Patent Description:
Tunnel Oxide Passivating Contacts solar cell (TOPCon) was proposed in <NUM>. The solar cell includes a tunnel oxide layer and a doped polysilicon layer. The tunnel oxide layer can selectively transport carriers, and the doped polysilicon layer acts as field passivation. The electrodes of the solar cell penetrate a functional layer (such as an anti-reflection layer) located in the electrode region and contact the doped polysilicon layer.

The doped polysilicon layer in the solar cell has optical parasitic effects, which results in a decrease in the solar cell's utilization of incident light. Reducing the thickness of the doped polysilicon layer can reduce the absorption of incident light by the doped polysilicon layer, thereby improving the solar cell's utilization of incident light. However, the reduction in the thickness of the doped polysilicon layer increases the risk of the electrode burning through the polysilicon layer, which would result in contact between the electrode and the substrate. Contact between the electrode and the substrate will cause the recombination current density to increase, which will seriously affect the efficiency of the solar cell. <CIT> describes a preparation method of a solar cell, the solar cell and a photovoltaic module.

Therefore, how to balance the advantage of increasing the utilization rate of incident light with the disadvantage of the increased risk of the electrode burning through the doped polysilicon layer, both of which brought by the reduced thickness of the doped polysilicon layer, is a problem that needs to be solved urgently.

Some embodiments of the present disclosure are intended to provide a solar cell and a method for producing the solar cell that can reduce the thickness of the doped polysilicon layer while preventing the electrode from burning through the doped polysilicon layer. The invention provides the solar cell according to claim <NUM> and the method for producing a solar cell according to claim <NUM>.

Some embodiments provide a solar cell, comprising: a substrate having a first surface and a second surfaces opposite to each other in a first direction, the first direction is a thickness direction of the substrate; a tunnel oxide layer located on the first surface and/or the second surface; a doped polysilicon layer located on a surface of the tunnel oxide layer away from the substrate; a barrier layer located in an electrode region of the solar cell and in contact with the doped polysilicon layer, a doping type of the barrier layer is the same as the doped polysilicon layer; and an electrode located in the electrode region and in contact with the barrier layer; wherein a method of forming the barrier layer includes etching the doped polysilicon layer in the electrode region in the first direction to form a groove with a predetermined depth, and forming the barrier layer in the groove, the predetermined depth is equal to or less than a thickness of the doped polysilicon layer, a material of the barrier layer includes silicon carbide and/or zinc oxide.

In an embodiment, the barrier layer goes deep into the doped polysilicon layer to the predetermined depth in the first direction.

In an embodiment, the barrier layer is located on the surface of the tunnel oxide layer away from the substrate.

In an embodiment, a surface of the barrier layer away from the substrate is flush with a surface of the doped polysilicon layer away from the substrate, or the surface of the barrier layer away from the substrate is closer to the substrate than the surface of the doped polysilicon layer away from the substrate, or the surface of the barrier layer away from the substrate is further away the substrate than the surface of the doped polysilicon layer away from the substrate.

In an embodiment, a recombination current density of the electrode region is equal to or less than <NUM> fA/cm<NUM>.

In an embodiment, the solar cell further comprises a dielectric layer, the dielectric layer is located on a surface of the doped polysilicon layer away from the substrate and a surface of the barrier layer away from the substrate.

In an embodiment, the electrode penetrates the dielectric layer and contacts the barrier layer.

In an embodiment, the thickness of the doped polysilicon layer is equal to or greater than <NUM>, and equal to or less than <NUM>.

Some embodiments further provide a method for producing a solar cell, comprising: providing a substrate having a first surface and a second surfaces opposite to each other in a first direction, the first direction is a thickness direction of the substrate; forming a tunnel oxide layer on the first surface and/or the second surface; forming a doped polysilicon layer on a surface of the tunnel oxide layer away from the substrate; forming a barrier layer in an electrode region of the solar cell, the barrier layer is in contact with the doped polysilicon layer, and a doping type of the barrier layer is the same as the doped polysilicon layer; and forming an electrode in contact with the barrier layer; wherein a method of forming the barrier layer includes etching the doped polysilicon layer in the electrode region in the first direction to form a groove with a predetermined depth, and forming the barrier layer in the groove, the predetermined depth is equal to or less than a thickness of the doped polysilicon layer, and a material of the barrier layer includes silicon carbide and/or zinc oxide.

In an embodiment, a method of forming the barrier layer includes: cleaning a surface of the doped polysilicon layer; and forming the barrier layer in the electrode region, the barrier layer is in contact with a surface of the doped polysilicon layer away from the substrate.

