CN212648258U

CN212648258U - Heterojunction solar cell

Info

Publication number: CN212648258U
Application number: CN202021770671.3U
Authority: CN
Inventors: 姚铮; 吴华德; 张达奇; 吴坚; 蒋方丹; 邢国强
Original assignee: Jiaxing Atlas Photovoltaic Technology Co Ltd
Current assignee: Jiaxing Canadian Solar Technology Research Institute
Priority date: 2020-08-21
Filing date: 2020-08-21
Publication date: 2021-03-02
Anticipated expiration: 2030-08-21

Abstract

The utility model provides a heterojunction solar cell, wherein an amorphous film is formed on the side surface of a monocrystalline silicon substrate of a heterojunction solar cell structure, and based on the specific structure of the heterojunction solar cell, the direct contact between a first transparent conductive film layer, a second transparent conductive film layer and the side surface of the monocrystalline silicon substrate can be avoided to cause electric leakage, thereby reducing the risk of the edge damage of the monocrystalline silicon substrate; and the side surface of the monocrystalline silicon substrate is wrapped by the first intrinsic amorphous layer and the second intrinsic amorphous layer, so that the overall passivation effect of the monocrystalline silicon substrate can be effectively improved, and the photoelectric conversion efficiency of the heterojunction cell is further improved.

Description

Heterojunction solar cell

Technical Field

The utility model relates to a photovoltaic field of making especially relates to a heterojunction solar cell.

Background

The heterojunction solar cell is a relatively high-efficiency crystalline silicon solar cell at present, combines the characteristics of a crystalline silicon cell and a silicon-based thin film cell, and has the advantages of short manufacturing process, low process temperature, high conversion efficiency, more generated energy and the like. Fig. 1 is a schematic structural diagram of a heterojunction solar cell in the prior art, which sequentially includes, from top to bottom, a first collector electrode 51 ', a first transparent conductive film 41 ', a first doped amorphous layer 31 ', a first intrinsic amorphous layer 21 ', a single crystal silicon substrate 10 ', a second intrinsic amorphous layer 22 ', a second doped amorphous layer 32 ', a second transparent conductive film 42 ', and a second collector electrode 52 '.

In the specific manufacturing process of the heterojunction solar cell in the prior art, the manufacturing of four amorphous silicon layers, namely a first intrinsic amorphous layer 21 ', a second intrinsic amorphous layer 22 ', a first doped amorphous layer 31 ' and a second doped amorphous layer 32 ', on two surfaces of a monocrystalline silicon substrate 10 ' is generally completed through a PECVD process; then, the first transparent conductive film layer 41 'and the second transparent conductive film layer 42' are manufactured by the PVD process; finally, the first collector electrode 51 'and the second collector electrode 52' are manufactured by a screen printing process.

In the specific process of fabricating the four amorphous silicon layers, the prior art needs to arrange the metal mask such that the first intrinsic amorphous layer 21 ', the second intrinsic amorphous layer 22', the first doped amorphous layer 31 'and the second doped amorphous layer 32' are formed only on two major surfaces of the single crystal silicon substrate 10 ', i.e. the first intrinsic amorphous layer 21', the second intrinsic amorphous layer 22 ', the first doped amorphous layer 31' and the second doped amorphous layer 32 'do not extend to the side of the single crystal silicon substrate 10'.

However, the heterojunction solar cell related to the prior art has the following problems: the side surface of the monocrystalline silicon substrate 10 'is not shielded by an amorphous silicon layer, and the first transparent conductive film layer 41' and the second transparent conductive film layer 42 'are easily in direct contact with the monocrystalline silicon substrate 10', so that the risk of electric leakage exists; direct edge exposure of the single crystal silicon substrate 10' increases the risk of edge damage; the edge region of the single crystal silicon substrate 10' is insufficiently passivated.

In view of the above, there is a need to provide an improved solution to the above problems.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that prior art exists at least, for realizing the utility model purpose of the aforesaid, the utility model provides a heterojunction solar cell, its concrete design as follows.

A heterojunction solar cell, comprising:

a single crystal silicon substrate having a first main surface and a second main surface that are opposite to each other, and a side surface that connects the first main surface and the second main surface, one of the first main surface and the second main surface being a light receiving surface and the other being a backlight surface;

the first amorphous film is positioned on the first main surface of the monocrystalline silicon substrate, the periphery of the first amorphous film extends to cover one side area of the side surface connected with the first main surface, and the first amorphous film points to the direction of the first amorphous film from the monocrystalline silicon substrate, and the first amorphous film comprises a first intrinsic amorphous layer and a first doped amorphous layer which are sequentially stacked;

the first transparent conductive film layer is positioned on the surface of one side, away from the monocrystalline silicon substrate, of the first amorphous film;

the first collector electrode is positioned on the surface of one side, away from the first amorphous film, of the first transparent conductive film layer;

the second amorphous film is positioned on the second main surface of the monocrystalline silicon substrate, the periphery of the second amorphous film extends to cover a side area of the side surface, connected with the second main surface, and an area of the first amorphous film, corresponding to the side surface, and the second amorphous film is oriented to the direction of the second amorphous film from the monocrystalline silicon substrate, and comprises a second intrinsic amorphous layer and a second doped amorphous layer, wherein the second intrinsic amorphous layer and the second doped amorphous layer are sequentially stacked and arranged, and the doping type of the second doped amorphous layer is opposite to that of the first doped amorphous layer;

the second transparent conductive film layer is positioned on the surface of one side, away from the monocrystalline silicon substrate, of the second amorphous film;

and the second collector electrode is positioned on the surface of one side, away from the second amorphous film, of the second transparent conductive film layer.

Further, the thickness of the first amorphous film and the second amorphous film on the light receiving surface is smaller than or equal to the thickness of the second amorphous film on the backlight surface.

Further, the thickness of the first amorphous film and the second amorphous film on the light receiving surface is 6-21nm, and the thickness of the first amorphous film and the second amorphous film on the backlight surface is 6-30 nm.

Further, the thickness of the first intrinsic amorphous layer and the second intrinsic amorphous layer on the light receiving surface is smaller than or equal to the thickness of the second intrinsic amorphous layer on the backlight surface.

Furthermore, the thickness of the first intrinsic amorphous layer and the second intrinsic amorphous layer on the light receiving surface is 3-6nm, and the thickness of the first intrinsic amorphous layer and the second intrinsic amorphous layer on the backlight surface is 3-10 nm.

Further, the thickness of the first doped amorphous layer and the second doped amorphous layer on the light receiving surface side is smaller than or equal to the thickness of the second doped amorphous layer on the backlight surface side.

Further, the thickness of the first doped amorphous layer and the second doped amorphous layer on one side of the light receiving surface is 3-15nm, and the thickness of the first doped amorphous layer and the second doped amorphous layer on one side of the backlight surface is 3-20 nm.

