Ohmic contact structure and method of manufacturing the same, photovoltaic module

Abstract

The present disclosure provides an ohmic contact structure and a manufacturing method thereof, and a photovoltaic module. The method for manufacturing the ohmic contact structure comprises: forming a paste layer on one side of a pre-prepared semiconductor structure, wherein the material of the paste layer comprises a metal; and forming an emitter and a semiconductor structure in ohmic contact with the emitter by laser-induced metal contact on the paste layer and the pre-prepared semiconductor structure. The method has fewer process steps and lower manufacturing cost.

Description

Technical Field

[0001] This disclosure relates to the semiconductor field, and in particular to an ohmic contact structure and its manufacturing method, and photovoltaic modules. Background Technology

[0002] Faced with the gradual depletion of non-renewable energy sources and the increasingly serious global climate problem, establishing an energy system based on renewable energy to achieve green and sustainable development has become a consensus. Currently, the global penetration rate of renewable energy remains low, indicating significant room for improvement. Among the various types of renewable energy, solar energy, with its advantages of safety, reliability, wide distribution, and low cost, has become one of the most promising energy sources. Photovoltaic power generation, utilizing solar energy, is becoming increasingly advantageous; its current cost per kilowatt-hour is already lower than that of coal-fired power, and this trend is expected to continue, making the development potential of photovoltaic power generation considerable.

[0003] Compared to the currently mainstream passivated emitter-back contact (PERC) crystalline silicon solar cells, all-back contact (XBC) solar cells have significant advantages. The most notable feature of XBC cells is that both the emitter and metal contacts are located on the back of the cell, with no metal electrodes obstructing the front. This results in a higher short-circuit current density. Furthermore, the back side allows for wider metal grid lines to reduce series resistance and improve the fill factor. XBC solar cells can be combined with tunneling oxidation and heterojunction technologies.

[0004] In the back-side structure of XBC solar cells, the grid structure, which collects and transports charge carriers from the PN junction, is crucial. Current manufacturing processes for the grid lines include, for example, co-firing and electroplating. Co-firing requires high temperatures, resulting in high energy consumption, and the ohmic contact of the grid lines is generally poor. Electroplating, on the other hand, may introduce contamination from the plating solution. Summary of the Invention

[0005] In view of this, it is necessary to provide a method for manufacturing ohmic contact structures to address at least one of the above problems.

[0006] This disclosure also provides an ohmic contact structure that can solve at least one of the problems of reducing manufacturing costs, improving conduction performance, and ensuring structural reliability.

[0007] This disclosure provides a method for manufacturing an ohmic contact structure, the method comprising: forming a paste layer located on one side of a pre-fabricated semiconductor structure, wherein the material of the paste layer includes metal; and forming an emitter and a semiconductor structure in ohmic contact with the emitter by laser-induced metal contact between the paste layer and the pre-fabricated semiconductor structure.

[0008] This configuration allows for laser-induced metal contact of the paste layer, enabling the paste layer to be directly formed as an emitter in a single process, achieving excellent ohmic contact between the emitter and the semiconductor structure. This method involves fewer process steps and lower manufacturing costs. The ohmic contact structure manufactured using this method exhibits good reliability and excellent conductivity at the contact point.

[0009] In some embodiments, the pre-fabricated semiconductor structure includes a dielectric portion and a pre-fabricated composite substrate disposed sequentially from one side to the other, and the step of forming an emitter includes: forming an emitter penetrating the dielectric portion; the step of forming the semiconductor structure includes: forming a composite substrate in ohmic contact with the emitter.

[0010] With this configuration, the composite substrate is used to achieve ohmic contact with the emitter, and the first dielectric layer can provide richer interface properties, improving the overall performance of the ohmic contact structure.

[0011] In some embodiments, the pre-fabricated semiconductor structure includes a first block, the first block including a first dielectric portion, a tunneling layer and a first pre-fabricated semiconductor substrate disposed sequentially, wherein the step of forming a paste layer includes: forming a first paste layer; the step of forming an emitter includes: forming a first emitter that penetrates the first dielectric portion and is in ohmic contact with the tunneling layer.

[0012] This configuration facilitates the formation of a first emitter, which serves as an N-type emitter, at the tunneling layer, ensuring good contact between the first emitter and the tunneling layer.

[0013] In some embodiments, the step of forming the first emitter includes: performing a laser scan on the first slurry layer with a laser wavelength of 355 nm.

[0014] This configuration ensures ohmic contact between the first emitter and the semiconductor structure, and prevents the laser from etching through the tunneling layer.

[0015] In some implementations, in a laser scanning process with a laser wavelength of 355 nm, the output power is 5 W to 20 W, the single pulse energy is 5 μJ to 20 μJ, the pulse repetition frequency is 400 kHz to 1 MHz, the pulse width is less than or equal to 10 ns@1 MHz, and the scanning speed is 5000 mm / s to 7000 mm / s.

[0016] With this setup, the laser can penetrate the first dielectric layer while ensuring that the tunneling layer is not penetrated; at the same time, the slurry layer is well induced to solidify, and the emitter formed by the slurry layer can make firm and full contact with the tunneling layer.

[0017] In some implementations, in a laser scanning process with a laser wavelength of 355 nm, the pulse repetition frequency is from 750 kHz to 1 MHz.

[0018] This configuration further protects the tunneling layer and reduces damage to it during the laser-induced metal contact process, while also ensuring good conductivity of the emitter.

[0019] In some embodiments, the pre-fabricated semiconductor structure includes a second block, the second block including a second dielectric portion and a second pre-fabricated semiconductor substrate disposed sequentially, the method further including: forming an opening penetrating the second dielectric portion and exposing the second pre-fabricated semiconductor substrate; the step of forming a paste layer includes: forming a second paste layer located at the opening, wherein the material of the second paste layer includes a doped material; the step of forming an emitter includes: forming a second emitter penetrating the second dielectric portion; the step of forming a semiconductor structure includes: forming a region of the second pre-fabricated semiconductor substrate that contacts the second emitter as a doped region in ohmic contact with the second emitter.

[0020] With this configuration, the doped region can be formed using the doped material in the second slurry layer through the formation process of the second emitter. This method involves fewer steps and can achieve a doped region and a second emitter with good performance.

[0021] In some embodiments, the material of the second slurry layer includes silver, the doping material includes at least one of boron and aluminum, and the material of the preformed semiconductor substrate includes silicon.

