Solar cell and method of production, production system, photovoltaic module

Abstract

The application provides a solar cell and a production method and system thereof, and a photovoltaic module, and relates to the technical field of photovoltaics. The solar cell comprises a silicon substrate, at least one first doped region in a local area of a light-receiving surface of the silicon substrate, the same doped type of each first doped region and the silicon substrate, and the same doped concentration of each first doped region and the silicon substrate, a chemical passivation film and a field passivation anti-reflection film sequentially and layerwisely distributed on the light-receiving side of the silicon substrate and the first doped region, at least one front grid line electrode on the light-receiving side of the silicon substrate, and the mutual contact of the at least one front grid line electrode and the at least one first doped region. In the solar cell, Auger recombination is less, process matching performance is good, the solar cell has good photoelectric conversion efficiency, and the production cost can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic, in particular to a solar cell, a production method and system thereof, and a photovoltaic module. BACKGROUND

[0002] Due to the high potential of photoelectric conversion efficiency, the solar cell has broad application prospects.

[0003] However, the existing solar cell still has some difficulties in improving the photoelectric conversion efficiency. At present, some problems can be appropriately solved by changing part of the structure. However, there is still a large space for improving the photoelectric conversion efficiency of the existing solar cell. SUMMARY

[0004] The present application provides a solar cell, a production method and system thereof, and a photovoltaic module, aiming to solve the problem of poor process matching of the existing solar cell, resulting in low photoelectric conversion efficiency.

[0005] In a first aspect, the present application provides a solar cell, comprising:

[0006] a silicon substrate;

[0007] at least one first doped region in a local area of the light-receiving surface of the silicon substrate; the doping type of each first doped region and the doping type of the silicon substrate are the same, and the doping concentration of each first doped region is greater than the doping concentration of the silicon substrate;

[0008] a chemical passivation film and a field passivation anti-reflection film successively stacked on the light-receiving side of the silicon substrate and the first doped region;

[0009] at least one front grid line electrode located on the light-receiving side of the silicon substrate; at least one front grid line electrode and at least one first doped region are in contact with each other.

[0010] In the present application, the chemical passivation film included on the light side can play a good chemical passivation role, the field passivation anti-reflection film can play a good field passivation and anti-reflection role, and the surface passivation ability of amorphous silicon can be basically achieved. And the above-mentioned chemical passivation film and field passivation anti-reflection film are weakly absorbed or basically not absorbed to the short wave and visible light of the incident light, so that the loss of short circuit current of the solar cell can be reduced. At the same time, the first doped region is only distributed on the local area of the light side of the silicon substrate, and there is basically no Auger recombination at the position without the first doped region, so that the Auger recombination caused by the first doped region is relatively small, the process matching is good, and the loss of short circuit current and open circuit voltage caused by Auger recombination can be reduced. At the same time, in the present application, the first doped region, the chemical passivation film and the field passivation anti-reflection film on the light side of the silicon substrate do not need to use amorphous silicon coating equipment and transparent conductive oxide coating equipment, so that the cost of production equipment and the space occupied by production equipment can be greatly reduced, for example, the cost of production equipment is reduced by about half and the space occupied by production equipment is reduced by about half. In addition, the transparent conductive oxide film does not need to be arranged on the light side of the silicon substrate, and the production cost can be reduced.

[0011] Optionally, the highest doping concentration of each first doped region is: 2×10 19 / cm 3 -5×10 20 / cm 3 .

[0012] Optionally, the depth of each first doped region is 0.1-0.5um; the direction of the depth of the first doped region is parallel to the stacking direction of the chemical passivation film and the field passivation anti-reflection film.

[0013] Optionally, the chemical passivation film includes a silicon oxide film or an aluminum oxide film; and / or, the field passivation anti-reflection film includes a silicon nitride film.

[0014] Optionally, the refractive index of the field passivation anti-reflection film is 1.9-2.2.

[0015] Optionally, the solar cell further includes an anti-reflection film located on the light side of the field passivation anti-reflection film.

[0016] Optionally, the material of the anti-reflection film is selected from silicon oxynitride.

[0017] Optionally, the solar cell further includes: an intrinsic amorphous silicon film, a doped amorphous silicon film with a doping type different from that of the silicon substrate, a transparent conductive oxide film and a back electrode which are sequentially and layerwisely distributed on the back light side of the silicon substrate.

[0018] The back electrode is a full-area electrode layer covering the transparent conductive oxide film, the thickness of the transparent conductive oxide film is 5-80 nm; the direction of the thickness of the transparent conductive oxide film is parallel to the stacking direction of the chemical passivation film and the field passivation anti-reflection film.

[0019] Optionally, the thickness of the full-area electrode layer is 1-10 um.

[0020] Optionally, the back electrode is a nickel-copper-silver laminated electrode.

[0021] Optionally, in the nickel-copper-silver laminated electrode, the mass ratio of nickel element, copper element and silver element is (0.5-2.5):(5-9):(0.5-2.5).

[0022] Optionally, the front grid line electrode is a nickel-copper-silver laminated grid line electrode.

[0023] Optionally, in the nickel-copper-silver laminated grid line electrode, the mass ratio of nickel element, copper element and silver element is (0.5-2.5):(5-9):(0.5-2.5).

[0024] Optionally, each of the front grid line electrodes and each of the first doped regions correspond to each other in position and contact each other.

[0025] Optionally, the projection of each of the front grid line electrodes on the first doped region corresponding in position in a first direction has a size equal to the size of the first doped region corresponding in position in the first direction, and the projection of each of the front grid line electrodes on the first doped region corresponding in position in a second direction has a size smaller than the size of the first doped region corresponding in position in the second direction by 15-50 um; the first direction and the second direction are both parallel to the light-receiving surface of the silicon substrate, and the first direction and the second direction are perpendicular to each other.

[0026] And / or, the height of each of the front grid line electrodes is 5-20 um; the direction of the height is parallel to the stacking direction of the chemical passivation film and the field passivation anti-reflection film.

[0027] And / or, the size of each of the front grid line electrodes in the second direction is 15-50 um.

[0028] Optionally, in the case where the chemical passivation film is a silicon oxide film, the thickness of the chemical passivation film is 0.5-5 nm.

[0029] In the case that the chemical passivation film is an aluminum oxide film, the thickness of the chemical passivation film is 2-10 nm; the direction of the thickness is parallel to the stacking direction of the chemical passivation film and the field passivation anti-reflection film.

[0030] Optionally, the silicon substrate is an N-type silicon substrate, the first doped region is a phosphorus-doped region, and the doped amorphous silicon film is a boron-doped amorphous silicon film.

[0031] In a second aspect of the present application, a photovoltaic module is provided, comprising a plurality of the solar cell of any preceding aspect.

[0032] In a third aspect of the present application, a method for producing a solar cell is provided, comprising:

[0033] forming at least one first doped region on a partial area of the light-receiving surface of the silicon substrate; the doped type of each of the first doped regions is the same as the doped type of the silicon substrate, and the doped concentration of each of the first doped regions is greater than the doped concentration of the silicon substrate;

[0034] forming a chemical passivation film and a field passivation anti-reflection film in sequence on the light-receiving surface of the silicon substrate; forming at least one front grid electrode on the light-receiving surface of the silicon substrate; and the position of at least one of the front grid electrodes is in contact with at least one of the first doped regions.

[0035] Optionally, the forming of the at least one first doped region on the partial area of the light-receiving surface of the silicon substrate comprises:

[0036] forming an ultrathin silicon oxide film on the light-receiving surface of the silicon substrate by ultraviolet ozone oxidation;

[0037] infiltrating the light-receiving surface of the silicon substrate with an ultrathin silicon oxide film with a liquid-phase phosphorus source, so that the surface of the ultrathin silicon oxide film has the liquid-phase phosphorus source;

[0038] solidifying the liquid-phase phosphorus source on the surface of the ultrathin silicon oxide film to form a solidified phosphorus source;

[0039] heat-treating the solidified phosphorus source on the surface of the ultrathin silicon oxide film, so that the solidified phosphorus source and the ultrathin silicon oxide film form a silicon phosphide composite;

[0040] irradiating a partial area of the silicon phosphide composite with laser light, so that the phosphorus atoms in the silicon phosphide composite in the irradiated partial area diffuse to the light-receiving side of the silicon substrate to form at least one first doped region on the partial area of the light-receiving surface of the silicon substrate.

[0041] Optionally, after the forming of the at least one first doped region on the partial area of the light-receiving surface of the silicon substrate, the method further comprises:

[0042] cleaning the light side of the silicon substrate with at least one first doped region to remove the residual solidified phosphorus source, the ultra-thin silicon oxide film and the silicon phosphide composite.

[0043] Optionally, the cleaning the light side of the silicon substrate with at least one first doped region includes:

[0044] cleaning the light side of the silicon substrate with at least one first doped region to remove the residual solidified phosphorus source, the ultra-thin silicon oxide film and the silicon phosphide composite.

[0045] etching the light side of the silicon substrate with a first mixed solution to clean the light side of the silicon substrate to remove the residual solidified phosphorus source and the silicon phosphide composite; the first mixed solution includes a mixed solution of hydrofluoric acid and nitric acid, and / or a mixed solution of hydrofluoric acid and ozone.

[0046] Optionally, in the process of etching the light side of the silicon substrate with the first mixed solution, the thickness of the etched light side of the silicon substrate is 20-150 nm; the thickness direction is parallel to the stacking direction of the ultra-thin silicon oxide film and the solidified phosphorus source.