Furthermore, in a direction from the backlight surface to the light receiving surface, the first doped amorphous layer and the second doped amorphous layer, which are located on the light receiving surface, sequentially include a first doped amorphous silicon film and a doped amorphous silicon oxide film, a doped amorphous silicon carbide film or a doped amorphous silicon carbide/doped amorphous silicon oxide composite film, which are located on the surface of the first doped amorphous silicon film.

Further, the first doped amorphous layer and the second doped amorphous layer on the light receiving surface further include a second doped amorphous silicon film on the surface of the doped amorphous silicon oxide film, the doped amorphous silicon carbide film or the doped amorphous silicon carbide/doped amorphous silicon oxide composite film.

Furthermore, in a direction from the light receiving surface to the backlight surface, a third doped amorphous silicon film and a fourth doped amorphous silicon film, which is located on the surface of the third doped amorphous silicon film and has a doping concentration greater than that of the third doped amorphous silicon film, are sequentially included in the first doped amorphous layer and the second doped amorphous layer, which are located on the backlight surface.

Further, the thickness of the region, where the first intrinsic amorphous layer and the second intrinsic amorphous layer extend to cover the side face, is not less than 1 nm.

Further, the first intrinsic amorphous layer and the second intrinsic amorphous layer respectively include at least two intrinsic films stacked.

Further, one layer of the intrinsic film, which is farthest from the single crystal silicon substrate, of the first intrinsic amorphous layer and/or the second intrinsic amorphous layer is an intrinsic amorphous silicon oxide film.

Further, one of the first doped amorphous layer and the second doped amorphous layer, which is located on one side of the light receiving surface, is an n-type doped amorphous layer, and one of the first doped amorphous layer and the second doped amorphous layer, which is located on one side of the backlight surface, is a p-type doped amorphous layer.

Furthermore, the first transparent conductive film layer and the second transparent conductive film layer are positioned on the light receiving surface and comprise a first TCO film attached to the surface of the n-type doped amorphous layer and a second TCO film attached to the surface of the first TCO film and doped with an oxide with a mass ratio smaller than that of the doped oxide in the first TCO film.

Further, the first transparent conductive film layer and the second transparent conductive film layer which are positioned on the light receiving surface also comprise a third TCO film which is attached to the surface of the second TCO film and has a doped oxide mass ratio larger than that of the mixed oxide in the second TCO film.

Further, the first transparent conductive film layer and the second transparent conductive film layer are located on the backlight surface and comprise a fourth TCO film attached to the surface of the p-type doped amorphous layer and a fifth TCO film attached to the surface of the fourth TCO film and doped with an oxide with a mass ratio larger than that of a doped oxide in the fourth TCO film.

Further, the thicknesses of the first transparent conductive film layer and the second transparent conductive film layer on the light receiving surface are less than or equal to the thicknesses of the first transparent conductive film layer and the second transparent conductive film layer on the backlight surface.

Further, one of the first transparent conductive film layer and the second transparent conductive film layer covers a region of the second doped amorphous layer corresponding to the side surface.

The utility model has the advantages that: based on the heterojunction solar cell provided by the utility model, the direct contact between the first transparent conductive film layer, the second transparent conductive film layer and the side surface of the monocrystalline silicon substrate can be avoided to cause electric leakage, and the risk of damage to the edge of the monocrystalline silicon substrate is reduced; and the side surface of the monocrystalline silicon substrate is wrapped by the first intrinsic amorphous layer and the second intrinsic amorphous layer, so that the overall passivation effect of the monocrystalline silicon substrate can be effectively improved, and the photoelectric conversion efficiency of the heterojunction cell is further improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a schematic diagram of a prior art heterojunction solar cell;

fig. 2 is a schematic diagram of a first embodiment of the heterojunction solar cell of the present invention;

FIG. 3 is an enlarged view of a portion a of FIG. 2

FIG. 4 is a partial schematic view of a first embodiment of a heterojunction solar cell of the embodiment shown in FIG. 2;

FIG. 5 is a partial schematic view of a second embodiment of a heterojunction solar cell of the embodiment shown in FIG. 2;

FIG. 6 is a partial schematic view of a third embodiment of a heterojunction solar cell of the embodiment shown in FIG. 2;

FIG. 7 is a partial schematic view of a fourth embodiment of a heterojunction solar cell of the embodiment shown in FIG. 2;

FIG. 8 is a partial schematic view of a fifth embodiment of a heterojunction solar cell of the embodiment shown in FIG. 2;

fig. 9 is a schematic diagram of a second embodiment of the heterojunction solar cell of the present invention;

fig. 10 is a schematic diagram of a third embodiment of the heterojunction solar cell of the present invention;

fig. 11 is a schematic diagram illustrating a fourth embodiment of the heterojunction solar cell of the present invention;

fig. 12 is a schematic diagram illustrating a state of a first amorphous film in a heterojunction solar cell according to the present invention;

FIG. 13 is a schematic diagram illustrating the state of the second amorphous film in the heterojunction solar cell of the present invention

Fig. 14 is a schematic diagram illustrating a state of the transparent conductive film layer in the heterojunction solar cell according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Referring to fig. 2, 9, 10 and 11, the heterojunction solar cell according to the present invention includes a single crystal silicon substrate 10, a first amorphous film, a first transparent conductive film layer 41, a first collector electrode 51, a second amorphous film, a second transparent conductive film layer 42 and a second collector electrode 52. The first amorphous film, the first transparent conductive film layer 41, and the first collector 51 are sequentially disposed on the first main surface side, and the second amorphous film, the second transparent conductive film layer 42, and the second collector 52 are sequentially disposed on the second main surface side.

The single crystal silicon substrate 10 according to the present invention has a first main surface and a second main surface which are opposite to each other, and a side surface connecting the first main surface and the second main surface. One of the first main surface and the second main surface is a light receiving surface, and the other is a backlight surface.

In the present invention, referring to fig. 2, fig. 3, fig. 9, fig. 10 and fig. 11, the first amorphous film is located on the first main surface of the single crystal silicon substrate 10 and extends to a side region where the covering of the whole side surface 103 is connected to the first main surface 101, and the first amorphous film includes the first intrinsic amorphous silicon layer 21 and the first doped amorphous silicon layer 32 which are stacked in sequence in the direction of the first amorphous film pointed by the single crystal silicon substrate 10.

More specifically, in the present invention, the first intrinsic amorphous layer 21 is located on the first main surface of the single crystal silicon substrate 10 and extends peripherally to cover a side region where the entire side surface is connected to the first main surface. As shown in the drawing, a portion of the periphery of the first intrinsic amorphous layer 21 extending to the side surface is a first intrinsic side edge portion 210, and the first intrinsic side edge portion 210 covers a side region of the side surface connected to the first main surface.

The first doped amorphous layer 31 is located on a surface of the first intrinsic amorphous layer 21 on a side facing away from the single crystal silicon substrate 10 and forms a cover for the first intrinsic amorphous layer 21. As shown in fig. 3, the first doped amorphous layer 31 has a region outside the side of the single crystal silicon substrate 10 and disposed corresponding to the first intrinsic side edge portion 210, in addition to a region corresponding to the first main surface overlying the first intrinsic amorphous layer 21. That is, the first doped amorphous layer 31 has a first doped side portion 310 overlying the outer surface of the first intrinsic side portion 210.

