the volume flow rate ratio of the silane, hydrogen and phosphine is (25-35):(100-120):(1-4); (b5) the reaction temperature is 430-440℃; (b6) the reaction time is 120-240s; (b7) the reaction pressure is 2700-3500mtorr, the frequency of the radio frequency power supply is 40KHz, the radio frequency power is 15000-15500W, and the duty cycle is 1:13-1:

18.

5. The PE-poly process of claim 1, wherein, The preparation of the second tunneling oxide layer comprises at least one of (c1)-(c7): (c1) the second tunneling oxide layer is a silicon oxide layer; (c2) the thickness of the second tunneling oxide layer is 1-1.5nm; (c3) the gas during the reaction is nitrous oxide; (c4) the flow rate of the gas during the reaction is 7000-15000sccm; (c5) the reaction temperature is 430-440℃; (c6) the reaction time is 50-85s; (c7) the reaction pressure is 1500-2000mtorr, the frequency of the radio frequency power supply is 40KHz, the radio frequency power is 10000-15000W, and the duty cycle is 1:80-1:

110.

6. The PE-poly process of claim 1, wherein, The preparation of the phosphorus heavily doped amorphous silicon layer comprises at least one of (d1)-(d7): (d1) the thickness of the phosphorus heavily doped amorphous silicon layer is 70-100 nm; (d2) the phosphorus-doped concentration of the phosphorus heavily doped amorphous silicon layer is 3.0 x 1019atoms / cm3 20 ~ 7.0 x 1019atoms / cm3 20 cm -3 ; (d3) two phosphorus doping processes are performed when preparing the phosphorus heavily doped amorphous silicon layer; (d4) when (d3) is included, the gas introduced in the first phosphorus doping reaction is silane, hydrogen, and phosphine, the volume flow ratio of the silane, hydrogen, and phosphine is (4.75-5):(15-20):1, the reaction time is 300-400 s, the reaction temperature is 430-440℃, the reaction pressure is 2700-3500mtorr, the radio frequency power source frequency is 40 KHz, the radio frequency power is 10000-15000 W, and the duty cycle is 1:8-1:13; (d5) when (d3) is included, the gas introduced in the second phosphorus doping reaction is silane, hydrogen, and phosphine, the volume flow ratio of the silane, hydrogen, and phosphine is (4.75-7):(15-20):1, the reaction time is 70-110 s, the reaction temperature is 430-440℃, the reaction pressure is 2700-3500mtorr, the radio frequency power source frequency is 40 KHz, the radio frequency power is 10000-15000 W, and the duty cycle is 1:8-1:

13.

7. Use of the PE-poly process method according to any one of claims 1-6 in the preparation of a TOPCon solar cell.

8. A method for manufacturing a TOPCon solar cell, characterized by, comprising the steps of: providing an N-type silicon substrate; performing texturing, boron diffusion, SE, oxidation, BSG removal, and alkali etching on the N-type silicon substrate in sequence; performing Poly-Si deposition on the N-type silicon substrate after alkali etching, wherein the Poly-Si deposition adopts the PE-poly process method according to any one of claims 1-6; performing annealing, PSG removal, RCA cleaning, MAD machine, back film plating, screen printing, sintering, light injection, laser sintering, and testing on the N-type silicon substrate after Poly-Si deposition in sequence to obtain the TOPCon solar cell.

9. The method of producing a TOPCon solar cell according to claim 8, characterized by, The alkali etching adopts hydrochloric acid for pickling.

10. A TOPCon solar cell prepared by the preparation method of the TOPCon solar cell according to any one of claims 8-9.

11. Use of the TOPCon solar cell according to claim 10 in a photovoltaic device.

Images