[0047] Optionally, the thickness of the formed silicon phosphide composite is 10-100 nm; the thickness direction is parallel to the stacking direction of the ultra-thin silicon oxide film and the solidified phosphorus source.

[0048] Optionally, the liquid phase phosphorus source includes a water solution of phosphoric acid and an organic solvent dissolved in the water solution of phosphoric acid; the organic solvent is used to improve the wettability of the water solution of phosphoric acid on the light side of the silicon substrate with the ultra-thin silicon oxide film; the concentration of phosphoric acid in the liquid phase phosphorus source is 0.1%-5%.

[0049] Optionally, in the process of heat treatment, the heating rate of the light side of the silicon substrate is 25℃ / s-50℃ / s, the heat treatment temperature is 700-950℃, and the heat treatment duration is 0.5-2 min.

[0050] Optionally, the sequentially forming the layer-stacked distribution of the chemical passivation film, the field passivation anti-reflection film includes:

[0051] forming a silicon oxide film by tube heat oxidation, or depositing an aluminum oxide film;

[0052] depositing a silicon nitride film on the silicon oxide film or the aluminum oxide film.

[0053] Optionally, the method further includes sequentially forming, on the back light side of the silicon substrate, a layer-stacked distribution of an intrinsic amorphous silicon film, a doped amorphous silicon film with a doping type different from that of the silicon substrate, a transparent conductive oxide film, and a back electrode.

[0054] The forming of the front side grid line electrode comprises: slotting the chemical passivation film and the field passivation anti-reflection film to expose the first doped region, and electroplating a nickel-copper-silver stacked grid line electrode on the exposed first doped region;

[0055] And / or, the forming of the back side electrode comprises: electroplating a whole layer of nickel-copper-silver stacked electrode on the transparent conductive oxide film.

[0056] Optionally, laser slotting is adopted; after laser slotting and before electroplating, the method further comprises: cleaning at least one of the chemical passivation film, the field passivation anti-reflection film, and silicon oxide produced due to thermal effect in the slotting process, remaining in the laser slotting area, and etching part of the first doped region with a second mixed solution to remove laser damage of the first doped region; the second mixed solution comprises: a mixed solution of hydrofluoric acid and nitric acid, and / or a mixed solution of hydrofluoric acid and ozone.

[0057] Optionally, the thickness of the etched part of the first doped region is 20-80 nm; the direction of the depth is parallel to the stacking direction of the chemical passivation film and the field passivation anti-reflection film.

[0058] In a fourth aspect, the present application provides a production system of a solar cell, comprising:

[0059] A doping component is configured to form at least one first doped region on a local area of a light-receiving surface of a silicon substrate; the doping type of each of the first doped regions is the same as the doping type of the silicon substrate, and the doping concentration of each of the first doped regions is greater than the doping concentration of the silicon substrate;

[0060] A front side film layer processing component is configured to form, in sequence, a chemical passivation film and a field passivation anti-reflection film on the light-receiving side of the silicon substrate;

[0061] A front side grid line electrode setting component is configured to form at least one front side grid line electrode on the light-receiving side of the silicon substrate; the at least one front side grid line electrode and the at least one first doped region are in contact with each other.

[0062] Optionally, the doping component comprises a chain device, which comprises, in sequence, an ultraviolet ozone oxidation device, a liquid-phase phosphorus source tank, an illumination drying device, a heat treatment device, a laser generating device, and a transmission device between adjacent devices;

[0063] The ultraviolet ozone oxidation device is configured to form an ultrathin silicon oxide film on the light-receiving surface of the silicon substrate through ultraviolet ozone oxidation;

[0064] The liquid-phase phosphor source tank is used for infiltrating the liquid-phase phosphor source into the light-receiving surface of the silicon substrate with the ultra-thin silicon oxide film formed thereon, so that the surface of the ultra-thin silicon oxide film has the liquid-phase phosphor source.

[0065] The light irradiation drying device is used for solidifying the liquid-phase phosphor source on the surface of the ultra-thin silicon oxide film, to form a solidified phosphor source.

[0066] The heat treatment device is used for heat treating the solidified phosphor source on the surface of the ultra-thin silicon oxide film, so that the solidified phosphor source and the ultra-thin silicon oxide film form a silicon phosphide composite.

[0067] The laser generating device is used for irradiating a local area of the silicon phosphide composite with laser, so that the phosphorus atoms in the silicon phosphide composite in the local area irradiated with laser diffuse to the light-receiving side of the silicon substrate, to form at least one first doped region in the local area of the light-receiving surface of the silicon substrate.

[0068] Optionally, the light irradiation drying device comprises parallelly arranged lamp tubes; and / or, the heat treatment device comprises parallelly arranged halogen tungsten lamps.

[0069] Optionally, the solar cell production system further comprises:

[0070] The back surface structure setting member is used for sequentially forming a laminated distribution of an intrinsic amorphous silicon film, a doped amorphous silicon film with a doping type different from that of the silicon substrate, a transparent conductive oxide film, and a back surface electrode on the back light side of the silicon substrate. BRIEF DESCRIPTION OF DRAWINGS

[0071] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative labor based on these drawings.

[0072] Figure 1 A structure schematic diagram of a solar cell in an embodiment of the present application is shown;

[0073] Figure 2 A step flow chart of a production method of a solar cell in an embodiment of the present application is shown;

[0074] Figure 3 A structure schematic diagram of a silicon substrate in an embodiment of the present application is shown;

[0075] Figure 4 A partial structure schematic diagram of a first solar cell in an embodiment of the present application is shown;

[0076] Figure 5 Fig. 2 shows a partial structural schematic diagram of a second solar cell in the embodiment of the present application;

[0077] Figure 6 Fig. 3 shows a partial structural schematic diagram of a third solar cell in the embodiment of the present application;

[0078] Figure 7 Fig. 4 shows a partial structural schematic diagram of a fourth solar cell in the embodiment of the present application;

[0079] Figure 8 Fig. 5 shows a partial structural schematic diagram of a fifth solar cell in the embodiment of the present application;

[0080] Figure 9 Fig. 6 shows a partial structural schematic diagram of a sixth solar cell in the embodiment of the present application;

[0081] Figure 10 Fig. 7 shows a partial structural schematic diagram of a seventh solar cell in the embodiment of the present application;

[0082] Figure 11 Fig. 8 shows a partial structural schematic diagram of an eighth solar cell in the embodiment of the present application;

[0083] Figure 12 Fig. 9 shows a partial structural schematic diagram of a ninth solar cell in the embodiment of the present application;

[0084] Figure 13 Fig. 10 shows a partial structural schematic diagram of a tenth solar cell in the embodiment of the present application;

[0085] Figure 14 Fig. 11 shows a structural schematic diagram of a chain device in the embodiment of the present application.

[0086] BRIEF DESCRIPTION OF DRAWINGS

[0087] 1 - silicon substrate, 11 - first doped region, 2 - chemical passivation film, 3 - field passivation anti-reflection film, 4 - front grid electrode, 5 - intrinsic amorphous silicon film, 6 - doped amorphous silicon film, 7 - transparent conductive oxide film, 8 - back electrode, 91 - solidified phosphorus source, 92 - silicon phosphide composite. DETAILED DESCRIPTION

[0088] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0089] Figure 1 A structure diagram of a solar cell in an embodiment of the present application is shown. The solar cell comprises a silicon substrate 1, and a light-receiving side of the silicon substrate 1 is a side on which the silicon substrate 1 mainly receives light. A light-receiving surface of the silicon substrate 1 is a surface on which the silicon substrate 1 mainly receives light. The solar cell comprises at least one first doped region 11 formed in a partial region of the light-receiving surface of the silicon substrate 1. The number of the first doped regions 11 is not specifically limited. Figure 1 The number of the first doped regions 11 in the partial region of the light-receiving surface of the silicon substrate 1 in the shown solar cell is two.

[0090] The area of the projection of all the first doped regions 11 on the light-receiving surface of the silicon substrate 1 is less than the area of the light-receiving surface of the silicon substrate 1. The area of the projection of all the first doped regions 11 on the silicon substrate 1 is less than the area of the light-receiving surface of the silicon substrate 1 by an amount which is not specifically limited. That is, the first doped regions 11 are distributed in a partial region of the light-receiving side of the silicon substrate 1 and do not completely cover the light-receiving side of the silicon substrate 1. The doping type of each of the first doped regions 11 is the same as the doping type of the silicon substrate 1, and the doping concentration of each of the first doped regions 11 is greater than the doping concentration of the silicon substrate 1. That is, the doping type of the first doped regions 11 is the same as the doping type of the silicon substrate 1, and the first doped regions 11 and the silicon substrate 1 form a high-low junction. The type of the silicon substrate 1 is not specifically limited in the present application. For example, the silicon substrate 1 can be an N-type silicon substrate.

[0091] Referring to Figure 1 As shown, the solar cell further comprises a chemical passivation film 2 and a field passivation anti-reflection film 3 which are sequentially and layerwisely distributed on the light-receiving side of the silicon substrate 1. The chemical passivation film 2 functions to provide good chemical passivation. The field passivation anti-reflection film 3 functions to provide good field passivation and anti-reflection.