[0022] This configuration allows for the formation of a P-type doped region and a P-type emitter.

[0023] In some embodiments, the step of forming the second emitter includes: performing a laser scan of the second slurry layer with a laser wavelength of 1064 nm.

[0024] This configuration allows for a robust and reliable ohmic contact between the emitter and the semiconductor structure, resulting in a good filling effect of the emitter on the microscopic gaps in the semiconductor structure and full curing of the emitter material. At the same time, the doping effect of the doped regions in the semiconductor structure is also good.

[0025] In some implementations, in the laser scanning process with a laser wavelength of 1064 nm, the output power is 50 W to 100 W, the single pulse energy is 5 mJ to 15 mJ, the pulse repetition frequency is 10 kHz to 20 kHz, the pulse width is less than or equal to 100 ns@10 kHz, and the scanning speed is 3500 mm / s to 5000 mm / s.

[0026] This configuration ensures the condition of the contact cross-section between the emitter and the semiconductor structure, reduces cross-sectional damage, and minimizes the accumulation of non-slurry layer material at the interface. Laser-induced metal contact using infrared lasers offers high processing speeds, thus this method also boasts high processing speeds.

[0027] In some embodiments, the step of forming the second emitter includes: performing a laser scan of the second slurry layer with a laser wavelength of 532 nm.

[0028] This configuration also enables a robust and reliable ohmic contact between the emitter and the semiconductor structure, resulting in a good filling effect of the emitter on the microscopic gaps in the semiconductor structure and full curing of the emitter material. At the same time, the doping effect of the doped regions in the semiconductor structure is also good.

[0029] In some embodiments, in a laser scanning process with a laser wavelength of 532 nm, the output power is 10 W to 50 W, the single pulse energy is 1 μJ to 50 μJ, the pulse repetition frequency is 5 kHz to 50 kHz, the pulse width is less than or equal to 10 ns@10 kHz, and the scanning speed is 3000 mm / s to 4500 mm / s.

[0030] This configuration ensures the condition of the contact cross-section between the emitter and the semiconductor structure, reduces cross-sectional damage, and minimizes the accumulation of non-slurry layer material at the interface. Ohmic contact structures formed using laser-induced metal contact technology with green lasers also exhibit excellent electrical performance.

[0031] In some embodiments, the step of forming the paste layer includes: forming a patterned paste layer by a printing process; and drying the patterned paste layer.

[0032] This setup allows for the rapid and accurate formation of patterned slurry layers and the drying of organic matter, reducing the impact on the contact surfaces of the emitter and semiconductor structure.

[0033] In some embodiments, the method further includes forming a pre-formed semiconductor, the step of forming the pre-formed semiconductor comprising: texturing one end of a pre-formed semiconductor substrate to form a first textured structure, wherein the pre-formed semiconductor substrate has a first region and a second region, and the first textured structure is located in the second region; forming a tunneling layer located in the first region; forming a first dielectric portion located on the side of the tunneling layer opposite to the pre-formed semiconductor substrate, and forming a second dielectric portion located in the first textured structure; texturing the other end of the pre-formed semiconductor substrate to form a second textured structure; and forming a dielectric layer located in the second textured structure.

[0034] The ohmic contact structure formed by the embodiments of this disclosure can be a solar cell structure, which utilizes the photovoltaic effect to generate an electromotive force, and the emitter can be either a positive or negative electrode. This solar cell structure integrates quantum tunneling technology and heterojunction technology, and has high conversion efficiency and performance.

[0035] This disclosure provides an ohmic contact structure, which includes: a semiconductor structure; and an emitter in ohmic contact with the semiconductor structure. The emitter is formed by a laser-induced metal contact process, and the material of the emitter includes metal.

[0036] This configuration results in a favorable contact interface morphology between the emitter and the semiconductor structure, leading to excellent emitter electrical performance. This ohmic contact structure offers low cost, good electrical performance, and reliable structural strength.

[0037] In some implementations, the emitter material comprises a subset of the materials used in semiconductor structures.

[0038] With this configuration, the emitter is different from emitters formed by alloy co-firing or electroplating.

[0039] In some embodiments, the semiconductor structure includes a first dielectric layer and a composite substrate disposed sequentially, with the emitter penetrating the first dielectric layer and in ohmic contact with the composite substrate.

[0040] With this configuration, the first dielectric layer helps improve the surface properties of the composite matrix, resulting in better overall performance of the ohmic contact structure.

[0041] In some embodiments, the composite matrix includes a tunneling layer, the emitter includes a first dielectric portion penetrating the first dielectric layer and in ohmic contact with the tunneling layer, and the material of the first emitter comprises the material of the first dielectric layer.

[0042] With this configuration, the ohmic contact structure can be used as a solar cell structure, the first emitter can be used as an N-type emitter, and the tunneling layer can ensure that the majority carriers in the semiconductor region tunnel through, reducing the recombination of minority carriers.

[0043] In some implementations, the first emitter is formed by a laser-induced metal contact process with a laser wavelength of 355 nm.

[0044] This configuration creates a first emitter with stable contact and good conductivity, and the tunneling layer in the ohmic contact structure has good shape and performance.

[0045] In some embodiments, the composite matrix includes a doped region, and the emitter includes a second dielectric portion that penetrates the first dielectric layer and is in ohmic contact with the doped region. The material of the second emitter includes the doped material of the doped region.

[0046] With this configuration, the second emitter differs from the emitter formed by alloy co-firing or electroplating, resulting in better performance and higher contact strength between the second emitter and the doped region.

[0047] In some embodiments, the material of the second emitter includes at least one of boron and aluminum, as well as silver.

[0048] With this configuration, the ohmic contact structure can be a solar cell structure, and the second emitter can be used as a P-type emitter.

[0049] In some embodiments, the second emitter is formed by a laser-induced metal contact process with a laser wavelength of 1064 nm or a laser-induced metal contact process with a laser wavelength of 532 nm.

[0050] With this configuration, the manufacturing cost of the ohmic contact structure is lower, the shape of the emitter is better, and the solidification morphology of the material inside the emitter is better.

[0051] In some embodiments, the semiconductor structure includes a second dielectric layer located on the side of the composite substrate opposite to the first dielectric layer, and the composite substrate includes a first textured structure corresponding to the first dielectric layer and a second textured structure corresponding to the second dielectric layer.

