Patent Description:
Solar cells have good photoelectric conversion capabilities. A tunneling oxide layer and a doped conductive layer are generally prepared on a surface of a substrate to suppress carrier recombination on the surface of the substrate in the solar cell and enhance the passivation effect on the substrate. The tunneling oxide layer has good chemical passivation effect, and the doped conductive layer has good field passivation effect. In addition, in order to transport and collect photogenerated carriers generated by the solar cell, electrodes are also prepared on part of the surface of the substrate.

However, the existing solar cells are still low in photoelectric conversion efficiency.

<CIT> relates to a solar cell, a preparation method thereof and a photovoltaic module, where the solar cell comprises a tunneling oxide layer, a doped conductive layer and a first passivation layer which are located on the first surface of a substrate and are sequentially arranged in the direction away from the substrate; the first metal electrode penetrates through the first passivation layer to be electrically connected with the doped conductive layer, the second metal electrode is connected to the surface, facing the substrate, of the first metal electrode, the second metal electrode penetrates through the tunneling oxide layer to be in contact with the substrate, and the width of the second metal electrode is smaller than that of the first metal electrode; and the local doping region is located in the substrate, the local doping region wraps the second metal electrode located in the substrate, the local doping region and the substrate have doping elements of the same conduction type, and the doping concentration of the local doping region is larger than that of the substrate. The embodiment of the invention is beneficial to reducing the series resistance of the solar cell.

<CIT> relates to a solar cell, including: a substrate, an interface passivation layer covering a rear surface of the substrate, and an electrode disposed at a side of the interface passivation layer facing away from the substrate, the interface passivation layer including a first interface passivation sub-layer corresponding to a portion of the interface passivation layer between adjacent electrodes and a second interface passivation sub-layer corresponding to a portion of the interface passivation layer where disposed between the substrate and the electrode; a field passivation layer, at least partially disposed between the interface passivation layer and the electrode; and a conductive enhancement layer, at least partially disposed at a side of the first interface passivation sub-layer away from the substrate to enable carriers in the first interface passivation sub-layer to flow to the electrode, where a resistivity of the conductive enhancement layer is smaller than a resistivity of the field passivation layer.

Embodiments of the disclosure provide a solar cell, a method for manufacturing the solar cell, and a photovoltaic module, which are at least conducive to improving the photoelectric conversion efficiency of the solar cell.

In the present invention, the solar cell includes a substrate, a tunneling dielectric layer, a doped conductive layer, a plurality of first electrodes, at least one transmission layer, and at least one diffusion region. The tunneling dielectric layer and the doped conductive layer that are arranged over a first surface of the substrate in a direction away from the first surface of the substrate, where the doped conductive layer at least includes a plurality of main body portions arranged at intervals. The plurality of first electrodes arranged at intervals. Each of the plurality of first electrodes extends in a first direction. Each first electrode is disposed on a side of a corresponding main body portion facing away from the substrate and is electrically connected to the corresponding main body portion. Each transmission layer of the at least one transmission layer is disposed between a corresponding pair of adjacent main body portions of the plurality of main body portions and is in contact with a side surface of each of the corresponding pair of the adjacent main body portions. Each diffusion region of the at least one diffusion region is partially located in a corresponding transmission layer and extends into the tunneling dielectric layer and the substrate. A doping ion concentration of the each diffusion region is greater than a doping ion concentration of the substrate.

In some embodiments, the each diffusion region includes a first region in the substrate, a second region in the tunneling dielectric layer, and a third region in the corresponding transmission layer, where a doping ion concentration of the first region is less than a doping ion concentration of the second region, and the doping ion concentration of the second region is less than a doping ion concentration of the third region.

In some embodiments, a ratio of the doping ion concentration of the first region to the doping ion concentration of the substrate is in a range of <NUM>×<NUM><NUM> to <NUM>×<NUM><NUM>.

In some embodiments, in a direction perpendicular to the first surface, a ratio of a thickness of the first region to a thickness of the substrate is in a range of <NUM> to <NUM>.

In some embodiments, the thickness of the first region is in a range of <NUM> to <NUM>.

In some embodiments, in an arrangement direction of the plurality of main body portions, a width of the first region is in a range of <NUM> to <NUM>.

In some embodiments, a projection of the each diffusion region on a surface of the corresponding transmission layer has a rectangular shape, a circular shape, or a round-like shape.

In some embodiments, there are a plurality of diffusion regions in a respective transmission layer of the at least one transmission layer.

In some embodiments, the at least one diffusion region and the substrate are doped with doping ions of a same type.

In some embodiments, the at least one diffusion region and the substrate are doped with doping ions of different types.

In some embodiments, the substrate is doped with a doping ion of an N-type, and the substrate and the at least one transmission layer are doped with doping ions of a same type.

In the present invention, a material from which the at least one transmission layer is made is the same as a material from which the doped conductive layer is made.

In some embodiments, there are a plurality of transmission layers between each two adjacent first electrodes, and the plurality of transmission layers are arranged at intervals along the first direction.

In some embodiments, the at least one transmission layer is configured as a plurality of transmission layers, the plurality of transmission layers are arranged at intervals, and there is at least one first electrode between adjacent transmission layers.

In some embodiments, a top surface of the tunneling dielectric layer not covered by the plurality of main body portions is exposed.

In some embodiments, the doped conductive layer includes the plurality of main body portions and at least one connection portion. Each connection portion of the at least one connection portion is connected between the corresponding pair of the adjacent main body portions, and a top surface of the each connection portion away from the first surface is not higher than a top surface of the each of the corresponding pair of the adjacent main body portions away from the first surface.

In some embodiments, the solar cell further includes at least one second electrode, where each second electrode of the at least one second electrode extends in a direction perpendicular to the first direction, and is electrically connected to the plurality of the first electrodes.

Embodiments of the disclosure further provide a photovoltaic module. The photovoltaic module includes at least one cell string each including a plurality of solar cells, at least one encapsulating layer, and at least one cover plate. Each of the plurality of solar cells being a solar cell provided in any of the above embodiments. Each encapsulating layer is configured to cover a surface of the at least one cell string. Each cover plate is configured to cover a surface of a corresponding encapsulating layer of the at least one encapsulating layer facing away from the at least one cell string.

The present invention further provides a method for manufacturing a solar cell. The method includes the following. A substrate is provided. A tunneling dielectric layer and a doped conductive layer are arranged over a first surface of the substrate in a direction away from the first surface of the substrate. The doped conductive layer at least includes a plurality of main body portions arranged at intervals. At least one transmission layer is formed by forming a respective transmission layer between a corresponding pair of adjacent main body portions, where the respective transmission layer of the at least one transmission layer is in contact with a side surface of each of the corresponding pair of the adjacent main body portions. At least one diffusion region is formed. Each diffusion region of the at least one diffusion region is partially located in a corresponding transmission layer and extends into the tunneling dielectric layer and the substrate, where a doping ion concentration of the each diffusion region is greater than a doping ion concentration of the substrate. A respective first electrode is formed on a side of a corresponding main body portion of the plurality of main body portions away from the substrate to form a plurality of first electrodes. The plurality of first electrodes are arranged at intervals and extend along a first direction, and the respective first electrode is electrically connected to the corresponding main body portion.

