A boron, phosphorus doped poly layer passivated contact structure and cell therefor

Abstract

The application discloses a boron and phosphorus doped poly layer passivation contact structure and a battery thereof. The passivation contact structure is formed by combining low-temperature and low-pressure oxidation, high-temperature and normal-pressure oxidation and low-temperature and normal-pressure oxidation to grow a tunneling oxide layer with thin and dense sides and thick and loose middle on the surface of a silicon wafer. The application improves the overall thickness of the tunneling oxide layer by stacking different density oxide layers, so that the tunneling oxide layer structure is not obviously damaged in the subsequent boron and phosphorus diffusion process, and the passivation effect of the boron and phosphorus doped poly layer is obviously improved. The application can obtain poly silicon layers and doped poly layers with different thicknesses, and can be applied to all batteries requiring boron poly and phosphorus poly.

Description

[0001] This invention is a divisional application of the Chinese invention patent filed on May 30, 2025, with application number 202510712254.4, entitled "A Passivation Method for a Boron-Phosphorus Doped Poly Layer, Its Passivation Contact Structure, and a Battery". Technical Field

[0002] This invention belongs to the field of solar cell technology, specifically relating to a passivated contact structure with boron and phosphorus doped Poly layers and its cell. Background Technology

[0003] When sunlight shines on a solar cell, it excites two types of charge carriers inside the cell: negatively charged electrons and positively charged holes. During the production of solar cells, it is necessary to minimize internal defects and the interface state density on each surface, and enhance passivation to reduce electron-hole recombination within the cell, thereby reducing internal energy loss and maximizing the reach of charge carriers to the positive and negative electrodes, ultimately increasing the cell's photoelectric conversion efficiency.

[0004] In the manufacture of solar cells, passivation of boron- and phosphorus-doped polysilicon (a polycrystalline silicon structure with a tunneling oxide layer) is a common surface treatment method.

[0005] In boron-doped poly layers, boron atoms diffuse into the N-type silicon substrate and form a PN junction. The passivation mechanism involves two aspects: firstly, the PN junction allows holes to pass through while blocking electrons, creating a hole-dominated environment on one side and an electron-dominated environment on the other, thus reducing recombination and annihilation at defects. Secondly, numerous defects exist at the interface between the single-crystal silicon and the poly layer. Growing a dense tunneling oxide layer between the two interfaces significantly reduces the interface state density, resulting in less recombination when holes pass through the tunneling oxide layer. The combined effect of the tunneling oxide layer and the PN junction contributes to the excellent passivation effect of boron-doped poly. The passivation effect is generally characterized by recombination current density (the magnitude of recombination current per unit area); a lower recombination current density indicates better surface passivation.

[0006] The passivation mechanism of phosphorus-doped Poly layers is similar. Poly layers contain a high concentration of phosphorus atoms, and some phosphorus atoms will pass through the tunneling oxide layer to form a high-low junction structure with the N-type substrate, which will cause the energy band near the tunneling oxide layer to bend. On the one hand, this reduces the number of minority carriers (holes) near the tunneling oxide layer and reduces recombination. On the other hand, it can selectively allow majority carriers (electrons) to pass through the tunneling oxide layer, thereby greatly enhancing the passivation effect.

[0007] Currently, the common passivation method for boron and phosphorus-doped Poly layers involves placing a silicon wafer in a quartz furnace tube and introducing oxygen at temperatures above 600°C. The oxygen reacts directly with the silicon on the wafer surface at this high temperature, forming a 1-2 nm thick silicon oxide film (tunneling oxide layer). A Poly silicon layer (polycrystalline silicon layer) is then deposited directly on this tunneling oxide layer. The wafer is then placed in a high-temperature diffusion furnace tube for deposition and oxidation propagation steps, and finally cooled to room temperature to obtain the desired boron-Poly or phosphorus-Poly structure. However, this method does not produce a very good passivation effect, resulting in a high recombination current density; especially for boron-Poly, the recombination current density is around 15 fA / cm². 2 The above. Moreover, this passivation method results in poor passivation effect because the boron and phosphorus-doped Poly layer, which is grown by direct high-temperature oxidation, has a relatively loose tunneling oxide layer. High boron and phosphorus doping concentrations can easily lead to severe internal expansion. At the same time, it is greatly affected by subsequent processes and cannot form a better morphology structure. It cannot meet the requirements of complex battery structures (such as BC structure batteries) that require secondary processing on the Poly layer. Summary of the Invention

[0008] To address the problem of poor passivation effect of boron and phosphorus-doped Poly layers caused by direct high-temperature growth of tunneling oxide layers, the present invention aims to provide a passivation method for boron and phosphorus-doped Poly layers with optimized passivation effect based on LPCVD process, as well as its passivation contact structure and battery.

[0009] The present invention achieves the aforementioned technical effects through the following technical solutions.

[0010] In a first aspect, the passivation method for boron- and phosphorus-doped Poly layers provided by the present invention includes the following steps:

[0011] S1. Provide clean and polished silicon wafers. Using LPCVD equipment, vacuum is drawn, oxygen is introduced, and the silicon wafers are oxidized for the first time at a low temperature and low pressure below 600℃, so that a dense first oxide layer with a thickness of 0.3~0.8nm is grown on the surface of the silicon wafer.

[0012] S2. In step 1, the temperature is increased by 50~220℃, oxygen is continuously introduced, and the silicon wafer is oxidized for the second time under a pressure greater than or equal to 1 standard atmosphere, so that a loose second oxide layer with a thickness of 0.5~1nm is grown on the surface of the silicon wafer.

[0013] S3. Stop the oxygen supply, keep the pressure constant, and lower the temperature to below 600℃ to perform the third oxidation on the silicon wafer, and continue to grow a dense third oxide layer with a thickness of 0.1~0.4nm on the surface of the silicon wafer; at this point, a tunneling oxide layer structure with a loose middle and dense sides is grown on the surface of the silicon wafer.

[0014] S4. Continue using the LPCVD equipment. The temperature in step S3 is increased by 0~50℃. After vacuuming, silane is introduced. Under high temperature and low pressure, a Poly silicon layer is deposited on the first oxide layer until the required film thickness is achieved.

[0015] S5. A high-temperature diffusion tube is used to deposit and oxidize boron or phosphorus atoms, so that the polysilicon layer is doped with a certain concentration of boron or phosphorus to form a doped polysilicon layer.