[0052] With this configuration, the ohmic contact structure can serve as a solar cell structure with a high fill factor. The textured surface helps improve light-gathering efficiency, and the dielectric layers contribute to enhancing the surface properties of the composite matrix.

[0053] This disclosure also provides a photovoltaic module, which includes: a power transmission line; and the aforementioned ohmic contact structure connected in series with the power transmission line to supply power to the power transmission line when it is irradiated by light.

[0054] This photovoltaic module has high output power and output efficiency. Attached Figure Description

[0055] Figure 1 This is a schematic flowchart of a method for manufacturing an ohmic contact structure according to an embodiment of the present disclosure;

[0056] Figure 2 This is a schematic diagram of the prefabricated semiconductor structure in the embodiments of this disclosure;

[0057] Figure 3 This is a schematic diagram of the prefabricated semiconductor structure after slotting in the embodiments of this disclosure;

[0058] Figure 4 This is a schematic top view of the prefabricated semiconductor structure in the embodiments of this disclosure;

[0059] Figure 5 This is a schematic diagram of the prefabricated semiconductor structure after the pads are formed in the embodiments of this disclosure;

[0060] Figure 6 This is a schematic diagram of the pre-fabricated semiconductor structure after the formation of the first slurry layer in the embodiments of this disclosure;

[0061] Figure 7 This is a schematic diagram of the ohmic contact structure in the embodiments of this disclosure;

[0062] Figure 8This is a schematic diagram of the ohmic contact structure after the formation of the second slurry layer in the embodiments of this disclosure;

[0063] Figure 9 This is a schematic diagram of another ohmic contact structure in the embodiments of this disclosure;

[0064] Figure 10 This is a schematic diagram of the working state of the laser scanning device in the embodiments of this disclosure;

[0065] Figure 11 Performance chart for laser pulse repetition frequency;

[0066] Figure 12 An image of the bottom of a trench formed by laser scanning;

[0067] Figure 13 An image of the trench bottom formed by another type of laser scanning;

[0068] Figure 14 An image of the trench bottom formed by another type of laser scanning;

[0069] Figure 15 A performance graph of laser pulse energy density;

[0070] Figure 16 Performance chart for laser scanning speed;

[0071] Figure 17 Images of other trench bottoms formed by a laser scan

[0072] Figure 18 Images of other trench bottoms formed by another type of laser scanning;

[0073] Figure 19 Images of ohmic contact structures provided for embodiments of this disclosure;

[0074] Figure 20 An image of damage caused to the emitter by a laser;

[0075] Figure 21 Image of damage to the emitter caused by another type of laser.

[0076] Figure 22 This is an image of damage to the emitter caused by another type of laser.

[0077] Reference numerals: 1. Pre-fabricated semiconductor substrate; 11. First block; 12. Second block; 10. Semiconductor substrate; 100. Ohmic contact structure; 101. First textured structure; 102. Second textured structure; 103. Doped region; 104. Semiconductor region; 2. Second dielectric layer; 3. Tunneling layer; 4. First dielectric layer; 41. First dielectric portion; 42. Second dielectric portion; 421. Opening; 5. Pad; 60. First paste layer; 6. First emitter; 70. Second paste layer; 7. Second emitter; 20. Laser scanning equipment; 21. Laser; 22. Optical device. Detailed Implementation

[0078] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this disclosure.

[0079] It should be noted that when a component is said to be "installed on" another component, it can be directly on the other component or it may be in a component that is centered on it. When a component is said to be "set on" another component, it can be directly set on the other component or it may also be in a component that is centered on it. When a component is said to be "fixed to" another component, it can be directly fixed to the other component or it may also be in a component that is centered on it.

[0080] The structural dimensions shown in the accompanying drawings in this article do not represent actual dimensions and may be adjusted as needed during actual production. The directional terms "up," "down," "left," and "right" used in this article refer to the orientation shown in the drawings and should not be considered as limitations on the actual use of the product unless explicitly stated otherwise.

[0081] The terms "first," "second," "third," etc., used in this article are only used to distinguish the same features. Understandably, the first slurry layer in this article can also be called the second slurry layer, and the second slurry layer can also be called the first slurry layer.

[0082] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0083] like Figure 1As shown, this disclosure provides a method 1000 for manufacturing an ohmic contact structure, the method 1000 including the following steps.

[0084] Step S101: Forming a first paste layer. Specifically, the first paste layer is formed on one side of the pre-fabricated semiconductor structure. The material of the first paste layer includes metals, such as silver, copper, or gold.

[0085] In step S102, a first emitter is formed and a semiconductor structure is formed by laser-induced metal contact between the first slurry layer and the prefabricated semiconductor structure. The first emitter and the semiconductor structure are in ohmic contact. The first emitter, containing metal, forms an ohmic contact structure with the semiconductor structure containing semiconductor material. This first emitter can also be referred to as a second emitter. Exemplarily, after the laser irradiates the slurry layer, it can heat the slurry layer and penetrate through the slurry layer to affect the prefabricated semiconductor structure. The slurry layer is cured under the induction of the laser. The steps of forming the emitter and forming the semiconductor structure can be performed simultaneously. During the formation of the emitter, the emitter contacts and is fixed to the semiconductor structure.

[0086] For example, the ohmic contact structure to be formed includes two types of emitters, at least one of which is formed by a laser-induced metal contact process.

[0087] In an exemplary embodiment, the method 1000 further includes: step S103, forming a second paste layer; and step S104, performing laser-induced metal contact to form a second emitter. The second paste layer may be located on one side of the pre-fabricated semiconductor structure. In other embodiments, it may also be located on the other side to form an emitter on the other side.

[0088] This disclosure provides an ohmic contact structure that can be manufactured by the aforementioned method 1000 for manufacturing ohmic contact structures. This ohmic contact structure can be at least a part of a solar cell structure having a high fill factor and low series resistance. This ohmic contact structure can also be used for other applications, corresponding to the design and construction of prefabricated semiconductor structures.

[0089] The following is based on Figures 2 to 9 The present disclosure describes in detail a method for manufacturing an ohmic contact structure according to embodiments thereof.