[0092] At least one front grid line electrode 4 is located on the light-receiving side of the silicon substrate 1, and the at least one front grid line electrode 4 and the at least one first doped region 11 are in contact with each other. For example, only one front grid line electrode 4 and one first doped region 11 can be in contact with each other, or each front grid line electrode 4 and each first doped region 11 located in a corresponding position can be in contact with each other, or each front grid line electrode 4 and each first doped region 11 located in a corresponding position can be in ohmic contact with each other. The front grid line electrode can collect the photovoltaic current generated by the first doped region 11 under light. This is not specifically limited in the embodiment of the present application.

[0093] Specifically, the inventors found that the amorphous silicon film and the transparent conductive oxide film need to be set on both the front and back surfaces of the solar cell. On the one hand, the raw material of the conductive oxide film is relatively expensive. On the other hand, the amorphous silicon film coating equipment and the transparent conductive oxide film coating equipment are needed in the preparation process of the front and back surfaces of the solar cell. These two kinds of equipment have large floor area and high cost. In order to reduce the cost, the existing solar cell uses a part of the polycrystalline silicon layer to replace one side of the amorphous silicon and the transparent conductive oxide film. However, the photoelectric conversion efficiency of the solar cell is reduced. The inventors found that the main reason for the reduction of the photoelectric conversion efficiency of the solar cell is that the above-mentioned polycrystalline silicon layer has strong absorption of short-wave and visible light of incident light, which causes serious loss of short-circuit current of the solar cell. Moreover, with the increase of the thickness of the polycrystalline silicon layer, the absorption of short-wave and visible light of incident light by the polycrystalline silicon layer is more intense. In order to ensure good passivation effect, etc., the thickness of the polycrystalline silicon layer in the existing solar cell needs to be set to 60 nm or more, which causes serious absorption of short-wave and visible light of incident light by the polycrystalline silicon layer, resulting in more serious loss of short-circuit current of the solar cell. For example, the loss of short-circuit current of the solar cell caused by this is more than 500 mA. In order to reduce the cost, the existing solar cell also uses an entire surface diffusion layer to replace one side of the amorphous silicon and the transparent conductive oxide film. However, the photoelectric conversion efficiency of the solar cell is reduced. The inventors found that the main reason for the reduction of the photoelectric conversion efficiency of the solar cell is that the entire surface diffusion layer causes serious Auger recombination, which causes poor process matching and reduces the short-circuit current and open-circuit voltage of the solar cell. At the same time, the entire surface diffusion layer takes a long time to diffuse, which reduces the production efficiency.

[0094] In the present application, the chemical passivation film 2 on the light side can play a good chemical passivation role, the field passivation and anti-reflection film 3 can play a good field passivation and anti-reflection role, and the surface passivation ability of amorphous silicon can basically be achieved. Moreover, the chemical passivation film 2 and the field passivation and anti-reflection film 3 have weak or basically no absorption to the short wave and visible light of the incident light, so that the loss of short-circuit current of the solar cell can be reduced. Meanwhile, the first doped region 11 is not distributed on the light side of the silicon substrate 1 in the whole area, but is distributed on the light side of the silicon substrate 1 in a partial area, and there is basically no Auger recombination at the position without the first doped region 11, so that the Auger recombination caused by the first doped region 11 is relatively less, and the loss of short-circuit current and open-circuit voltage caused by the Auger recombination can be reduced. Moreover, compared with forming a diffusion layer in the whole area, the present application forms the first doped region 11 in the partial area on the light side of the silicon substrate 1, so that the time for forming the first doped region 11 is relatively less, and the production efficiency can be improved. Meanwhile, in the present application, the first doped region 11, the chemical passivation film 2 and the field passivation and anti-reflection film 3 on the light side of the silicon substrate 1 do not need to use amorphous silicon coating equipment and transparent conductive oxide coating equipment, so that the cost of production equipment and the space occupied by the production equipment can be greatly reduced, for example, the cost of production equipment and the space occupied by the production equipment can be reduced by about half. In addition, the transparent conductive oxide film is not arranged on the light side of the silicon substrate 1, so that the production cost can be reduced.

[0095] It should be noted that the type of the solar cell is not specifically limited in the embodiments of the present application, for example, the solar cell can be a heterojunction solar cell.

[0096] Optionally, the chemical passivation film 2 includes a silicon oxide film or an aluminum oxide film, the chemical passivation film 2 has weak or basically no absorption to the short wave and visible light of the incident light, and the loss of short-circuit current of the solar cell can be reduced. Moreover, the chemical passivation film 2 has a good chemical passivation effect, for example, has a good hydrogen passivation effect, and the surface passivation ability of amorphous silicon can basically be achieved.

[0097] Optionally, the field passivation and anti-reflection film 3 includes a silicon nitride film, the field passivation and anti-reflection film 3 has weak or basically no absorption to the short wave and visible light of the incident light, and the loss of short-circuit current of the solar cell can be reduced. Moreover, the field passivation and anti-reflection film 3 has a good field passivation and anti-reflection effect, and the surface passivation ability of amorphous silicon can basically be achieved.

[0098] Optionally, the highest doping concentration of each first doped region 11 is 2×10 19 / cm 3 -5×10 20 / cm 3 . The highest doping concentration of the first doped region 11 is in the range, which is beneficial to the separation of carriers.

[0099] Optionally, the depth of each first doped region 11 is 0.1-0.5um, and the direction of the depth is parallel to the stacking direction of the chemical passivation film 2 and the field passivation anti-reflection film 3. Figure 1 In the figure, the direction indicated by the dashed line L1 is the stacking direction of the chemical passivation film 2 and the field passivation anti-reflection film 3. The first doped region 11 of the light-facing surface of the silicon substrate 1 is flush with the light-facing surface of the silicon substrate 1, which means that the first doped region 11 is located within 0.1-0.5um from the light-facing surface of the silicon substrate 1 towards the interior of the silicon substrate 1. The position of the height difference formed by the first doped region 11 and the silicon substrate 1 is 0.1-0.5um from the light-facing surface of the silicon substrate 1. The height difference within this height range is conducive to the formation and separation of carriers.

[0100] Optionally, the refractive index of the field passivation anti-reflection film 3 is 1.9-2.2. The field passivation anti-reflection film 3 has better anti-reflection performance within this range of refractive index.

[0101] Optionally, the solar cell further comprises an anti-reflection film on the light-facing side of the field passivation anti-reflection film 3 to enhance the front anti-reflection effect.

[0102] Optionally, the material of the anti-reflection film is selected from silicon oxynitride, which has better anti-reflection effect.

[0103] Optionally, the total thickness of the anti-reflection film and the field passivation anti-reflection film 3 is 60-90nm. Within this thickness range, the solar cell has better front field passivation and anti-reflection effects, and the cost is relatively low. The direction of the thickness is parallel to the stacking direction of the chemical passivation film 2 and the field passivation anti-reflection film 3. It should be noted that the direction of the thickness, height and depth mentioned throughout the text is defined as such.

[0104] Optionally, in the case where the chemical passivation film 2 is a silicon oxide film, the thickness of the chemical passivation film 2 is 0.5-5nm. Within this thickness range, the silicon oxide film has better chemical passivation effect, and the cost is relatively low.

[0105] In the case where the chemical passivation film 2 is an aluminum oxide film, the thickness of the chemical passivation film 2 is 2-10nm. Within this thickness range, the aluminum oxide film has better chemical passivation effect, and the cost is relatively low.

[0106] Referring to Figure 1 As shown in the figure, the back light side of the silicon substrate 1 and the light-facing side of the silicon substrate 1 are oppositely distributed. The solar cell further comprises an intrinsic amorphous silicon film 5, a doped amorphous silicon film 6 with a doping type different from that of the silicon substrate 1, a transparent conductive oxide film 7, and a back electrode 8, which are sequentially stacked on the back light side of the silicon substrate 1. For example, if the silicon substrate 1 is N-type, the doped amorphous silicon film 6 is P-type.

[0107] The back electrode 8 is a full-area electrode layer covering the transparent conductive oxide film, and the thickness of the transparent conductive oxide film 7 is 5-80 nm. In comparison with the prior art in which the thickness of the transparent conductive oxide film 7 is greater than 80 nm, the thickness of the transparent conductive oxide film 7 in the present application is thinner, which can greatly reduce the cost of the solar cell. Moreover, in the present application, since the back electrode 8 is a full-area electrode layer, the back electrode 8 itself has good lateral carrier collection capability, and thus the thickness of the transparent conductive oxide film 7 can be set to be lower, and the lateral conductivity of the solar cell is still good due to the compensation of the back electrode 8 for the reduced lateral conductivity of the transparent conductive oxide film 7.

[0108] Optionally, the thickness of the full-area electrode layer is 1-10 um, in which range the back electrode 8 can achieve good carrier extraction performance and has a low cost.

[0109] The inventors have found that in the prior art, the electrodes of the solar cell are all silver paste electrodes, which have a high cost, particularly for low-temperature silver paste, and the shape of the silver particles in the silver paste electrode makes the contact between the silver particles less, and the organic components in the silver paste also affect the contact between the silver particles, resulting in a high resistivity of the silver paste electrode. Optionally, in the present application, the front grid electrode 4 is a nickel-copper-silver laminated grid electrode, and / or the back electrode 8 is a nickel-copper-silver laminated electrode. The contact between the electrode materials in the nickel-copper-silver laminated grid electrode and the nickel-copper-silver laminated electrode is tight, so that the resistivity of the nickel-copper-silver laminated grid electrode and the nickel-copper-silver laminated electrode is low, which can improve the electrical performance of the solar cell, and the content of silver in the nickel-copper-silver laminated grid electrode and the nickel-copper-silver laminated electrode is low, which has a low cost. At the same time, the nickel-copper-silver laminated grid electrode and the nickel-copper-silver laminated electrode can be prepared by electroplating, and the purity of the formed nickel-copper-silver laminated grid electrode and the nickel-copper-silver laminated electrode is high, so that the resistivity of the nickel-copper-silver laminated grid electrode and the nickel-copper-silver laminated electrode is also low, which can improve the electrical performance of the solar cell and has a low cost. At the same time, since the back electrode 8 is a nickel-copper-silver laminated electrode, the thickness of the transparent conductive oxide film 7 can be further appropriately reduced while ensuring that the electrical performance of the solar cell is not affected, and the reduction of the thickness of the transparent conductive oxide film 7 can reduce the cost.