In the present invention, referring to fig. 2, fig. 3, fig. 9, fig. 10, and fig. 11, the second amorphous film is located on the second main surface 102 of the single crystal silicon substrate 10 and the periphery extends to the area covering one side of the side surface 103 connected to the second main surface 101 and the area corresponding to the side surface 103, and the second amorphous film includes the second intrinsic amorphous silicon layer 22 and the second doped amorphous silicon layer 32 stacked in sequence in the direction pointing to the second amorphous film from the single crystal silicon substrate 10.

More specifically, in the present invention, the second intrinsic amorphous layer 22 is located on the second main surface of the single crystal silicon substrate 10 and the periphery extends to cover the area of the side surface connected to the second main surface and the area of the first doped amorphous layer 310 corresponding to the side surface. The region of the first doped amorphous layer 31 corresponding to the side surface is the first doped side portion 310, the second intrinsic amorphous layer 22 has a region covering the second main surface, a region corresponding to the first doped side portion 310 and a region covering the side surface and connected to the second main surface, the region of the second intrinsic amorphous layer 22 corresponding to the first doped side portion 310 and located outside the side surface of the single crystal silicon substrate 10, and a region covering the side surface and connected to the second main surface, which together form the second intrinsic side portion 220.

A second doped amorphous layer 32 is located on a surface of the second intrinsic amorphous layer 22 facing away from the single crystal silicon substrate 10 and forms a cover for the second intrinsic amorphous layer 22. As shown in fig. 3, the second doped amorphous layer 32 has a region located outside the side of the single crystal silicon substrate 10 and corresponding to the second intrinsic side portion 220, in addition to a region corresponding to the second main surface overlying the second intrinsic amorphous layer 22. I.e., the second doped amorphous layer 32 has a second doped side portion 320 overlying the outer surface of the second intrinsic side portion 220.

In the present invention, the doping type of the second doped amorphous layer 32 is opposite to the doping type of the first doped amorphous layer 31. In the specific implementation process, the first doped amorphous layer 31 is one of an N-type doped amorphous layer and a P-type doped amorphous layer, and the second doped amorphous layer 32 is the other of the N-type doped amorphous layer and the P-type doped amorphous layer. Specifically, the N-type doped amorphous layer is doped with phosphorus, and the P-type doped amorphous layer is doped with boron.

Further, the first transparent conductive film layer 41 of the present invention is located on a side surface of the first doped amorphous layer 31 away from the first intrinsic amorphous layer 21; the first collector electrode 51 is positioned on the surface of the first transparent conductive film layer 41 on the side away from the first doped amorphous layer 31; a second transparent conductive film layer 42 is disposed on a surface of the second doped amorphous layer 32 facing away from the second intrinsic amorphous layer 22; the second collector electrode 52 is located on a side surface of the second transparent conductive film layer 42 facing away from the second doped amorphous layer 32.

Based on the heterojunction solar cell provided by the utility model, the direct contact between the first transparent conductive film layer 41 and the second transparent conductive film layer 42 and the side surface of the monocrystalline silicon substrate 10 can be avoided to cause electric leakage, and the risk of damage to the edge of the monocrystalline silicon substrate 10 is reduced; the side surface of the monocrystalline silicon substrate 10 is wrapped by the first intrinsic amorphous layer 21 and the second intrinsic amorphous layer 22, so that the passivation effect of the side surface of the monocrystalline silicon substrate 10 can be effectively improved, and the heterojunction solar cell has higher photoelectric conversion efficiency compared with a cell piece with an unpassivated edge in the prior art.

In the embodiment shown in fig. 2 and 10 of the present invention, the first main surface is a light receiving surface, and the second main surface is a backlight surface. However, in another embodiment of the present invention, as shown in fig. 9 and 11, unlike the embodiment shown in fig. 2 and 10, the second main surface of the embodiments is a light receiving surface and the first main surface is a backlight surface.

The utility model discloses in, the thickness that lies in the sensitive surface in first amorphous film and the second amorphous film is less than or equal to the thickness that lies in the backlight face, and two thickness sums that lie in the sensitive surface in first intrinsic amorphous layer 21, first doping amorphous layer 31, second intrinsic amorphous layer 22 and the second doping amorphous layer 32 are less than or equal to both thickness sums that lie in the backlight face promptly. Preferably, a thickness of the first amorphous film and the second amorphous film on the light receiving surface is smaller than a thickness of the second amorphous film on the backlight surface.

For the heterojunction solar cell, the influence of the light absorption effect of the light receiving surface on the photoelectric conversion efficiency of the cell is far larger than the influence of the light absorption effect of the backlight surface on the photoelectric conversion efficiency of the cell, and because the thickness of the first amorphous film and the second amorphous film on the light receiving surface is smaller than or equal to the thickness of the backlight surface, the loss of sunlight when the sunlight enters the light receiving surface can be effectively reduced, the short-circuit current of the heterojunction solar cell can be improved, and the heterojunction solar cell has better photoelectric conversion efficiency.

For the structure shown in fig. 2 and 10, two of the first intrinsic amorphous layer 21, the first doped amorphous layer 31, the second intrinsic amorphous layer 22 and the second doped amorphous layer 32 on the light receiving surface are the first intrinsic amorphous layer 21 and the first doped amorphous layer 31, and two of the first intrinsic amorphous layer 21 and the second doped amorphous layer 32 on the backlight surface are the second intrinsic amorphous layer 22 and the second doped amorphous layer 32, wherein the sum of the thicknesses of the first intrinsic amorphous layer 21 and the first doped amorphous layer 31 is less than or equal to the sum of the thicknesses of the second intrinsic amorphous layer 22 and the second doped amorphous layer 32.

More specifically, in the embodiments shown in FIGS. 2 and 10, the sum of the thicknesses of the first intrinsic amorphous layer 21 and the first doped amorphous layer 31 is 6 to 21nm, and the sum of the thicknesses of the second intrinsic amorphous layer 22 and the second doped amorphous layer 32 is 6 to 30 nm.

In the embodiment structure shown in fig. 2 and 10, the thickness d1 of the first intrinsic amorphous layer 21 is less than or equal to the thickness d2 of the second intrinsic amorphous layer 22. It is preferable that the thickness d1 of the first intrinsic amorphous layer 21 is smaller than the thickness d2 of the second intrinsic amorphous layer 22. In a specific embodiment, the thickness d1 of the first intrinsic amorphous layer 21 is 3-6nm, and the thickness d2 of the second intrinsic amorphous layer 22 is 3-10 nm.

Further, the thickness of the first doped amorphous layer 31 is less than or equal to the thickness of the second doped amorphous layer 32. It is preferable that the thickness of the first doped amorphous layer 31 is smaller than that of the second doped amorphous layer 32. In specific implementation, the thickness of the first doped amorphous layer 31 is 3-15nm, and the thickness of the second doped amorphous layer 32 is 3-20 nm.