[0090] Figure 2 A prefabricated semiconductor structure is shown. In an exemplary embodiment, the method includes forming... Figure 2 The prefabricated semiconductor structure shown. Formation Figure 2The steps of the illustrated pre-formed semiconductor structure include: texturing the upper end of the pre-formed semiconductor substrate 1 to form a first textured structure 101, wherein the pre-formed semiconductor substrate 1 has a first region A and a second region B, and the first textured structure 101 corresponds to the second region B; forming a tunneling layer 3 on the upper side of the pre-formed semiconductor substrate 1, the tunneling layer 3 being located in the first region A; and forming a first dielectric layer 4 located in the second region B and on the side of the tunneling layer 3 facing away from the pre-formed semiconductor substrate 1. Specifically, the step of forming the first dielectric layer 4 may include: forming a first dielectric portion 41 located on the side of the tunneling layer 3 facing away from the pre-formed semiconductor substrate 1, and forming a second dielectric portion 42 located in the first textured structure 101. For example, forming... Figure 2 The steps of the pre-formed semiconductor structure shown further include: texturing the lower end of the pre-formed semiconductor substrate 1 to form a second textured structure 102; and forming a second dielectric layer 2 located on the second textured structure 102. This disclosure does not limit the order of processes at both ends of the pre-formed semiconductor substrate 1. The formation processes of each functional layer of the pre-formed semiconductor structure may include processes such as physical vapor deposition and chemical vapor deposition.

[0091] like Figure 2 As shown, the pre-fabricated semiconductor structure may include a pre-fabricated semiconductor substrate 1, a tunneling layer 3, a first dielectric layer 4, and a second dielectric layer 2. The pre-fabricated semiconductor substrate 1 and the tunneling layer 3 can be used to form a pre-fabricated composite substrate. The first dielectric layer 4, the pre-fabricated composite substrate, and the second dielectric layer 2 can be sequentially arranged along the Z-axis. The thickness direction of the pre-fabricated semiconductor structure can be along the Z-axis, as shown in the reference diagram. Figure 2 The top of the prefabricated semiconductor structure can be the back side, and the bottom can be the front side.

[0092] Exemplarily, the pre-fabricated semiconductor structure further includes an interface passivation layer (not shown) located between the pre-fabricated semiconductor substrate 1 and the tunneling layer 3. Exemplarily, the first dielectric layer 4 and the second dielectric layer 2 are composite layers. The first dielectric layer 4 includes an interface passivation layer and a reflective layer, the interface passivation layer being located between the reflective layer and the pre-fabricated composite substrate. The reflective layer is adapted to reflect light transmitted from the pre-fabricated composite substrate back to the pre-fabricated composite substrate. The second dielectric layer 2 may include an interface passivation layer and an anti-reflection dielectric layer, the interface passivation layer being located between the anti-reflection dielectric layer and the pre-fabricated semiconductor substrate 1. The anti-reflection dielectric layer can increase the transmittance of light incident on the pre-fabricated semiconductor substrate 1.

[0093] In, for example, the X-axis direction, the tunneling layer 3 does not completely cover the pre-fabricated semiconductor substrate 1. The first region A may correspond to the tunneling layer 3, and the second region B may correspond to the first textured structure 101 that is not covered by the tunneling layer 3. The first dielectric layer 4 may include a first dielectric portion 41 located at the tunneling layer 3 and a second dielectric portion 42 located outside the tunneling layer 3.

[0094] On the other hand, it can Figure 2The pre-fabricated semiconductor structure shown is considered to include multiple blocks, such as a first block 11 and a second block 12 arranged side-by-side along the X direction. The first block 11 includes a first dielectric portion 41, a tunneling layer 3, a first pre-fabricated semiconductor substrate (i.e., a portion of the pre-fabricated semiconductor substrate 1), and a first portion of the second dielectric layer 2, arranged sequentially from one side to the other. The second block 12 includes a second dielectric portion 42, a second pre-fabricated semiconductor substrate (i.e., another portion of the pre-fabricated semiconductor substrate 1), and a second portion of the second dielectric layer 2, arranged sequentially from one side to the other.

[0095] Exemplarily, the method further includes: forming an opening 421 through the first dielectric layer 4 and exposing the pre-fabricated semiconductor substrate 1, thereby obtaining... Figure 3 The pre-fabricated semiconductor structure is shown. Exemplarily, opening 421 is located in the second region B, i.e., opening 421 penetrates the second dielectric portion 42. The first textured structure 101 of the pre-fabricated semiconductor substrate 1 may be exposed, and the second dielectric portion 42 may not be completely removed.

[0096] In an exemplary embodiment, the step of forming opening 421 may include laser grooving. Exemplarily, the laser used in the laser grooving process has the following process parameters: laser wavelength 532 nm, spot diameter approximately 35 μm, frequency approximately 450 kHz, laser power 85%, and table power approximately 35 W.

[0097] Figure 4 A schematic top view of the prefabricated semiconductor structure is shown. Figure 3 The pre-fabricated semiconductor structure shown can be Figure 4 This is a portion of the prefabricated semiconductor structure shown. Opening 421 can extend along the Y-axis. First region A and second region B can be alternately arranged along the X-axis.

[0098] In an exemplary embodiment, the method includes the step of forming pads. Specifically, an electrode layer may first be printed, the electrode layer weighing between 20 mg and 80 mg, and the material comprising metal; the electrode layer is then dried to form... Figure 5 The pad 5 in the prefabricated semiconductor structure shown can be dried using a drying oven at a temperature of 350°C for 60 seconds. This drying process removes organic matter from the electrode layer. The pad 5 is suitable for electrical connection to the emitter to be formed and for electrical connection to external devices.

[0099] For example, the step of forming a slurry layer includes: forming a patterned first slurry layer, and then drying the patterned first slurry layer to obtain, as shown in the example. Figure 6The first paste layer 60 in the prefabricated semiconductor structure shown can be patterned by screen printing, with a printing weight ranging from 40 mg to 100 mg. A drying process can be performed using a drying oven at a temperature between 300°C and 450°C for 60 seconds. Figure 6 As shown, the first slurry layer 60 is located on the side of the first dielectric layer 4 opposite to the prefabricated composite substrate and is located in the first region A. The material of the first slurry layer 60 may include silver.