[0110] Optionally, in the nickel-copper-silver laminated grid line electrode and the nickel-copper-silver laminated electrode, the mass ratio of the three elements of nickel, copper and silver is (0.5-2.5):(5-9):(0.5-2.5), and the mass ratio of the noble metal silver in the nickel-copper-silver laminated grid line electrode and the nickel-copper-silver laminated electrode is relatively low, accounting for only 5%-25%, so the cost of the nickel-copper-silver laminated grid line electrode and the nickel-copper-silver laminated electrode is relatively low. For example, in the nickel-copper-silver laminated grid line electrode and the nickel-copper-silver laminated electrode, the mass ratio of the three elements of nickel, copper and silver can be 1:8:1.

[0111] Optionally, each front grid line electrode 4 and each first doped region 11 are in one-to-one correspondence and in contact with each other, so that each first doped region 11 is fully used for transmitting and collecting carriers, which can improve the photoelectric conversion efficiency of the solar cell.

[0112] Optionally, the projection of each front grid line electrode 4 on the position corresponding first doped region 11 in the first direction has a size equal to the size of the position corresponding first doped region 11 in the first direction, and the projection of each front grid line electrode 4 on the position corresponding first doped region 11 in the second direction has a size smaller than the size of the position corresponding first doped region 11 in the second direction by 15-50 um. The first direction and the second direction are both parallel to the light-receiving surface of the silicon substrate, and the first direction and the second direction are perpendicular to each other. That is, the projection of each front grid line electrode 4 on the position corresponding first doped region 11 falls completely within the position corresponding first doped region. At the same time, in the surface parallel to the light-receiving surface of the silicon substrate 1, in the two mutually perpendicular directions, the size of the front grid line electrode 4 in the first direction is equal to the size of the position corresponding first doped region 11, and in the second direction, the size of the first doped region 11 is larger than the size of the position corresponding front grid line electrode 4 by 15-50 um, which is beneficial to the collection and export of carriers. For example, Figure 1 The direction indicated by L2 in the figure is the direction in which the second direction is located, and the first direction can be parallel to the direction extending inwardly toward the paper surface. It should be noted that the first direction and the second direction mentioned below are defined as such. That is, each front grid line electrode 4 and the position corresponding first doped region are in complete electrical contact, which is beneficial to improving the electrical performance of the solar cell. For example, Figure 1 As shown in the figure, 15 um≤d1+d2≤50 um.

[0113] And / or, the height of each front grid line electrode 4 is 5-20 um, which is beneficial to the collection and export of carriers. For example, the front grid line electrode 4 is a nickel-copper-silver laminated grid line electrode, and the height thereof is 10 um.

[0114] Optionally, the size d3 of each front side gate line electrode 4 in the second direction is 15-50 um, in which size range, the collection and export of carriers are facilitated. For example, the front side gate line electrode 4 is a nickel-copper-silver laminated gate line electrode, and the size d3 of the front side gate line electrode 4 in the second direction is 25 um.

[0115] Optionally, the silicon substrate 1 is an N-type silicon substrate, the resistivity of the silicon substrate 1 is 0.3-7 ohm.cm, and the thickness of the silicon substrate 1 is 50-150 um. The material of the intrinsic amorphous silicon film 5 on the back light side of the silicon substrate 1 can be hydrogenated amorphous silicon, and a small amount of oxygen elements or carbon elements can be doped in the intrinsic amorphous silicon film 5. In the intrinsic amorphous silicon film 5, the proportion of hydrogen atoms is between 10-30%, and the proportion of oxygen elements or carbon elements is between 0-5%. The thickness of the intrinsic amorphous silicon film 5 is between 5-15 nm. The doped amorphous silicon film 6 can be a boron-doped amorphous silicon film. In the doped amorphous silicon film 6, a part of microcrystalline silicon can be contained, the proportion of boron elements is between 0.1-5%, and the thickness of the doped amorphous silicon film 6 is between 10-40 nm.

[0116] The present application also provides a photovoltaic module comprising a plurality of any of the aforementioned solar cells. The photovoltaic module has the same or similar advantages as the aforementioned solar cells, and will not be described here again in order to avoid repetition.

[0117] Figure 2 A step flow chart of a production method of a solar cell in an embodiment of the present application is shown. The present application also provides a production method of a solar cell. Referring to Figure 2 the drawing, the method comprises the following steps:

[0118] In step S1, at least one first doped region is formed in a local area of the light-receiving surface of the silicon substrate; the doping type of each of the first doped regions and the doping type of the silicon substrate are the same, and the doping concentration of each of the first doped regions is greater than the doping concentration of the silicon substrate.

[0119] Figure 3 A structure schematic diagram of a silicon substrate in an embodiment of the present application is shown. Referring to Figure 3 the drawing, before the above step S1, the silicon substrate 1 can be etched and cleaned. Specifically, the alkali polishing can be used to remove the damaged layer on the surface of the silicon substrate 1, pre-cleaning, alkali etching, RCA cleaning, HF rinsing, water washing, and drying. The thickness of the silicon substrate 1 removed by alkali polishing is 10-40 um, the size of the pyramids in alkali etching is about 2-5 um, and the reflectivity is about 10%-13%.

[0120] The way of forming at least one first doped region 11 in a local area of the light-receiving surface of the silicon substrate 1 can adopt tube-type phosphorus diffusion or other ways.

[0121] Step S2, sequentially forming a chemical passivation film, a field passivation anti-reflection film on the light side of the silicon substrate.

[0122] The chemical passivation film 2 and the field passivation anti-reflection film 3 can be formed by deposition or sputtering, etc. The forming method of the two is not specifically limited.

[0123] Step S3, forming at least one front grid line electrode on the light side of the silicon substrate; at least one of the front grid line electrodes and at least one of the first doped regions are in contact with each other.

[0124] As can be, the front grid line electrode can be formed by electroplating, screen printing, laser transfer, etc.

[0125] The production method of the solar cell has the same or similar beneficial effects as the aforementioned solar cell, and the two can be mutually referred to.

[0126] Optionally, the above step S1 can include the following sub-steps: forming an ultra-thin silicon oxide film on the light side of the silicon substrate; infiltrating the liquid-phase phosphorus source on the light side of the silicon substrate with the ultra-thin silicon oxide film, so that the surface of the ultra-thin silicon oxide film has a liquid-phase phosphorus source; solidifying the liquid-phase phosphorus source on the surface of the ultra-thin silicon oxide film to form a solidified phosphorus source; heat treating the solidified phosphorus source on the surface of the ultra-thin silicon oxide film, so that the solidified phosphorus source and the ultra-thin silicon oxide film form a silicon phosphide composite; irradiating a local area of the silicon phosphide composite on the surface of the ultra-thin silicon oxide film with a laser, so that the phosphorus atoms in the silicon phosphide composite in the local area irradiated with the laser diffuse to the light side of the silicon substrate to form at least one first doped region on the local area of the light side of the silicon substrate.

[0127] Figure 4 A partial structure schematic diagram of a first solar cell in an embodiment of the present application is shown. Figure 5 A partial structure schematic diagram of a second solar cell in an embodiment of the present application is shown. Figure 6 A partial structure schematic diagram of a third solar cell in an embodiment of the present application is shown.

[0128] Specifically, referring to Figure 4As shown, the silicon substrate 1 can be transferred to the ultraviolet ozone oxidation device through the chain device, and the ultrathin silicon dioxide film is formed on the light-receiving surface of the silicon substrate 1 by ultraviolet ozone oxidation. Then, the light-receiving surface of the silicon substrate 1 on which the ultrathin silicon dioxide film is formed is immersed in a liquid-phase phosphorus source to make the surface of the ultrathin silicon dioxide film have the liquid-phase phosphorus source. For example, the silicon substrate 1 on which the ultrathin silicon dioxide film is formed can be immersed in a phosphorus source tank, and the remaining surface of the silicon substrate 1 on which the ultrathin silicon dioxide film is not formed is basically not immersed in the liquid-phase phosphorus source, and only the surface on which the ultrathin silicon dioxide film is formed is immersed in the liquid-phase phosphorus source. The liquid-phase phosphorus source on the surface of the ultrathin silicon dioxide film is solidified to form a solidified phosphorus source 91. The ultrathin silicon dioxide film is used to improve the wettability of the aqueous solution of phosphoric acid on the light-receiving surface of the silicon substrate 1.

[0129] Optionally, the liquid-phase phosphorus source includes an aqueous solution of phosphoric acid and an organic solvent dissolved in the aqueous solution of phosphoric acid, and the organic solvent is used to improve the wettability of the aqueous solution of phosphoric acid on the light-receiving surface of the silicon substrate 1 on which the ultrathin silicon dioxide film is formed. The specific component of the organic solvent is not limited. The concentration of phosphoric acid in the liquid-phase phosphorus source is 0.1% to 5%. For example, the concentration of phosphoric acid is 0.1%, 1.2%, 2.5% or 5%. The phosphorus source with the above components is easy to be immersed on the light-receiving surface of the silicon substrate 1 on which the ultrathin silicon dioxide film is formed.