The utility model discloses in, for guaranteeing that monocrystalline silicon substrate 10 side has better passivation effect, in the concrete implementation process, first intrinsic amorphous layer 21 and the regional thickness that the intrinsic amorphous layer 22 of second extended coverage side are not less than 1nm, and the regional thickness that first intrinsic side portion 210 and the intrinsic side portion of second directly attached to the side is not less than 1nm promptly.

In the structure shown in fig. 2 and 10, the oxygen content in the first doped amorphous layer 31 is greater than or equal to the oxygen content in the second doped amorphous layer 32. Generally, the high oxygen content in the first doped amorphous layer 31 forms amorphous silicon oxide with high light transmittance, thereby improving the light receiving effect of the light receiving surface of the heterojunction solar cell.

As a further specific embodiment of the structure shown in fig. 2 and 10, referring to fig. 4, the first doped amorphous layer 31 includes a first doped amorphous silicon film 301 on the surface of the first intrinsic amorphous layer 21 and a doped amorphous silicon oxide film, a doped amorphous silicon carbide film or a doped amorphous silicon carbide/doped amorphous silicon oxide composite film 302 on the surface of the first doped amorphous silicon film 301. It is easy to understand that the doped amorphous silicon carbide/doped amorphous silicon oxide composite film refers to a film layer formed by compounding a doped amorphous silicon oxide film and a doped amorphous silicon carbide film.

The doped amorphous silicon oxide and the doped amorphous silicon carbide have more excellent light transmittance compared with the doped amorphous silicon. The first doped amorphous layer 31' of the related art is generally a single-layer doped amorphous silicon film structure; in this embodiment, the first doped amorphous layer 31 is designed as a double-layer film, wherein the first doped amorphous silicon film 301 can ensure that the first doped amorphous layer 31 and the first intrinsic amorphous layer 21 have a good contact, and the doped amorphous silicon oxide film, the doped amorphous silicon carbide film or the doped amorphous silicon carbide/doped amorphous silicon oxide composite film 302 is equivalent to replacing a part of doped amorphous silicon in the prior art with doped amorphous silicon oxide or doped amorphous silicon carbide with high transmittance, so that the overall transmittance of the first doped amorphous layer 31 can be improved. Based on the cooperation of the first doped amorphous silicon film 301 and the doped amorphous silicon oxide film, the doped amorphous silicon carbide film or the doped amorphous silicon carbide/doped amorphous silicon oxide composite film 302, the heterojunction solar cell has more excellent performance.

In the embodiment shown in fig. 4, the thickness of the first doped amorphous silicon film 301 is preferably generally less than the thickness of the doped amorphous silicon oxide film, the doped amorphous silicon carbide film, or the doped amorphous silicon carbide/doped amorphous silicon oxide composite film 302. Thus, while ensuring a good contact between the first doped amorphous layer 31 and the first intrinsic amorphous layer 21, the first doped amorphous layer 31 can have a good transmittance to a great extent.

In the specific implementation process, the thickness of the doped amorphous silicon oxide film, the doped amorphous silicon carbide film or the doped amorphous silicon carbide/doped amorphous silicon oxide composite film 302 is 2-10 nm. Accordingly, the thickness of the first doped amorphous silicon film 301 is 1 to 5 nm.

To ensure a better contact between the first doped amorphous layer 31 and the first intrinsic amorphous layer 21, the first doped amorphous silicon film 301 is a highly doped film with a carrier concentration of 5E 19-5E 21/cm³。

In other embodiments of the structure of fig. 2 and 10, as shown in fig. 5, the first doped amorphous layer 31 further includes a second doped amorphous silicon film 303 on the surface of the doped amorphous silicon oxide film, the doped amorphous silicon carbide film or the doped amorphous silicon carbide/doped amorphous silicon oxide composite film 302. The doped amorphous silicon generally has excellent conductivity, and the second doped amorphous silicon film 303 in the embodiment shown in fig. 5 is disposed to make the first doped amorphous layer 31 and the first transparent conductive film 41 have better contact, so that the contact resistance can be reduced compared to the embodiment shown in fig. 4, and thus the heterojunction solar cell has a higher fill factor.

In the embodiment shown in fig. 5, the thickness of the second doped amorphous silicon film 303 is also generally smaller than the thickness of the doped amorphous silicon oxide film, the doped amorphous silicon carbide film or the doped amorphous silicon carbide/doped amorphous silicon oxide composite film 302, so that the first doped amorphous layer 31 has better light transmittance. In specific implementation, the thickness of the first doped amorphous silicon film 301 is 1-4nm, the thickness of the doped amorphous silicon oxide film, the doped amorphous silicon carbide film or the doped amorphous silicon carbide/doped amorphous silicon oxide composite film 302 is 1-7nm, and the thickness of the second doped amorphous silicon film 303 is 1-4 nm.

In order to ensure a better contact between the first doped amorphous layer 31 and the first transparent conductive film 41, the second doped amorphous silicon film 303 is also a highly doped film with a carrier concentration of 5E 19-5E 21/cm³。

Referring to fig. 4 and 5, in still other embodiments of the present invention, the second doped amorphous layer 32 includes a third doped amorphous silicon film 304 on the surface of the second intrinsic amorphous layer 22 and a fourth doped amorphous silicon film 305 on the surface of the third doped amorphous silicon film 304 and having a doping concentration greater than that of the third doped amorphous silicon film 304.

Preferably, the carrier concentration of the third doped amorphous silicon film 304 is 5E 18-5E 19/cm³The carrier concentration of the fourth doped amorphous silicon film 305 is 5E 19-5E 21/cm³。

In the embodiment shown in fig. 4 and 5, the third doped amorphous silicon film 304 has a relatively low doping concentration, so that the influence on the second intrinsic amorphous layer 22 can be reduced, the lattice distortion of the second intrinsic amorphous layer 22 can be reduced, and the passivation effect of the backlight surface of the heterojunction solar cell can be effectively ensured; the fourth doped amorphous silicon film 305 has a relatively high doping concentration, so that the contact between the second doped amorphous layer 32 and the second transparent conductive film can be improved, the contact resistance between the second doped amorphous layer and the second transparent conductive film can be reduced, and the cell fill factor can be improved.

Preferably, the thickness of the third doped amorphous silicon film 304 is generally smaller than that of the fourth doped amorphous silicon film 305. In specific implementation, the thickness of the third doped amorphous silicon film 304 is 1-5nm, and the thickness of the fourth doped amorphous silicon film 305 is 2-15 nm.

It should be understood that in the embodiments of the present invention shown in fig. 9 and 11, two of the first intrinsic amorphous layer 21, the first doped amorphous layer 31, the second intrinsic amorphous layer 22 and the second doped amorphous layer 32 on the light receiving surface are the second intrinsic amorphous layer 22 and the second doped amorphous layer 32, and two of the first intrinsic amorphous layer 21 and the first doped amorphous layer 31 on the backlight surface are the second intrinsic amorphous layer 22 and the second doped amorphous layer 32, wherein the sum of the thicknesses of the second intrinsic amorphous layer 22 and the second doped amorphous layer 32 is less than or equal to the sum of the thicknesses of the first intrinsic amorphous layer 21 and the first doped amorphous layer 31.