[0100] In an exemplary embodiment, the method includes: forming a first emitter 6 that penetrates the first dielectric layer 4 and is in ohmic contact with the tunneling layer 3, and subsequently forming a... Figure 7 The ohmic contact structure is shown. Exemplarily, the step of forming the first emitter 6 includes: performing a laser scan of the first slurry layer 60 with a laser wavelength of 355 nm. During the laser scan, the first dielectric portion 41 of the first dielectric layer 4 is etched and subsequently etched through, the first slurry layer 60 contacts the tunneling layer 3 and solidifies under laser induction, forming an ohmic contact with the tunneling layer 3 during the solidification process. A portion of the etched material of the first dielectric layer 4 can become part of the first emitter 6 and be embedded in the metal structure of the first emitter 6.

[0101] For example, in the laser-induced metal contact process, a laser with a wavelength of 355 nm is used. The output power of the laser is 5 W to 20 W, such as 8 W, 10 W, 15 W, or 18 W. The single pulse energy of the laser is 5 μJ to 20 μJ, such as 8 μJ, 12 μJ, 15 μJ, or 17 μJ. The pulse repetition frequency of the laser is 400 kHz to 1 MHz, such as 500 kHz, 600 kHz, 700 kHz, 800 kHz, or 900 kHz. For example, the pulse repetition frequency is 750 kHz to 1 MHz. The pulse width of the laser is less than or equal to 10 ns@1 MHz, such as 1 ns@1 MHz, 3 ns@1 MHz, 5 ns@1 MHz, or 7 ns@1 MHz. The scanning speed of the laser is 5000 mm / s to 7000 mm / s, such as 5500 mm / s. This ultraviolet laser has a short wavelength and concentrated energy, and in particular, it has the characteristic of "cold processing," meaning it can directly break the chemical bonds of the connecting materials without generating heating on the surroundings. The laser with a wavelength of 355nm can control the penetration of the metallic material contained in the first slurry layer 60 into the first dielectric section 41 and then into the tunneling layer 3.

[0102] like Figure 7 As shown, the ohmic contact structure includes a semiconductor structure and a first emitter 6. In some embodiments, the structure corresponding to a first region A can be considered as an ohmic contact structure, and thus can be considered as... Figure 7The diagram illustrates two ohmic contact structures. Exemplarily, the semiconductor structure includes a first dielectric portion 41 and a composite substrate sequentially disposed along the Z-axis from one side to the other. A first emitter 6 penetrates the first dielectric portion 41 and makes ohmic contact with the composite substrate. The composite substrate includes a tunneling layer 3 and a first semiconductor substrate sequentially disposed along the Z-axis from one side to the other. The first semiconductor substrate can be an N-type region, and the tunneling layer 3 makes ohmic contact with the first emitter 6.

[0103] In some comparative examples, the first emitter, the second emitter, and the P-type doped region in contact with the second emitter can all be formed using existing techniques. Exemplarily, the ohmic contact structure provided in this disclosure is used as a solar cell structure, wherein only the first emitter 6 (N-type emitter) is formed using a laser-induced metal contact process. Compared to the solar cell structures provided in these comparative examples, the ohmic contact structure provided in this embodiment exhibits: an increase in open-circuit voltage (Voc) of 0.0008V, a decrease in short-circuit current (Isc) of 0.007A, an increase in fill factor (FF) of 0.20%, and an improvement in overall cell conversion efficiency (NCell) of 0.08%.

[0104] For example, in Figure 7 Based on the ohmic contact structure shown, the method for manufacturing an ohmic contact structure provided in this disclosure may include: forming a second paste layer located on one side of a pre-fabricated semiconductor structure, the material of the paste layer including metal; and performing laser-induced metal contact between the second paste layer and the pre-fabricated semiconductor structure to form a second emitter and form a semiconductor structure in ohmic contact with the second emitter.

[0105] The preceding process has already formed an opening 421 that penetrates the second dielectric portion 42 and exposes the pre-formed semiconductor substrate 1. Subsequently, a patterned second paste layer can be formed located at the opening 421, and then a drying process is performed to form the second paste layer 70, thus obtaining the desired result. Figure 8 The ohmic contact structure is shown. Exemplarily, the material of the second paste layer 70 includes silver and a doped material. The doped material includes at least one of boron and aluminum. The material of the pre-fabricated semiconductor substrate 1 may include silicon. The patterned second paste layer can be formed by screen printing, with a printing weight in the range of 100 mg to 300 mg, and the patterned second paste layer is located on top of the pre-fabricated semiconductor structure. A drying process can be used to dry organic materials. Specifically, the drying process can be performed using a drying oven, with a drying temperature in the range of 300°C to 500°C, for 60 seconds.

[0106] Exemplarily, an emitter is formed that penetrates the first dielectric layer 4 and is in ohmic contact with the composite substrate. Exemplarily, the step of forming the emitter includes: forming a second emitter 7 that penetrates the first dielectric layer 4, specifically, the second emitter 7 penetrates the second dielectric portion 42; the step of forming the semiconductor structure includes: forming a doped region 103 in the region of the pre-fabricated semiconductor substrate 1 that contacts the second emitter 7. Figure 9 As shown, the doped region 103 is in ohmic contact with the second emitter 7. Other portions of the pre-fabricated semiconductor substrate 1 may be semiconductor regions 104, and subsequently, the doped region 103 and semiconductor regions 104 may be used to form the semiconductor substrate 10. The doped region 103 may be a P-type region, and the semiconductor region 104 may be an N-type region.

[0107] In an exemplary embodiment, the step of forming the second emitter 7 includes: performing a laser scan on the second slurry layer 70 with a laser wavelength of 1064 nm.

[0108] For example, in the laser-induced metal contact process, a laser with a wavelength of 1064 nm is used, and the output power of the laser is 50 W to 100 W, such as 60 W, 70 W, 80 W, or 90 W. The single pulse energy of the laser is 5 mJ to 15 mJ, such as 8 mJ, 10 mJ, or 13 mJ. The pulse repetition frequency of the laser is 10 kHz to 20 kHz, such as 12 kHz, 14 kHz, 16 kHz, or 18 kHz. The pulse width of the laser is less than or equal to 100 ns@10 kHz, such as 1 ns@10 kHz, 10 ns@10 kHz, or 50 ns@10 kHz. The scanning speed of the laser is 3500 mm / s to 5000 mm / s, such as 4000 mm / s.

