Solar cell and photovoltaic module
By setting dielectric layers in different regions on the semiconductor substrate of solar cells and etching and removing them using the difference in silicon-nitrogen ratio, the damage problem of the laser groove process to the substrate is solved, achieving more efficient electrode production and performance improvement.
Patent Information
- Application Number
- CN202510074377.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-16
- Publication Date
- 2025-05-30
AI Technical Summary
The laser groove process can easily damage the semiconductor substrate when preparing the dielectric layer of the solar cell.
By setting dielectric layers in different regions on the semiconductor substrate, using the difference in the number ratio of silicon elements and nitrogen elements, etching is used to remove dielectric layers in areas with poor corrosion resistance, thereby realizing partial removal of dielectric layers or forming holes to reduce damage to the substrate.
This method can effectively reduce the damage caused by laser to the semiconductor substrate, improve the reliability of electrode production, and improve the performance of solar cells.
Smart Images
Figure CN120076485A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of photovoltaic technology, and in particular, to a solar cell and a photovoltaic module. Background Art
[0002] At present, as a new energy alternative, solar cells are used more and more widely. Among them, a photovoltaic solar cell is a device that converts solar light energy into electrical energy. Specifically, a solar cell utilizes the photovoltaic effect to generate carriers, and then uses electrodes to extract the carriers, so as to facilitate the effective utilization of electrical energy.
[0003] The dielectric layer of a solar cell generally uses laser grooving to prepare electrodes in the grooved area; however, the laser energy required for laser grooving is relatively high, which is likely to damage the substrate. Summary of the Invention
[0004] The purpose of this application is to provide a solar cell and a photovoltaic module to reduce the damage of the laser to the semiconductor substrate.
[0005] In order to achieve the above purpose, this application provides the following technical solutions:
[0006] A solar cell, the solar cell includes a semiconductor substrate and a dielectric layer disposed on the semiconductor substrate, and the semiconductor substrate includes a first functional area and a second functional area;
[0007] The ratio of the number of silicon elements to the number of nitrogen elements in the dielectric layer covering the first functional area is greater than the ratio of the number of silicon elements to the number of nitrogen elements in the dielectric layer covering the second functional area.
[0008] By adopting the above technical solution, in this application, the difference in corrosion resistance in different regions of the dielectric layer can be utilized, and the dielectric layer in the region with poor corrosion resistance can be etched and removed by using a corrosive solution, so as to achieve partial removal of the dielectric layer or form holes in some regions of the dielectric layer, which is beneficial to the subsequent production of electrodes. Compared with the prior art of using laser grooving technology to open holes in the dielectric layer, the damage of the laser to the semiconductor substrate can be reduced.
[0009] In one embodiment, the dielectric layer includes one or more laminated layers of a silicon nitride layer and a silicon oxynitride layer.
[0010] In one embodiment, the alkali resistance of the dielectric layer covering the first functional area is lower than that of the dielectric layer covering the second functional area; and / or, the acid resistance of the dielectric layer covering the first functional area is higher than that of the dielectric layer covering the second functional area.
[0011] In one embodiment, the amount of nitrogen element contained in the dielectric layer covering the first functional area is less than the amount of nitrogen element contained in the dielectric layer covering the second functional area;
[0012] And / or, the number of silicon elements contained in the dielectric layer covering the first active region is less than the number of silicon elements contained in the dielectric layer covering the second active region.
[0013] In one embodiment, the dielectric layer includes an opposite first dielectric layer surface and a second dielectric layer surface, and the first dielectric layer surface is farther from the semiconductor substrate than the second dielectric layer surface;
[0014] In the first active region, the ratio of the number of silicon elements to the number of nitrogen elements on the first dielectric layer surface is greater than the ratio of the number of silicon elements to the number of nitrogen elements on the second dielectric layer surface; and / or, the number of nitrogen elements on the first dielectric layer surface is less than the number of nitrogen elements on the second dielectric layer surface.
[0015] In one embodiment, the dielectric layer includes an opposite first dielectric layer surface and a second dielectric layer surface, and the first dielectric layer surface is farther from the semiconductor substrate than the second dielectric layer surface;
[0016] In the first active region, the ratio of the number of silicon elements to the number of nitrogen elements on the first dielectric layer surface is greater than the ratio of the number of silicon elements to the number of nitrogen elements in the dielectric layer in the second active region; and / or, the number of nitrogen elements on the first dielectric layer surface in the first active region is less than the number of nitrogen elements in the dielectric layer in the second active region.
[0017] In one embodiment, the surface of the dielectric layer covering the first active region includes an oxide layer.
[0018] In one embodiment, the thickness of the oxide layer is 10% - 50% of the thickness of the dielectric layer;
[0019] And / or, the oxide layer includes silicon oxide.
[0020] In one embodiment, the dielectric layer covering the first active region includes holes.
[0021] In one embodiment, the solar cell further includes: a first doped semiconductor layer and a first electrode;
[0022] Wherein, the semiconductor substrate has a first surface; the entire layer or a part of the first doped semiconductor layer is disposed on the first surface, and the dielectric layer is located on a side of the first doped semiconductor layer away from the semiconductor substrate;
[0023] The dielectric layer covers the first active region and the second active region;
[0024] The dielectric layer covering the first active region includes holes filled with a conductive material; the first electrode is electrically connected to the first doped semiconductor layer through the conductive material.