More specifically, the first intrinsic amorphous layer 21 and the first doped amorphous layer 31 in the implementation structure shown in fig. 9 and 11 can be respectively referred to the design of the second intrinsic amorphous layer 22 and the second doped amorphous layer 32 in the implementation structure shown in fig. 2 and 10, and the second intrinsic amorphous layer 22 and the second doped amorphous layer 32 in the implementation structure shown in fig. 9 and 11 can be respectively referred to the design of the first intrinsic amorphous layer 21 and the first doped amorphous layer 31 in the implementation structure shown in fig. 2 and 10. Details are not described herein.

Preferably, the first intrinsic amorphous layer 21 and the second intrinsic amorphous layer 22 of the present invention each include at least two intrinsic films stacked one on another, each of the intrinsic films being formed of one of an intrinsic amorphous silicon film, an intrinsic amorphous silicon oxide film, and an intrinsic amorphous silicon carbide film.

Referring to fig. 8, a specific embodiment of the structure of fig. 2 is shown, in which the first intrinsic amorphous layer 21 and the second intrinsic amorphous layer 22 include three intrinsic films stacked one on another. In a direction away from the single crystal silicon substrate 10, the first intrinsic amorphous layer 21 sequentially includes a first intrinsic film 201, a second intrinsic film 202, and a third intrinsic film 203, and the second intrinsic amorphous layer 22 sequentially includes a fourth intrinsic film 204, a fifth intrinsic film 205, and a sixth intrinsic film 206. It is understood that the number of layers of the first intrinsic amorphous layer 21 and the second intrinsic amorphous layer 22 is not limited to the three-layer structure in other embodiments of the present invention.

The utility model discloses in, because first intrinsic amorphous layer 21 and second intrinsic amorphous layer 22 all include the intrinsic membrane of at least two-layer range upon range of setting, in the concrete implementation in-process, can be convenient for through the characteristic of controlling each rete, and then form the better first intrinsic amorphous layer 21 of comprehensive properties and second intrinsic amorphous layer 22.

As a preferred embodiment of the present invention, in the specific implementation process, the layer of the intrinsic film of the first intrinsic amorphous layer 21 farthest from the single crystal silicon substrate 10 is set as an intrinsic amorphous silicon oxide film. Referring to fig. 8, in this embodiment, the third intrinsic film 203 is an intrinsic film of the first intrinsic amorphous layer 21 farthest from the single crystal silicon substrate 10, and the third intrinsic film 203 in this embodiment preferably uses intrinsic amorphous silicon oxide. It is to be understood that in other embodiments of the present invention, the layer of the intrinsic film of the second intrinsic amorphous layer 22 farthest from the single crystal silicon substrate 10 can also be set as intrinsic amorphous silicon oxide, i.e. the sixth intrinsic film 206 farthest from the single crystal silicon substrate 10 in this embodiment can be set as intrinsic amorphous silicon oxide film.

The intrinsic amorphous silicon oxide film has a lower passivation effect than the intrinsic amorphous silicon film and the intrinsic amorphous silicon carbide film, but has a better light transmittance than the intrinsic amorphous silicon film and the intrinsic amorphous silicon carbide film, and in the heterojunction solar cell, the intrinsic film, which is the farthest layer from the monocrystalline silicon substrate 10, of the first intrinsic amorphous layer 21 and the second intrinsic amorphous layer 22 has a limited passivation effect on the monocrystalline silicon substrate 10 due to the distance, and the intrinsic amorphous silicon oxide film with the optimal light transmittance can optimize the photoelectric conversion efficiency of the heterojunction solar cell to a certain extent.

As a further preferred feature of the present invention, in the present invention, the intrinsic film hydrogen content near the single crystal silicon substrate 10 in the first intrinsic amorphous layer 21 is higher than the intrinsic film hydrogen content far from the single crystal silicon substrate, and the intrinsic film hydrogen content near the single crystal silicon substrate 10 in the second intrinsic amorphous layer 22 is higher than the intrinsic film hydrogen content far from the single crystal silicon substrate.

Referring to fig. 8, in this embodiment, the hydrogen contents of the first, second, and third

intrinsic films

201, 202, and 203 in the first intrinsic amorphous layer 21 are sequentially reduced, and the hydrogen contents of the fourth, fifth, and sixth

intrinsic films

204, 205, and 206 in the second intrinsic amorphous layer 22 are also sequentially reduced. It can be easily understood that the intrinsic films of the first and second intrinsic

amorphous layers

21 and 22 closer to the single crystal silicon substrate 10 have more significant passivation effect, and the first and fourth

intrinsic films

201 and 204 are directly attached to the single crystal silicon substrate 10, and have the highest hydrogen content such that the first and second intrinsic

amorphous layers

21 and 22 have the optimal passivation effect on the single crystal silicon substrate 10.

As a preferred aspect of the present invention, when the first intrinsic amorphous layer 21 and the second intrinsic amorphous layer 22 respectively include three intrinsic films stacked on each other, the hydrogen content of the three intrinsic films of the first intrinsic amorphous layer 21 and the second intrinsic amorphous layer 22 respectively ranges from 20% to 40%, from 10% to 25% and from 8% to 20% in the direction away from the single crystal silicon substrate 10. That is, the hydrogen content of the first and fourth

intrinsic films

201 and 204 ranges from 20% to 40%, the hydrogen content of the second and fifth

intrinsic films

202 and 205 ranges from 10% to 25%, and the hydrogen content of the third and sixth

intrinsic films

203 and 206 ranges from 8% to 20%.

Further preferably, in the embodiment shown in fig. 8, the hydrogen content of the first intrinsic film 201 and the fourth intrinsic film 204 ranges from 24% to 30%, the hydrogen content of the second intrinsic film 202 and the fifth intrinsic film 205 ranges from 12% to 18%, and the hydrogen content of the third intrinsic film 203 and the sixth intrinsic film 206 ranges from 10% to 15%.

As a further preferred embodiment of the present invention shown in fig. 8, when the first main surface of the single crystal silicon substrate 10 is a light receiving surface, the thickness ranges of the first intrinsic film 201, the second intrinsic film 202 and the third intrinsic film 203 in the first intrinsic amorphous layer 21 are 1 to 3nm, 2 to 4nm and 1 to 3nm in this order, and the thickness ranges of the fourth intrinsic film 204, the fifth intrinsic film 205 and the sixth intrinsic film 206 in the second intrinsic amorphous layer 22 are 1 to 5nm, 3 to 10nm and 0 to 5nm in this order.