In an embodiment, the recombination current density of the electrode region is equal to or less than 100fA/cm<NUM>.

The solar cell and the producing method thereof of the present disclosure provide the barrier layer in contact with the doped polysilicon layer in the electrode region, which reduces the risk of the electrode burning through the doped polysilicon layer. The thickness of the doped polysilicon can be further reduced, thereby reducing the absorption of incident light by the doped polysilicon layer and improving the utilization rate of incident light by the solar cell.

In order to make the above purposes, features, and advantages of the present disclosure more obvious and more understandable, the embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

Substrate <NUM>, first surface <NUM>, second surface <NUM>, tunnel oxide layer <NUM>, doped polysilicon layer <NUM>, initial barrier layer <NUM>, surface <NUM>, barrier layer <NUM>, bottom surface <NUM>, top surface <NUM>, first side surface <NUM>. Second side <NUM>, electrode <NUM>, electrode region <NUM>, dielectric layer <NUM>, and groove <NUM>.

In order to make the above objects, features, and advantages of the present disclosure more obvious and understandable, the specific implementation modes of the present disclosure are described in detail below with reference to the accompanying drawings.

Many specific details are set forth in the following description to fully understand the present disclosure, but the present disclosure can also be implemented in other ways different from those described here, so the present disclosure is not limited by the specific embodiments disclosed below.

As shown in this disclosure and claims, words such as "a", "an", and/or "the" do not specifically refer to the singular and may include the plural unless the context clearly indicates an exception. Generally speaking, the terms "comprising" and "comprising" only imply the inclusion of clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or apparatus may also include other steps or elements.

In addition, it should be noted that the use of words such as "first" and "second" to define parts is only to facilitate the distinction between corresponding parts. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood. To limit the scope of protection of this disclosure. In addition, although the terms used in this disclosure are selected from well-known and commonly used terms, some terms mentioned in the specification of this disclosure may be selected by the applicant based on his or her judgment, and their detailed meanings are set out herein. stated in the relevant section of the description. Furthermore, the disclosure is required to be understood not merely by the actual terms used, but also by the meaning connoted by each term.

Flowcharts are used in this disclosure to illustrate operations performed by systems according to embodiments of this disclosure. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, the various steps can be processed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or a step or steps may be removed from these processes.

The solar cell and the method of the present disclosure will be described through specific embodiments.

<FIG> is a schematic front view of a solar cell according to an embodiment not forming part of the claimed invention but useful for the understanding thereof. Referring to <FIG>, a solar cell includes a substrate <NUM>, a tunnel oxide layer <NUM>, a doped polysilicon layer <NUM>, a barrier layer <NUM>, and an electrode <NUM>. The substrate <NUM> has a first surface <NUM> and a second surface <NUM> opposite in the first direction D1 (which is also a thickness direction of the substrate <NUM>). The first surface <NUM> and the second surface <NUM> may be polished or have a pyramid-textured topography. The tunnel oxide layer <NUM> is disposed on the first surface <NUM>, and the doped polysilicon layer <NUM> is disposed on a surface of the tunnel oxide layer <NUM> away from the substrate <NUM> in the first direction D1. The tunnel oxide layer <NUM> and the doped polysilicon layer <NUM> together form a tunnel oxide layer-doped polysilicon layer passivation structure. It should be noted that in some other embodiments, the tunnel oxide layer <NUM> can also be formed on the second surface <NUM>, or formed on both the first surface <NUM> and the second surface <NUM>.

The substrate <NUM> may be a silicon substrate, for example, a single crystal silicon substrate or a polycrystalline silicon substrate. The substrate <NUM> may be doped, such as N-type doping and P-type doping. The material of the tunnel oxide layer <NUM> may be silicon oxide (SiOx), and the thickness of the tunnel oxide layer <NUM> may be any value from <NUM> to <NUM>, for example, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. The tunnel oxide layer <NUM> has a selective collection effect on carriers. The material of the doped polysilicon layer <NUM> can be selected from polysilicon, and the present disclosure does not limit the grain size of the polysilicon. The doping type of the doped polysilicon layer <NUM> may be the same as that of the substrate <NUM>, or may be opposite to that of the substrate <NUM>.

The solar cell has an electrode region, which is identified in <FIG> using a dashed rectangular frame <NUM>. The electrodes of the solar cell are located in the electrode region. The electrodes are used to collect the electrical energy generated by the solar cell and transmit the electrical energy to the outside.