[0025] In one embodiment, the solar cell further includes: a second doped semiconductor layer and a second electrode;
[0026] Wherein, the first surface includes a first region, a second region arranged at intervals, and an isolation region between the first region and the second region;
[0027] The first doped semiconductor layer is disposed in the first region, and the second doped semiconductor layer is disposed in the second region; the conductive types of the first doped semiconductor layer and the second doped semiconductor layer are opposite;
[0028] The dielectric layer is located on the side of the first doped semiconductor layer and the second doped semiconductor layer away from the semiconductor substrate;
[0029] The dielectric layer covering the first active region includes holes filled with a conductive material;
[0030] The second electrode is electrically connected to the second doped semiconductor layer through the conductive material.
[0031] In one embodiment, the solar cell further includes: a third doped semiconductor layer and a fourth doped semiconductor layer;
[0032] Wherein, the semiconductor substrate has a first surface, and the first surface includes a first region, a second region arranged at intervals, and an overlapping region between the first region and the second region;
[0033] The dielectric layer covers the first active region and the second active region; the second active region is located at the edge of the first active region;
[0034] The third doped semiconductor layer is disposed in the first region and the overlapping region; the fourth doped semiconductor layer is disposed in the second region and at least part of the overlapping region;
[0035] The conductive types of the third doped semiconductor layer and the fourth doped semiconductor layer are opposite;
[0036] In the overlapping region, the dielectric layer is disposed on the third doped semiconductor layer and is farther from the semiconductor substrate than the third doped semiconductor layer.
[0037] In one embodiment, the solar cell further includes: a first doped semiconductor layer and an electrode;
[0038] Wherein, the semiconductor substrate has a first surface;
[0039] The first doped semiconductor layer is entirely or partially disposed on the first surface, and the dielectric layer is located on a side of the first doped semiconductor layer away from the semiconductor substrate;
[0040] The dielectric layer covers the first active region and the second active region; the first active region is located at the edge of the second active region;
[0041] The electrode passes through the dielectric layer and is electrically connected to the first doped semiconductor layer.
[0042] A photovoltaic module includes the solar cell according to any one of the above.
[0043] Compared with the prior art, the beneficial effects of the photovoltaic module provided by the embodiments of the present application are the same as those of the above solar cell, and will not be elaborated here. Description of the Drawings
[0044] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:
[0045] Figure 1 It is a schematic diagram of the nitrogen element content of the dielectric layer provided by the embodiments of the present application varying with the laser energy;
[0046] Figure 2 It is a schematic diagram of the silicon element content of the dielectric layer provided by the embodiments of the present application varying with the laser energy;
[0047] Figure 3 It is a cross-sectional view of the solar cell provided by the embodiments of the present application;
[0048] Figure 4 It is a cross-sectional view of another solar cell provided by the embodiments of the present application;
[0049] Figure 5 It is a cross-sectional view of another solar cell provided by the embodiments of the present application;
[0050] Figure 6 It is a schematic diagram of a dielectric layer provided by another embodiment of the present application.
[0051] Reference Signs:
[0052] 1 - Semiconductor substrate, 1a - Laser irradiation area, 1b - Non - laser action area, 1c - Laser influence area, 2 - Dielectric layer, 2a - Hole. Detailed Embodiments
[0053] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, the following further details this application in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.
[0054] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.
[0055] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, "a plurality of" means two or more, unless otherwise specifically defined. "Several" means one or more, unless otherwise specifically defined.
[0056] In the description of this application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to this application.
[0057] In the description of this application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0058] The solar cell provided by the embodiment of the present application includes a semiconductor substrate and a dielectric layer 2 disposed on the semiconductor substrate, and the dielectric layer 2 has a passivation effect. The semiconductor substrate includes a first functional region and a second functional region. The ratio of the number of silicon atoms to the number of nitrogen atoms in the dielectric layer 2 covering the first functional region is greater than the ratio of the number of silicon atoms to the number of nitrogen atoms in the dielectric layer 2 covering the second functional region. Herein, the number of nitrogen atoms refers to the number of nitrogen atoms, and the number of silicon atoms refers to the number of silicon atoms. For example, the ratio of the number of silicon atoms to the number of nitrogen atoms in the dielectric layer 2 covering the first functional region is a, and the ratio of the number of silicon atoms to the number of nitrogen atoms in the dielectric layer 2 covering the second functional region is b, and a > b.
[0059] The applicant has found through research that due to the difference in the silicon-nitrogen ratio between the dielectric layer 2 covering the first functional region and the dielectric layer 2 covering the second functional region, the corrosion resistance of the part of the dielectric layer 2 covering the first functional region and the part of the dielectric layer 2 covering the second functional region also shows differences. As Figure 1 shown, Figure 1 in which the abscissa is the binding energy, and the ordinate is the change in the number of nitrogen atoms per second with the laser (counts per second). Figure 1 In [figure], 1-5 represent the gradually increasing laser intensity, BL is the number of nitrogen atoms per second without laser modification. It can be seen from Figure 1 that after laser irradiation modification, the number of nitrogen atoms in the first functional region gradually decreases, and the higher the laser energy, the fewer the number of nitrogen atoms. As Figure 2 shown, Figure 2 in which the abscissa is the binding energy, and the ordinate is the change in the number of silicon atoms per second with the laser (counts per second). Figure 2 In [figure], 1-5 represent the gradually increasing laser intensity, BL is the number of silicon atoms per second without laser modification. It can be seen from Figure 2 that after laser irradiation modification, the number of silicon atoms in the first functional region gradually decreases, and the higher the laser energy, the fewer the number of silicon atoms. However, on the premise of the same laser energy, the number of silicon atoms reduced is smaller than the number of nitrogen atoms reduced.