Accordingly, it can be understood that when the first main surface of the single crystal silicon substrate 10 is a back light surface, the thicknesses of the fourth intrinsic film 204, the fifth intrinsic film 205, and the sixth intrinsic film 206 in the second intrinsic amorphous layer 22 are in the order of 1-3nm, 2-4nm, and 1-3nm, and the thicknesses of the first intrinsic film 201, the second intrinsic film 202, and the third intrinsic film 203 in the first intrinsic amorphous layer 21 are in the order of 1-5nm, 3-10nm, and 0-5 nm.

As a further preferred aspect, the ratio of bonded hydrogen atoms in the first intrinsic amorphous layer 21 and the second intrinsic amorphous layer 22 is 15% to 25% of the total hydrogen atoms. When specific passivation is used, bonding hydrogen atom plays decisive role, and bonding hydrogen atom accounts for about 10% usually in the intrinsic layer amorphous layer among the prior art to total hydrogen atom ratio, the utility model discloses in through improving bonding hydrogen atom accounts for total hydrogen atom's ratio in first intrinsic amorphous layer 21 and the intrinsic amorphous layer 22 of second, also can improve the passivation effect of first intrinsic amorphous layer 21 and the intrinsic amorphous layer 22 of second to monocrystalline silicon substrate 10 surface, and then further improve the open circuit voltage of corresponding heterojunction solar wafer.

In other embodiments of the present invention, the average concentration of hydrogen atoms in the first intrinsic amorphous layer 21 and the second intrinsic amorphous layer 22 is 1e22-5e22/cm³(ii) a Preference is given toIs 2.5e22-5e22/cm³. The concentration of hydrogen atoms in the intrinsic layer amorphous silicon layer of the heterojunction solar cells of the prior art is generally less than 1e22 atoms/cm³The low concentration of hydrogen atom content makes the intrinsic layer amorphous silicon layer have a poor passivation effect. The utility model discloses in through the hydrogen atom concentration that improves in first intrinsic amorphous layer 21 and the intrinsic amorphous layer 22 of second, can effectively improve the passivation effect of first intrinsic amorphous layer 21 and the intrinsic amorphous layer 22 of second to monocrystalline silicon substrate 10 surface, and then improve the open circuit voltage of corresponding heterojunction solar wafer.

In the present invention, preferably, the first doped amorphous layer 31 and the second doped amorphous layer 32 are located on one side of the light receiving surface and are n-type doped amorphous layers, and the first doped amorphous layer 31 and the second doped amorphous layer 32 are located on one side of the backlight surface and are p-type doped amorphous layers. Although the single crystal silicon substrate 10 may specifically be a p-type single crystal silicon substrate, an n-type single crystal substrate silicon may also be selected; however, in a preferred embodiment of the present invention, the single crystal silicon substrate 10 is an n-type single crystal silicon substrate.

When the first doped amorphous layer 31 and the second doped amorphous layer 32 are located on the light receiving surface side and are n-type doped amorphous layers, and the first doped amorphous layer 31 and the second doped amorphous layer 32 are located on the backlight surface side and are p-type doped amorphous layers, the present invention relates to a first transparent conductive film 41 and a second transparent conductive film 42 further having the following design.

For the embodiments shown in fig. 2 and 10, one embodiment of which is shown in fig. 6, the first transparent conductive film layer 41 includes a first TCO film 401 attached to the surface of the n-type doped amorphous layer (first doped amorphous layer 31) and a second TCO film 402 attached to the surface of the first TCO film 401, wherein the mass fraction of doped oxide in the first TCO film 401 is greater than the mass fraction of doped oxide in the second TCO film 402.

In the heterojunction solar cell structure provided by the embodiment, based on the specific design structure, the first TCO film 401 can ensure that the first transparent conductive film layer 41 and the n-type doped amorphous layer (first doped amorphous layer 31) have better contact due to high doping, so that the contact resistance is reduced, and the fill factor of the heterojunction solar cell can be improved; the light transmittance of the first transparent conductive film layer 41 can be increased on the whole due to the low doping of the second TCO film 402, so that the short-circuit current of the heterojunction solar cell can be increased.

Preferably, in the specific implementation process of the structure, the mass ratio of the doped oxide in the first TCO film 401 is 5% to 20%, and the mass ratio of the doped oxide in the second TCO film 402 is 0.5% to 5%.

Further, the carrier concentration of the first TCO film 401 is 3e20-1e21/cm³The carrier concentration of the second TCO film 402 is 5e19-4e20/cm³. In a specific implementation process, the carrier concentration in the first TCO film 401 and the second TCO film 402 is in a positive correlation with the mass ratio of the doped oxide in the corresponding film layers, but in a specific manufacturing process, the carrier concentration can be further adjusted to some extent by controlling the film forming atmosphere (for example, adjusting the oxygen concentration) of the first TCO film 401 and the second TCO film 402.

As a preferable structure of this embodiment, the thickness of the first TCO film 401 is smaller than that of the second TCO film 402. More specifically, referring to FIG. 6, the first TCO film 401 has a thickness of 5-15nm, with 5-10nm being preferred; the thickness of the second TCO film 402 is 40-90nm, with 60-80nm being most preferred.

The first TCO film 401 is mainly disposed to form a better contact between the first transparent conductive film 41 and the n-type doped amorphous layer (the first doped amorphous layer 31), and a relatively thin thickness can satisfy the requirement. The second TCO film 402 has a good light transmittance due to a low doping concentration, and when the first transparent conductive film layer 41 has a sufficient thickness, the second TCO film 402 is set to have a relatively thick thickness, so that the first transparent conductive film layer 41 can also ensure an excellent light transmittance, and further, the heterojunction solar cell has a high short-circuit current.

As further shown in fig. 7, in other embodiments of the present invention, the first transparent conductive film layer 41 further includes a third TCO film 403 attached to the surface of the second TCO film 402, and the mass ratio of the doped oxide in the third TCO film 403 is greater than the mass ratio of the doped oxide in the second TCO film 402. In specific implementation, the mass ratio of the doped oxide in the third TCO film 403 is 5% to 20%.

Since the doping concentration of the third TCO film 403 has a relatively high value, it can ensure that the first transparent conductive film layer 41 and the first collector electrode 51 have a good contact therebetween, and can also reduce the contact resistance therebetween, thereby further improving the fill factor of the heterojunction solar cell.

In a specific implementation, the thickness of the third TCO film 403 is less than the thickness of the second TCO film 402. In the embodiment shown in FIG. 7, the first TCO film 401 has a thickness of 5-15nm, the second TCO film 402 has a thickness of 35-75nm, and the third TCO film 403 has a thickness of 5-15 nm. The consideration for setting the thickness of the third TCO film 403 to a relatively small value may refer to the consideration for setting the thickness of the first TCO film 401, and will not be further described here.

In the specific implementation process of the present embodiment, the first TCO film 401, the second TCO film 402, and the third TCO film 403 are all formed by doping doped oxide in indium oxide or zinc oxide, where the doped oxide is Al2O₃、Ga₂O₃、In₂O₃、SnO₂、WO₃、TiO₂、ZrO₂And MoO₂One or more of (a). Among them, the doped oxide is preferably SnO₂And the reliability is better. It is understood that the mass fraction of doped oxide in a respective TCO film refers to the ratio of the mass of doped oxide to the total mass of the respective TCO film.