As shown in <FIG>, the barrier layer <NUM> is disposed in the electrode region, and is in contact with the doped polysilicon layer <NUM>. The doping type of the barrier layer <NUM> is the same as the doping type of the doped polysilicon layer <NUM>. For example, the doping type of the doped polysilicon layer <NUM> and the doping type of the barrier layer <NUM> are both N-type, and the corresponding doping elements can be selected from phosphorus (P), bismuth (Bi), antimony (Sb), arsenic (As), and other V group elements. The doping type of the doped polysilicon layer <NUM> and the doping type of the barrier layer <NUM> can also be P-type, and the corresponding doping elements can be selected from one or more III group elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

Continuing with reference to <FIG>, the electrode <NUM> is in contact with the barrier layer <NUM>. It should be understood that the number of the electrode regions and the electrodes <NUM> in the solar cell is not limited to the one shown in <FIG>. The solar cell includes a certain number of electrode regions and electrodes <NUM> spaced apart in the second direction D2, which are not shown in <FIG> due to the limited size of <FIG>.

In an embodiment, in <FIG>, the solar cell further includes a dielectric layer <NUM>. The dielectric layer <NUM> is disposed on the surface of the doped polysilicon layer <NUM> and the barrier layer <NUM> away from the substrate <NUM> in the first direction D1. In other words, the dielectric layer <NUM> covers the exposed surfaces of the doped polysilicon layer <NUM> and the barrier layer <NUM>. The electrode <NUM> penetrates the dielectric layer <NUM> and contacts the barrier layer <NUM>. The dielectric layer <NUM> can be a laminated passivation film, which has a passivation effect on the solar cell, and the dielectric layer <NUM> can also be an anti-reflection film.

In <FIG>, the barrier layer <NUM> is disposed on the surface of the doped polysilicon layer <NUM> away from the substrate <NUM> in the first direction D1. The electrode <NUM> is in contact with the barrier layer <NUM> through a firing process, thereby forming an electrical connection with the barrier layer <NUM> and the doped polysilicon layer <NUM> (there is an electrical connection between the doped polysilicon layer <NUM> and the barrier layer <NUM> due to their contact). In <FIG>, the electrode <NUM> goes deep into the barrier layer <NUM> and does not go deep into the doped polysilicon layer <NUM>. In some other embodiments, the electrode <NUM> can also penetrate through the barrier layer <NUM> and further go deep into the doped polysilicon layer <NUM>.

The firing process has an ablation effect on the barrier layer <NUM> and the doped polysilicon layer <NUM>, which results in the situation in which the electrode <NUM> burns through the doped polysilicon layer <NUM> and then contacts the substrate <NUM>. The contact between the electrode <NUM> and the substrate <NUM> will cause the recombination current density in the electrode region to increase sharply, thereby causing the efficiency of the solar cell to decrease.

Embodiments of the present disclosure form the barrier layer <NUM> that is in contact with the doped polysilicon layer <NUM> in the electrode region (where the electrode <NUM> is fired). When firing the electrode <NUM>, the doped polysilicon layer <NUM> will be ablated only after the electrode <NUM> burns through the barrier layer <NUM>. Therefore, the barrier layer <NUM> reduces the risk of the electrode <NUM> burning through the doped polysilicon layer <NUM>.

In one embodiment, the material of the barrier layer <NUM> is selected from materials that are more resistant to ablation than the doped polysilicon layer <NUM>, such as silicon carbide and/or zinc oxide. Compared with polysilicon with a lower crystallization rate, polysilicon with a higher crystallization rate is more resistant to ablation. In some embodiments, the crystallization rate of the polysilicon in the barrier layer <NUM> is equal to or greater than <NUM>%, and the crystallization rate of the doped polysilicon layer <NUM> is <NUM>% to <NUM>%. For example, the crystallization rate of the polysilicon in the barrier layer <NUM> maybe <NUM> %, <NUM>%, <NUM>%, or <NUM> %, and the crystallization rate of the doped polysilicon layer <NUM> may be <NUM>%, <NUM>%, <NUM> %, or <NUM>%. In some embodiments, the crystallization rate of the polysilicon in the barrier layer <NUM> decreases as the distance from the substrate <NUM> in the first direction D1 decreases.

The material of the barrier layer <NUM> may also be a mixture of any two or more of silicon carbide, zinc oxide, and polysilicon.