[0060] By adopting the above technical solution, in the present application, the difference in corrosion resistance in different regions of the dielectric layer 2 can be utilized, and the dielectric layer 2 in the region with poor corrosion resistance can be etched and removed by using a corrosion solution, so as to realize partial removal of the dielectric layer 2 or form holes 2a in some regions of the dielectric layer 2, which is beneficial to the subsequent fabrication of electrodes. Compared with the prior art in which a laser grooving process is used to open holes in the dielectric layer 2, the damage to the semiconductor substrate 1 caused by the laser can be reduced.
[0061] In some embodiments, the dielectric layer 2 includes one or more stacked layers of a silicon nitride layer and a silicon oxynitride layer. Specifically, when the dielectric layer 2 has a single-layer structure, the dielectric layer 2 can be a silicon nitride layer or a silicon oxynitride layer. When the dielectric layer 2 has a double-layer structure, the dielectric layer 2 can include a stacked silicon nitride layer and a silicon oxynitride layer, and the stacking order of each layer can be set according to actual conditions. The dielectric layer 2 made of the above various materials has a low cost, has a passivation effect, good adhesiveness, and is easy to manufacture.
[0062] In some embodiments, the first action area includes a laser irradiation area 1a (the area where the dielectric layer 2 is irradiated by the laser) and a laser influence area 1c (the area where the dielectric layer 2 is affected by the laser heat), and the second action area includes a non-laser action area 1b (the area that is not affected by the laser at all). In this technical solution, the dielectric layer 2 covers the first action area and the second action area, that is, the dielectric layer 2 covers the laser irradiation area 1a, the laser influence area 1c, and the non-laser action area 1b. Among them, the number of the first action areas is multiple and the multiple first action areas are independent of each other and do not connect. In this way, the dielectric layer 2 covering the first action area (the laser irradiation area 1a and the laser influence area 1c) can be used as a connection layer between the electrode and the doped semiconductor layer, which is beneficial to improving the bonding force between the doped semiconductor layer and the electrode and improving the pulling force.
[0063] Alternatively, the first action area includes a laser irradiation area 1a (the area where the dielectric layer 2 is irradiated by the laser), and the second action area includes a laser influence area 1c (the area where the dielectric layer 2 is affected by the laser heat) and a non-laser action area (the area that is not affected by the laser at all).
[0064] As Figure 3 shown, the laser influence area 1c is arranged around the edge of the laser irradiation area 1a and the laser influence area 1c is located between the laser irradiation area 1a and the non-laser action area 1b (the area that is not affected by the laser at all). The ratio of the number of silicon elements to nitrogen elements contained in the part of the dielectric layer 2 corresponding to the laser irradiation area 1a increases. Although the laser influence area 1c is not directly irradiated by the laser, the ratio of the number of silicon elements to nitrogen elements it contains also increases due to the influence of the laser heat.
[0065] In some embodiments, the first acting area includes a laser affected area 1c, and the second acting area includes a non-laser acting area 1b (an area that is completely unaffected by the laser). The area of the dielectric layer 2 corresponding to the laser irradiation area 1a is removed to form a hollow hole. In this technical solution, the dielectric layer 2 covers the laser affected area 1c and the non-laser acting area. Specifically, during the process of removing the dielectric layer 2 covering the laser irradiation area 1a with an etching solution and retaining the dielectric layer 2 covering the non-laser acting area 1b and the laser affected area 1c, patterning of the dielectric layer 2 is achieved, and a hollow hole is formed in the area of the dielectric layer 2 corresponding to the laser irradiation area 1a. By adopting this technical solution, the dielectric layer 2 can play a masking effect, and other functional layers can be formed in the area of the hollow hole. In addition, the electrode can directly contact the doped semiconductor layer through multiple hollow holes, which is beneficial to the processing and manufacturing of the electrode.
[0066] In some embodiments, the first acting area includes a laser irradiation area 1a, the second acting area includes a laser affected area 1c, and the second acting area is located at the edge of the first acting area, that is, the laser affected area 1c is located at the edge of the laser irradiation area 1a. In this technical solution, the dielectric layer 2 covers the first acting area and the second acting area, that is, the dielectric layer 2 covers the laser irradiation area 1a and the laser affected area 1c. The area of the dielectric layer 2 corresponding to the non-laser acting area is removed to form a hollow hole. Specifically, during the process of removing the dielectric layer 2 covering the non-laser acting area 1b with an etching solution and retaining the dielectric layer 2 covering the laser irradiation area 1a and the laser affected area 1c, a hollow hole is formed in the area of the dielectric layer 2 corresponding to the non-laser acting area 1b. By adopting this technical solution, the retained dielectric layer 2 of the laser irradiation area 1a and the laser affected area 1c can be used as an isolation material between doped semiconductor layers with opposite conductivity types to prevent leakage between doped semiconductor layers with opposite conductivity types.