[0109] In an exemplary embodiment, the step of forming the second emitter 7 includes: performing a laser scan of the second slurry layer 70 with a laser wavelength of 532 nm. The focusing temperature of the laser generated by an infrared laser with a laser wavelength of 1064 nm or a green laser with a laser wavelength of 532 nm can reach 700°C to 1100°C. By setting the aforementioned laser parameters in this embodiment, a high-performance ohmic contact structure can be manufactured.

[0110] During the laser scanning process, the metal material in the second slurry layer 70 is doped into the pre-fabricated semiconductor substrate 1 to form a doped region 103. At the same time, the second slurry layer 70 absorbs the energy of the laser and is subsequently induced to solidify.

[0111] For example, in the laser-induced metal contact process, a laser with a wavelength of 532 nm is used, and the output power of the laser is 10W to 50W, such as 20W, 30W, or 40W. The single pulse energy of the laser is 1μJ to 50μJ, such as 5μJ, 10μJ, or 25μJ. The pulse repetition frequency of the laser is 5kHz to 50kHz, such as 15kHz, 25kHz, or 35kHz. The pulse width of the laser is less than or equal to 10ns@10kHz, such as 1ns@10kHz or 5ns@10kHz. The scanning speed of the laser is 3000mm / s to 4500mm / s, such as 3500mm / s or 4000mm / s. The laser scanning method provided by the embodiments of this disclosure can effectively overcome the influence of aluminum absorption and reflection of laser light on the processing when the slurry layer contains aluminum, thus achieving good contact between the emitter and the semiconductor structure.

[0112] In the method for manufacturing ohmic contact structures provided in this disclosure, conveyor belts can be used to transfer prefabricated semiconductor structures or ohmic contact structures between adjacent workstations, and the process can be carried out step-by-step using assembly line equipment. For example, after manufacturing the ohmic contact structure, it can be transported to the testing and screening process using a conveyor belt.

[0113] In other embodiments, the first emitter can be formed by existing methods, such as alloy co-firing or electroplating, while the second emitter 7 is formed using a laser-induced metal contact process. Compared to the solar cell structures provided in these comparative examples, the ohmic contact structure provided by this embodiment exhibits: an increase of 0.0012V in open-circuit voltage (Voc), a decrease of 0.020A in short-circuit current (Isc), an increase of 0.13% in fill factor (FF), and an improvement of 0.05% in overall cell conversion efficiency (NCell).

[0114] For example, in the ohmic contact structure provided in this embodiment, both the first emitter 6 and the second emitter 7 are formed by a laser-induced metal contact process. Compared with the solar cell structures provided in these comparative examples, the ohmic contact structure provided in this embodiment has the following advantages: an increase in open-circuit voltage (Voc) of 0.0028V, a decrease in short-circuit current (Isc) of 0.006A, an increase in fill factor (FF) of 0.38%, and an improvement in overall cell conversion efficiency (NCell) of 0.20%.

[0115] In summary, refer to Figure 9 This disclosure provides an ohmic contact structure 100, which includes a semiconductor structure and an emitter (6-7). The emitter is in ohmic contact with the semiconductor structure and is formed by a laser-induced metal contact process.

[0116] The emitter material includes metals, such as silver. Exemplarily, the emitter material may comprise a subset of the materials used in semiconductor structures.

[0117] The semiconductor structure includes a first dielectric layer 4, a tunneling layer 3, and a semiconductor substrate 10 arranged sequentially. The tunneling layer 3 and the semiconductor substrate 10 can be considered as constituting a composite substrate. The projection of the tunneling layer 3 along the Z-axis does not completely cover the semiconductor substrate 10; therefore, for the second region B, the semiconductor structure can also be considered to include the first dielectric layer 4 and the semiconductor substrate 10 arranged sequentially. In other words, the semiconductor structure includes the first dielectric layer 4 and the composite substrate arranged sequentially. It should be noted that the concept of "layer" used herein does not specifically refer to a planar layer; even the semiconductor substrate 10 in the embodiments of this disclosure may still be curved or flexible, and therefore should be understood as a structure with a certain thickness that extends along an arbitrarily set extension direction.

[0118] The emitter includes a first emitter 6 and a second emitter 7. The first emitter 6 penetrates the first dielectric portion 41 of the first dielectric layer 4 and is in ohmic contact with the tunneling layer 3. The material of the first emitter 6 may contain the material of the first dielectric layer 4. The second emitter 7 penetrates the second dielectric portion 42 of the first dielectric layer 4 and is in ohmic contact with the doped region 103. The material of the second emitter 7 contains the doped material of the doped region 103.

[0119] The ohmic contact structure provided in this disclosure can be manufactured by the aforementioned method, and has the advantages of low manufacturing cost, good conduction effect and high structural reliability.

[0120] The ohmic contact structure provided in this disclosure can be used for solar power generation. For example... Figure 9 As shown, the bottom of the ohmic contact structure is the front, and the top is the back. In use, the front can be facing the light source so that ambient light shines on it. Ambient light passes through the second dielectric layer 2 and enters the semiconductor substrate 10, thereby exciting carrier migration between the doped region 103 and the semiconductor region 104. A potential difference exists between the doped region 103 and the semiconductor region 104. The first emitter 6 can be externally connected as the negative electrode, the tunneling layer 3 ensures quantum tunneling of electrons, and the second emitter 7 can be externally connected as the positive electrode.

[0121] The ohmic contact structure can be made using Figure 10 The laser scanning device 20 shown is manufactured.

[0122] The laser scanning device 20 may include a laser 21 and an optical device 22. The laser 21 generates and emits laser light. The optical device 22 is used to adjust the optical path of the laser and transmit the scanning laser L required for processing; it may include optical path deflection elements and focusing elements. The scanning laser L is used to realize the laser-induced metal contact process, which can penetrate the paste layer and affect the pre-fabricated semiconductor structure. After being scanned and irradiated by the scanning laser L, the pre-fabricated semiconductor structure and the paste layer are formed into a semiconductor structure and an emitter. The scanning irradiation process of the scanning laser L allows for a certain amount of material exchange between the pre-fabricated semiconductor structure and the paste layer. Specifically, according to… Figures 11 to 22 Detailed description.