The technical effect of "the barrier layer <NUM> can prevent the electrode <NUM> from burning through the doped polysilicon layer <NUM>" is briefly described here. In <FIG>, the barrier layer <NUM> is disposed on the surface of the doped polysilicon layer <NUM> away from the substrate <NUM>, which increases the path length for the electrode <NUM> to burn through the doped polysilicon layer <NUM>, thereby preventing the electrode <NUM> from burning through the doped polysilicon layer <NUM>. Moreover, when the barrier layer <NUM> is selected from an ablation-resistant material, the barrier layer <NUM> can also prevent the electrode <NUM> from burning through the doped polysilicon layer <NUM> by its own ablation-resistant properties. In short, the barrier layer <NUM> can prevent the doped polysilicon layer <NUM> from being burned through by the electrode <NUM> by both aspects "increasing the burn-through path" and "its own ablation resistance properties". It should be understood that the barrier layer <NUM> can prevent the polysilicon layer <NUM> from being burned through by the electrode <NUM> through only one, instead of two of the above aspects.

In addition, the doped polysilicon layer <NUM> has optical parasitic effect, which reduces the utilization of incident light by the solar cell. Reducing the thickness of doped polysilicon layer <NUM> can reduce its absorption of incident light. However, the technical solution of reducing the thickness of the doped polysilicon layer <NUM> in the conventional technology has a side effect of increasing the risk of the electrode <NUM> burning through the tunnel oxide layer <NUM>. The technical solution of setting the barrier layer <NUM> in the electrode region in the present disclosure increases the difficulty for the electrode <NUM> to burn through the doped polysilicon layer <NUM>. Therefore, even if the thickness of the doped polysilicon layer <NUM> is reduced, it can be ensured that the electrode <NUM> does not burn through the doped polysilicon layer <NUM>, which reduces the absorption of incident light by the doped polysilicon layer <NUM> and improves the solar cell's utilization rate of incident light. In some embodiments, the thickness of the doped polysilicon layer <NUM> is equal to or greater than <NUM> and equal to or less than <NUM>. For example, the thickness of the doped polysilicon layer <NUM> maybe <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM>. Since the thickness of the doped polysilicon layer <NUM> is equal to or greater than <NUM>, it can ensure the lateral transport capability of carriers and ensure that the field passivation of the substrate <NUM> meets the requirements. Here,the thickness of the doped polysilicon layer <NUM> refers to the dimension of the doped polysilicon layer <NUM> in the first direction D1.

In <FIG>, the barrier layer <NUM> is disposed on the surface of the doped polysilicon layer <NUM> away from the substrate <NUM> in the first direction D1. In the present disclosure, the positional relationship between the barrier layer <NUM> and the doped polysilicon layer <NUM> is not limited to that shown in <FIG>, which will be described next.

<FIG> is a schematic front view of a solar cell according to another embodiment, and <FIG> is an enlarged view of the partial structure in <FIG>. Referring to <FIG> and <FIG>, the difference from <FIG> is that the barrier layer <NUM> in <FIG> and <FIG> goes deep into in the doped polysilicon layer <NUM> with a predetermined depth d1 in the first direction D1. The predetermined depth d1 is equal to or less than the thickness d2 of the doped polysilicon layer <NUM>. The present disclosure does not limit the predetermined depth d1, which can be <NUM> %, <NUM> %, <NUM> %, <NUM> %, <NUM> %, <NUM> %, <NUM>%, <NUM> %, <NUM>% or <NUM> % of the thickness d2. It should be understood that when the predetermined depth d1 is equal to the thickness d2 of the doped polysilicon layer <NUM>, the bottom surface <NUM> of the barrier layer <NUM> is in contact with the surface of the tunnel oxide layer <NUM> away from the substrate <NUM> in the first direction D1. In other words, as shown in <FIG>, the barrier layer <NUM> is disposed on the surface of the tunnel oxide layer <NUM> away from the substrate <NUM> in the first direction D1.

<FIG> are schematic front views of solar cells in two embodiments. Referring to <FIG>, the barrier layer <NUM> is disposed on the surface of the tunnel oxide layer <NUM> away from the substrate <NUM> in the first direction D1, that is, the bottom surface <NUM> of the barrier layer <NUM> is in contact with the tunnel oxide layer <NUM>. The barrier layer <NUM> has a top surface <NUM> away from the substrate <NUM> in the first direction D1, and the doped polysilicon layer <NUM> has a surface <NUM> away from the substrate <NUM> in the first direction D1. In <FIG>, the top surface <NUM> of the barrier layer <NUM> is flush with the surface <NUM> of the doped polysilicon layer <NUM>. Referring to <FIG>, the difference between <FIG> is that the top surface <NUM> of the barrier layer <NUM> in <FIG> is closer to the substrate <NUM> than the surface <NUM> of the doped polysilicon layer <NUM>. In some other embodiments, the top surface <NUM> may also be far away from the substrate <NUM> than the surface <NUM> in the first direction D, that is, the barrier layer <NUM> protrudes from the surface <NUM> away from the substrate <NUM>.