[0067] In some embodiments, under the action of laser irradiation or laser thermal influence, the alkali resistance of the dielectric layer 2 covering the first acting area is reduced, resulting in the alkali resistance of the dielectric layer 2 covering the first acting area being lower than that of the dielectric layer 2 covering the second acting area of the dielectric layer 2. By adopting this technical solution, as Figure 3 shown, an alkali solution can be used to etch and remove part of the dielectric layer, and then the dielectric layer 2 corresponding to the laser irradiation area 1a is removed, while the dielectric layer 2 covering the non-laser acting area 1b is retained, thereby realizing patterning of the dielectric layer 2, and enabling the dielectric layer 2 to play a masking role.
[0068] It can be understood that the alkali resistance of the dielectric layer 2 covering the laser irradiation area 1a is lower than that of the dielectric layer 2 covering the laser affected area 1c. By controlling the concentration of the alkali solution, the dielectric layer 2 covering the laser affected area 1c can be selectively etched and removed or retained.
[0069] In some other embodiments, under the action of laser irradiation or laser thermal influence, the acid resistance of the dielectric layer 2 covering the first action area is improved, resulting in the acid resistance of the dielectric layer 2 covering the first action area being higher than that of the dielectric layer 2 covering the second action area. With this technical solution, as Figure 5 shown, part of the dielectric layer can be etched away using an acid solution, thereby removing the dielectric layer 2 covering the non-laser action area 1b, while retaining the dielectric layer 2 covering the laser irradiation area 1a and the laser influence area 1c, thus realizing patterning of the dielectric layer 2.
[0070] It can be understood that the acid resistance of the dielectric layer 2 covering the laser irradiation area 1a is also higher than that of the dielectric layer 2 covering the laser influence area 1c. By controlling the concentration of the acid solution, it is possible to choose to etch away or retain the dielectric layer 2 covering the laser influence area 1c.
[0071] In some embodiments, the first action area includes a first sub-action area and a second sub-action area. The ratio of the number of silicon elements to the number of nitrogen elements contained in the dielectric layer covering the first sub-action area is greater than the ratio of the number of silicon elements to the number of nitrogen elements contained in the dielectric layer covering the second sub-action area. The first sub-action area can be the area directly irradiated by the laser, and the second sub-action area can be the area affected by laser thermal radiation. Since the second sub-action area is not directly irradiated by the laser but only affected by laser thermal radiation, the ratio of the number of silicon elements to the number of nitrogen elements contained in the dielectric layer 2 covering the first sub-action area is greater than the ratio of the number of silicon elements to the number of nitrogen elements contained in the dielectric layer 2 covering the second sub-action area. With this technical solution, from the part of the dielectric layer 2 covering the first sub-action area to the part of the dielectric layer 2 covering the second action area, the number of silicon elements and the number of nitrogen elements form an intermediate transition in the part of the dielectric layer 2 covering the second sub-action area, avoiding too large a change in the ratio of the number of silicon elements to the number of nitrogen elements in the adjacent area and affecting the performance of the entire dielectric layer 2.
[0072] In some embodiments, the number of nitrogen elements contained in the dielectric layer 2 covering the first action area is less than the number of nitrogen elements contained in the dielectric layer 2 covering the second action area. That is, the number of nitrogen atoms in the dielectric layer 2 covering the first action area is less than the number of nitrogen atoms in the dielectric layer 2 covering the second action area. According to well-known technology, the fewer the number of nitrogen elements, the more acid-resistant. Therefore, in this technical solution, the number of nitrogen atoms in the part of the dielectric layer 2 covering the first action area is less than the number of nitrogen atoms in the part of the dielectric layer 2 covering the second action area, thereby significantly improving the acid resistance of the part of the dielectric layer 2 covering the first action area.
[0073] Further, the dielectric layer includes opposite first and second dielectric surfaces, and the first dielectric surface is farther from the semiconductor substrate than the second dielectric surface; the amount of nitrogen element on the first dielectric surface is less than the amount of nitrogen element on the second dielectric surface. The ratio of the amount of silicon element to the amount of nitrogen element on the first dielectric surface in the first active region is greater than the ratio of the amount of silicon element to the amount of nitrogen element in the dielectric layer in the second active region; and / or, the amount of nitrogen element on the first dielectric surface in the first active region is less than the amount of nitrogen element in the dielectric layer in the second active region.
[0074] In some other embodiments, the amount of silicon element contained in the dielectric layer 2 covering the first active region is less than the amount of silicon element contained in the dielectric layer 2 covering the second active region. Since silicon atoms have stable chemical properties, when the dielectric layer 2 covering the second active region contains a larger number of silicon atoms, the performance of the second active region is more stable.
[0075] Among them, along the thickness direction of the dielectric layer 2, the two opposite surfaces on both sides of the dielectric layer 2 are the first surface and the second surface respectively, and a part of the first surface is irradiated by laser, while the second surface is not irradiated by laser as a whole.