[0016] Preferably, in step S1, the temperature is 400~590℃, the pressure is 0.1~0.5 standard atmospheres, and the first oxidation time is 10~20 minutes.

[0017] Furthermore, in step S2, the temperature is 610~640℃, the pressure is atmospheric pressure, and the second oxidation time is 10~20 minutes.

[0018] Furthermore, in step S3, the temperature is 550~590℃, the pressure is atmospheric pressure, and the third oxidation time is 10~20 minutes.

[0019] Furthermore, in step S4, the temperature is 550~640℃ and the vacuum pressure is 180~300mTorr.

[0020] Furthermore, the silicon wafer is an N-type silicon wafer or a P-type silicon wafer.

[0021] Furthermore, in steps S1 and S2, the oxygen flow rate is 5~30L / min.

[0022] In step S5, during the boron atom deposition and oxidation propulsion process (boron diffusion), the deposition temperature is 800~850℃, the oxidation propulsion temperature is 940~1000℃, and the optimal oxidation propulsion temperature is 960℃. During the phosphorus atom deposition and oxidation propulsion process (phosphorus diffusion), the deposition temperature is 800~850℃, and the oxidation propulsion temperature is 880~920℃. The tunneling oxide layer is grown using a combination of low-temperature low-pressure oxidation, high-temperature atmospheric pressure oxidation, and low-temperature atmospheric pressure oxidation. This minimizes the impact of subsequent boron and phosphorus diffusion oxidation temperature fluctuations, allowing for approximately 30℃ of temperature variation above the optimal oxidation propulsion temperature.

[0023] Secondly, the present invention provides a passivated contact structure of a boron- and phosphorus-doped poly layer, the passivated contact structure comprising a first oxide layer, a second oxide layer, a third oxide layer, and a doped polysilicon layer grown on a silicon wafer using the aforementioned passivation method, wherein the doped polysilicon layer is on top of the first oxide layer, the first oxide layer, the second oxide layer, and the third oxide layer constitute a tunneling oxide layer, the second oxide layer of the doped polysilicon layer is located in the middle of the tunneling oxide layer, and is thick and porous; the first oxide layer and the third oxide layer are located on both sides of the tunneling oxide layer, and are thin and dense.

[0024] Thirdly, the present invention provides a battery having a passivated contact structure with a boron- and phosphorus-doped Poly layer, the battery comprising a silicon wafer and a passivated contact structure as described above formed on the surface of the silicon wafer.

[0025] Furthermore, the battery is a TOPCon battery, a TBC battery, or a perovskite tandem battery.

[0026] Compared with the prior art, the present invention has the following beneficial effects.

[0027] This invention uses a combination of low-temperature low-pressure oxidation, high-temperature atmospheric pressure oxidation, and low-temperature atmospheric pressure oxidation to grow tunneling oxide layers. The resulting tunneling oxide layer has a stacked structure that is thin and dense on both sides and thick and loose in the middle. By stacking different dense oxide layers, the passivation effect of boron and phosphorus doped Poly layer structures is improved.

[0028] The thin and dense oxide layers on both sides are grown at low temperatures, resulting in fewer interface defects in contact with the poly silicon layer. This significantly reduces the interface state density at the oxide-silicon interface, decreases carrier recombination at the interface, and significantly improves the passivation effect.

[0029] Meanwhile, the high-temperature grown second oxide layer is thick and porous, which not only increases the overall thickness of the tunnel oxide layer (although the thickness of the three oxide layers is roughly equal to that of the conventional tunnel oxide layer), but also provides a channel for impurity atoms to pass through the tunnel oxide layer to form a PN junction during subsequent boron diffusion (doping) and / or phosphorus diffusion (doping), thereby protecting the tunnel oxide layer from significant damage and further improving the passivation effect.

[0030] Compared with the boron and phosphorus doped Poly layer produced by the traditional direct high-temperature oxidation process, the passivation method of this invention significantly improves minority carrier lifetime, iVoc, iFF and PL brightness, and significantly reduces recombination current density J0, demonstrating a better passivation effect.

[0031] This invention achieves better passivation results by optimizing parameters such as pressure, temperature, and time in LPCVD equipment. The desired structure can be obtained in a single process. Compared with other passivation methods such as annealing, hydrogen injection, and adding layers of different materials, the process time is shorter, less special gases are used, and production costs can be effectively reduced.

[0032] The passivated contact structure of this invention exhibits good robustness, ensuring that the passivation effect of the boron and phosphorus-doped Poly layer is not significantly affected by minor fluctuations in parameters such as the temperature and gas flow of the high-temperature furnace tube during LPCVD equipment operation. The tunneling oxide layer grown using this invention is less affected by fluctuations in the boron and phosphorus diffusion oxidation temperature, and can tolerate fluctuations of up to 30°C above the optimal oxidation propagation temperature.

[0033] When the passivated contact structure of the present invention is applied to the fabrication of batteries (such as BC structure batteries) that require secondary processing on boron and phosphorus doped Poly layers to form complex structures, the subsequent laser process will not have a significant impact on the tunneling oxide layer structure. The plane after wet etching is flatter and can form a better morphology structure.

[0034] This invention can obtain poly silicon layers and doped polycrystalline silicon layers of different thicknesses as required. The passivation performance of boron or phosphorus doped poly layers is excellent and can be applied to all batteries that require the use of boron poly or phosphorus poly. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the passivated contact structure of the present invention.

[0037] Figure 2 This is a comparison diagram of the depth-concentration of boron-doped Poly layers in the present invention and in the prior art.

[0038] Figure 3 This is a schematic diagram of the TOPCon battery structure.

[0039] Figure 4 This is a schematic diagram of the TBC battery structure.

[0040] Figure 5 This is a comparison of the depth-concentration of boron-doped Poly layers after laser removal and cleaning removal.

[0041] Figure 6This is a scanning electron microscope (SEM) image of the back side of a BC-structured solar cell prepared using the passivation method of this invention.

[0042] In the diagram: 1-Silicon wafer, 2-First oxide layer, 3-Second oxide layer, 4-Third oxide layer, 5-Doped polycrystalline silicon layer. Detailed Implementation

[0043] To make the technical problems solved, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments described herein are only some, not all, of the embodiments of this invention, and are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the protection scope of this invention.

[0044] In a first aspect, the present invention provides a passivation method for a boron- and phosphorus-doped Poly layer, comprising the following steps:

[0045] S1. Provide clean and polished silicon wafers. Using LPCVD equipment, vacuum is drawn, oxygen is introduced, and the silicon wafers are oxidized for the first time at a low temperature and low pressure below 600℃, so that a thin and dense first oxide layer is grown on the surface of the silicon wafer.