In <FIG>, the bottom surface <NUM> of the barrier layer <NUM> is in contact with the doped polysilicon layer <NUM>. In <FIG>, in addition to the bottom surface <NUM>, the side surfaces of the barrier layer <NUM> are also in contact with the doped polysilicon layer <NUM>. Taking <FIG> as an example, the barrier layer <NUM> has a first side <NUM> and a second side <NUM> opposite to each other in the second direction D2. The first side <NUM> and the second side <NUM> are both in contact with the doped polysilicon layer <NUM>. Increasing the contact area between the barrier layer <NUM> and the doped polysilicon layer <NUM> is beneficial to reducing resistance.

In one embodiment, the recombination current density of the electrode region in <FIG> is equal to or less than <NUM> fA/cm<NUM>. Reducing the recombination current density helps to improve the efficiency of solar cells. A major factor in the recombination current density being equal to or less than <NUM> fA/cm<NUM> is that the electrode <NUM> does not burn through the doped polysilicon layer <NUM>, thereby avoiding contact between the electrode <NUM> and the substrate <NUM>. In some other embodiments, an ohmic contact is formed between the electrode <NUM> and the barrier layer <NUM>, and the contact resistance between the two is equal to or less than <NUM> mohm·cm<NUM>. The contact resistance can be adjusted by adjusting the doping concentration of the barrier layer <NUM>, for example, increasing the doping concentration can reduce the contact resistance.

The solar cell in the above embodiments of the present disclosure is provided with a barrier layer in contact with the doped polysilicon layer in the electrode region, which reduces the risk of the electrode burning through the doped polysilicon layer. The thickness of the doped polysilicon layer can be further reduced, which reduces the absorption of incident light by the doped polysilicon layer and improves the utilization rate of incident light by the solar cell.

The present disclosure also includes a method for producing a solar cell, and the method will be described following.

<FIG> is a flow chart of a method for producing a solar cell according to an embodiment. Referring to <FIG>, the method according to the embodiment includes the following steps,.

Next, steps S210 to S250 will be described in detail.

Referring to <FIG>, in step S210, a substrate <NUM> is provided. The substrate <NUM> has a first surface <NUM> and a second surface <NUM> opposite to each other in the first direction D1. In step S220, a tunnel oxide layer <NUM> is formed on the first surface <NUM>. In some other embodiments, a tunnel oxide layer may be formed on the second surface <NUM>, or a tunnel oxide layer may be formed on both the first surface <NUM> and the second surface <NUM>. In step S230, a doped polysilicon layer <NUM> is formed on the surface of the tunnel oxide layer <NUM> away from the substrate <NUM> in the first direction D1. Methods for forming the tunnel oxide layer <NUM> and the doped polysilicon layer <NUM> include chemical vapor deposition (Chemical Vapor Deposition, CVD), physical vapor deposition (Physical Vapor Deposition, PVD), and thermal oxidation. For other descriptions about the substrate <NUM>, the tunnel oxide layer <NUM>, and the doped polysilicon layer <NUM>, please refer to the relevant parts above and would not be elaborated here.

In one embodiment, the thickness of the doped polysilicon layer <NUM> is equal to or greater than <NUM> and equal to or less than <NUM>. For example, the thickness of the doped polysilicon layer <NUM> maybe <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM>. Since the thickness of the doped polysilicon layer <NUM> is equal to or greater than <NUM>, it can ensure the lateral transmission capability of carriers and ensure that the field passivation of the substrate <NUM> meets the requirements.

Continuing to refer to <FIG>, in step S240, a barrier layer <NUM> is formed in the electrode region of the solar cell. The barrier layer <NUM> is in contact with the doped polysilicon layer <NUM>, and the doping type of the barrier layer <NUM> is the same with the doping type of the doped polysilicon layer <NUM>. The doping type of the barrier layer <NUM> and the doping type of the doped polysilicon layer <NUM> may both be N-type or P-type.

In one embodiment, the method of forming the barrier layer <NUM> in <FIG> includes the following steps,.