[0076] In some embodiments, the ratio of the amount of silicon element to the amount of nitrogen element in the part of the first surface located in the first active region is greater than the ratio of the amount of silicon element to the amount of nitrogen element in the part of the first surface located in the second active region. That is, on the surface of the dielectric layer 2 on the side irradiated by laser, the ratio of the amount of silicon element to the amount of nitrogen element on the surface of the region of the dielectric layer 2 irradiated by laser is greater than the ratio of the amount of silicon element to the amount of nitrogen element on the surface of the region of the dielectric layer 2 not irradiated by laser. With this technical solution, the difference in corrosion resistance between the part of the first surface located in the first active region and the part of the first surface located in the second active region is greater, which is more conducive to subsequent etching of the dielectric layer 2 in the region with poor corrosion resistance by the etching solution, and the selection space of the etching solution is larger, reducing the process difficulty.
[0077] In some embodiments, in the first active region, in the range where the depth is less than or equal to h from the first surface to the second surface, the ratio of the amount of silicon element to the amount of nitrogen element contained in the dielectric layer 2 covering the first active region is greater than the ratio of the amount of silicon element to the amount of nitrogen element contained in the dielectric layer 2 covering the second active region. For example: h is less than or equal to 500 nm, such as: 10 nm, 20 nm, 50 nm, 70 nm, 80 nm, 100 nm, 120 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 500 nm. With such a setting, it is ensured that within the range of depth h, the difference in corrosion resistance between the part of the dielectric layer 2 covering the first active region and the part of the dielectric layer 2 covering the second active region is greater, so as to meet different process requirements.
[0078] In the first action area, the ratio of the number of silicon elements to the number of nitrogen elements contained in the first surface is greater than the ratio of the number of silicon elements to the number of nitrogen elements contained in the second surface. In other words, the difference in the ratio of silicon elements to nitrogen elements between the two parts of the dielectric layer 2 corresponding to the first action area on both sides is relatively large, so that the corrosion resistance difference between the two parts of the dielectric layer 2 corresponding to the first action area on both sides is relatively large. By adopting this technical solution, the difference in corrosion resistance between the two parts of the dielectric layer 2 corresponding to the first action area on both sides can be utilized to select a suitable etching solution to retain the part of the second surface of the dielectric layer 2 corresponding to the first action area to meet different process requirements. For example, when the dielectric layer 2 covering the first action area is used as the connection layer between the electrode and the doped semiconductor layer, the adhesion between the electrode and the doped semiconductor layer can be improved by retaining the part of the second surface of the dielectric layer 2 corresponding to the first action area, and the pulling force can be increased.
[0079] In some embodiments, in the direction from the first surface to the second surface, the ratio of the number of silicon elements to the number of nitrogen elements contained in the dielectric layer 2 covering the first action area gradually decreases. In other words, in the direction from the first surface to the second surface, the corrosion resistance of the dielectric layer 2 covering the first action area gradually becomes stronger or gradually becomes worse, so that etching solutions with different concentrations can be selected to set the thickness of the part of the dielectric layer 2 corresponding to the first action area to be retained.
[0080] In other embodiments, during the process of laser irradiation or laser thermal influence, the surface of the first action area is in contact with oxygen, resulting in the formation of an oxide layer on the surface of the dielectric layer 2 covering the first action area, that is, the surface of the dielectric layer 2 covering the first action area includes an oxide layer. Among them, the properties of the oxide are more stable. The formation of an oxide on the surface of the dielectric layer 2 in the first action area can further improve the stability of the dielectric layer 2 and further improve the reliability of the solar cell.
[0081] In some embodiments, if the thickness of the oxide layer is too thick, the manufacturing difficulty is relatively large; if the thickness of the oxide layer is too thin, the stability of the dielectric layer 2 is affected. Therefore, in this technical solution, the thickness of the oxide layer is 10% - 50% of the thickness of the dielectric layer 2. In this way, while ensuring the stability of the dielectric layer 2, the processing difficulty of the oxide layer is reduced. Exemplarily, the thickness of the oxide layer is 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48% or 50% of the thickness of the dielectric layer 2, etc.
[0082] In addition, the oxide layer includes silicon oxide. Specifically, the silicon atoms on the surface of the dielectric layer 2 covering the first action area come into contact with oxygen and react to form silicon oxide.
[0083] In some embodiments, the laser irradiation area 1a on the first surface of the dielectric layer 2 is irradiated with laser, and the entire second surface of the dielectric layer 2 is not irradiated with laser. In this technical solution, in the first action area, the oxygen content on the first surface of the dielectric layer 2 is greater than that on the second surface, that is, in the dielectric layer covering the first action area, the oxygen content on the surface irradiated with laser is greater than that on the surface not irradiated with laser. Alternatively, along the thickness direction of the dielectric layer 2 and from the first surface to the second surface of the dielectric layer 2, the oxygen content in the dielectric layer 2 covering the first action area gradually decreases.
[0084] In some embodiments, as Figure 6 shown, the dielectric layer 2 covering the first action area includes holes 2a. With this technical solution, the dielectric layer 2 in the first action area does not need to be completely removed. There are holes 2a inside, and through the conductive material in the holes 2a, electrical contact between the electrode and the doped semiconductor layer on the side of the dielectric layer 2 close to the semiconductor substrate can be achieved. Especially for electrodes made by methods such as electroplating, electroless plating, and physical vapor deposition, the pulling force of the electrode on the solar cell can be greatly improved and it is not easy to fall off.