[0130] Referring to Figure 5 As shown, the solidified phosphorus source 91 is subjected to heat treatment, and the solidified phosphorus source 91 and the ultrathin silicon dioxide film form a silicon phosphide (SiP) composite 92.

[0131] Optionally, during the heat treatment of the solidified phosphorus source 91, the temperature rising rate of the light-receiving side of the silicon substrate 1 is 25°C / s to 50°C / s, the heat treatment temperature is 700°C to 950°C, and the heat treatment duration is 0.5 min to 2 min. Under the heat treatment environment, the solidified phosphorus source 91 and the ultrathin silicon dioxide film can quickly and sufficiently form the silicon phosphide (SiP) composite 92. For example, during the heat treatment of the solidified phosphorus source 91, the temperature rising rate of the light-receiving side of the silicon substrate 1 is 40°C / s, the heat treatment temperature is 800°C, and the heat treatment duration is 1 min. It should be noted that, during the heat treatment of the solidified phosphorus source 91, the carbon-containing components possibly existing in the solidified phosphorus source 91 and the silicon phosphide (SiP) composite 92 on the light-receiving side of the silicon substrate 1 can be combusted in the heat environment, so as to avoid the above carbon-containing components affecting the performance of the solar cell. Meanwhile, compared with the conventional tube-type phosphorus diffusion, the heat treatment in this step is relatively short. The conventional tube-type phosphorus diffusion is usually subjected to whole-surface heat treatment, and at least needs about half an hour. However, the heat treatment in this step only needs 0.5 min to 2 min, which is obviously shortened. The heat treatment in this step not only can improve the production efficiency, but also can obviously shorten the heat treatment time, so that the silicon substrate is less affected by the thermal stress, and the occurrence of the silicon substrate warping is reduced.

[0132] Optionally, the thickness of the formed silicon phosphide composite 92 is 10-100nm, the direction of the thickness is parallel to the stacking direction of the ultrathin silicon oxide film and the solidified phosphorus source 91, and the thickness of the formed silicon phosphide composite 92 is in the range, so that the size and concentration of the formed first doped region are appropriate, and material waste is avoided.

[0133] Referring to Figure 6 As shown in the figure, a local area of the silicon phosphide composite 92 is irradiated with a laser, so that the phosphorus atoms in the silicon phosphide composite 92 in the local area irradiated with the laser diffuse to the light side of the silicon substrate 1 to form at least one first doped region 11 on the light side of the silicon substrate 1.

[0134] Specifically, a nanosecond green laser with a wavelength of 532nm can be used during the process of irradiating the local area of the silicon phosphide composite 92 with a laser, and the local area of the silicon phosphide composite 92 is irradiated with the laser. Under the action of the laser, the phosphorus atoms in the silicon phosphide composite 92 diffuse to the partial area on the light side of the silicon substrate 1. It should be noted that the shape of the local area corresponds to the pattern of the subsequent front gate line electrode.

[0135] Meanwhile, the phosphorus doping of the local area formed in this step has the following advantages compared with conventional tube type phosphorus diffusion: on the one hand, conventional tube type phosphorus diffusion is usually full-area diffusion, which takes at least about half an hour, while the phosphorus doping of the local area formed in this application basically only takes 10 minutes or less, and the time is significantly shortened; on the other hand, the laser irradiation in this step is only for the local area of the silicon substrate, and the total heating time is significantly shortened, so that the thermal stress of the silicon substrate is significantly reduced, and the occurrence of silicon substrate warping is reduced.

[0136] Figure 7 A fourth local structure of a solar cell in an embodiment of the application is shown. Referring to Figure 7 Optionally, after the two first doped regions 11 are formed, the method further includes: cleaning the silicon substrate on which at least one first doped region 11 is formed, to clean the residual solidified phosphorus source 91, silicon phosphide composite 92 and ultrathin silicon oxide film on the light side of the silicon substrate 1.

[0137] Optionally, cleaning the silicon substrate 1 includes: using hydrofluoric acid (HF) to remove the residual ultrathin silicon oxide film on the light-facing side of the silicon substrate 1, and then using a first mixed solution to etch the residual solidified phosphorus source and silicon phosphide composite on the light-facing side of the silicon substrate 1. The first mixed solution here includes: a mixed solution of hydrofluoric acid and nitric acid, and / or, a mixed solution of hydrofluoric acid and ozone. During the etching of the light-facing side of the silicon substrate 1 using the first mixed solution, a portion of the light-facing area of ​​the silicon substrate 1 is also appropriately etched away, thereby rounding the pyramids on the surface of the silicon substrate 1. This eliminates the need for separate rounding of the pyramids on the surface of the silicon substrate 1, reducing the number of process steps.

[0138] More specifically, after etching the light-facing side of the silicon substrate with the first mixed solution, the following steps can be performed in sequence: RCA cleaning, hydrofluoric acid cleaning, water washing, and drying.

[0139] Optionally, during the etching of the light-facing side of the silicon substrate 1 using the first mixed solution, the thickness of the etched silicon substrate 1 on the light-facing side is 20-150 nm, and the direction of this thickness is parallel to the stacking direction of the ultrathin silicon oxide film and the solidified phosphorus source. The thickness of the etched silicon substrate 1 on the light-facing side includes: residual solidified phosphorus source 91, residual silicon phosphide composite 92, possibly residual ultrathin silicon oxide film, and the silicon substrate itself. Within this range, the etched thickness of the silicon substrate 1 on the light-facing side not only thoroughly removes the residual solidified phosphorus source 91, residual silicon phosphide composite 92, and possibly residual ultrathin silicon oxide film, but also achieves a suitable degree of pyramidal rounding on the light-facing side of the silicon substrate 1.

[0140] Optionally, step S2 may include: forming a silicon oxide film by tubular thermal oxidation on the light-facing side of the silicon substrate 1, or depositing an aluminum oxide film, such as by ALD (atomic layer deposition), and depositing a silicon nitride film on the silicon oxide film or aluminum oxide film, such as by using PECVD (Plasma Enhanced Chemical Vapor Deposition). The above processes are simple and mature.

[0141] Figure 8 A partial structural schematic diagram of a fifth type of solar cell according to an embodiment of the present invention is shown. For example, refer to... Figure 8 As shown, a chemical passivation film 2 is deposited on the light-facing side of the silicon substrate 1. This chemical passivation film can be an aluminum oxide film. Figure 9 A partial structural schematic diagram of a sixth type of solar cell according to an embodiment of the present invention is shown. For example, refer to... Figure 9 As shown, a field passivation antireflection film 3 is formed on the chemical passivation film 2.

[0142] Figure 10 A partial structure diagram of a seventh solar cell in an embodiment of the present application is shown. Optionally, referring to Figure 10 As shown, the step S3 can include: slotting the chemical passivation film 2 and the field passivation anti-reflection film 3, so that the first doped region 11 is exposed.

[0143] Optionally, the slotting method can be laser slotting, which has a faster slotting rate. The laser slotting can use a picosecond ultraviolet laser or a picosecond green laser to irradiate a local area of the light side of the silicon substrate 1, so as to remove the field passivation anti-reflection film 3 in the local area of the light side of the silicon substrate 1 and the chemical passivation film 2 in the local area.

[0144] Figure 11 A partial structure diagram of an eighth solar cell in an embodiment of the present application is shown. Optionally, after the laser slotting and before the electroplating of the front grid electrode, the method can further include: cleaning at least one of the chemical passivation film, the field passivation anti-reflection film, and the silicon oxide produced due to the thermal effect in the slotting process remaining in the laser slotting area, and etching part of the first doped region using a second mixed solution, so as to remove the laser damage of the first doped region 11. The second mixed solution includes: a mixed solution of hydrofluoric acid and nitric acid, and / or a mixed solution of hydrofluoric acid and ozone.

[0145] For example, a small amount of at least one of the chemical passivation film, the field passivation anti-reflection film, and the silicon oxide produced due to the thermal effect in the slotting process remaining in the local slotting area of the picosecond laser can be washed away using an HF solution, and then a local heat treatment area of the picosecond laser is etched using a mixed solution of HF / HNO3 or HF / O3, so as to remove the laser damage in the area. Subsequently, RCA cleaning, HF cleaning, water washing, and drying are performed.

[0146] Optionally, the thickness of the part of the first doped region 11 etched is 20-80 nm, and the direction of the depth is parallel to the stacking direction of the chemical passivation film 2 and the field passivation anti-reflection film 3. The thickness of the part of the first doped region 11 etched in this range can not only completely remove the laser damage, but also reduce material waste.

[0147] Figure 12A partial structure diagram of a ninth solar cell in an embodiment of the present application is shown. After etching the laser-damaged part of the first doped region and cleaning, the intrinsic amorphous silicon film 5 and the doped amorphous silicon film 6 with a doping type different from that of the silicon substrate are formed in the back light side of the silicon substrate 1 in a stacked distribution. The intrinsic amorphous silicon film 5 and the doped amorphous silicon film 6 with a doping type different from that of the silicon substrate can be formed by PECVD (Plasma Enhanced Chemical Vapor Deposition) or hot wire CVD.