[0123] Figure 11 This shows the relationship between the laser grooving depth and grooving width and the laser pulse repetition frequency when no slurry layer is applied. The laser satisfies: ΔE = 114 × 10⁻⁶. 3 J / m 2 V = 20 mm / s, where V is the scanning speed and ΔE is the pulse energy density. The one-dimensional surface morphology curve of the sample was measured using a Talysurf 5-120 surface profilometer in the direction perpendicular to the groove, thus obtaining the groove depth. Figure 11 This reflects the performance of the laser pulse repetition frequency, with the left data axis representing depth and width, and the right data axis representing frequency. Specifically, when the pulse repetition frequency increases from 1kHz to 2kHz, the groove depth increases significantly; when the pulse repetition frequency is in the range of 3–6kHz, the groove depth decreases with increasing frequency; when the pulse repetition frequency is in the ranges of 2–3kHz and 6–10kHz, the groove depth does not change significantly. The pulse repetition frequency has no significant effect on the groove width.

[0124] Figure 12 The image shows a scanning electron microscope (SEM) image of the bottom of a groove when the laser pulse repetition frequency is 1 kHz. Figure 13 The image shows a photograph of the bottom of the groove when the laser pulse repetition frequency is 2 kHz. Figure 14 This image shows the bottom of the groove when the laser pulse repetition frequency is 6 kHz. The width and internal condition of the groove can be observed and measured using a CSM950 scanning electron microscope. Figure 13As shown, when the pulse repetition frequency is 2kHz, there is a significant amount of deposit inside the groove, formed by the resolidification of molten or vaporized material. These deposits absorb laser energy during scanning, thus slowing down the further deepening of the groove. Therefore, when there is a large amount of deposit, the groove depth does not change significantly with the pulse repetition frequency. As the pulse repetition frequency increases, the material cannot vaporize in large quantities due to the decrease in pulse peak power, so the change in groove depth is also small. However, the increase in the average laser output power also increases the thermal impact on the material. Figure 14 It can be seen that when the pulse repetition frequency is high, obvious cracks have already formed inside the slot.

[0125] Figure 15 This diagram illustrates the relationship between laser grooving depth and width and laser pulse energy density when no slurry layer is applied. The left data axis represents the width and depth, and the right data axis represents the pulse energy density. The laser satisfies: F = 1 kHz, V = 20 mm / s, where F is the pulse repetition frequency. Figure 15 As shown, both the depth and width of the grooves increase with increasing pulse energy density. This is because the energy absorbed by the material per unit time increases with increasing pulse energy density. Figure 15 It can be seen that the groove depth does not change significantly when the pulse energy density is high. This is because although the amount of material vaporization increases with increasing pulse energy density, the vaporized material absorbs some laser energy, may shield the laser, and the laser penetration depth is much smaller than the lateral heating dimension. Therefore, the change in groove width is more significant than the change in depth. At higher pulse energy densities, the groove depth remains essentially unchanged with pulse energy density. In the laser scanning process provided in this embodiment, the pulse energy density is not set to a very high value. Increasing the pulse energy density not only fails to increase the groove depth but also increases the groove width and the thermal effect of the laser on the material, thereby reducing material utilization.

[0126] Figure 16 This diagram illustrates the relationship between laser groove depth and groove width and laser scanning speed without a slurry layer. The left data axis represents the width and depth, and the right data axis represents the scanning speed. The laser satisfies: F = 1 kHz, ΔE = 114 × 10⁻⁶. 3 J / cm 2 .like Figure 16 As shown, the groove depth decreases with increasing scanning speed. This is because the interaction time between the laser and the material shortens with increasing scanning speed, resulting in a decrease in the amount of material vaporization. However, when the speed is very low, the groove depth increases with increasing scanning speed. Figure 17A photograph of the time slot is shown when the laser scanning speed is 80 mm / s. Figure 18 A photograph of the time slot is shown when the laser scanning speed is 40 mm / s. (Example) Figure 17 As shown, when the scanning speed is low, deposits will accumulate in the groove, and the lower the speed, the more deposits will accumulate. These deposits not only affect the material's absorption of the laser, but sometimes also reduce the depth of the groove. In the laser scanning process, since changing the scanning speed of the laser beam cannot change the pulse energy and the size of the spot, the laser scanning speed has little effect on the change in the width of the groove.

[0127] Figure 19 An image of an ohmic contact structure provided for an embodiment of this disclosure. Specifically, Figure 19 An image of a P-type emitter is shown, formed using a 1064nm infrared laser-induced metal contact process. It is clearly visible that the paste filling at the inverted triangular groove of the laser-induced metal contact is very full, meeting the requirements for ohmic contact. The emitter portion of the silicon substrate is doped with aluminum atoms to form a P-type doped region. The materials for the P-type emitter electrode include silver, aluminum, and glassy substances.

[0128] For example, in the laser-induced metal contact process, a laser with a wavelength of 355 nm is used, the output power of which is 5 W to 20 W, the single pulse energy is 5 μJ to 20 μJ, the pulse repetition frequency is 400 kHz to 1 MHz, the pulse width is less than or equal to 10 ns@1 MHz, and the scanning speed is 5000 mm / s to 7000 mm / s.

[0129] Figure 20 A photograph of the emitter surface is shown when the laser pulse repetition frequency is 500 kHz. Figure 21 A photograph of the emitter surface is shown when the laser pulse repetition frequency is 750 kHz. Figure 22 A photograph of the emitter surface is shown when the laser pulse repetition frequency is 1 MHz. At a pulse repetition frequency of 500 kHz, the emitter surface shows ablation pits, but the underlying tunneling layer is not damaged. Exemplarily, the pulse repetition frequency ranges from 750 kHz to 1 MHz. At a pulse repetition frequency of 1 MHz, the surface ablation is very shallow.

[0130] This disclosure also provides a photovoltaic module, which includes a power transmission line and the aforementioned ohmic contact structure. The emitter of the ohmic contact structure is connected in series with the power transmission line to supply power to the power transmission line when illuminated by light. This photovoltaic module has high output power and output efficiency.

[0131] When the 23.1% grade battery provided in the comparative example is used in a photovoltaic module, the maximum output power (Pmax) of the comparative photovoltaic module is 549.93W, and the cell-to-module (CTM) efficiency of the comparative photovoltaic module is 100.15%. When the 23.1% grade battery provided in this embodiment is used to construct a photovoltaic module, the maximum output power of the photovoltaic module is 551.74W. Specifically, the power of the photovoltaic module is increased by 1.81W, the open-circuit voltage is increased by 0.09V, the short-circuit current is increased by 0.002A, the fill factor is increased by 0.11%, and the cell-to-module efficiency is 100.48%. The efficiency of the photovoltaic module provided in this embodiment is increased by 0.33%.