[0046] S2. The temperature in step S1 is increased by 50~220℃, oxygen is continuously introduced, and the silicon wafer is oxidized a second time at a pressure greater than or equal to 1 standard atmosphere, so that a thick and loose second oxide layer continues to grow on the surface of the silicon wafer.

[0047] S3. Stop the oxygen supply, keep the pressure constant, and lower the temperature to below 600℃ to perform the third oxidation on the silicon wafer, so that a thin and dense third oxide layer continues to grow on the surface of the silicon wafer; at this point, a tunnel oxide layer structure with a loose middle and dense sides is grown on the surface of the silicon wafer.

[0048] S4. Continue using the LPCVD equipment. The temperature in step S3 is increased by 0~50℃. After vacuuming, silane is introduced. Under high temperature and low pressure, a Poly silicon layer is deposited on the first oxide layer until the required film thickness is achieved.

[0049] S5. A high-temperature diffusion tube is used to deposit and oxidize boron or phosphorus atoms, so that the polysilicon layer is doped with a certain concentration of boron or phosphorus to form a doped polysilicon layer.

[0050] In a preferred embodiment, in step S1, the temperature is 400~590℃, the pressure is 0.1~0.5 standard atmospheres, the first oxidation time is 10~20 minutes, and the thickness of the first oxide layer is 0.3~0.8 nm. Specifically, the temperature of the first oxidation can be 400℃, 430℃, 460℃, 490℃, 500℃, 520℃, 550℃, 570℃, or 590℃, etc.; more preferably, it is 500~580℃. The first oxidation time can be 10 minutes, 14 minutes, 16 minutes, 18 minutes, or 20 minutes, etc. The thickness of the first oxide layer can be 0.3 nm, 0.4 nm, 0.5 nm, 0.6 nm, 0.7 nm, or 0.8 nm, etc., more preferably 0.3~0.5 nm. In this way, a thin and dense tunneling oxide layer can be generated by low-temperature and low-pressure oxidation.

[0051] In a preferred embodiment, in step S2, the temperature is 610~640℃, the pressure is atmospheric pressure, the second oxidation time is 10~20 minutes, and the thickness of the second oxide layer is 0.5~1nm. Specifically, the temperature of the second oxidation can be 610℃, 620℃, 625℃, 632℃, or 640℃, etc. The second oxidation time can be 10 minutes, 14 minutes, 16 minutes, 18 minutes, or 20 minutes, etc. The thickness of the second oxide layer can be 0.5nm, 0.6nm, 0.7nm, 0.8nm, 0.9nm, or 1nm, etc. In this way, high-temperature and atmospheric-pressure oxidation can generate a thick and loose tunneling oxide layer.

[0052] In a preferred embodiment, in step S3, the temperature is 550~590℃, the pressure is atmospheric pressure, the third oxidation time is 10~20 minutes, and the thickness of the third oxide layer is 0.1~0.4nm. Specifically, the temperature of the third oxidation can be 550℃, 560℃, 570℃, 580℃, or 590℃, etc. The third oxidation time can be 10 minutes, 14 minutes, 16 minutes, 18 minutes, or 20 minutes, etc. The thickness of the third oxide layer can be 0.1nm, 0.18nm, 0.25nm, 0.3nm, 0.35nm, or 0.4nm, etc. In this way, a thin and dense tunneling oxide layer can be generated by oxidation at low temperature and atmospheric pressure.

[0053] In a preferred embodiment, in step S4, the temperature is 550~640℃, specifically, it can be 550℃, 560℃, 570℃, 580℃, 590℃, 600℃, 610℃, 620℃, 630℃, or 640℃, etc.; the vacuum pressure is 180~300mTorr, specifically, it can be 180mTorr, 200mTorr, 220mTorr, 250mTorr, 280mTorr, or 300mTorr, etc. This allows for the deposition of Poly silicon layers of varying thicknesses on the tunneling oxide layer.

[0054] In a preferred embodiment, the silicon wafer is an N-type silicon wafer or a P-type silicon wafer. The passivation method of the present invention is applicable not only to N-type silicon wafers but also to P-type silicon wafers.

[0055] As a preferred embodiment, in steps S1 and S2, the oxygen flow rate is 5~30L / min, which can meet the oxide layer thickness required to form passivation contact.

[0056] The oxygen flow rate can control the time it takes for the furnace tube to transition from vacuum to atmospheric pressure. Low-pressure oxidation and low-temperature oxidation are similar in nature; both can form a denser tunneling oxide layer. Step S1 is best done by slowly introducing oxygen to allow for low-temperature and low-pressure growth.

[0057] Step S3 does not require the introduction of oxygen; the existing oxygen in the tube can be used to continue oxidation.

[0058] As a preferred embodiment, in the process of boron atom deposition and oxidation propulsion (boron diffusion), the deposition temperature is 800~850℃, the oxidation propulsion temperature is 940~1000℃, and the optimal oxidation propulsion temperature is 960℃; in the process of phosphorus atom deposition and oxidation propulsion (phosphorus diffusion), the deposition temperature is 800~850℃, and the oxidation propulsion temperature is 880~920℃.

[0059] Specifically, the boron diffusion process involves introducing boron trichloride and oxygen, depositing at 800-850°C for 600-1500 seconds, then raising the temperature to 940-1000°C and continuing to introduce more oxygen for at least 20 minutes. The phosphorus diffusion process involves introducing phosphorus oxychloride and oxygen, depositing at 800-850°C for 600-1500 seconds, then raising the temperature to 880-920°C and continuing to introduce more oxygen for 10-20 minutes. The specific deposition amount, oxidation time, and temperature depend primarily on the LP process.

[0060] Oxidation propulsion temperature has a significant impact on diffusion. However, this invention uses a combination of low-temperature low-pressure oxidation, high-temperature atmospheric pressure oxidation, and low-temperature atmospheric pressure oxidation to grow the tunnel oxide layer. The subsequent effects of boron and phosphorus diffusion temperature fluctuations are relatively small, and fluctuations of approximately 30°C above the optimal oxidation propulsion temperature are acceptable.

[0061] After heteroatom diffusion, the doping concentration at different depths of the silicon wafer can be obtained using an ECV testing machine. Figure 2 As can be seen from the comparison, compared with the boron-doped Poly layer of the high-temperature oxidation growth of the tunnel oxide layer in the prior art, the present invention can reduce the inward expansion (the faster the decrease, the smaller the inward expansion) while obtaining a higher doping concentration, thereby improving the passivation performance.