[0148] Figure 13 A partial structure diagram of a tenth solar cell in an embodiment of the present application is shown. As shown in Figure 13 The transparent conductive oxide film 7 is deposited on the doped amorphous silicon film 6. The transparent conductive oxide film (TCO) 7 can be deposited by PVD (Physical Vapor Deposition) or RPD. The back electrode 8 is formed on the transparent conductive oxide film 7. The back electrode 8 can be formed by electroplating, screen printing, laser transfer, etc.

[0149] Optionally, as shown in Figure 1 The nickel-copper-silver stacked gate line electrode is formed on the exposed first doped region 11 by electroplating. The back electrode of the nickel-copper-silver stacked electrode is formed on the transparent conductive oxide film 7 by electroplating. The contact between the electrode materials in the nickel-copper-silver stacked gate line electrode and the nickel-copper-silver stacked electrode is tight, so that the resistivity of the nickel-copper-silver stacked gate line electrode and the nickel-copper-silver stacked electrode is low, which can improve the electrical performance of the solar cell and is low in cost. Meanwhile, since the back electrode 8 is the nickel-copper-silver stacked electrode, the thickness of the transparent conductive oxide film can be further appropriately reduced, which can ensure that the electrical performance of the solar cell is not affected, and the reduction of the thickness of the transparent conductive oxide film can reduce the cost.

[0150] The present application further provides a production system of a solar cell, comprising:

[0151] The doping component is used for forming at least one first doped region in a partial region of the light-facing surface of the silicon substrate; the doping type of each of the first doped regions is the same as the doping type of the silicon substrate, and the doping concentration of each of the first doped regions is greater than the doping concentration of the silicon substrate.

[0152] The front surface film layer processing component is used for sequentially forming a chemically passivated film, a field passivated anti-reflection film in a stacked distribution on the light-facing side of the silicon substrate; the front surface gate line electrode setting component is used for forming at least one front surface gate line electrode on the light-facing side of the silicon substrate; the at least one front surface gate line electrode and the at least one first doped region are in contact with each other, which can also be referred to as: the at least one front surface gate line electrode and the at least one first doped region are in ohmic contact with each other.

[0153] Optionally, the solar cell production system can further include: a back surface structure setting component, used for sequentially forming an intrinsic amorphous silicon film, a doped amorphous silicon film with a doping type different from that of the silicon substrate, a transparent conductive oxide film, and a back surface electrode in a stacked distribution on the back light side of the silicon substrate.

[0154] Optionally, the doping component includes: a chain device 200, Figure 14 A structure schematic diagram of a chain device in an embodiment of the present application is shown. Referring to Figure 14 As shown in the figure, the chain device 200 includes: an ultraviolet ozone oxidation device 201, a liquid-phase phosphorus source tank body 202, an illumination drying device 203, a heat treatment device 204, a laser generating device 205, and a transmission device between adjacent devices, which are sequentially distributed.

[0155] The ultraviolet ozone oxidation device 201 is used for forming an ultrathin silicon oxide film on the light-facing surface of the silicon substrate through ultraviolet ozone oxidation.

[0156] The liquid-phase phosphorus source tank body 202 is used for infiltrating the liquid-phase phosphorus source into the light-facing surface of the silicon substrate on which the ultrathin silicon oxide film is formed, so that the surface of the ultrathin silicon oxide film has the liquid-phase phosphorus source.

[0157] The illumination drying device 203 is used for solidifying the liquid-phase phosphorus source on the surface of the ultrathin silicon oxide film to form a solidified phosphorus source.

[0158] The heat treatment device 204 is used for heat treating the solidified phosphorus source on the surface of the ultrathin silicon oxide film, so that the solidified phosphorus source and the ultrathin silicon oxide film form a silicon phosphide composite.

[0159] The laser generating device 205 is used for irradiating a local area of the silicon phosphide composite with laser light, so that the phosphorus atoms in the silicon phosphide composite in the local area irradiated with the laser light diffuse to the light-facing side of the silicon substrate to form at least one first doped region in the local area on the light-facing surface of the silicon substrate.

[0160] The transfer device is used to transfer the silicon substrate processed by the previous device to the adjacent subsequent device. This transfer device can also serve as an operating table for a certain device; however, this is not specifically limited in this embodiment of the invention. The transfer device can be a roller, a track, etc. During the transfer of the silicon substrate, the transfer device can come into contact with a localized area of ​​the silicon substrate to reduce contamination of the silicon substrate by metal on the transfer device. This chain-type equipment 200 achieves highly efficient and mass-producible formation of the first doped region.

[0161] Optionally, in this solar cell production system, the photo-drying device 203 includes parallel-arranged lamps. Specifically, when the silicon substrate is transported to the area directly beneath the parallel-arranged lamps, the transport of the silicon substrate stops for approximately 1-3 seconds. During this period, the parallel-arranged lamps are turned on to rapidly heat and dry the silicon substrate, causing the surface temperature of the silicon substrate to rise rapidly from room temperature to 60-150°C, thus solidifying the liquid phosphorus source on the surface of the silicon substrate.

[0162] Optionally, the heat treatment apparatus 204 includes parallel-arranged halogen lamps. When the silicon substrate is transported directly under the parallel-arranged halogen lamps, the transport of the silicon substrate is stopped. During the period of stopped transport, the parallel-arranged halogen lamps are turned on to heat-treat the solidified phosphorus source on the surface of the ultrathin silicon oxide film, so that the solidified phosphorus source and the ultrathin silicon oxide film form a silicon phosphide composite.

[0163] The invention will be further described below with reference to specific embodiments:

[0164] Example

[0165] The process steps for producing this solar cell can be carried out according to the following process flow: silicon substrate texturing and cleaning → liquid phase phosphorus source coating → heat treatment → laser local doping → back washing → chemical passivation thin film growth → field passivation antireflection film deposition → cleaning → doped amorphous silicon film, doped amorphous silicon film deposition → TCO deposition → electroplating electrode.

[0166] Specifically, refer to Figure 3 As shown, the silicon substrate 1 is texturized and cleaned, then referred to Figure 4 As shown, a chain-type device is used to transport the silicon substrate 1 to an ultraviolet ozone oxidation device 201, where ultraviolet ozone oxidation forms an ultrathin silicon dioxide on the light-facing surface of the silicon substrate 1. Next, the silicon substrate 1 is transported to a liquid phosphorus source tank 202, which contains an aqueous solution of phosphoric acid and an organic solvent dissolved in the aqueous solution of the phosphoric acid. In the liquid phosphorus source tank 202, only the surface where the ultrathin silicon dioxide film is formed is wetted with the liquid phosphorus source. Then, the silicon substrate 1 is transported to a photo-drying device 203 to solidify the liquid phosphorus source on the surface of the ultrathin silicon dioxide film, forming a solidified phosphorus source 91. Next, refer to... Figure 5The silicon substrate 1 is transported to the heat treatment device 204, and the solidified phosphorus source 91 on the surface of the ultra-thin silicon oxide film is heat treated, so that the solidified phosphorus source 91 and the ultra-thin silicon oxide film form a silicon phosphide composite 92. Next, refer to Figure 6 The silicon substrate 1 is transported to the laser generating device 205, and a local area of the silicon phosphide composite 92 is irradiated with laser light, so that the phosphorus atoms in the silicon phosphide composite 92 in the local area irradiated with laser light diffuse to the light side of the silicon substrate 1 to form at least one first doped region 11 in the local area of the light side of the silicon substrate 1. Next, refer to Figure 7 The silicon substrate on which at least one first doped region 11 is formed is cleaned to remove the solidified phosphorus source 91, the silicon phosphide composite 92, and the ultra-thin silicon oxide film remaining on the light side of the silicon substrate 1. Next, refer to Figure 8 The aluminum oxide chemical passivation film 2 is formed on the light side of the silicon substrate 1 by ALD. Next, refer to Figure 9 The field passivation anti-reflection film 3 is formed on the chemical passivation film 2 by PECVD. Next, refer to Figure 10 The chemical passivation film 2 and the field passivation anti-reflection film 3 are laser grooved to expose the first doped region 11. Next, refer to Figure 11 At least one of the chemical passivation film, the field passivation anti-reflection film, and the silicon oxide produced due to thermal effects during the grooving process is removed by cleaning, and part of the first doped region is etched using a second mixed solution to remove laser damage of the first doped region 11. During the cleaning process, the back side of the silicon substrate 1 can also be cleaned. Next, refer to Figure 12 The intrinsic amorphous silicon film 5 and the doped amorphous silicon film 6 having a doping type different from that of the silicon substrate are sequentially formed on the back side of the silicon substrate 1. Next, refer to Figure 13 The transparent conductive oxide film 7 is deposited on the doped amorphous silicon film 6. Finally, refer to Figure 1 The nickel-copper-silver laminated gate line electrode is electroplated on the exposed first doped region 11, and the back electrode 8 of the nickel-copper-silver laminated electrode is electroplated on the transparent conductive oxide film 7.

[0167] It should be noted that the above-mentioned solar cell, photovoltaic module, and method for producing a solar cell can be mutually referred to and achieve the same or similar beneficial effects. To avoid repetition, the relevant parts will not be described again.