[0085] In some embodiments, in the dielectric layer 2 covering the first action area, the holes 2a formed on the first surface are smaller than the holes 2a formed on the second surface, that is, the holes 2a formed on the surface irradiated with laser are smaller than the holes 2a formed on the surface not irradiated with laser. In addition, in the dielectric layer 2 covering the first action area, the number of holes 2a formed on the first surface is smaller than the number of holes 2a formed on the second surface, that is, in the dielectric layer 2 covering the first action area, the number of holes 2a formed on the surface irradiated with laser is smaller than the number of holes 2a formed on the surface not irradiated with laser. With such a setting, it is ensured that the surface density of the dielectric layer 2 covering the first action area is higher, and the stability of the performance of the dielectric layer 2 is further improved.
[0086] In some embodiments, the first action area includes a first sub-action area and a second sub-action area. The dielectric layer 2 covers the first sub-action area and the second sub-action area. The size of the holes in the dielectric layer covering the first sub-action area is smaller than the size of the holes in the dielectric layer covering the second sub-action area; and / or, the number of holes in the dielectric layer covering the first sub-action area is smaller than the number of holes in the dielectric layer covering the second sub-action area. This makes the density of the dielectric layer 2 covering the first sub-action area higher. When the dielectric layer 2 covering the first action area is used as the connection layer between the electrode and the doped semiconductor layer, it is beneficial to improve the adhesion between the doped semiconductor layer and the electrode and increase the pulling force.
[0087] In some embodiments, the solar cell further includes a first doped semiconductor layer and an electrode. The semiconductor substrate 1 has a first surface. The first doped semiconductor layer can be disposed entirely on the first surface or partially on the first surface. The dielectric layer 2 is located on the side of the first doped semiconductor layer away from the semiconductor substrate 1. In this embodiment, as Figure 3 shown, the dielectric layer 2 covers the first active region and the second active region. The first active region is located at the edge of the second active region. The first active region includes the laser affected region 1c; the second active region includes the non-laser affected region 1b, that is, the laser affected region 1c is located at the edge of the non-laser affected region 1b. That is, the dielectric layer 2 covers the laser affected region 1c and the non-laser affected region 1b, and the dielectric layer 2 does not cover the laser irradiated region 1a, that is, a hollow is formed in the portion of the dielectric layer 2 corresponding to the laser irradiated region 1a. The electrode is electrically connected to the first doped semiconductor layer in the region corresponding to the laser irradiated region 1a.
[0088] In some embodiments, the dielectric layer 2 is a silicon nitride layer, and there is also an aluminum oxide layer between the dielectric layer 2 and the first doped semiconductor layer. At the hollow formed in the portion of the dielectric layer 2 corresponding to the laser irradiated region 1a, the edge of the aluminum oxide layer shrinks inward away from the hollow. In this technical solution, the first doped semiconductor layer can be a doped polysilicon layer.
[0089] In some embodiments, the solar cell further includes a first doped semiconductor layer and a first electrode. The semiconductor substrate 1 has a first surface. The first doped semiconductor layer can be disposed entirely on the first surface or partially on the first surface. The dielectric layer 2 is located on the side of the first doped semiconductor layer away from the semiconductor substrate 1. In this embodiment, the dielectric layer 2 covering the first active region includes a hole 2a filled with a conductive material. The solar cell further includes a first electrode, and the first electrode is electrically connected to the first doped semiconductor layer through the conductive material. The dielectric layer 2 covers the first active region and the second active region; the first active region includes the laser irradiated region 1a and the laser affected region 1c; the second active region includes the non-laser affected region 1b. With such a setting, the electrical contact between the first electrode and the first doped semiconductor layer can be realized through the conductive material in the hole 2a. Especially for electrodes made by methods such as electroplating, electroless plating, and physical vapor deposition, the pulling force of the first electrode on the solar cell can be greatly improved and it is not easy to fall off. The conductive material can be a conductive metal or a conductive adhesive, etc. In this embodiment, the solar cell can be a back contact cell or a bifacial cell.
[0090] In some embodiments, the solar cell further includes a second doped semiconductor layer and a second electrode. The first surface includes a first region, a second region arranged at intervals, and an isolation region located between the first region and the second region. The first doped semiconductor layer is disposed in the first region, and the second doped semiconductor layer is disposed in the second region. The first doped semiconductor layer and the second doped semiconductor layer have opposite conduction types to respectively collect and conduct electrons and holes, facilitating the formation of an electric current. The dielectric layer 2 is located on the side of the first doped semiconductor layer and the second doped semiconductor layer away from the semiconductor substrate. The dielectric layer 2 covers the first active region and the second active region; the first active region includes a laser irradiation region 1a and a laser influence region 1c; the second active region includes a non-laser active region 1b. The dielectric layer 2 covering the first active region includes holes 2a, and the holes 2a are filled with a conductive material; the second electrode is electrically connected to the second doped semiconductor layer through the conductive material, which can greatly improve the pulling force of the second electrode on the solar cell and is not easily detached.