[0062] Secondly, the present invention provides a passivated contact structure for a boron- and phosphorus-doped Poly layer, such as... Figure 1 As shown, the passivated contact structure includes a first oxide layer 2, a second oxide layer 3, a third oxide layer 4, and a doped polysilicon layer 5 grown on the silicon wafer 1 using the aforementioned passivation method. The doped polysilicon layer 5 is on top of the first oxide layer 2. The first oxide layer 2, the second oxide layer 3, and the third oxide layer 4 constitute a tunneling oxide layer. The second oxide layer 3 is located in the middle of the tunneling oxide layer and is thick and porous. The first oxide layer 2 and the third oxide layer 4 are located on both sides of the tunneling oxide layer and are thin and dense.

[0063] Thirdly, the present invention provides a battery having a passivated contact structure with a boron- and phosphorus-doped Poly layer, the battery comprising a silicon wafer and a passivated contact structure as described above formed on the surface of the silicon wafer.

[0064] As a preferred embodiment, the battery is a TOPCon battery, a TBC battery, or a perovskite tandem battery.

[0065] The passivation method of this invention can obtain polysilicon layers and doped polycrystalline silicon layers of different thicknesses as required. Boron and phosphorus-doped polysilicon layers exhibit excellent passivation performance and can be applied to all batteries requiring the use of boron-doped or phosphorus-doped polysilicon. For example... Figure 3 As shown, the passivation method of this invention can grow a tunneling oxide layer structure with a loose middle and dense sides in the N region of the TOPCon cell structure, and deposit a Poly silicon layer and an NPoly layer formed by boron or phosphorus doping to form a doped polycrystalline silicon layer. Figure 4 As shown, the passivation method of the present invention can grow a tunneling oxide layer structure with a loose middle and dense sides in the N and P regions of the TBC battery structure, and deposit a Poly silicon layer and an NPoly layer and a PPoly layer formed by boron or phosphorus doping to form a doped polycrystalline silicon layer.

[0066] For structures such as BC cells that require further processing of the boron-doped Poly layer structure, the tunneling oxide layer grown in this invention can effectively resist the influence of laser on the boron-doped Poly layer. Figure 5Concentration-depth curves for two BSG film removal methods—laser removal and cleaning removal—are presented, showing that the laser process has no significant impact on the subsequent inward diffusion of boron atoms. Furthermore, the uniform tunneling oxide film layer facilitates the formation of a smoother surface during subsequent wet etching. The BC structure solar cell prepared using the passivation method of this invention... Figure 6 As can be observed from the back-side scanning electron microscope image, the passivation method of the present invention can form P-regions, N-regions, and Gap regions with good flatness.

[0067] The specific embodiments of the present invention will be further explained and described below through examples and comparative examples.

[0068] Unless otherwise specified, all reagents, materials, and instruments used in the following description are conventional reagents, materials, and instruments, and are commercially available. The methods in the examples, unless otherwise specified, are conventional methods in the art.

[0069] Example 1

[0070] The passivation method for boron-doped Poly layers provided by the present invention includes the following steps.

[0071] S1. Prepare an N-type silicon wafer 1 with a resistivity of 10Ω·cm and a thickness of 180μm. Polish both sides, clean it, and place it in an LPCVD equipment. Evacuate the furnace to a near-vacuum state and slowly heat the furnace tube to 570℃. Slowly introduce oxygen into the furnace tube at a flow rate of 10L / min, keeping the pressure inside the furnace tube below 0.5 standard atmospheres during the heating process. Perform the first oxidation on the silicon wafer for 15 minutes in a low-temperature and low-pressure environment, and grow a dense first oxide layer 2 with a thickness of 0.4nm on the surface of silicon wafer 1.

[0072] S2. Oxygen is continuously introduced, the pressure inside the furnace tube is 1 standard atmosphere, the temperature inside the furnace tube is raised to 630℃, and the silicon wafer is oxidized for a second time for 12 minutes in a high temperature and normal pressure environment, so that a relatively loose second oxide layer 3 with a thickness of 0.8nm continues to grow on the surface of silicon wafer 1.

[0073] S3. Stop the oxygen supply, keep the pressure inside the furnace tube constant, and lower the temperature to 580℃. Perform the third oxidation on the silicon wafer for 12 minutes in a low temperature and normal pressure environment. Continue to grow a relatively dense third oxide layer 4 with a thickness of 0.2nm on the surface of silicon wafer 1. At this point, a tunnel oxide layer structure with a loose middle and dense sides is grown on the surface of the silicon wafer.

[0074] S4. Continue using the LPCVD equipment, control the temperature inside the furnace tube at 600℃, evacuate and then introduce silane at a vacuum pressure of 200mTorr. In a high temperature and low pressure environment, deposit a Poly silicon layer on the first oxide layer 2 until the required film thickness is achieved.

[0075] S5. Boron atoms are deposited and oxidized using a high-temperature diffusion tube. Boron trichloride and oxygen are introduced. Deposition is first carried out at 830°C for 1000 seconds, then the temperature is raised to 960°C, and more oxygen is introduced for 22 minutes to dope the polysilicon layer with a certain concentration of boron, forming a doped polycrystalline silicon layer 5.

[0076] Examples 2-4

[0077] Examples 2-4 include most of the operational steps in Example 1, the difference being the temperature, pressure, time, oxide layer thickness, and doped atoms of the three oxidation processes. Details are as follows.

[0078] Example 2

[0079] The passivation method for boron-doped Poly layers provided by the present invention includes the following steps.

[0080] S1. Prepare an N-type silicon wafer with a resistivity of 1 Ω·cm and a thickness of 130 μm. Polish both sides, clean it, and place it in an LPCVD equipment. Evacuate the furnace to a near-vacuum state and slowly heat the furnace tube to 500°C. Slowly introduce oxygen into the furnace tube at a flow rate of 5 L / min, keeping the pressure inside the furnace tube below 0.3 atmospheres during the heating process. Perform the first oxidation on the silicon wafer for 10 minutes in a low-temperature and low-pressure environment to grow a dense first oxide layer of 0.3 nm on the surface of the silicon wafer.