[0168] Table 1 shows the measurement results of the experimental group and the control group of the embodiment of the present application

[0169] Item Resistivity ohm.cm Efficiency Other index Experimental group 1 1.81 x 10 -6 ]] 25.34％ Voc= 734 mV, Jsc= 41.1 mA / cm2, FF = 84.0% Experimental group 2 1.81 x 10 -6 ]]> 25.43％ Voc= 735 mV, Jsc= 41.1 mA / cm2, FF = 84.2% Experimental group 3 1.81 x 10 -6 ]]> 25.34％ Voc= 735 mV, Jsc= 41.0 mA / cm2, FF = 84.1% Control group 5.75 x 10 -6 ]]> 25.35％ Voc= 746 mV, Jsc= 39.9 mA / cm2, FF = 85.0%

[0170] Experimental group 1

[0171] Refer to Figure 1The solar cell shown has a phosphorus-doped silicon substrate 1 with a doping concentration of 2 × 10⁻⁶. 15 / cm 3 Doped region 11 is phosphorus-doped, and the highest doping concentration in doped region 11 is 2 × 10⁻⁶. 20 / cm 3 The depth of doped region 11 is 0.3 μm, chemical passivation film 2 is a silicon oxide (SiO2) film with a thickness of 3 nm, and field passivation antireflection film 3 is a silicon nitride (SiN) film with a thickness of 76 nm. x The refractive index of the field passivation antireflection film 3 is 2.13. The front grid electrode 4 is a nickel-copper-silver stacked grid electrode with a thickness of 9 μm, and the mass ratio of nickel, copper and silver in the front grid electrode 4 is 1:8:1. Figure 1 In the figure, d3 = 20 μm, d1 + d2 = 20 μm. The thickness of the transparent conductive oxide film 7 is 80 nm, and the back electrode 8 is a nickel-copper-silver multilayer electrode with a thickness of 9 μm, and the mass ratio of nickel, copper and silver in the back electrode 8 is 1:8:1.

[0172] Experimental group 2

[0173] Reference Figure 1 The solar cell shown has a phosphorus-doped silicon substrate 1 with a doping concentration of 2 × 10⁻⁶. 15 / cm 3 Doped region 11 is phosphorus-doped, and the highest doping concentration in doped region 11 is 5 × 10⁻⁶. 20 / cm 3 The depth of doped region 11 is 0.3 μm, chemical passivation film 2 is a silicon oxide (SiO2) film with a thickness of 5 nm, and field passivation antireflection film 3 is a silicon nitride (SiN) film with a thickness of 77 nm. x The refractive index of the field passivation antireflection film 3 is 2.13. The front grid electrode 4 is a nickel-copper-silver stacked grid electrode with a thickness of 9 μm, and the mass ratio of nickel, copper and silver in the front grid electrode 4 is 1:8:1. Figure 1 In the figure, d3 = 20 μm, d1 + d2 = 20 μm. The thickness of the transparent conductive oxide film 7 is 80 nm, and the back electrode 8 is a nickel-copper-silver multilayer electrode with a thickness of 9 μm, and the mass ratio of nickel, copper and silver in the back electrode 8 is 1:8:1.

[0174] Experimental group 3

[0175] Reference Figure 1 The solar cell shown has a phosphorus-doped silicon substrate 1 with a doping concentration of 2 × 10⁻⁶. 15 / cm 3, the doping region 11 is phosphorus-doped, the highest doping concentration of the doping region 11 is 4x10 20 / cm 3 , the depth of the doping region 11 is 0.3um, the chemical passivation film 2 is a silicon oxide (SiO2) film with a thickness of 5nm, the field passivation anti-reflection film 3 is a silicon nitride (SiN x : H) film with a thickness of 78nm, the refractive index of the field passivation anti-reflection film 3 is 2.11, and the front side grid electrode 4 is a nickel-copper-silver laminated grid electrode with a thickness of 9um, and the mass ratio of the nickel element, the copper element and the silver element in the front side grid electrode 4 is 1:8:1. Figure 1 , d1+d2=20um. The thickness of the transparent conductive oxide film 7 is 80nm, the back side electrode 8 is a nickel-copper-silver laminated electrode with a thickness of 9um, and the mass ratio of the nickel element, the copper element and the silver element in the back side electrode 8 is 1:8:1.

[0176] Control group

[0177] The solar cell of the control group is a conventional HJT solar cell, i.e., the structure thereof is: a silicon substrate, an intrinsic amorphous silicon film, a doped amorphous silicon film with the same doping type as the silicon substrate, a transparent conductive oxide film and a back side grid electrode which are sequentially laminated on the back light side of the silicon substrate, and an intrinsic amorphous silicon film, a doped amorphous silicon film with a different doping type from the silicon substrate, a transparent conductive oxide film and a front side grid electrode which are sequentially laminated on the light side of the silicon substrate. The materials of the front side grid electrode and the back side grid electrode are both low-temperature silver paste.

[0178] Table 1 is the results obtained by measuring the relevant data of 100 solar cells shown in the experimental group 1 according to the IEC (International Electro technical Commission) standard, respectively, and taking the average value, the results obtained by measuring the relevant data of 100 solar cells shown in the experimental group 2 according to the IEC standard, respectively, and taking the average value, the results obtained by measuring the relevant data of 100 solar cells shown in the experimental group 3 according to the IEC standard, respectively, and taking the average value, and the relevant data of the conventional HJT solar cell shown in the control group according to the IEC standard.

[0179] More specifically, the resistivity in Table 1 is: the result obtained by measuring the resistivity of the front side grid electrode 4 of 100 solar cells shown in Experimental Group 1 according to IEC standards, respectively, and taking the average; the result obtained by measuring the resistivity of the front side grid electrode 4 of 100 solar cells shown in Experimental Group 2 according to IEC standards, respectively, and taking the average; the result obtained by measuring the resistivity of the front side grid electrode 4 of 100 solar cells shown in Experimental Group 3 according to IEC standards, respectively, and taking the average; and the resistivity of the front side grid electrode of the conventional HJT solar cell shown in the control group, which is disclosed to be measured according to IEC standards.

[0180] More specifically, the efficiency in Table 1 is: the result obtained by measuring the photoelectric conversion efficiency of 100 solar cells shown in Experimental Group 1 according to IEC standards, respectively, and taking the average; the result obtained by measuring the photoelectric conversion efficiency of 100 solar cells shown in Experimental Group 2 according to IEC standards, respectively, and taking the average; the result obtained by measuring the photoelectric conversion efficiency of 100 solar cells shown in Experimental Group 3 according to IEC standards, respectively, and taking the average; and the photoelectric conversion efficiency of the conventional HJT solar cell shown in the control group, which is disclosed to be measured according to IEC standards.

[0181] More specifically, the Voc in Table 1 is: the result obtained by measuring the open circuit voltage of 100 solar cells shown in Experimental Group 1 according to IEC standards, respectively, and taking the average; the result obtained by measuring the open circuit voltage of 100 solar cells shown in Experimental Group 2 according to IEC standards, respectively, and taking the average; the result obtained by measuring the open circuit voltage of 100 solar cells shown in Experimental Group 3 according to IEC standards, respectively, and taking the average; and the open circuit voltage of the conventional HJT solar cell shown in the control group, which is disclosed to be measured according to IEC standards.

[0182] More specifically, the Jsc in Table 1 is: the result obtained by measuring the short circuit current of 100 solar cells shown in Experimental Group 1 according to IEC standards, respectively, and taking the average; the result obtained by measuring the short circuit current of 100 solar cells shown in Experimental Group 2 according to IEC standards, respectively, and taking the average; the result obtained by measuring the short circuit current of 100 solar cells shown in Experimental Group 3 according to IEC standards, respectively, and taking the average; and the short circuit current of the conventional HJT solar cell shown in the control group, which is disclosed to be measured according to IEC standards.

[0183] More specifically, FF in Table 1 is: the result obtained by measuring the fill factor of 100 solar cells shown in the experimental group 1 according to IEC standard respectively and taking the average value; the result obtained by measuring the fill factor of 100 solar cells shown in the experimental group 2 according to IEC standard respectively and taking the average value; the result obtained by measuring the fill factor of 100 solar cells shown in the experimental group 3 according to IEC standard respectively and taking the average value; and the fill factor of the conventional HJT solar cell shown in the control group disclosed according to IEC standard.

[0184] From the above table, it can be concluded that the resistivity of the front grid electrode of the experimental group provided by the application is significantly lower than that of the front grid electrode of the conventional HJT solar cell shown in the control group. The specific reason is that the front grid electrode 4 of the experimental group provided by the application is a nickel-copper-silver laminated grid electrode, and the contact between the electrode materials in the front grid electrode 4 is tight, so that the resistivity of the nickel-copper-silver laminated grid electrode is low. The resistivity of the front grid electrode 4 of the experimental group provided by the application is low, and the content of silver in the nickel-copper-silver laminated grid electrode is less, and the mass percentage is only about 10%, which is low in cost.

[0185] From the above table, it can be concluded that the photoelectric conversion efficiency, open circuit voltage, short circuit current and fill factor of the experimental group provided by the application are basically flat with the photoelectric conversion efficiency, open circuit voltage, short circuit current and fill factor of the conventional HJT solar cell, respectively. The approximate reason is: first, the above thickness of the silicon oxide film, SiN x : H film can play a good chemical passivation, such as hydrogen passivation, field passivation and antireflection, and basically can achieve the surface passivation ability of amorphous silicon, and the above thickness of the silicon oxide film, SiN x : H film is weak or basically no absorption to short wave and visible light of incident light, which can reduce the loss of short circuit current of solar cell; secondly, the first doped region 11 is locally distributed on the light side of the silicon substrate 1, and there is basically no Auger recombination at the position without the first doped region 11. The Auger recombination caused by the first doped region is relatively less, and the process matching is good, which can reduce the loss of short circuit current and open circuit voltage caused by Auger recombination; thirdly, the back electrode 8 is a full-area electrode layer, and the back electrode 8 itself has good lateral carrier collection ability, which can compensate for the reduced lateral conductivity of the transparent conductive oxide film 7 by the back electrode 8.