[0091] Exemplarily, in a solar cell, the first doped semiconductor layer is a doped polysilicon layer, which can be P-type doped or N-type doped, and can be specifically determined according to actual requirements. The second doped semiconductor layer can also be a doped polysilicon layer. When the first doped semiconductor layer is an N-type doped polysilicon layer, the second doped semiconductor is a P-type doped polysilicon layer. That is, their conduction types are opposite.
[0092] In some embodiments, the solar cell further includes a first interface layer and a second interface layer. The first interface layer is located between the first doped semiconductor layer and the semiconductor substrate. When the first doped semiconductor layer is a doped polysilicon layer, the first interface layer can be a tunneling oxide layer. The second interface layer is located between the second doped semiconductor layer and the semiconductor substrate. When the second doped semiconductor layer is a doped polysilicon layer, the second interface layer can be a tunneling oxide layer. In this way, the passivation contact structure composed of the tunneling oxide layer and the doped polysilicon layer has excellent interface passivation effect and can achieve selective collection of carriers, reducing the carrier recombination rate on the first surface of the semiconductor substrate and further improving the photoelectric conversion efficiency of the solar cell. The material and thickness of the first interface layer can be set according to the material of the doped polysilicon layer and actual requirements, and are not specifically limited here.
[0093] The material of the semiconductor substrate 1 can be selected from materials such as silicon (Si), germanium (Ge), or gallium arsenide (GaAs), etc. Obviously, in terms of conduction type, the semiconductor substrate 1 can be an intrinsic conductive substrate, an n-type conductive substrate, or a p-type conductive substrate. Optionally, the semiconductor substrate 1 is a p-type conductive substrate or an n-type conductive substrate. Compared with the intrinsic conductive substrate, the p-type conductive substrate or the n-type conductive substrate has better conductivity, so that the finally manufactured solar cell has a lower bulk resistivity, thereby improving the efficiency of the solar cell.
[0094] Exemplarily, the semiconductor substrate 1 can be a p-type substrate or an n-type substrate. The n-type substrate has the advantages of high minority carrier lifetime, no optical decay, and good low-light performance.
[0095] In some other embodiments, the solar cell further includes a semiconductor substrate 1, a third doped semiconductor layer, and a fourth doped semiconductor layer. Among them, the semiconductor substrate 1 has a first surface, and the first surface includes a first region, a second region, and an overlapping region. The first region and the second region are spaced apart on the first surface, and the overlapping region is located between the first region and the second region. The third doped semiconductor layer is formed on the first region and the overlapping region, and the fourth doped semiconductor layer is formed on the second region and at least part of the overlapping region. And the conductive types of the third doped semiconductor layer and the fourth doped semiconductor layer are opposite to respectively collect and export electrons and holes, which is beneficial to form a current. The dielectric layer 2 covers the first active region and the second active region; the first active region includes a laser irradiation region 1a, and the second active region includes a laser influence region 1c. In addition, in the overlapping region, the dielectric layer 2 is disposed between the third doped semiconductor layer and the fourth doped semiconductor layer and is farther from the semiconductor substrate 1 than the third doped semiconductor layer. That is, in the overlapping region, at least part of the dielectric layer 2 on the side of the third doped semiconductor layer away from the semiconductor substrate is retained. In this embodiment, the dielectric layer 2 is locally disposed on the first surface, and the regions of the dielectric layer 2 corresponding to the laser irradiation region 1a and the laser influence region 1c are retained, and a second hollow hole is formed in the region of the dielectric layer 2 corresponding to the non-laser active region 1b. With such a setting, the regions of the dielectric layer 2 corresponding to the laser irradiation region 1a and the laser influence region 1c are retained in the overlapping region to isolate the third doped semiconductor layer and the fourth doped semiconductor layer and prevent leakage.
[0096] Exemplarily, in a solar cell, the third doped semiconductor layer is a doped polysilicon layer, which can be P-type doped or N-type doped, and can be specifically determined according to actual requirements. The fourth doped semiconductor layer is a doped amorphous silicon layer and / or a doped microcrystalline silicon layer. When the third doped semiconductor layer is an N-type doped polysilicon layer, the fourth doped semiconductor layer is a P-type doped amorphous silicon layer and / or a P-type doped microcrystalline silicon layer. That is, the conductive types of the two are opposite.
[0097] In some embodiments, the solar cell further includes a third interface layer and a fourth interface layer. The third interface layer is located between the third doped semiconductor layer and the semiconductor substrate. When the third doped semiconductor layer is a doped polysilicon layer, the third interface layer can be a tunneling oxide layer. The fourth interface layer is located between the fourth doped semiconductor layer and the semiconductor substrate. When the fourth doped semiconductor layer is a doped amorphous silicon layer and / or a doped microcrystalline silicon layer, the fourth interface layer can be an intrinsic amorphous silicon layer.
[0098] In addition, an embodiment of the present application further provides a photovoltaic module, which includes the solar cell provided in any one of the above embodiments. A plurality of solar cells are electrically connected together in series and / or in parallel. Compared with the prior art, the beneficial effects of the photovoltaic module provided by the embodiment of the present application are the same as those of the above-mentioned solar cell, and will not be elaborated herein.
[0099] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in a suitable manner in any one or more embodiments or examples.