In the present invention, the at least one transmission layer and the at least one diffusion region are doped with doping ions of a same type, and each diffusion region of the at least one diffusion region is formed as follows. Each diffusion region is formed by processing a predetermined region of the corresponding transmission layer with a laser process to diffuse doping ions on a top surface of the predetermined region of the transmission layer into the transmission layer, the tunneling dielectric layer, and the substrate. A doping ion concentration of the each diffusion region is greater than a doping ion concentration of the corresponding transmission layer.

In some embodiments, during the laser process, a laser wavelength used is in a range of <NUM> to <NUM>, a laser power used is in a range of 10W to 50W, a laser frequency used is in a range of <NUM> to <NUM>, and a laser pulse width used is in a range of 1ps to 10000ps.

Implementing the technical solutions of the disclosure has following advantageous effects.

According to the solar cell of the disclosure, by arranging the transmission layer between two adjacent main body portions and in contact with the side surface of the main body portion, the majority carriers can be transported into the adjacent main body portions through the transmission layer, and thus improving the transport efficiency of the carriers between the substrate and the doped conductive layer. In addition, the at least one diffusion region is provided. Each diffusion region is partially located in a corresponding transmission layer and extends into the tunneling dielectric layer and the substrate, where a doping ion concentration of the each diffusion region is greater than a doping ion concentration of the substrate. That is, the diffusion region is a heavily doped region to change Fermi level of the substrate around the diffusion region, so that carriers in the substrate around the diffusion region are more easily collected, and can arrive the transmission layer through the diffusion region, thereby further increasing the transport efficiency of the carriers by the transmission layer. Furthermore, since the diffusion region is partially located in the tunneling dielectric layer, the carriers can reach the doped conductive layer through the diffusion region in the tunneling dielectric layer without passing through the tunneling dielectric layer, which may further improve the transmission efficiency of the carriers, thereby preventing the tunneling dielectric layer <NUM> from blocking the carrier transmission and improving the carrier transmission efficiency and thus improving the photoelectric conversion efficiency of the solar cell.

One or more embodiments are described as examples with reference to the corresponding figures in the accompanying drawings and the exemplary description does not constitute a limitation to the embodiments. Unless otherwise stated, the figures in the accompanying drawings do not constitute a proportion limitation.

As discussed in the background art, the existing solar cells are still low in photoelectric conversion efficiency.

The analysis found that one of reasons for the low photoelectric conversion efficiency of the existing solar cells is that: to reduce absorption of light by the doped conductive layer, a doped conductive layer is arranged in a metallized region, and a doped conductive layer corresponding to a non-metallized region generally may be thinned or removed. However, in this way, the transmission capacity of carriers between doped conductive layers respectively corresponding to two adjacent electrodes on the substrate may be reduced. Furthermore, the lower the efficiency the carriers transported between the substrate and the doped conductive layer, the lower the power generation efficiency of the solar cell.

The present invention provides a solar cell. A corresponding transmission layer is disposed between each two adjacent main body portions of a doped conductive layer, which may provide a lateral transmission channel between the two adjacent main body portions for majority carriers, thereby improving the transmission efficiency of the carriers transported between the substrate and the doped conductive layer. In addition, a diffusion region is provided, part of the diffusion region is disposed in the transmission layer, and the diffusion region also extends into the tunneling dielectric layer and the substrate. A doping ion concentration of the diffusion region is greater than a doping ion concentration of the substrate. That is, the diffusion region is a heavily doped region to change Fermi level of the substrate around the diffusion region, so that carriers in the substrate around the diffusion region are more easily collected. Therefore, the carriers can arrive the transmission layer through the diffusion region, and are then transported to the doped conductive layer after passing through the transmission layer, thereby improving the transmission capability of the majority carriers. In addition, the carriers can reach the doped conductive layer through the diffusion region in the tunneling dielectric layer without passing through the tunneling dielectric layer, which may further improve the transmission efficiency of the carriers, thereby improving the photoelectric conversion efficiency of the solar cell.

The embodiments of the disclosure will be described in detail below with reference to the accompanying drawings. However, those of ordinary skill in the art can understand that, in various embodiments of the disclosure, many technical details are set forth in order to provide the reader with a better understanding of the disclosure. However, the technical solutions claimed in the disclosure may be realized even without these technical details and various changes and modifications based on the following embodiments.

<FIG> is a schematic top view of a solar cell according to embodiments of the disclosure. <FIG> is a schematic top view of a solar cell according to other embodiments of the disclosure. <FIG> is a schematic partial cross-sectional view of a solar cell according to embodiments of the disclosure. <FIG> is a partial enlarged view of part <NUM> in <FIG>.

As illustrated in <FIG>, a solar cell includes a substrate <NUM>, a tunneling dielectric layer <NUM>, a doped conductive layer <NUM>, a plurality of first electrodes <NUM>, at least one transmission layer <NUM>, and at least one diffusion region <NUM>. The tunneling dielectric layer <NUM> and the doped conductive layer <NUM> are sequentially arranged over a first surface of the substrate <NUM> and in a direction away from the first surface of the substrate <NUM>. The doped conductive layer <NUM> at least includes a plurality of main body portions <NUM> spaced apart from one another. The plurality of first electrodes <NUM> are arranged at intervals and extend in a first direction X. Each first electrode <NUM> is disposed on a side of a corresponding main body portion <NUM> facing away from the substrate <NUM> and is electrically connected to the corresponding main body portion <NUM>. Each transmission layer <NUM> is disposed between a corresponding pair of adjacent main body portions <NUM> and is in contact with a side surface of each of the corresponding pair of the adjacent main body portions <NUM>. Each diffusion region <NUM> is partially located in a corresponding transmission layer <NUM> and extends into the tunneling dielectric layer <NUM> and the substrate <NUM>. A doping ion concentration of each diffusion region <NUM> is greater than a doping ion concentration of the substrate <NUM>.

The substrate <NUM> is configured to absorb the incident light to produce photogenerated carriers. In some embodiments, the substrate <NUM> may be a silicon substrate. The silicon substrate may be made of at least one material selected from a group of consisting of single crystal silicon, polysilicon, amorphous silicon, and microcrystalline silicon. In other embodiments, the substrate <NUM> may be made of silicon carbide, organic materials, or multinary compounds. The multinary compounds may include, but are not limited to, materials such as perovskite, gallium arsenide, cadmium telluride, copper indium selenium, and the like.

In some embodiments, the substrate <NUM> is doped with a doping element of an N-type or a P-type. The N-type element may be a group-V element such as a phosphorus (P) element, a bismuth (Bi) element, an antimony (Sb) element, or an arsenic (As) element. The P-type element may be a group-III element, such as a boron (B) element, an aluminum (Al) element, a gallium (Ga) element, or an indium (In) element. For example, when the substrate <NUM> is a P-type substrate, the substrate <NUM> is doped with the doping element of the P-type. For another example, when the substrate <NUM> is an N-type substrate, the substrate <NUM> is doped with the doping element of the N-type.

In some embodiments, the solar cell is a tunnel oxide passivated contact solar cell. The substate <NUM> further has a second surface opposite to the first surface. Both the first surface and the second surface may be used to absorb the incident light or reflected light. In some embodiments, the first surface may be a rear surface of the substrate <NUM>, and the second surface may be a front surface of the substrate <NUM>. In some embodiments, the first surface may be the front surface of the substrate <NUM>, and the second surface may be the rear surface of the substrate <NUM>.