Referring to fig. 6 and 7, in these embodiments, the second transparent conductive film layer 42 includes a fourth TCO film 404 attached to the surface of the p-type doped amorphous layer (the second doped amorphous layer 32) and a fifth TCO film 405 attached to the surface of the fourth TCO film 404, wherein the mass fraction of the doped oxide in the fourth TCO film 404 is smaller than the mass fraction of the doped oxide in the fifth TCO film 405.

Since the fourth TCO film 404 is in direct contact with the p-type doped amorphous layer (the second doped amorphous layer 32), when the fourth TCO film 404 has a lower concentration of doping, the schottky contact barrier between the two is reduced, so that the two can have an optimal contact, thereby increasing the fill factor of the heterojunction solar cell. In addition, the fifth TCO film 405 has a higher doping concentration, so that the fifth TCO film has a better conductivity, and has a better electrical contact with the second collector, so that the fill factor of the heterojunction solar cell can be improved. It can be known that, because the second transparent conductive film layer 42 is located the backlight surface of heterojunction solar cell, when specifically applying, shine to the inside sunlight proportion of heterojunction solar cell very low through second transparent conductive film layer 42, its luminousness is little to heterojunction solar cell's wholeness ability influence.

In a specific implementation process, the mass percentage of the doped oxide in the fourth TCO film 404 is 0.5% to 5%, and the mass percentage of the doped oxide in the fifth TCO film 405 is 5% to 20%.

Correspondingly, the carrier concentration of the fourth TCO film 404 is 5e19-4e20/cm³The carrier concentration of the fifth TCO film 405 is 3e20-1e21/cm³。

Preferably, in this embodiment, the thickness of the fourth TCO film 404 is generally smaller than the thickness of the fifth TCO film 405. The fourth TCO film 404 is set to a relatively small value so as to satisfy the excellent contact with the p-type doped amorphous layer (the second doped amorphous layer 32), and the fifth TCO film 405 is set to a relatively large value so as to satisfy the requirement of the total thickness of the second transparent conductive film 42 and improve the electrical properties of the second transparent conductive film 42.

In some embodiments, the fourth TCO film 404 has a thickness of 5-15nm and the fifth TCO film 405 has a thickness of 40-90 nm.

The fourth TCO film 404 and the fifth TCO film 405 in this embodiment are formed by doping the doped oxide with indium oxide or zinc oxide, where the doped oxide is Al2O₃、Ga2O₃、In₂O₃、SnO₂、WO₃、TiO₂、ZrO₂And MoO₂One or more of (a). Among them, SnO2 is preferable as the doped oxide, and the reliability is better.

In the present embodiment, the thickness of the first transparent conductive film layer 41 is less than or equal to the thickness of the second transparent conductive film layer 42. Among them, the thickness of the first transparent conductive film layer 41 is preferably smaller than the thickness of the second transparent conductive film layer 42. The total thickness of the first transparent conductive film layer 41 is 60-120nm, preferably 60-90 nm.

For the heterojunction solar cell, the influence of the light absorption effect of the light receiving surface on the photoelectric conversion efficiency of the cell is far larger than the influence of the light absorption effect of the backlight surface on the photoelectric conversion efficiency of the cell, and the loss of sunlight on the light receiving surface when the sunlight passes through the first transparent conductive film layer 41 can be effectively reduced due to the small thickness of the first transparent conductive film layer 41, so that the heterojunction solar cell has better photoelectric conversion efficiency.

It is understood that in other embodiments of the present embodiment structure, the second transparent conductive film layer 42 may be a single-layer structure, that is, only the first transparent conductive film layer 41 may be a double-layer film or a three-layer film structure.

It should be understood that in the embodiment structures shown in fig. 9 and 11 of the present invention, the second transparent conductive film layer 42 is located on the light receiving surface and the first transparent conductive film layer 41 is located on the backlight surface of the first transparent conductive film layer 41 and the second transparent conductive film layer 42. At this time, the design of the second transparent conductive film layer 42 in the implementation structure shown in fig. 2 and 10 can be referred to for the first transparent conductive film layer 41 in the implementation structure shown in fig. 9 and 11, and the design of the first transparent conductive film layer 41 in the implementation structure shown in fig. 2 and 10 can be referred to for the second transparent conductive film layer 42 in the implementation structure shown in fig. 9 and 11. Details are not described herein.

Further, in the present invention, one of the first transparent conductive film layer 41 and the second transparent conductive film layer 42 covers the area of the second doped amorphous layer 32 corresponding to the side surface. Therefore, the current collection can be carried out on the surface of the heterojunction solar cell more comprehensively, and the photoelectric conversion efficiency of the cell piece is improved. More specific reference may be made to the following different embodiments.

Referring to fig. 2 and 11, in the two embodiments, the first transparent conductive film layer 41 has a side edge portion 410 of the first conductive layer extending out of the side surface to cover the second doped side edge portion 320. At this time, the second transparent conductive film layer 42 covers only the region of the second doped amorphous layer 32 corresponding to the second main surface, and a blank region insulated from the side edge portion 410 of the first conductive layer is formed around the second doped amorphous layer.

Referring to fig. 9 and 10, in both embodiments, the second transparent conductive film layer 42 has a second conductive layer side portion 420 extending out of the side surface to cover the second doped side portion 320. At this time, the first transparent conductive film layer 41 covers only the region of the first doped amorphous layer 31 corresponding to the first main surface, and a blank region insulated from the side edge portion 420 of the second conductive layer is formed around the first transparent conductive film layer.

In the embodiments shown in fig. 2 and 9, one of the first transparent conductive film layer 41 and the second transparent conductive film layer 42 on the light receiving surface side extends out of the side surface. In the embodiments shown in fig. 10 and 11, one of the first transparent conductive film layer 41 and the second transparent conductive film layer 42 on the backlight surface extends out of the side surface, and other similar implementation structures are not further developed here.

In a specific implementation process, a width of a blank region between the first transparent conductive film layer 41 and the second transparent conductive film layer 42 for insulating the two layers is in a range of 0.5-2 mm.

The utility model also provides a heterojunction solar cell's manufacturing approach, this method is used for making as above heterojunction solar cell, and it includes:

and a monocrystalline silicon substrate texturing step of texturing the first main surface, the second main surface and the side surfaces of the monocrystalline silicon substrate 10.

A first amorphous film manufacturing step, in which the first amorphous film includes a first intrinsic amorphous layer 21 and a first doped amorphous layer 31, as shown in fig. 12, the first amorphous layer 10 is placed on the first carrier plate 61 with the first main surface facing upward, the first carrier plate 61 has a first groove 610 for placing the single crystal silicon substrate 10, the first intrinsic amorphous layer 21 and the first doped amorphous layer 31 are sequentially deposited on the first main surface side of the single crystal silicon substrate 10 from the upper side of the first carrier plate 61, the first intrinsic amorphous layer 21 is wound to cover a side region where the side surface is connected with the first main surface, and the first doped amorphous layer 31 covers the first intrinsic amorphous layer 21. That is, the first intrinsic side portion 210 and the first doped side portion 310 are formed around the first intrinsic amorphous layer 21 and the first doped amorphous layer 31, respectively.