[0081] S2. Oxygen is continuously introduced, the pressure inside the furnace tube is 1 standard atmosphere, and the temperature inside the furnace tube is raised to 610℃. The silicon wafer is oxidized for 10 minutes in a high temperature and normal pressure environment, and a relatively loose second oxide layer with a thickness of 0.5nm continues to grow on the surface of the silicon wafer.

[0082] S3. Continue to introduce oxygen, keep the pressure inside the furnace tube constant, and reduce the temperature to 550℃. Perform the third oxidation on the silicon wafer for 10 minutes in a low temperature and normal pressure environment. A relatively dense third oxide layer with a thickness of 0.2nm will continue to grow on the surface of the silicon wafer. Thus, a tunnel oxide layer structure with a loose middle and dense sides will be grown on the surface of the silicon wafer.

[0083] S4. Continue using the LPCVD equipment, control the temperature inside the furnace tube at 550℃, introduce silane, and simultaneously evacuate to a vacuum pressure of 180mTorr. In a high-temperature and low-pressure environment, deposit a poly silicon layer on the first oxide layer until the required film thickness is achieved.

[0084] S5. Boron atoms are deposited and oxidized using a high-temperature diffusion tube. Boron trichloride and oxygen are introduced, and the deposition is first carried out at 810℃ for 1200 seconds. Then the temperature is raised to 990℃, and more oxygen is introduced to continue the process for 30 minutes, so that a certain concentration of boron is doped into the polysilicon layer to form a doped polycrystalline silicon layer.

[0085] Example 3

[0086] The passivation method for phosphorus-doped Poly layers provided by the present invention includes the following steps.

[0087] S1. Prepare an N-type silicon wafer with a resistivity of 20 Ω·cm and a thickness of 220 μm. Polish both sides, clean it, and place it in an LPCVD equipment. Evacuate the furnace to a near-vacuum state and slowly heat the furnace tube to 580°C. Slowly introduce oxygen into the furnace tube at a flow rate of 20 L / min, keeping the pressure inside the furnace tube below 0.5 atmospheres during the heating process. Perform the first oxidation on the silicon wafer for 20 minutes in a low-temperature and low-pressure environment, growing a dense first oxide layer of 0.8 nm on the surface of the silicon wafer.

[0088] S2. Oxygen is continuously introduced, the pressure inside the furnace tube is 1 standard atmosphere, and the temperature inside the furnace tube is raised to 640°C. The silicon wafer is subjected to a second oxidation for 20 minutes in a high temperature and normal pressure environment, and a relatively loose second oxide layer with a thickness of 1nm continues to grow on the surface of the silicon wafer.

[0089] S3. Continue to introduce oxygen, keep the pressure inside the furnace tube constant, and lower the temperature to 590℃. Perform the third oxidation on the silicon wafer for 20 minutes in a low temperature and normal pressure environment. A relatively dense third oxide layer with a thickness of 0.4nm will continue to grow on the surface of the silicon wafer. Thus, a tunnel oxide layer structure with a loose middle and dense sides will be grown on the surface of the silicon wafer.

[0090] S4. Continue using the LPCVD equipment, control the temperature inside the furnace tube at 640℃, and after evacuation, introduce silane at a vacuum pressure of 300mTorr. In a high temperature and low pressure environment, deposit a poly silicon layer on the first oxide layer until the required film thickness is achieved.

[0091] S5. Phosphorus atoms are deposited and oxidized using a high-temperature diffusion tube. Phosphorus oxychloride and oxygen are introduced. Deposition is first carried out at 850°C for 600 seconds, then the temperature is raised to 920°C, and more oxygen is introduced for another 10 minutes to dope the polysilicon layer with a certain concentration of phosphorus, forming a doped polycrystalline silicon layer.

[0092] Example 4

[0093] The passivation method for phosphorus-doped Poly layers provided by the present invention includes the following steps.

[0094] S1. Prepare an N-type silicon wafer with a resistivity of 12Ω·cm and a thickness of 200μm. Polish both sides, clean it, and place it in an LPCVD equipment. Evacuate the furnace to a near-vacuum state and slowly heat the furnace tube to 580℃. Slowly introduce oxygen into the furnace tube at a flow rate of 30L / min, keeping the pressure inside the furnace tube below 0.3 standard atmospheres during the heating process. Perform the first oxidation on the silicon wafer for 13 minutes in a low-temperature and low-pressure environment to grow a dense first oxide layer of 0.5nm on the surface of the silicon wafer.

[0095] S2. Oxygen is continuously introduced, the pressure inside the furnace tube is 1 standard atmosphere, and the temperature inside the furnace tube is raised to 620°C. The silicon wafer is oxidized for a second time for 15 minutes in a high temperature and normal pressure environment, and a relatively loose second oxide layer with a thickness of 0.9nm continues to grow on the surface of the silicon wafer.

[0096] S3. Stop the oxygen supply, keep the pressure inside the furnace tube constant, and lower the temperature to 570℃. Perform the third oxidation on the silicon wafer for 14 minutes in a low temperature and normal pressure environment. A relatively dense third oxide layer with a thickness of 0.25nm will continue to grow on the surface of the silicon wafer. At this point, a tunnel oxide layer structure with a loose middle and dense sides will be grown on the surface of the silicon wafer.

[0097] S4. Continue using the LPCVD equipment, control the temperature inside the furnace tube at 620℃, and after evacuation, introduce silane at a vacuum pressure of 240mTorr. In a high-temperature and low-pressure environment, deposit a poly silicon layer on the first oxide layer until the required film thickness is achieved.

[0098] S5. Phosphorus atoms are deposited and oxidized using a high-temperature diffusion tube. Phosphorus oxychloride and oxygen are introduced. The deposition is first carried out at 800℃ for 1500 seconds, then the temperature is raised to 880℃, and more oxygen is introduced for another 20 minutes to dope the polysilicon layer with a certain concentration of phosphorus, thus forming a doped polycrystalline silicon layer.

[0099] Comparative Example 1

[0100] The difference between Comparative Example 1 and Examples 1 and 2 is that the existing direct high-temperature growth tunnel oxide layer is used, as detailed below.

[0101] S1. Prepare an N-type silicon wafer with a resistivity of 10Ω·cm and a thickness of 180μm. Polish both sides, clean it, place it in the LPCVD equipment, evacuate the vacuum, and wait for the furnace tube to slowly heat up to 620℃. Then, introduce oxygen at a flow rate of 36L / min to bring the furnace tube back to normal pressure. At the same time, oxidize the silicon wafer to grow a 2nm thick tunneling oxide layer on the surface of the silicon wafer.