In some embodiments, the first surface of the substrate <NUM> may be a non pyramid-textured surface, such as a layered step shape, so that the tunneling dielectric layer <NUM> on the first surface of the substrate <NUM> has a high density and uniformity, and the tunneling dielectric layer <NUM> has a good passivation effect on the first surface of the substrate <NUM>. The second surface of the substrate <NUM> may be a pyramid-textured surface, to reduce light reflection of the second surface of the substrate <NUM> to the incident light, thereby increasing the absorption and utilization of the light.

In some embodiments, the tunneling dielectric layer <NUM> and the doped conductive layer <NUM> may form a passivation contact structure on the surface of the substrate <NUM>. By forming the tunneling dielectric layer <NUM> and the doped conductive layer <NUM>, recombination of carriers on the surface of the substrate <NUM> can be reduced, thereby increasing an open-circuit voltage of the solar cell and improving the photoelectric conversion efficiency of the solar cell. In addition, the tunneling dielectric layer <NUM> can also be used to avoid or prevent dopant of the doped conductive layer <NUM> from diffusing into the substrate <NUM>.

The doped conductive layer <NUM> is configured to form a field passivation layer, to enable minority carriers to escape from the interface, thereby reducing the concentration of the minority carriers, so that the carrier recombination rate on the interface of the substrate <NUM> is relatively low, and thus the open-circuit voltage, a short-circuit current, and a fill factor are relatively large, thereby improving the photoelectric conversion performance of the solar cell. In some embodiments, the doped conductive layer <NUM> and the substrate <NUM> are doped with doping elements of a same conductivity type. For example, the doped conductive layer <NUM> may be doped silicon, and the doped silicon may specifically be one or more of doped polysilicon, doped microcrystalline silicon, or doped amorphous silicon.

The doped conductive layer <NUM> includes the plurality of main body portions <NUM>. The main body portion <NUM> can be understood as a protruding structure of the doped conductive layer <NUM>. Each main body portion <NUM> extends along the first direction X. The plurality of main body portions <NUM> are arranged along a second direction Y. The first direction X is perpendicular to the second direction Y. By enabling the main body portion <NUM> to be electrically connected to the first electrode <NUM>, the first electrode <NUM> can easily collect carriers from the substrate <NUM>. In addition, the protruding structure is only provided at a part of the doped conductive layer <NUM> corresponding to the first electrode <NUM>, thereby reducing the parasitic light absorption effect of the remaining part of the doped conductive layer <NUM> not corresponding to the first electrode <NUM> and improving the utilization rate of light by the substrate <NUM>.

As illustrated in <FIG>, in some embodiments, the doped conductive layer <NUM> may merely include the plurality of main body portions <NUM> arranged at intervals. A top surface of the tunneling dielectric layer <NUM> not covered by the plurality of main body portions <NUM> is exposed. That is, no doped conductive layer <NUM> is provided on the surface of the substrate <NUM> corresponding to a non-metallized region. Compared with a metallized region (i.e., the surface of the substrate <NUM> corresponding to the first electrode <NUM>), the substrate <NUM> corresponding to the non-metallized region has a higher absorption utilization rate of the incident light.

In some embodiments, the tunneling dielectric layer <NUM> may be made of a dielectric material with a tunneling effect, including but not limited to, a silicon oxide material, a silicon nitride material, a silicon oxynitride material, an intrinsic amorphous silicon material, and an intrinsic polysilicon material. Specifically, the tunneling dielectric layer <NUM> may be formed by a silicon oxide layer including silicon oxide (SiOx). The silicon oxide has good passivation properties, and the carriers can easily tunnel through the silicon oxide layer.

In some embodiments, the tunneling dielectric layer <NUM> may have a thickness in a range of <NUM> to <NUM>, particularly <NUM> to <NUM>, and further particularly <NUM> to <NUM>. When the tunneling dielectric layer <NUM> has the thickness in this range, the tunneling dielectric layer <NUM> may not be too thin, which may be beneficial to simplify the process of forming the tunneling dielectric layer <NUM>. On the other hand, the tunneling dielectric layer <NUM> may not be too thick, which may be beneficial to avoid a relatively weak tunneling effect of the tunneling dielectric layer <NUM> due to the excessively large thickness.

As illustrated in <FIG>, in some embodiments, the doped conductive layer <NUM> may include the plurality of main body portions <NUM> and at least one connection portion <NUM>. Each connection portion <NUM> is connected between the adjacent main body portions <NUM>. A top surface of each connection portion <NUM> away from the first surface is not higher than a top surface of a corresponding main body portion <NUM> away from the first surface. In other words, a thickness of a part of the doped conductive layer <NUM> on the surface of the substrate <NUM> corresponding to the non-metallized region is thinner than that of the remaining part of the doped conductive layer <NUM> on the surface of the substrate <NUM> corresponding to the metallized region, so that the parasitic absorption of the incident light by the part of the doped conductive layer <NUM> corresponding to the non-metallized region can be reduced. In addition, the at least one connection portion <NUM> located in the non-metallized region can also provide a transmission channel for majority carriers between the adjacent main body portions <NUM>.

As can be seen, for the case in which the doped conductive layer <NUM> only includes the main body portions <NUM>, the part of the doped conductive layer <NUM> corresponding to the non-metallized region is removed. For the case in which the doped conductive layer <NUM> includes the main body portions <NUM> and the at least one connection portion, the part of the doped conductive layer <NUM> corresponding to the non-metallized region is thinned, so that the carrier transport capability of the substrate <NUM> corresponding to the non-metallized region is relatively weak. Therefore, a corresponding transmission layer <NUM> is disposed between each two adjacent main body portions <NUM>, which provides a lateral transmission channel between the two adjacent main body portions <NUM> for the majority carriers, so that the transmission efficiency of the carriers in the substrate <NUM> transported between the two adjacent main body portions <NUM> of the doped conductive layer <NUM> can be improved, thereby improving the fill factor and the photoelectric conversion efficiency of the solar cell.

In addition, in order to improve the transmission efficiency of the carriers between the substrate <NUM> and the transmission layer <NUM> to further improve the transmission efficiency of the carriers transported from the transmission layer <NUM> to the adjacent main body portions <NUM>, at least one diffusion region <NUM> is further provided. Each diffusion region <NUM> is partially located in a corresponding transmission layer <NUM>. A top surface of the diffusion region <NUM> is exposed, i.e., a surface of the transmission layer <NUM> away from the first surface is substantially flush with a surface of the diffusion region <NUM> away from the first surface. The diffusion region <NUM> further extends into the tunneling dielectric layer <NUM> and the substrate <NUM>. In other words, the diffusion region <NUM> penetrates through the transmission layer <NUM> and the tunneling dielectric layer <NUM> to be in contact with the substrate <NUM>.

Specifically, <FIG> and <FIG> illustrate schematic diagrams of the diffusion region facilitating carrier transport. Since a doping ion concentration of the diffusion region <NUM> is greater than a doping ion concentration of the substrate <NUM>, the Fermi level of the substrate <NUM> around the diffusion region <NUM> can be changed, so that the carriers in the substrate <NUM> around the diffusion region <NUM> are gathered around the diffusion region <NUM>. Therefore, the carriers in the substrate <NUM> are more easily collected through the diffusion region <NUM> and transported to the transmission layer <NUM>, and then transported from the transmission layer <NUM> to the main body portions <NUM>. Providing the diffusion region <NUM> is equivalent to providing an additional transmission channel for the carriers in the substrate <NUM>. The carriers in the substrate <NUM> can directly reach the transmission layer <NUM> through the diffusion region <NUM> without passing through the tunneling dielectric layer <NUM>, thereby preventing the tunneling dielectric layer <NUM> from blocking the carrier transmission and improving the carrier transmission efficiency.