[0186] It should be noted that, for the method embodiments, the steps are described in a specific sequence for simplicity, but the skilled person should understand that the application is not limited to the sequence of the steps, and some steps can be performed in other sequences or at the same time according to the application. In addition, the skilled person should understand that the embodiments described in the specification are all preferred embodiments, and the steps involved are not necessarily essential to the application.

[0187] It should be noted that, in this document, the terms "comprise", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method, article or device. Without more limitations, the element defined by the statement "comprises a" does not exclude the presence of other identical elements in the process, method, article or device that includes the element.

[0188] From the above description of the embodiments, those skilled in the art can clearly understand that the above-mentioned method of the embodiments can be realized by means of software and necessary general hardware platform, of course, it can also be realized by hardware, but in many cases the former is a better embodiment. Based on such understanding, the technical solutions of the present application or the part that contributes to the prior art can be embodied in the form of software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a plurality of instructions for making a terminal (which can be a mobile phone, computer, server, air conditioner, or network device, etc.) execute the method described in each embodiment of the present application.

[0189] The embodiments of the present application are described above in combination with the drawings, but the present application is not limited to the above-mentioned specific embodiments, and the above-mentioned specific embodiments are only illustrative, not restrictive, and those skilled in the art can make many forms under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims.

Claims

1. A solar cell, characterized by, The solar cell comprises: a silicon substrate; at least one first doped region is located in a local region of the light-receiving surface of the silicon substrate; the doping type of each of the first doped regions and the doping type of the silicon substrate are the same, and the doping concentration of each of the first doped regions is greater than the doping concentration of the silicon substrate; the first doped region is located within 0.1-0.5 um from the light-receiving surface of the silicon substrate towards the interior of the silicon substrate; a chemical passivation film and a field passivation anti-reflection film are sequentially and layerwisely distributed on the light-receiving side of the silicon substrate and the first doped region; an intrinsic amorphous silicon film and a doped amorphous silicon film with a doping type different from that of the silicon substrate are sequentially and layerwisely distributed on the back side of the silicon substrate; at least one front-side gate line electrode is located on the light-receiving side of the silicon substrate; at least one of the front-side gate line electrodes and at least one of the first doped regions are in contact with each other.

2. The solar cell according to claim 1, characterized in that, The chemical passivation film comprises a silicon oxide film or an aluminum oxide film; and / or, the field passivation anti-reflection film comprises a silicon nitride film.

3. The solar cell according to claim 2, characterized in that, The solar cell further comprises an anti-reflection film located on the light-receiving side of the field passivation anti-reflection film.

4. The solar cell according to any one of claims 1 to 3, wherein The solar cell further comprises a transparent conductive oxide film and a back electrode which are sequentially and layerwisely distributed on the doped amorphous silicon film; the back electrode is a full-area electrode layer covering the transparent conductive oxide film, the thickness of the transparent conductive oxide film is 5-80 nm; the direction of the thickness of the transparent conductive oxide film is parallel to the layering direction of the chemical passivation film and the field passivation anti-reflection film.

5. The solar cell according to claim 4, characterized in that, the thickness of the full-area electrode layer is 1-10 um.

6. The solar cell according to any one of claims 1 to 3, wherein the front-side gate line electrode is a nickel-copper-silver laminated gate line electrode.

7. The solar cell according to claim 6, characterized in that, in the nickel-copper-silver laminated gate line electrode, the mass ratio of nickel element, copper element and silver element is (0.5-2.5):(5-9):(0.5-2.5).

8. The solar cell according to any one of claims 1-3, wherein: each of the front-side gate line electrodes and each of the first doped regions are in one-to-one correspondence and in contact with each other.

9. The solar cell of claim 8, wherein, the projection of each of the front-side gate line electrodes on the first doped region corresponding to the position in the first direction has a size equal to the size of the first doped region corresponding to the position in the first direction, and the projection of each of the front-side gate line electrodes on the first doped region corresponding to the position in the second direction has a size smaller than the size of the first doped region corresponding to the position in the second direction by 15-50 um; the first direction and the second direction are both parallel to the light-receiving surface of the silicon substrate, and the first direction and the second direction are perpendicular to each other; and / or, the height of each of the front-side gate line electrodes is 5-20 um; the direction of the height is parallel to the layering direction of the chemical passivation film and the field passivation anti-reflection film; and / or, the size of each of the front-side gate line electrodes in the second direction is 15-50 um.

10. The solar cell of claim 2, wherein, in the case where the chemical passivation film is a silicon oxide film, the thickness of the chemical passivation film is 0.5-5 nm; In the case where the chemical passivation film is an aluminum oxide film, the thickness of the chemical passivation film is 2-10 nm; the direction of the thickness is parallel to the stacking direction of the chemical passivation film and the field passivation anti-reflection film.

11. A photovoltaic module, characterized by The method comprises: The solar cell comprises:

12. A method for producing a solar cell, characterized by, The method comprises: forming at least one first doped region on a partial region of a light-receiving surface of a silicon substrate; the doped type of each of the first doped regions is the same as the doped type of the silicon substrate, and the doped concentration of each of the first doped regions is greater than the doped concentration of the silicon substrate; the first doped region is located within 0.1-0.5 um from the light-receiving surface of the silicon substrate to the inside of the silicon substrate; forming, on the light-receiving side of the silicon substrate, a chemical passivation film, a field passivation anti-reflection film, and a front surface passivation film in a stacked manner; forming, on the back light side of the silicon substrate, an intrinsic amorphous silicon film, a doped amorphous silicon film with a doped type different from that of the silicon substrate, and a back surface passivation film in a stacked manner; forming at least one front surface grid line electrode on the light-receiving side of the silicon substrate; at least one of the front surface grid line electrodes and at least one of the first doped regions are in contact with each other.

13. The method of producing a solar cell according to claim 12, wherein The method of forming at least one first doped region on a partial region of a light-receiving surface of a silicon substrate comprises: forming an ultrathin silicon oxide film on the light-receiving surface of the silicon substrate by ultraviolet ozone oxidation; infiltrating the light-receiving surface of the silicon substrate with an ultrathin silicon oxide film with a liquid-phase phosphorus source, so that the surface of the ultrathin silicon oxide film has a liquid-phase phosphorus source; solidifying the liquid-phase phosphorus source on the surface of the ultrathin silicon oxide film to form a solidified phosphorus source; heat-treating the solidified phosphorus source on the surface of the ultrathin silicon oxide film, so that the solidified phosphorus source and the ultrathin silicon oxide film form a silicon phosphide composite; irradiating a local region of the silicon phosphide composite with laser light, so that the phosphorus atoms in the silicon phosphide composite in the irradiated local region diffuse to the light-receiving side of the silicon substrate to form at least one first doped region on a partial region of the light-receiving surface of the silicon substrate.

14. A production system of a solar cell, characterized by, The method comprises: a doped component for forming at least one first doped region on a partial region of a light-receiving surface of a silicon substrate; the doped type of each of the first doped regions is the same as the doped type of the silicon substrate, and the doped concentration of each of the first doped regions is greater than the doped concentration of the silicon substrate; the first doped region is located within 0.1-0.5 um from the light-receiving surface of the silicon substrate to the inside of the silicon substrate; a front surface film layer processing component for forming, on the light-receiving side of the silicon substrate, a chemical passivation film, a field passivation anti-reflection film, and a front surface passivation film in a stacked manner; a back surface structure setting component for forming, on the back light side of the silicon substrate, an intrinsic amorphous silicon film, a doped amorphous silicon film with a doped type different from that of the silicon substrate, and a back surface passivation film in a stacked manner; a front surface grid line electrode setting component for forming at least one front surface grid line electrode on the light-receiving side of the silicon substrate; at least one of the front surface grid line electrodes and at least one of the first doped regions are in contact with each other.

15. The system for producing a solar cell according to claim 14, wherein The doping component comprises a chain device, which comprises, in sequence, an ultraviolet ozone oxidation device, a liquid-phase phosphorus source tank, an illumination drying device, a heat treatment device, a laser generating device, and a transmission device between adjacent devices. The ultraviolet ozone oxidation device is configured to form an ultrathin silicon oxide film on the light-receiving surface of the silicon substrate by ultraviolet ozone oxidation. The liquid-phase phosphorus source tank is configured to immerse the light-receiving surface of the silicon substrate on which the ultrathin silicon oxide film is formed in a liquid-phase phosphorus source, so that the surface of the ultrathin silicon oxide film has the liquid-phase phosphorus source. The illumination drying device is configured to solidify the liquid-phase phosphorus source on the surface of the ultrathin silicon oxide film, thereby forming a solidified phosphorus source. The heat treatment device is configured to heat treat the solidified phosphorus source on the surface of the ultrathin silicon oxide film, so that the solidified phosphorus source and the ultrathin silicon oxide film form a silicon phosphide composite. The laser generating device is configured to irradiate a local area of the silicon phosphide composite with laser light, so that phosphorus atoms in the silicon phosphide composite in the local area irradiated with the laser light diffuse to the light-receiving side of the silicon substrate, thereby forming at least one doped region in the local area of the light-receiving surface of the silicon substrate.

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