[0102] S2. Continue using the LPCVD equipment, control the temperature inside the furnace tube at 600℃, evacuate and then introduce silane at a vacuum pressure of 200mTorr, depositing a poly silicon layer on the tunneling oxide layer.

[0103] S3. Boron atoms are deposited and oxidized using a high-temperature diffusion tube. Boron trichloride and oxygen are introduced, and the deposition is first carried out at 830°C for 1000 seconds. Then the temperature is raised to 960°C, and more oxygen is introduced to continue the process for 22 minutes, so that a certain concentration of boron is doped into the polysilicon layer to form a doped polycrystalline silicon layer.

[0104] Comparative Example 2

[0105] The difference between Comparative Example 2 and Examples 3 and 4 is that the existing direct high-temperature growth tunnel oxide layer is used, as detailed below.

[0106] S1. Prepare an N-type silicon wafer with a resistivity of 20Ω·cm and a thickness of 220μm. Polish both sides, clean it, and place it in the LPCVD equipment. Evacuate the furnace tube and wait for it to heat up to 610℃. Then, introduce oxygen at a flow rate of 36L / min to bring the furnace tube back to normal pressure. At the same time, oxidize the silicon wafer and grow a 1.6nm tunneling oxide layer on the surface of the silicon wafer.

[0107] S2. Continue using LPCVD equipment, control the temperature inside the furnace tube at 615℃, evacuate and then introduce silane at a vacuum pressure of 300mTorr. In a high temperature and low pressure environment, deposit a poly silicon layer on the tunneling oxide layer until the required film thickness is achieved.

[0108] S3. Phosphorus atoms are deposited and oxidized using a high-temperature diffusion tube. Phosphorus oxychloride and oxygen are introduced. Deposition is first carried out at 850°C for 600 seconds, then the temperature is raised to 920°C, and more oxygen is introduced for another 10 minutes to dope the polysilicon layer with a certain concentration of phosphorus, forming a doped polycrystalline silicon layer.

[0109] Comparative Example 3

[0110] The difference between Comparative Example 3 and Examples 1 and 2 is that a two-layer tunneling oxide layer is grown using low-temperature low-pressure oxidation and high-temperature normal-pressure oxidation, as detailed below.

[0111] S1. Prepare an N-type silicon wafer with a resistivity of 10 Ω·cm and a thickness of 180 μm. Polish both sides, clean it, and place it in an LPCVD equipment. Evacuate the furnace and wait for the furnace tube to heat up to 570°C. Then, introduce oxygen at a flow rate of 10 L / min to keep the pressure inside the furnace tube below 0.5 atmospheres during the heating process. Perform the first oxidation of the silicon wafer for 15 minutes in a low-temperature and low-pressure environment to grow a dense oxide layer of 0.4 nm on the surface of the silicon wafer.

[0112] S2. Oxygen is continuously introduced, and the pressure inside the furnace tube is 1 standard atmosphere. The temperature inside the furnace tube is raised to 630°C. The silicon wafer is oxidized for a second time for 12 minutes in a high temperature and normal pressure environment, and a relatively loose oxide layer with a thickness of 0.8nm continues to grow on the surface of the silicon wafer. Thus, a tunnel oxide layer structure with a loose inner side and a dense outer side is grown on the surface of the silicon wafer.

[0113] S3. Continue using LPCVD equipment, control the temperature inside the furnace tube at 600℃, evacuate and then introduce silane at a vacuum pressure of 200mTorr, deposit a Poly silicon layer on the first oxide layer 2 in a high temperature and low pressure environment.

[0114] S4. Boron atoms are deposited and oxidized using a high-temperature diffusion tube. Boron trichloride and oxygen are introduced, and the deposition is first carried out at 830°C for 1000 seconds. Then the temperature is raised to 960°C, and more oxygen is introduced to continue the process for 22 minutes, so that a certain concentration of boron is doped into the polysilicon layer to form a doped polycrystalline silicon layer.

[0115] Comparative Example 4

[0116] The difference between Comparative Example 4 and Examples 1 and 2 is that a two-layer tunneling oxide layer is grown by combining high-temperature atmospheric pressure oxidation and low-temperature atmospheric pressure oxidation, as detailed below.

[0117] S1. Prepare an N-type silicon wafer with a resistivity of 10Ω·cm and a thickness of 180μm. Polish both sides, clean it, place it in an LPCVD equipment, evacuate the vacuum, and wait for the furnace tube to heat up to 630℃. Then, introduce oxygen at a flow rate of 10L / min to atmospheric pressure and oxidize the silicon wafer for 12 minutes in a high temperature and atmospheric pressure environment. A relatively loose oxide layer with a thickness of 0.8nm will continue to grow on the surface of the silicon wafer.

[0118] S2. Continue to introduce oxygen, keep the pressure inside the furnace tube constant, and lower the temperature to 580℃. Oxidize the silicon wafer for 12 minutes in a low temperature and normal pressure environment to grow a relatively dense oxide layer with a thickness of 0.2nm on the silicon wafer surface. Thus, a tunnel oxide layer structure with a dense inner side and a loose outer side is grown on the silicon wafer surface.

[0119] S3. Continue using LPCVD equipment, control the temperature inside the furnace tube at 600℃, evacuate and then introduce silane at a vacuum pressure of 200mTorr, deposit a Poly silicon layer on the first oxide layer 2 in a high temperature and low pressure environment.

[0120] S4. Boron atoms are deposited and oxidized using a high-temperature diffusion tube. Boron trichloride and oxygen are introduced, and the deposition is first carried out at 830°C for 1000 seconds. Then the temperature is raised to 960°C, and more oxygen is introduced to continue the process for 22 minutes, so that a certain concentration of boron is doped into the polysilicon layer to form a doped polycrystalline silicon layer.

[0121] Comparative Example 5

[0122] The difference between Comparative Example 5 and Examples 1 and 2 is that a two-layer tunneling oxide layer is grown by combining low-temperature low-pressure oxidation with low-temperature normal-pressure oxidation. The deposition and oxidation propagation temperatures are different, as detailed below.

[0123] S1. Prepare an N-type silicon wafer with a resistivity of 10 Ω·cm and a thickness of 180 μm. Polish both sides, clean it, and place it in an LPCVD equipment. Evacuate the furnace and wait for the furnace tube to heat up to 570°C. Then, introduce oxygen at a flow rate of 10 L / min to keep the pressure inside the furnace tube below 0.2 atmospheres during the heating process. Oxidize the silicon wafer for 15 minutes in a low-temperature and low-pressure environment to grow a dense oxide layer of 0.8 nm on the surface of the silicon wafer.