Continue referring to <FIG>, in some embodiments, the diffusion region <NUM> includes a first region in the substrate <NUM>, a second region in the tunneling dielectric layer <NUM>, and a third region in the transmission layer <NUM>. A doping ion concentration of the first region is less than a doping ion concentration of the second region, and the doping ion concentration of the second region is less than a doping ion concentration of the third region. In other words, in a direction from the substrate <NUM> to the transmission layer <NUM>, the doping ion concentration of the diffusion region <NUM> may be increased gradually, so that a concentration gradient of doping ions of a same type is established in the substrate <NUM>, the tunneling dielectric layer <NUM>, and the transmission layer <NUM>, and a direction of the concentration gradient is the same as a transmission direction of the carriers. In this way, a barrier effect may be produced in the diffusion region <NUM> for the carriers, which can not only effectively collect the carriers and improve the transmission efficiency of the carriers, but also reduce the recombination of the carriers, increase the carrier concentration, and improve the short-circuit current and the open-circuit voltage of the solar cell.

It can be understood that in some embodiments, the doping ion concentration of the third region is greater than a doping ion concentration of the transmission layer <NUM>. That is, compared with the transmission layer <NUM>, the third region of the diffusion region <NUM> is a heavily doped region, which makes the third region of the diffusion region <NUM> have a lower square resistance, and thus has a smaller resistance loss. Therefore, the carrier transmission efficiency of the diffusion region <NUM> is further increased.

The doping ion concentration of the first region is greater than a doping ion concentration of the substrate <NUM>, so that the first region of the diffusion region <NUM> is a heavily doped region, and the heavily doped region can form a high-low junction with the substrate <NUM>, thereby reducing the recombination of the carriers on the surface of the substrate <NUM> and increasing the concentration of the carriers. In addition, the Fermi level of the substrate <NUM> in contact with the heavily doped region is changed, so that the carriers in the substrate <NUM> in contact with the heavily doped region are more easily collected, so as to improve the transmission rate of the carriers in the substrate <NUM> transmitted to the doped conductive layer <NUM>. In some embodiments, a ratio of the doping ion concentration of the first region to the doping ion concentration of the substrate <NUM> is set to <NUM>×<NUM><NUM>~<NUM>×<NUM><NUM>, for example, <NUM>×<NUM><NUM>~<NUM>×<NUM><NUM>, <NUM>×<NUM><NUM>~<NUM>×<NUM><NUM>,<NUM>×<NUM><NUM>~<NUM>×<NUM><NUM>, <NUM>×<NUM><NUM>~<NUM>×<NUM><NUM>, or <NUM>×<NUM><NUM>~<NUM>×<NUM><NUM>. When the ratio of the doping ion concentration of the first region to the doping ion concentration of the substrate is within this range, the first region of the diffusion region <NUM> and the substrate <NUM> form the high-low junction to reduce the recombination of the carriers, and the Fermi level of the substrate <NUM> around the first region can be easily changed, thereby improving the collection efficiency of the carriers in the substrate <NUM> and the transmission rate of the carriers.

In some embodiments, in a direction perpendicular to the first surface, a ratio of a thickness of the first region of the diffusion region <NUM> to the thickness of the substrate <NUM> is <NUM>~<NUM>, for example, <NUM>~<NUM>, <NUM>~<NUM>, <NUM>~<NUM>, <NUM>~<NUM>, <NUM> ~<NUM>, <NUM>~<NUM>, <NUM>~<NUM>, <NUM>~<NUM>, or <NUM>~<NUM>. When the ratio of the thickness of the first region to the thickness of the substrate <NUM> is within this range, the first region has a relatively deep depth in the substrate <NUM>, so that an area of the substrate <NUM> in contact with the first region of the diffusion region <NUM> is relatively large. Therefore, the area of the substrate <NUM> where the Fermi level is changed is relatively large and more carriers can be collected. In addition, when the ratio of the thickness of the first region to the thickness of the substrate <NUM> is within this range, the thickness of the first region of the diffusion region <NUM> is not too large compared to the thickness of the substrate <NUM>, so that the first region does not have too deep depth in the substrate <NUM>, which may prevent the performance of the substrate <NUM> from being affected due to the excessively large proportion of the heavily doped region in the substrate <NUM>. Therefore, in some embodiments, the first region of the diffusion region <NUM> may have a thickness in a range of <NUM>~<NUM>. Specifically, in some embodiments, the thickness of the first region may be <NUM>~<NUM>, <NUM>~<NUM>, <NUM>~<NUM>, <NUM>~<NUM>, <NUM>~<NUM>, <NUM>~<NUM>, or <NUM>~<NUM>.

In some embodiments, along the second direction Y, a width of the first region of the diffusion region <NUM> is <NUM>~<NUM>, and the second direction Y is an arrangement direction of the plurality of main body portions <NUM>. When the width of the first region is within this range, the first region of the diffusion region <NUM> is relatively wide, so that the area of the substrate <NUM> in contact with the first region is relatively large, and thus the collection rate of the carriers in the substrate <NUM> can be increased. In addition, since the width of the first region of the diffusion region <NUM> is relatively large, the number of the carriers transported through the diffusion region <NUM> can also be increased, thereby increasing the transmission rate of the carriers. On the other hand, when the width of the first region is within this range, the first region of the diffusion region <NUM> is not too wide, thereby preventing the Auger recombination of the carriers in the substrate <NUM> due to the excessively large area of the heavily doped region. Specifically, in some embodiments, the width of the first region of the diffusion region may be in a range of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, or <NUM> to <NUM>.

It can be understood that, in some embodiments, the width of the third region, a width of the second region, and the width of the first region of the diffusion region <NUM> are equal. Therefore, by arranging the width of the first region of the diffusion region <NUM> not too large, the width of the third region and the width of the second region of the diffusion region <NUM> are also not too large. In this way, it is possible to prevent the overall doping concentration of the transmission layer <NUM> from being too high due to the excessively large width of the third region located in the transmission layer <NUM>, thereby avoiding a large Auger recombination of the carriers located in the transmission layer <NUM> and a reduced concentration of doping ions transported into the doped conductive layer <NUM>. In addition, the second region of the diffusion region <NUM> accounts for a small proportion of the tunneling dielectric layer <NUM>, such that it is possible to avoid affecting the interface passivation performance of the tunneling dielectric layer <NUM> due to the large area of the second region located in the tunneling dielectric layer <NUM>.

In embodiments of the disclosure, the diffusion region <NUM> is merely provided in part of the transmission layer <NUM>, part of the tunneling dielectric layer, and part of the substrate <NUM>, that is, the diffusion region <NUM> is used as a local doped region. Therefore, the diffusion region <NUM> may be functioned as a carrier transport channel, and normal performance of the transmission layer <NUM>, the tunneling dielectric layer, and the substrate <NUM> may be maintained, thereby improving the overall photoelectric conversion performance of the solar cell. In some embodiments, a projection of each diffusion region <NUM> on a surface of the corresponding transmission layer <NUM> has a rectangular shape, a circular shape, or a round-like shape. It can be understood that there is no restriction on the shape of the projection of the diffusion region <NUM> on the surface of the transmission layer <NUM>.