[0132] When the 23.0% capacity battery provided in the comparative example is used in a photovoltaic module, the maximum output power of the comparative photovoltaic module is 547.99W, and the unit module efficiency of the comparative photovoltaic module is 100.23%. When the 23.0% capacity battery provided in this embodiment is used to construct a photovoltaic module, the maximum output power of the photovoltaic module is 549.79W. Specifically, the power of the photovoltaic module is increased by 1.80W, the open-circuit voltage is increased by 0.13V, the short-circuit current is reduced by 0.0237A, the fill factor is increased by 0.19%, and the unit module efficiency is 100.56%. The efficiency of the photovoltaic module provided in this embodiment is increased by 0.33%.

[0133] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0134] The above-described various forms of processes can be used, and steps can be reordered, added, or deleted. The steps described in the embodiments of this disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution provided by the embodiments of this disclosure can be achieved, and no limitation is imposed herein.

[0135] The embodiments described above are merely illustrative of several implementations of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the disclosed patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this disclosure, and these all fall within the protection scope of this disclosure. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A method of fabricating an ohmic contact structure, characterized by, The method comprises: forming an opening through a second dielectric portion in a second block of a prefabricated semiconductor structure and exposing a second prefabricated semiconductor base in the second block, wherein the first block comprises a first dielectric portion, a tunneling layer and a first prefabricated semiconductor base arranged in sequence from one side to the other side, and the second dielectric portion and the second prefabricated semiconductor base are arranged in sequence from the one side to the other side; forming a paste layer on one side of the prefabricated semiconductor structure, comprising: forming a first paste layer on the first dielectric portion and forming a second paste layer on the opening, wherein the material of the paste layer comprises metal, and the material of the second paste layer comprises a doping material; and forming an emitter and a semiconductor structure in ohmic contact with the emitter by laser-induced metal contact on the paste layer and the prefabricated semiconductor structure, comprising: laser scanning the first paste layer with a laser wavelength of 355 nm to form a first emitter through the first dielectric portion and in ohmic contact with the tunneling layer; and laser scanning the second paste layer with a laser wavelength of 1064 nm or 532 nm to form a second emitter and form a region of the second prefabricated semiconductor base in contact with the second emitter as a doped region in ohmic contact with the second emitter.

2. The method of fabricating an ohmic contact structure according to claim 1, wherein, In the process of laser scanning with a laser wavelength of 355 nm, the output power is 5 W to 20 W, the single pulse energy is 5 μJ to 20 μJ, the pulse repetition frequency is 400 kHz to 1 MHz, the pulse width is less than or equal to 10 ns@1 MHz, and the scanning speed is 5000 mm / s to 7000 mm / s.

3. The method of fabricating an ohmic contact structure according to claim 2, wherein, In the process of laser scanning with a laser wavelength of 355 nm, the pulse repetition frequency is 750 kHz to 1 MHz.

4. The method of fabricating an ohmic contact structure according to claim 1, wherein, The material of the second paste layer comprises silver, the doping material comprises at least one of boron and aluminum, and the material of the prefabricated semiconductor base comprises silicon.

5. The method of fabricating an ohmic contact structure according to claim 1, wherein, In the process of laser scanning with a laser wavelength of 1064 nm, the output power is 50 W to 100 W, the single pulse energy is 5 mJ to 15 mJ, the pulse repetition frequency is 10 kHz to 20 kHz, the pulse width is less than or equal to 100 ns@10 kHz, and the scanning speed is 3500 mm / s to 5000 mm / s.

6. The method of fabricating an ohmic contact structure according to claim 1, wherein, In the process of laser scanning with a laser wavelength of 532 nm, the output power is 10 W to 50 W, the single pulse energy is 1 μJ to 50 μJ, the pulse repetition frequency is 5 kHz to 50 kHz, the pulse width is less than or equal to 10 ns@10 kHz, and the scanning speed is 3000 mm / s to 4500 mm / s.

7. The method of fabricating an ohmic contact structure according to claim 1, wherein, The step of forming the paste layer comprises: forming a patterned paste layer by a printing process; and drying the patterned paste layer.

8. The method of fabricating an ohmic contact structure according to claim 1, wherein, The method further comprises forming a prefabricated semiconductor, and the step of forming the prefabricated semiconductor comprises: texturing one end of a prefabricated semiconductor base to form a first textured structure, wherein the prefabricated semiconductor base has a first region and a second region, and the first textured structure is located in the second region; forming a tunneling layer on the first region; forming a first dielectric part on a side of the tunneling layer facing away from the prefabricated semiconductor base and forming a second dielectric part on the first textured structure; texturing the other end of the prefabricated semiconductor base to form a second textured structure; forming a dielectric layer on the second textured structure.

9. An ohmic contact structure, characterized by comprising: a semiconductor structure comprising a first dielectric layer and a composite base arranged in sequence, the composite base comprising a tunneling layer and a doped region arranged side by side, the first dielectric layer comprising a first dielectric part corresponding to the tunneling layer and a second dielectric part corresponding to the doped region; and and an emitter comprising a first emitter penetrating through the first dielectric part and being in ohmic contact with the tunneling layer and a second emitter penetrating through the second dielectric part and being in ohmic contact with the doped region, wherein the first emitter is formed by a laser-induced metal contact process with a laser wavelength of 355 nm, the second emitter is formed by a laser-induced metal contact process with a laser wavelength of 1064 nm or a laser-induced metal contact process with a laser wavelength of 532 nm, the material of the emitter comprises a metal, the material of the first emitter comprises the material of the first dielectric layer, and the material of the second emitter comprises a doping material of the doped region.

10. The ohmic contact structure of claim 9, wherein, The material of the second emitter comprises at least one of boron and aluminum and silver.

11. The ohmic contact structure of claim 9, wherein, The semiconductor structure comprises a second dielectric layer on a side of the composite base facing away from the first dielectric layer, the composite base comprising a first textured structure corresponding to the first dielectric layer and a second textured structure corresponding to the second dielectric layer.

12. A photovoltaic module, characterized by, comprising: a power line; and the ohmic contact structure of any one of claims 9 to 11 in series with the power line to supply power to the power line when illuminated by light. ​

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