[0124] S2. Continue to introduce oxygen, maintain the pressure inside the furnace tube at 1 standard atmosphere, and the temperature inside the furnace tube at 580℃. Oxidize the silicon wafer for 12 minutes in a low-temperature and normal-pressure environment, and continue to grow a relatively dense oxide layer with a thickness of 0.4nm on the surface of the silicon wafer. At this point, two dense tunneling oxide layer structures have been grown on the surface of the silicon wafer.

[0125] S3. Continue using LPCVD equipment, control the temperature inside the furnace tube at 600℃, evacuate and then introduce silane at a vacuum pressure of 200mTorr, deposit a Poly silicon layer on the first oxide layer 2 in a high temperature and low pressure environment.

[0126] S4. Boron atoms are deposited and oxidized using a high-temperature diffusion tube. Boron trichloride and oxygen are introduced, and the deposition is first carried out at 830°C for 1000 seconds. Then the temperature is raised to 950°C, and more oxygen is introduced to continue the process for 22 minutes, so that a certain concentration of boron is doped into the polysilicon layer to form a doped polycrystalline silicon layer.

[0127] Comparative Example 6

[0128] The difference between Comparative Example 6 and Examples 1 and 2 is that a two-layer tunneling oxide layer is grown by combining low-temperature low-pressure oxidation with low-temperature normal-pressure oxidation, as detailed below.

[0129] S1. Prepare an N-type silicon wafer with a resistivity of 10 Ω·cm and a thickness of 180 μm. Polish both sides, clean it, and place it in an LPCVD equipment. Evacuate the furnace and wait for the furnace tube to heat up to 570°C. Then, introduce oxygen at a flow rate of 10 L / min to keep the pressure inside the furnace tube below 0.2 atmospheres during the heating process. Oxidize the silicon wafer for 15 minutes in a low-temperature and low-pressure environment to grow a dense oxide layer of 0.8 nm on the surface of the silicon wafer.

[0130] S2. Continue to introduce oxygen, maintain the pressure inside the furnace tube at 1 standard atmosphere, and the temperature inside the furnace tube at 580℃. Oxidize the silicon wafer for 12 minutes in a low-temperature and normal-pressure environment, and continue to grow a relatively dense oxide layer with a thickness of 0.4nm on the surface of the silicon wafer. At this point, two dense tunneling oxide layer structures have been grown on the surface of the silicon wafer.

[0131] S3. Continue using LPCVD equipment, control the temperature inside the furnace tube at 600℃, evacuate and then introduce silane at a vacuum pressure of 200mTorr, deposit a Poly silicon layer on the first oxide layer 2 in a high temperature and low pressure environment.

[0132] S4. Boron atoms are deposited and oxidized using a high-temperature diffusion tube. Boron trichloride and oxygen are introduced, and the deposition is first carried out at 830°C for 1000 seconds. Then the temperature is raised to 960°C, and more oxygen is introduced to continue the process for 22 minutes, so that a certain concentration of boron is doped into the polysilicon layer to form a doped polycrystalline silicon layer.

[0133] Comparative Example 7

[0134] The difference between Comparative Example 7 and Examples 1 and 2 is that a two-layer tunneling oxide layer is grown by combining low-temperature low-pressure oxidation with low-temperature normal-pressure oxidation. The deposition and oxidation propagation temperatures are different, as detailed below.

[0135] S1. Prepare an N-type silicon wafer with a resistivity of 10 Ω·cm and a thickness of 180 μm. Polish both sides, clean it, and place it in an LPCVD equipment. Evacuate the furnace and wait for the furnace tube to heat up to 570°C. Then, introduce oxygen at a flow rate of 10 L / min to keep the pressure inside the furnace tube below 0.2 atmospheres during the heating process. Oxidize the silicon wafer for 15 minutes in a low-temperature and low-pressure environment to grow a dense oxide layer of 0.8 nm on the surface of the silicon wafer.

[0136] S2. Continue to introduce oxygen, maintain the pressure inside the furnace tube at 1 standard atmosphere, and the temperature inside the furnace tube at 580℃. Oxidize the silicon wafer for 12 minutes in a low-temperature and normal-pressure environment, and continue to grow a relatively dense oxide layer with a thickness of 0.4nm on the surface of the silicon wafer. At this point, two dense tunneling oxide layer structures have been grown on the surface of the silicon wafer.

[0137] S3. Continue using LPCVD equipment, control the temperature inside the furnace tube at 600℃, evacuate and then introduce silane at a vacuum pressure of 200mTorr, deposit a Poly silicon layer on the first oxide layer 2 in a high temperature and low pressure environment.

[0138] S4. Boron atoms are deposited and oxidized using a high-temperature diffusion tube. Boron trichloride and oxygen are introduced, and the deposition is first carried out at 830°C for 1000 seconds. Then the temperature is raised to 970°C, and more oxygen is introduced to continue the process for 22 minutes, so that a certain concentration of boron is doped into the polysilicon layer to form a doped polycrystalline silicon layer.

[0139] Performance testing

[0140] The silicon wafers with passivated contact structures obtained using the passivation methods described in the above embodiments and comparative examples were subjected to performance testing. All data in Table 1 were obtained by directly testing N-type silicon wafers with symmetrical structures after double-sided poly layer growth and double-sided boron expansion.

[0141] Minority carrier lifetime, recombination current density (J0), implicit open-circuit voltage (iVoc), and implicit fill factor (iFF) were measured using a WCT-120 instrument from Sinton Instruments, USA. Photoluminescence luminance was measured using a PL-R3 instrument, with the excitation luminance set at one solar standard luminance (1 Sun). The test results are shown in Table 1.

[0142] Table 1

[0143]

[0144] As can be seen from the test results of Examples 1 and 2 and Comparative Example 1, the passivation method of the present invention significantly improves the minority carrier lifetime, iVoc, iFF and PL brightness of the boron-doped Poly layer prepared by the prior art, and significantly reduces the recombination current density J0, showing a better passivation effect.

[0145] As can be seen from the test results of Examples 3 and 4 and Comparative Example 2, although phosphorus Poly itself has good passivation performance, the passivation effect of the passivation method of the present invention is still improved compared with the phosphorus-doped Poly layer prepared by the prior art. The minority carrier lifetime and PL brightness are significantly improved, iVoc and iFF are improved, and the recombination current density J0 is reduced.