In some embodiments, there are a plurality of diffusion regions <NUM> in each of the at least one transmission layer <NUM>. In this way, the majority carriers in the substrate <NUM> can be simultaneously provided with a plurality of lateral transmission channels between the two adjacent main body portions <NUM>, so that a rate at which the carriers are transported to the doped conductive layer <NUM> at a same time can be improved. Specifically, in some embodiments, there are two, three, or four diffusion regions <NUM> in a same transmission layer <NUM>.

In some embodiments, a doping ion type of the substrate <NUM> is an N-type. The substrate <NUM> is doped with doping ions of the N-type, such as phosphorus ions, bismuth ions, antimony ions, or arsenic ions.

In some embodiments, the at least one diffusion region <NUM> and the substrate <NUM> are doped with doping ions of a same type. For example, the at least one diffusion region <NUM> is doped with doping ions of the N-type and the substrate <NUM> is doped with the doping ions of the N-type. For another example, when the substrate <NUM> is doped with doping ions of a P-type, the at least one diffusion region <NUM> is doped with doping ions of the P-type. The diffusion region <NUM> and the substrate <NUM> are doped with the doping ions of the same type, and the doping ion concentration of the diffusion region <NUM> is greater than the doping ion concentration of the substrate <NUM>, so that the diffusion region <NUM> and the substrate <NUM> form a high-low junction, and thus the diffusion region <NUM> can reduce the recombination of the carriers on the interface of the substrate <NUM>, thereby increasing the concentration of the carriers.

In other embodiments, the diffusion region <NUM> and the substrate <NUM> are doped with doping ions of different types. For example, when the diffusion region <NUM> is doped with the doping ions of the N-type, the substrate <NUM> is doped with the doping ions of the P-type. Alternatively, when the substrate <NUM> is doped with the doping ions of the N-type, the diffusion region <NUM> is doped with the doping ions of the P-type. As can be seen, there is no restriction on the type of the doping ions in the diffusion region <NUM> and the substrate <NUM>, and merely the doping ion concentration of the diffusion region <NUM> being greater than the doping ion concentration of the substrate <NUM> needs to be met.

In the present invention, a material from which the at least one transmission layer <NUM> is made is the same as a material from which the doped conductive layer <NUM> is made. By enabling the transmission layer <NUM> and the doped conductive layer <NUM> to be made of the same material, the types of materials in the entire production process can be reduced, so as to facilitate management. In addition, by enabling the transmission layer <NUM> and the doped conductive layer <NUM> to be made of the same material, the carriers may have a similar or same transmission rate in the transmission layer <NUM> and the doped conductive layer <NUM>, so that the transmission efficiency of the carriers transmitted from the transmission layer <NUM> to the main body portions <NUM> of the doped conductive layer <NUM> can be improved, and the transmission loss can be reduced. Specifically, in some embodiments, the transmission layer <NUM> and the doped conductive layer <NUM> each may be made of at least one material selected from a group of consisting of polysilicon, amorphous silicon, and microcrystalline silicon. In other embodiments, the transmission layer <NUM> and the doped conductive layer <NUM> each may be made of one material of doped amorphous silicon, doped polysilicon, and doped microcrystalline silicon.

In some embodiments, there are a plurality of transmission layers <NUM> between each two adjacent first electrodes <NUM>. The plurality of transmission layers <NUM> are arranged at intervals along the first direction X. In other words, the plurality of transmission layers <NUM> are spaced apart from each other, such that a surface of the tunneling dielectric layer <NUM> between adjacent transmission layers <NUM> may be exposed, that is, an overall area of the transmission layers <NUM> may not be too large. Since the transmission layers <NUM> and the doped conductive layer <NUM> are made of same materials, when the overall area of the transmission layers <NUM> is not too large, it is possible to avoid that the substrate <NUM> has a low utilization rate to the incident light due to the excessive light absorption ability of the transmission layers <NUM> to the incident light. In addition, by arranging the plurality of transmission layers <NUM> and providing a corresponding diffusion region <NUM> in a respective transmission layer <NUM>, it is possible to provide a plurality of transmission channels for the transmission of the majority carriers in the substrate <NUM> between the adjacent main body portions <NUM>, thereby further improving the lateral transmission capability of the solar cell.

In some embodiments, the at least one transmission layer <NUM> is configured as a plurality of transmission layers <NUM>. The plurality of transmission layers <NUM> are arranged at intervals. There is at least one first electrode <NUM> disposed between adjacent transmission layers <NUM>. In other words, the plurality of transmission layers <NUM> are arranged along the second direction Y, where the second direction Y is the arrangement direction of the plurality of main body portions <NUM>. Since the first electrode <NUM> is disposed on the main body portion <NUM>, the first electrode <NUM> is configured to collect carriers transmitted to the main body portion <NUM>. The more carriers transmitted to the main body portion <NUM>, the more carriers collected by the first electrode <NUM>. The at least one first electrode <NUM> is arranged between the adjacent transmission layers <NUM>, in other words, the transmission layer <NUM> is arranged between a plurality of adjacent first electrodes <NUM>, so that the collection efficiency of the carriers by the plurality of first electrodes <NUM> can be improved. Specifically, along the second direction Y, the at least one first electrode <NUM> is arranged between the adjacent transmission layers <NUM>. When there is only one first electrode <NUM> between the adjacent transmission layers <NUM>, there is a corresponding transmission layer <NUM> disposed between each two adjacent main body portions <NUM>. When there are a plurality of first electrodes <NUM> disposed between the adjacent transmission layers <NUM>, the transmission layers <NUM> are discontinuously disposed. For example, in the second direction Y, there is a transmission layer <NUM> between the first of the first electrodes <NUM> and the second of the first electrodes <NUM>, and there is no transmission layer <NUM> between the second of the first electrodes <NUM> and the third of the first electrodes <NUM>.

In some embodiments, the solar cell further includes a first passivation layer <NUM>. The first passivation layer <NUM> covers the plurality of main body portions and the at least one transmission layer <NUM>. The first electrode <NUM> penetrates through the first passivation layer <NUM> to be electrically connected to the main body portion <NUM>. The first passivation layer <NUM> is configured to reduce the reflection of the incident light by the substrate <NUM>. In some embodiments, the first passivation layer <NUM> may be a single-layer or multi-layer structure. The first passivation layer <NUM> may be made of at least one material selected from a group of consisting of magnesium fluoride, silicon oxide, aluminum oxide, silicon oxynitride, silicon nitride, and titanium oxide.

In some embodiments, the solar cell further includes at least one second electrode <NUM>. Each second electrode <NUM> extends in a direction perpendicular to the first direction X, and is electrically connected to the plurality of first electrodes <NUM>. The at least one second electrode is configured to gather current collected by the first electrode <NUM> and transmit the current from the solar cell to the outside.

In some embodiments, the transmission layer <NUM> and the second electrode <NUM> are spaced from each other. In this way, the second electrode can be limited by the transmission layer <NUM>, so as to facilitate printing of the second electrode, so that the position of the second electrode can be determined without additional positioning processing, which is convenient for the process production.