[0100] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.
Claims
1. A solar cell, characterized in that: The solar cell comprises a semiconductor substrate and a dielectric layer arranged on the semiconductor substrate, wherein the semiconductor substrate comprises a first active region and a second active region; The ratio of silicon to nitrogen contained in the dielectric layer covering the first active region is greater than the ratio of silicon to nitrogen contained in the dielectric layer covering the second active region.
2. The solar cell according to claim 1, characterized in that The dielectric layer includes one or more stacked layers of a silicon nitride layer and a silicon oxynitride layer.
3. The solar cell according to claim 1, characterized in that The dielectric layer covering the first active region has lower alkali resistance than the dielectric layer covering the second active region; and / or the dielectric layer covering the first active region has higher acid resistance than the dielectric layer covering the second active region.
4. The solar cell according to claim 1, characterized in that The amount of nitrogen contained in the dielectric layer covering the first active region is less than the amount of nitrogen contained in the dielectric layer covering the second active region; And / or, the amount of silicon elements contained in the dielectric layer covering the first active region is less than the amount of silicon elements contained in the dielectric layer covering the second active region.
5. The solar cell according to claim 1, characterized in that: The dielectric layer comprises a first dielectric layer surface and a second dielectric layer surface which are opposite to each other, and the first dielectric layer surface is away from the semiconductor substrate relative to the second dielectric layer surface; In the first active region, the ratio of the silicon element to the nitrogen element on the first surface of the dielectric layer is greater than the ratio of the silicon element to the nitrogen element on the second surface of the dielectric layer; And / or, the amount of nitrogen elements on the first surface of the dielectric layer is less than the amount of nitrogen elements on the second surface of the dielectric layer.
6. The solar cell according to claim 1, characterized in that The dielectric layer comprises a first dielectric layer surface and a second dielectric layer surface which are opposite to each other, and the first dielectric layer surface is away from the semiconductor substrate relative to the second dielectric layer surface; The ratio of silicon to nitrogen in the first surface of the dielectric layer in the first active region is greater than the ratio of silicon to nitrogen in the dielectric layer in the second active region; And / or, the amount of nitrogen elements in the first surface of the dielectric layer in the first active region is less than the amount of nitrogen elements in the dielectric layer in the second active region.
7. The solar cell according to any one of claims 1 to 6, characterized in that: The surface of the dielectric layer covering the first active region includes an oxide layer.
8. The solar cell according to claim 7, characterized in that: The thickness of the oxide layer is 10% to 50% of the thickness of the dielectric layer; And / or, the oxide layer includes silicon oxide.
9. The solar cell according to any one of claims 1 to 6, characterized in that: The dielectric layer covering the first active region includes holes.
10. The solar cell according to any one of claims 1 to 6, characterized in that: The solar cell further comprises: a first doped semiconductor layer and a first electrode; The semiconductor substrate has a first surface; the first doped semiconductor layer is entirely or partially disposed on the first surface, and the dielectric layer is located on a side of the first doped semiconductor layer away from the semiconductor substrate; The dielectric layer covers the first active area and the second active area; The dielectric layer covering the first active area includes holes, and the holes are filled with conductive materials; the first electrode is electrically connected to the first doped semiconductor layer through the conductive material.
11. The solar cell according to claim 10, characterized in that The solar cell further comprises: a second doped semiconductor layer and a second electrode; Wherein, the first surface includes a first area, a second area and an isolation area between the first area and the second area; The first doped semiconductor layer is disposed in the first region, and the second doped semiconductor layer is disposed in the second region; the first doped semiconductor layer and the second doped semiconductor layer have opposite conductivity types; The dielectric layer is located on a side of the first doped semiconductor layer and the second doped semiconductor layer away from the semiconductor substrate; The dielectric layer covering the first active area includes holes, and the holes are filled with conductive material; The second electrode is electrically connected to the second doped semiconductor layer through the conductive material.
12. The solar cell according to any one of claims 1 to 6, characterized in that: The solar cell further comprises: a third doped semiconductor layer and a fourth doped semiconductor layer; The semiconductor substrate has a first surface, and the first surface includes a first region, a second region and an overlapping region between the first region and the second region. The dielectric layer covers the first active area and the second active area; the second active area is located at the edge of the first active area; The third doped semiconductor layer is disposed in the first region and the overlapping region; the fourth doped semiconductor layer is disposed in the second region and at least a portion of the overlapping region; The conductivity type of the third doped semiconductor layer is opposite to that of the fourth doped semiconductor layer; In the overlapping region, the dielectric layer is disposed on the third doped semiconductor layer and is farther away from the semiconductor substrate than the third doped semiconductor layer.
13. The solar cell according to any one of claims 1 to 6, characterized in that: The solar cell further comprises: a first doped semiconductor layer and an electrode; Wherein, the semiconductor substrate has a first surface; The first doped semiconductor layer is entirely or partially disposed on the first surface, and the dielectric layer is located on a side of the first doped semiconductor layer away from the semiconductor substrate; The dielectric layer covers the first active area and the second active area; the first active area is located at the edge of the second active area; The electrode is electrically connected to the first doped semiconductor layer.
14. A photovoltaic module, characterized in that: The invention comprises the solar cell according to any one of claims 1 to 13.