[0146] As can be seen from the test results of Examples 1 and 2 and Comparative Examples 3-7, the present invention, through the superposition of three oxide layers with different densities, can greatly improve the passivation effect of the boron- and phosphorus-doped Poly layer structure compared to a two-layer structure; minority carrier lifetime, iVoc, iFF, and PL brightness are all significantly improved, while the recombination current density J0 is significantly reduced, demonstrating a better passivation effect. Moreover, the tunneling oxide layer grown in the present invention is less affected by subsequent boron diffusion temperature fluctuations and can accept fluctuations of up to 30°C at the optimal oxidation propagation temperature.

[0147] As can be seen from the test results of Examples 1 and 2 and Comparative Examples 5 to 7, when the tunneling oxide layer is passivated under different oxidation propulsion temperatures of boron diffusion, if a dense tunneling oxide layer is grown at a low temperature throughout the process (Comparative Examples 5 to 7), a good passivation effect can usually be achieved at the optimal oxidation propulsion temperature of boron diffusion (Comparative Example 6). However, it is very sensitive to changes in oxidation propulsion temperature. When the temperature fluctuates by about 10°C (Comparative Examples 5 and 7), the passivation effect decreases significantly, which is not conducive to large-scale industrial production.

[0148] The present invention has been further described above with reference to specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the nature and scope of the present invention. Various modifications made to the above embodiments by those skilled in the art after reading this specification are all within the scope of protection of the present invention.

Claims

1. A passivated contact structure with a boron- and phosphorus-doped poly layer, characterized in that, The passivation contact structure includes a first oxide layer (2), a second oxide layer (3), a third oxide layer (4), and a doped polysilicon layer (5) grown on a silicon wafer (1). The doped polysilicon layer (5) is above the first oxide layer (2). The first oxide layer (2), the second oxide layer (3), and the third oxide layer (4) constitute a tunneling oxide layer. The second oxide layer (3) is located in the middle of the tunneling oxide layer and has a thickness of 0.5~1nm and is porous. The first oxide layer (2) and the third oxide layer (4) are located on both sides of the tunneling oxide layer. The first oxide layer (2) has a thickness of 0.3~0.8nm and is dense, and the third oxide layer (4) has a thickness of 0.1~0.4nm and is dense. The passivated contact structure is prepared by the following method: S1. Provide a clean and polished silicon wafer. Use an LPCVD device to evacuate and introduce oxygen. At a low temperature and low pressure of 400~590℃ and 0.1~0.5 standard atmospheres, perform the first oxidation on the silicon wafer to grow the first oxide layer (2) on the surface of the silicon wafer (1). S2. When the temperature in step S1 is increased by 50~220℃, oxygen is continuously introduced and the silicon wafer is oxidized for the second time under a pressure greater than or equal to 1 standard atmosphere, and a second oxide layer (3) is grown on the surface of the silicon wafer (1). S3. Stop the oxygen supply, keep the pressure constant, lower the temperature to below 600℃, and perform a third oxidation on the silicon wafer to continue growing a third oxide layer (4) on the surface of the silicon wafer (1). S4. Continue to use LPCVD equipment. The temperature in step S3 is increased by 0~50℃. After vacuuming, silane is introduced. Under high temperature and low pressure, a Poly silicon layer is deposited on the first oxide layer (2) until the film thickness required by the process is achieved. S5. Using a high-temperature diffusion tube, boron or phosphorus atoms are deposited and oxidized to dope the polysilicon layer with a certain concentration of boron or phosphorus, forming a doped polysilicon layer (5).

2. The passivated contact structure of the boron- and phosphorus-doped Poly layer according to claim 1, characterized in that, The thickness of the three oxide layers is equal to that of a conventional tunneling oxide layer.

3. The passivated contact structure of the boron- and phosphorus-doped Poly layer according to claim 1, characterized in that, In step S1, the temperature is 500~580℃, and the first oxidation time is 10~20 minutes.

4. The passivated contact structure of the boron- and phosphorus-doped Poly layer according to claim 1, characterized in that, In step S2, the temperature is 610~640℃, the pressure is atmospheric pressure, and the second oxidation time is 10~20 minutes.

5. The passivated contact structure of the boron- and phosphorus-doped Poly layer according to claim 1, characterized in that, In step S3, the temperature is 550~590℃, the pressure is atmospheric pressure, and the third oxidation time is 10~20 minutes.

6. The passivated contact structure of the boron- and phosphorus-doped Poly layer according to claim 1, characterized in that, In steps S1 and S2, the oxygen flow rate is 5~30L / min.

7. The passivated contact structure of the boron- and phosphorus-doped Poly layer according to claim 1, characterized in that, In step S4, the temperature is 550~640℃ and the vacuum pressure is 180~300mTorr.

8. The passivated contact structure of the boron- and phosphorus-doped Poly layer according to claim 1, characterized in that, In step S5, during the deposition and oxidation process of boron atoms, the deposition temperature is 800~850℃ and the oxidation process is 940~1000℃; during the deposition and oxidation process of phosphorus atoms, the deposition temperature is 800~850℃ and the oxidation process is 880~920℃.

9. The passivated contact structure of the boron- and phosphorus-doped Poly layer according to claim 8, characterized in that, During the deposition and oxidation process of boron atoms, boron trichloride and oxygen are introduced. Deposition is first carried out at 800-850℃ for 600-1500 seconds, then the temperature is raised to 940-1000℃, and a larger amount of oxygen is introduced for more than 20 minutes. During the deposition and oxidation process of phosphorus atoms, phosphorus oxychloride and oxygen are introduced. Deposition is first carried out at 800-850℃ for 600-1500 seconds, then the temperature is raised to 880-920℃, and a larger amount of oxygen is introduced for 10-20 minutes.

10. The passivated contact structure of the boron- and phosphorus-doped Poly layer according to claim 1, characterized in that, The silicon wafer is an N-type silicon wafer.

11. A battery with a passivated contact structure having a boron- and phosphorus-doped poly layer, characterized in that, The battery includes a silicon wafer and a passivated contact structure formed on the surface of the silicon wafer with a boron- or phosphorus-doped Poly layer as described in any one of claims 1 to 10.

12. The battery with a passivated contact structure having a boron- and phosphorus-doped Poly layer according to claim 11, characterized in that, The battery is a TOPCon battery, a TBC battery, or a perovskite tandem battery.

Images