In some embodiments, the second surface of the substrate <NUM> may be provided with an emitter (not illustrated). The emitter and the doped conductive layer <NUM> may be doped with doping ions of different types. In some embodiments, an antireflection layer may be provided on a surface of the emitter away from the substrate <NUM>, and the antireflection layer may play the role of anti-reflection for the incident light. In some embodiments, the antireflection layer may be a silicon nitride layer, and the silicon nitride layer may be made of a silicon nitride material. In other embodiments, the antireflection layer may be a multi-layer structure, for example, a stacked layer structure including one or more materials selected from silicon nitride, silicon oxide, or silicon oxynitride.

In some embodiments, the second surface of the substrate <NUM> may also be provided with a structure which is similar to that on the first surface of the substrate <NUM>. For example, a second tunneling dielectric layer and a second doped conductive layer are stacked in sequence over the second surface of the substrate <NUM> and in a direction away from the second surface of the substrate <NUM>. The second doped conductive layer and the doped conductive layer <NUM> may be doped with doping ions of different types.

In some embodiments, the solar cell further includes at least one third electrode (not illustrated). The at least one third electrode is disposed on the second surface of the substrate <NUM>. When the emitter is provided on the second surface of the substrate <NUM>, the at least one third electrode penetrates through the antireflection layer to be electrically connected to the emitter. When the second surface of the substrate <NUM> has a structure similar to that on the first surface of the substrate <NUM>, the at least one third electrode is electrically connected to the second doped conductive layer.

In the solar cell provided in the foregoing embodiments, the transmission layer <NUM> is arranged between the two adjacent main body portions <NUM> of the doped conductive layer <NUM>, which may provide a lateral transmission channel between the two adjacent main body portions <NUM> for the majority carriers and improve the transmission efficiency of the carriers transported between the substrate <NUM> and the doped conductive layer <NUM>. In addition, the at least one diffusion region <NUM> is provided, and each diffusion region <NUM> is partially located in the transmission layer <NUM>, and the diffusion region <NUM> also extends into the tunneling dielectric layer <NUM> and the substrate <NUM>. The doping ion concentration of the diffusion region <NUM> is greater than that of the substrate <NUM>. That is, the diffusion region <NUM> is a heavily doped region to change the Fermi energy level of the substrate <NUM> around the diffusion region <NUM>, so that the carriers in the substrate <NUM> around the diffusion region <NUM> can be more easily collected, then can reach the transmission layer <NUM> through the diffusion region <NUM>, and finally are transported to the doped conductive layer <NUM> through the transmission layer <NUM>, thereby improving the transmission capacity of the majority carriers. Furthermore, the carrier can reach the doped conductive layer <NUM> through the diffusion region <NUM> located in the tunneling dielectric layer <NUM> without passing through the tunneling dielectric layer <NUM>, which further improves the transmission efficiency of the carriers, thereby improving the photoelectric conversion efficiency of the solar cell.

Embodiments of the disclosure further provide a photovoltaic module. As illustrated in <FIG>, the photovoltaic module includes one or more cell strings. Each cell string is formed by connecting a plurality of solar cells <NUM>. Each of the plurality of solar cells <NUM> is a solar cell provided in the above embodiments. The photovoltaic module further includes at least one encapsulating layer <NUM> and at least one cover plate <NUM>. Each encapsulating layer <NUM> is configured to cover a surface of each of the at least one cell string. Each cover plate <NUM> is configured to cover a surface of a corresponding encapsulating layer of the at least one encapsulating layer <NUM> facing away from the at least one cell string. The solar cells <NUM> are electrically connected in the form of a whole piece or multiple pieces to form a plurality of cell strings, and the plurality of cell strings are electrically connected in series and/or parallel.

In some embodiments, the plurality of solar cells can be electrically connected through a conductive tape <NUM> and the plurality of cell strings can also be electrically connected through a conductive tape <NUM>. The encapsulation layer <NUM> is configured to cover the front surface and the back surface of the solar cell <NUM>. Specifically, the encapsulation layer <NUM> may be an organic encapsulation adhesive film such as an ethylene-vinyl acetate copolymer (EVA) adhesive film, a polyethylene octene co-elastomer (POE) adhesive film, or a polyethylene terephthalate (PET) adhesive film. In some embodiments, the cover plate <NUM> may be a cover plate <NUM> with a light-transmitting function, such as a glass cover plate, a plastic cover plate, or the like. Specifically, a surface of the cover plate <NUM> facing the encapsulation layer <NUM> may be an uneven surface, thereby increasing the utilization rate of the incident light.

The present invention further provides a method for manufacturing a solar cell. The method for manufacturing the solar cell can form the solar cell provided in the foregoing embodiments of the disclosure. The following may describe in detail the method for manufacturing the solar cell provided by another embodiment of the disclosure with reference to the accompanying drawings.

<FIG> are schematic views illustrating a respective structure corresponding to each operation of a method for manufacturing a solar cell according to embodiments of the disclosure.

As illustrated in <FIG>, the substrate <NUM> is provided.

The substrate <NUM> is configured to absorb incident light to produce photogenerated carriers. In some embodiments, the substrate <NUM> is a silicon substrate, and the silicon substrate may be made of at least one material of single crystal silicon, polysilicon, amorphous silicon, and microcrystalline silicon. In other embodiments, the substrate <NUM> may be made of materials such as silicon carbide, organic materials, or multinary compounds. The multinary compounds may include, but are not limited to, materials such as perovskite, gallium arsenide, cadmium telluride, copper indium selenium, and the like.

In some embodiments, the substrate <NUM> is doped with a doping element of an N-type or a P-type. The N-type element may be a group-V element such as a phosphorus (P) element, a bismuth (Bi) element, an antimony (Sb) element, or an arsenic (As) element. The P-type element may be a group-III element such as a boron (B) element, an aluminum (Al) element, a gallium (Ga) element, or an indium (In) element. For example, when the substrate <NUM> is a P-type substrate, the substrate <NUM> is doped with the doping element of the P-type. For another example, when the substrate <NUM> is an N-type substrate, the substrate <NUM> is doped with the doping element of the N-type.

Referring to <FIG>, the tunneling dielectric layer <NUM> and the doped conductive layer <NUM> are sequentially arranged over the first surface of the substrate <NUM> and in the direction away from the first surface of the substrate <NUM>. The doped conductive layer <NUM> at least includes the plurality of main body portions <NUM> arranged at intervals.

As illustrated in <FIG>, the tunneling dielectric layer <NUM> is used to achieve interface passivation of the substrate <NUM>. In some embodiments, the tunneling dielectric layer <NUM> may be formed by a deposition process, such as a chemical vapor deposition process. In other embodiments, the tunneling dielectric layer <NUM> can be formed by an in-situ synthesis process. For example, the tunneling dielectric layer <NUM> may be an in-situ formed tunneling dielectric layer on the substrate <NUM> by a thermal oxidation process and nitric acid passivation process. Specifically, the tunneling dielectric layer <NUM> may be made of a dielectric material, such as silicon oxide.

The doped conductive layer <NUM> is configured to form field passivation. In some embodiments, the material of the doped conductive layer <NUM> can be doped silicon. Specifically, in some embodiments, the doped conductive layer <NUM> and the substrate <NUM> are doped with doping elements of a same conductivity type. The doped silicon may include one or more of doped polysilicon, doped microcrystalline silicon, or doped amorphous silicon.

In some embodiments, each main body portion <NUM> may be formed as follows.