The method of forming the barrier layer <NUM> in step <NUM> includes chemical vapor deposition and physical vapor deposition. The material of the barrier layer <NUM> includes one or more of silicon carbide, and zinc oxide.

The intermediate products in the process of producing the solar cells are shown in <FIG>, <FIG>, and <FIG>. In one embodiment, the method of forming the barrier layer <NUM> in <FIG> and <FIG> include the following steps:.

The present disclosures do not limit the method of etching the doped polysilicon layer <NUM>. For example, it may be physical etching or chemical etching. As shown in <FIG> and <FIG>, the barrier layer <NUM> protrudes from the doped polysilicon layer <NUM> away from the substrate <NUM>. In some other embodiments, the surface of the barrier layer <NUM> away from the substrate <NUM> may be flush with the surface of the doped polysilicon layer <NUM> away from the substrate <NUM>.

As shown in <FIG> and <FIG>, when the predetermined depth d3 is equal to the thickness d4 of the doped polysilicon layer <NUM>, the barrier layer <NUM> formed in the groove <NUM> is in contact with the surface of the tunnel oxide layer <NUM> away from the substrate <NUM>.

In one embodiment, the recombination current density of the electrode region is equal to or less than <NUM> fA/cm<NUM>. Reducing the recombination current density helps improve the efficiency of solar cells.

Returning to <FIG>, in step S250, an electrode is formed, and the electrode is in contact with the barrier layer. Taking <FIG> as an example for explanation, an electrode <NUM> is formed in contact with the barrier layer <NUM>. An electrical connection is established between the barrier layer <NUM> and the electrode <NUM> through contact. The electrode <NUM> in contact with the barrier layer <NUM> may be formed by a firing method. This disclosure does not limit the depth of the electrode <NUM> into the barrier layer <NUM>. In some embodiments, the electrode <NUM> may also penetrate the barrier layer <NUM>, and further go deep into the doped polysilicon layer <NUM>, but not penetrate the polysilicon layer <NUM>.

Referring to <FIG>, in some embodiments, a step is further included before step S250: forming a dielectric layer <NUM> covering a surface of the doped polysilicon layer <NUM> away from the substrate <NUM> and a surface of the barrier layer <NUM> away from the substrate <NUM>. In step S250, the electrode <NUM> penetrates the dielectric layer <NUM> and goes deep into the barrier layer <NUM>.

The producing method in the above embodiments of the present disclosure sets a barrier layer in contact with the doped polysilicon layer in the electrode region, which reduces the risk of the electrode burning through the doped polysilicon layer. The thickness of the doped polysilicon layer can be further reduced, which helps to reduce the absorption of incident light by the doped polysilicon layer and improve the utilization rate of incident light by the solar cell.

The basic concepts have been described above. Obviously, for those skilled in the art, the above disclosure disclosures are only examples and do not constitute limitations to the present disclosure. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this disclosure.

At the same time, this disclosure uses specific words to describe the embodiments of the disclosure. For example, "one embodiment", "an embodiment", and/or "some embodiments" means a certain feature, structure or characteristic related to at least one embodiment of the present disclosure. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more at different places in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of the present disclosure may be appropriately combined.

Claim 1:
A solar cell, comprising:
a substrate(<NUM>) having a first surface(<NUM>) and a second surface(<NUM>) opposite to each other in a first direction(D1), wherein the first direction(D1) is a thickness direction of the substrate(<NUM>);
a tunnel oxide layer(<NUM>) located on the first surface(<NUM>) and/or the second surface(<NUM>);
a doped polysilicon layer(<NUM>) located on a surface of the tunnel oxide layer(<NUM>) away from the substrate(<NUM>);
a barrier layer(<NUM>) located in an electrode region(<NUM>) of the solar cell and in contact with the doped polysilicon layer(<NUM>), wherein a doping type of the barrier layer(<NUM>) is the same as the doped polysilicon layer(<NUM>);
an electrode(<NUM>) located in the electrode region(<NUM>) and in contact with the barrier layer(<NUM>);
characterized in that a method of forming the barrier layer(<NUM>) includes etching the doped polysilicon layer(<NUM>) in the electrode region(<NUM>) in the first direction to form a groove(<NUM>) with a predetermined depth(d3), and forming the barrier layer(<NUM>) in the groove(<NUM>), wherein the predetermined depth(d3) is equal to or less than a thickness of the doped polysilicon layer(<NUM>), a material of the barrier layer(<NUM>) includes silicon carbide and/or zinc oxide.