As illustrated in <FIG>, an initial doped conductive layer <NUM> is formed by the deposition process. Specifically, intrinsic polysilicon can be deposited on a surface of the tunneling dielectric layer <NUM> away from the substrate <NUM> to form a polysilicon layer, and the polysilicon layer is doped with doping ions by ion implantation and source diffusion to form a doped polysilicon layer, and the doped polysilicon layer is used as the initial doped conductive layer <NUM>.

As illustrated in <FIG>, a patterning process is performed on the initial doped conductive layer <NUM>. A preset region of the initial doped conductive layer <NUM> is etched by an etching process, and thus a remaining part of the initial doped conductive layer <NUM> other than the preset region forms the main body portions <NUM>. In some embodiments, when the doped conductive layer <NUM> merely includes the plurality of main body portions <NUM> arranged at intervals, and a top surface of the tunneling dielectric layer <NUM> between adjacent main body portions <NUM> is exposed, the preset region of the initial doped conductive layer <NUM> may be completely etched by the etching process until the top surface of the tunneling dielectric layer <NUM> is exposed. In other embodiments, the doped conductive layer <NUM> may include the plurality of main body portions <NUM> and the at least one connection portion <NUM>. The connection portion <NUM> is connected between the adjacent main body portions <NUM>, and a top surface of the connection portion <NUM> away from the first surface is not higher than a top surface of the main body portion <NUM> away from the first surface. In this case, the preset region of the initial doped conductive layer <NUM> is etched by the etching process to a predetermined thickness.

As illustrated in <FIG>, the corresponding transmission layer <NUM> is formed between each two adjacent main body portions <NUM> and is in contact with a side surface of each of the two adjacent main body portions <NUM>. It can be understood that, since the doped conductive layer <NUM> between the adjacent main body portions <NUM> is thinned or removed, the carriers in the substrate <NUM> have poor transport ability between the two adjacent main body portions <NUM>. Therefore, arranging the transmission layer <NUM> between the two adjacent main body portions <NUM> provides for the majority carriers a lateral transport channel between the two adjacent body portions <NUM>.

In the present invention, the transmission layer <NUM> and the doped conductive layer <NUM> are made of a same material. Therefore, a method of forming the transmission layer <NUM> may be the same as the method of forming the doped conductive layer <NUM>. Specifically, an initial transmission layer <NUM> mat be formed between the two adjacent main body portions <NUM> by adopting a deposition process, and a side wall of the initial transmission layer <NUM> is in contact with the side surface of the main body portion <NUM>. The initial transmission layer <NUM> may be an intrinsic polysilicon layer. Thereafter, the initial transmission layer <NUM> is subjected to a doping process by means of ion implantation and source diffusion, to implant doping ions into the initial transmission layer <NUM> to form the transmission layer <NUM>.

Specifically, in some embodiments, when the doped conductive layer <NUM> merely includes the plurality of main body portions <NUM> spaced apart from each other, the initial transmission layer <NUM> may be deposited on the surface of the tunneling dielectric layer <NUM> between the two adjacent body portions <NUM>.

In other embodiments, when the doped conductive layer <NUM> includes the plurality of main body portions <NUM> and the at least one connection portion <NUM>, and the connection portion <NUM> is connected between the adjacent main body portions <NUM>, the initial transmission layer <NUM> may be deposited on a top surface of the connection portion <NUM>.

As illustrated in <FIG>, at least one diffusion region <NUM> is formed. Each diffusion region is partially located in a corresponding transmission layer <NUM>, and the diffusion region <NUM> also extends into the tunneling dielectric layer <NUM> and the substrate <NUM>. The doping ion concentration of each diffusion region <NUM> is greater than the doping ion concentration of the substrate <NUM>. The diffusion region <NUM> penetrates through the transmission layer <NUM> and the tunneling dielectric layer <NUM> to be in contact with the substrate <NUM>. Since the doping ion concentration of the diffusion region <NUM> is greater than the doping ion concentration of the substrate <NUM>, the Fermi level of the substrate <NUM> around the diffusion region <NUM> can be changed, so that the carriers in the substrate <NUM> around the diffusion region <NUM> are concentrated around the diffusion region <NUM>. Therefore, the carriers in the substrate <NUM> are more easily collected through the diffusion region <NUM> and transported to the transmission layer <NUM>, and then transported from the transmission layer <NUM> to the main body portion <NUM>. Providing the diffusion region <NUM> is equivalent to providing an additional transmission channel for the carriers in the substrate <NUM>. The carriers in the substrate <NUM> can directly reach the transmission layer <NUM> through the diffusion region <NUM> without passing through the tunneling dielectric layer <NUM>, thereby preventing the tunneling dielectric layer <NUM> from blocking the carrier transmission and improving the carrier transmission efficiency.

In the present invention, the transmission layer <NUM> and the diffusion region <NUM> are doped with doping ions of a same type. Each diffusion region <NUM> is formed as follows. A predetermined region of the transmission layer <NUM> is processed by a laser process, to diffuse doping ions on a top surface of the predetermined region of the transmission layer <NUM> into the transmission layer <NUM>, the tunneling medium layer <NUM>, and the substrate <NUM> to form the diffusion region <NUM>. The doping ion concentration of the diffusion region <NUM> is greater than the doping ion concentration of the transmission layer <NUM>. After the doping process is performed on the initial transmission layer <NUM> to form the transmission layer <NUM>, a doping source concentration of a top surface of the transmission layer <NUM> is greater than a doping source concentration inside the transmission layer <NUM>. Therefore, after the top surface of the predetermined region of the transmission layer <NUM> is processed by the laser process, a doping source on the top surface of the predetermined region of the transmission layer <NUM> may diffuse into the transmission layer <NUM>, the tunneling dielectric layer <NUM>, and the substrate <NUM> under the thermal effect of the laser. In other words, the doping source on the top surface of the transmission layer <NUM> after laser processing is diffused into the transmission layer <NUM>, so that the doping ion concentration of the formed diffusion region <NUM> is greater than that of the transmission layer <NUM>. Since the doping ion concentration of the substrate <NUM> is less than that of the transmission layer <NUM>, the doping ion concentration of the diffusion region <NUM> may be greater than the doping ion concentration of the substrate <NUM>.

Specifically, in some embodiments, the substrate is doped with doping ions of the N-type. The substrate and the transmission layer are doped with doping ions of a same type. That is, the transmission layer is also doped with doping ions of the N-type. Therefore, the doping source in the transmission layer may be an N-type doping element, such as a phosphorus element.

As illustrated in <FIG>, after the transmission layer <NUM> is formed, a layer of phosphorous silicate glass layer <NUM> is formed on the top surface of the transmission layer <NUM> through thermal oxidation treatment. The phosphorous silicate glass layer <NUM> stores more phosphorus sources.

After the phosphorous silicate glass layer <NUM> is formed, the laser processing is performed on a preset region of the phosphorous silicate glass layer <NUM> by a laser process. Since the phosphorous silicate glass layer <NUM> has a high concentration of phosphorous source, under the thermal effect of the laser process, phosphorus atoms in the phosphorous silicate glass layer can be implanted into the transmission layer <NUM>, the diffusion region <NUM>, and the substrate <NUM>. Therefore, the formed diffusion region <NUM> and the substrate <NUM> may be doped with doping ions of the same type. In addition, since the structure of the phosphorous silicate glass layer <NUM> is relatively hard, the phosphorous silicate glass layer <NUM> can also protect the top surface of the transmission layer <NUM> to a certain extent, so as to avoid damage to the top surface of the transmission layer <NUM> during the laser processing.

In some embodiments, after forming the diffusion region <NUM>, the method further includes: removing the phosphorous silicate glass layer <NUM>.

It can be understood that, in other embodiments, when the type of doping ions in the formed diffusion region needs to be different from the type of doping ions in the substrate, the substrate can be doped with doping ions of the N-type, and the transmission layer <NUM> can be doped with doping ions of the P-type. That is, the doping source in the transmission layer can be a P-type doping element, for example, a boron element. After the transmission layer is formed, a borosilicate glass layer is formed on the top surface of the transmission layer through thermal oxidation treatment, and more boron sources are stored in the phosphorous silicate glass layer <NUM>.

The diffusion region <NUM> is formed by the laser process, so that the diffusion region <NUM> can be formed only in the laser-treated region, and local heavily doping of the transmission layer <NUM>, the tunneling dielectric layer <NUM>, and the substrate <NUM> can be realized. Therefore, the transmission efficiency of the carriers may be improved, and the normal performance of the transmission layer <NUM>, the tunneling dielectric layer <NUM>, and the substrate <NUM> can also be maintained.

In some embodiments, a laser wavelength used in the laser process may be <NUM>~<NUM>, for example, <NUM>~<NUM>, <NUM>~<NUM>, <NUM>~<NUM>, or <NUM>~<NUM>. A laser power used in the laser process may be 10W~50W, for example, 10W~20W, 20W~30W, 30W~40W, or 40W~50W. A laser frequency used in the laser process may be <NUM>~<NUM>, for example, <NUM>~<NUM>, <NUM>~<NUM>, <NUM>~<NUM>, <NUM>~<NUM>, or <NUM>~<NUM>. A laser pulse width used in the laser process may be 1ps~10000ps, for example, 1ps~1000ps, 1000ps~2000ps, 2000ps~4000ps, 4000ps~6000ps, 6000ps~8000ps, or 8000ps~10000ps. Within this range, it can be guaranteed that the doping source on the top surface of the transmission layer <NUM> may be diffused into the tunneling dielectric layer <NUM> and the substrate <NUM> after the laser process, so that a connected transmission channel may be formed in the transmission layer <NUM>, the tunneling dielectric layer <NUM>, and the substrate <NUM>. In addition, the depth and the width of the diffusion region <NUM> in the substrate <NUM> can also be controlled by the laser process, so that the shape of the diffusion region <NUM> can meet expectations.

As illustrated in <FIG>, in some embodiments, the method further includes the following. The first passivation layer <NUM> is formed on a side of the main body portions <NUM> away from the substrate <NUM>. The first passivation layer <NUM> is disposed on a tope surface of each main body portion <NUM> and a top surface of each transmission layer <NUM>. In some embodiments, the first passivation layer <NUM> may be a single-layer or multi-layer structure, and the first passivation layer <NUM> may be made of at least one material selected from a group of consisting of magnesium fluoride, silicon oxide, aluminum oxide, silicon oxynitride, silicon nitride, and titanium oxide. Specifically, in some embodiments, the first passivation layer <NUM> may be formed by using a plasma enhanced chemical vapor deposition (PECVD) method.

In some embodiments, after the first passivation layer <NUM> is formed, a respective first electrode <NUM> is formed on a side of a corresponding main body portion <NUM> of the plurality of main body portions <NUM> away from the substrate <NUM>. The first electrodes <NUM> are arranged at intervals and extend along the first direction X. Each first electrode <NUM> is electrically connected to the corresponding main body portion <NUM>.

In some embodiments, each first electrode <NUM> is formed as follows. Conductive paste is printed on a top surface of the first passivation layer <NUM> corresponding to the main body portion <NUM>. The conductive material in the conductive paste can be at least one of silver, aluminum, copper, tin, gold, lead, or nickel. The conductive paste is sintered, for example, the conductive paste is sintered at a peak temperature from <NUM> to <NUM>, to form the first electrode <NUM>.

In some embodiments, the method further includes the following. At least one second electrode is formed. Each second electrode extends in a direction perpendicular to the first direction X, and is electrically connected to the plurality of the first electrodes <NUM>.

In some embodiments, the method of forming the second electrode may be the same as the method of forming the first electrode <NUM>. Specifically, each second electrode is formed as follows. Conductive paste is printed on a top surface of a specific region of the first passivation layer <NUM> and each of the first electrodes <NUM>. The conductive material in the conductive paste can be at least one of silver, aluminum, copper, tin, gold, lead, or nickel. The conductive paste is sintered, for example, the conductive paste is sintered at a peak temperature from <NUM> to <NUM>, to form the second electrode.

In the method of manufacturing the solar cell provided in foregoing embodiments, the transmission layer <NUM> is formed between the two adjacent main body portions <NUM> of the doped conductive layer <NUM> to provide lateral transport channels for majority carriers between the two adjacent main body portions <NUM>. In addition, the at least one diffusion region <NUM> is also formed, part of the diffusion region <NUM> is located in the transmission layer <NUM>, and the diffusion region <NUM> also extends into the tunneling dielectric layer <NUM> and the substrate <NUM>. The doping ion concentration of the diffusion region <NUM> is greater than that of the substrate <NUM>. The diffusion region <NUM> is used as the heavily doped region to change the Fermi level of the substrate <NUM> around the diffusion region <NUM>, so that the carriers in the substrate <NUM> around the diffusion region <NUM> are more easily collected. Therefore, the carriers can reach the transmission layer <NUM> through the diffusion region <NUM>, and then be transported to the doped conductive layer <NUM> through the transmission layer <NUM>, thereby improving the transport capability of the majority carriers.

Claim 1:
A solar cell, comprising:
a substrate (<NUM>);
a tunneling dielectric layer (<NUM>) disposed over a first surface of the substrate and a doped conductive layer (<NUM>) disposed on a surface of the tunneling dielectric layer away from the first surface of the substrate, wherein the doped conductive layer comprises a plurality of main body portions (<NUM>) arranged at intervals;
a plurality of first electrodes (<NUM>) arranged at intervals, each of the plurality of first electrodes extending in a first direction (X), wherein each first electrode is disposed on a side of a corresponding main body portion facing away from the substrate and is electrically connected to the corresponding main body portion;
at least one transmission layer (<NUM>), wherein each transmission layer of the at least one transmission layer is disposed between a corresponding pair of adjacent main body portions of the plurality of main body portions and is in contact with a side surface of each of the corresponding pair of the adjacent main body portions, wherein the at least one transmission layer and the doped conductive layer include a same material; and
at least one diffusion region (<NUM>), wherein the at least one diffusion region and the at least one transmission layer are doped with doping ions of a same type, wherein each diffusion region of the at least one diffusion region is partially located in a corresponding transmission layer and extends into the tunneling dielectric layer and the substrate, wherein a doping ion concentration of the each diffusion region is greater than a doping ion concentration of the substrate and greater than a doping ion concentration of the corresponding transmission layer;
wherein the at least one transmission layer is configured to provide a lateral transmission channel between two adjacent main body portions for majority carriers and to improve transmission efficiency of the carriers transported between the substrate and the doped conductive layer.