A second amorphous film manufacturing step, in which the second amorphous film includes a second intrinsic amorphous layer 22 and a second doped amorphous layer 32, as shown in fig. 13, the monocrystalline silicon substrate 10 after the first amorphous film manufacturing step is placed on a second carrier 62 with the second main surface facing upward, the second carrier 62 has a second recess 620 for placing the monocrystalline silicon substrate 10, the second intrinsic amorphous layer 22 and the second doped amorphous layer 32 are sequentially deposited on the second main surface side of the monocrystalline silicon substrate 10 from the upper side of the second carrier 62, the second intrinsic amorphous layer 22 is wound to cover a region of the side surface connected to the second main surface and a region of the first doped amorphous layer 31 corresponding to the side surface, and the second doped amorphous layer 32 covers the second intrinsic amorphous layer 22. That is, second intrinsic side portions 220 and second doped side portions 320 are formed around the second intrinsic amorphous layer 22 and the second doped amorphous layer 32, respectively.

And a transparent conductive film layer manufacturing step, wherein the transparent conductive film layer comprises a first transparent conductive film layer 41 and a second transparent conductive film layer 42, and the first main surface side and the second main surface side which finish the second amorphous film manufacturing step are respectively deposited to form the first transparent conductive film layer 41 and the second transparent conductive film layer 42.

And a collector manufacturing step, wherein the collector comprises a first collector 51 and a second collector 52, the first collector 51 is formed on the surface of the first transparent conductive film layer 41, which is far away from the first doped amorphous layer 31, and the second collector 52 is formed on the surface of the second transparent conductive film layer 42, which is far away from the second doped amorphous layer 32.

In the specific implementation, firstly, an HF solution with the dilution solubility of 5% is used for removing a surface oxide layer, and then, by utilizing the anisotropic corrosion characteristic of monocrystalline silicon, a solution of KOH or NaOH or tetramethyl ammonium hydroxide (TMAH) and alcohol is used for texturing.

In a specific transparent conductive film layer manufacturing step, referring to fig. 14, the monocrystalline silicon substrate 10 having the second amorphous film manufacturing step is placed on the third carrier 70 with the first main surface facing upward, the third carrier 70 includes a through hole 700 penetrating from top to bottom, a carrier 701 for carrying the monocrystalline silicon substrate 10 and shielding a side edge of the second main surface of the monocrystalline silicon substrate 10 is disposed in the through hole 700, a size of an upper side area of the through hole 700 on the carrier 701 is larger than a size of the monocrystalline silicon substrate 10, and a typical difference range is 2-4 mm. The first transparent conductive film layer 41 and the second transparent conductive film layer 42 are respectively formed on the first main surface side and the second main surface side by deposition of the third carrier 70, so that the heterojunction solar cell with the structure shown in fig. 2 or fig. 11 can be formed.

In this embodiment, since the size of the through hole 700 at the upper side of the supporting portion 701 is larger than the size of the single crystal silicon substrate 10, the first transparent conductive film layer 41 will extend to the side of the single crystal silicon substrate 10 during the formation process to form the side portion 410 of the first conductive layer, and a blank area is formed at the portion of the side edge of the second main surface of the single crystal silicon substrate 10, which is shielded by the supporting portion 701.

In another embodiment of the present invention, the single crystal silicon substrate 10 having the second amorphous film forming step can be placed on a third carrier 70 (not shown) with the second major surface facing upward, so as to form a heterojunction solar cell having the structure shown in fig. 9 or fig. 10, which will not be further described herein.

In order to ensure that the first intrinsic side portion 210, the first doped side portion 310, the second intrinsic side portion 220 and the second doped side portion 320 are sequentially formed on the side surface of the monocrystalline silicon substrate 10, in the specific implementation process of the present invention, the difference between the side length of the first groove 610 and the corresponding side length of the monocrystalline silicon substrate 10 is less than 2mm, and the difference between the side length of the second groove 620 and the corresponding side length of the monocrystalline silicon substrate 10 is 2-4 mm. Since the difference between the side length dimension of the first groove 610 and the corresponding side length dimension of the single crystal silicon substrate 10 is small, the first intrinsic amorphous layer 21 and the first doped amorphous layer 31 can cover only a partial region outside the side surface when the side surface of the single crystal silicon substrate 10 is subjected to the plating; and because the difference between the side length of the second groove 620 and the corresponding side length of the monocrystalline silicon substrate 10 is large, the second intrinsic amorphous layer 22 and the second doped amorphous layer 32 can be fully wound and plated outside the side surface of the monocrystalline silicon substrate 10, thereby forming the four-layer amorphous silicon structure shown in the utility model.

The four amorphous silicon layers of the first intrinsic amorphous layer 21, the second intrinsic amorphous layer 22, the first doped amorphous layer 31 and the second doped amorphous layer 32 involved in the utility model are all formed by adopting PECVD deposition process. The first transparent conductive film layer 41 and the second transparent conductive film layer 42 involved in the utility model are formed by PVD deposition, RPD deposition or magnetron sputtering deposition process. The first collector electrode 51 and the second collector electrode 52 according to the present invention are formed by a screen printing process.

Based on the structure of the heterojunction solar cell, when the four amorphous silicon layers are specifically manufactured, the first intrinsic amorphous layer 21 and the first doped amorphous layer 31 are sequentially formed on one side of the first surface 101, and the second intrinsic amorphous layer 22 and the second doped amorphous layer 32 are sequentially formed on one side of the second surface 101, so that the overturning action of the monocrystalline silicon substrate 10 in the manufacturing process of the amorphous film can be reduced as much as possible, the problem of reduction of the yield of the cell caused by pollution caused by the overturning action in the prior art can be avoided, and the production cycle of the heterojunction solar cell can be shortened.

For better understanding the utility model discloses, following still demonstrates the concrete mode of making of four layers amorphous silicon layers of heterojunction solar wafer: introducing pure SiH4 to one side of the first side face of the monocrystalline silicon substrate 10, introducing SiH4 diluted by H2, and growing a first intrinsic amorphous layer 21 under the action of a 13.56MHz radio frequency power supply; then, introducing PH3, SiH4 and H2 to one side of the first side face of the monocrystalline silicon substrate 10 to manufacture a first doped amorphous layer 31; then, introducing pure SiH4 to one side of the second side surface of the monocrystalline silicon substrate 10, introducing SiH4 diluted by H2, and growing a second intrinsic amorphous layer 22 under the action of a 13.56MHz radio frequency power supply; finally, B2H6, SiH4, and H2 are introduced to the second side of the single crystal silicon substrate 10 to form a second doped amorphous layer 32.

It is to be understood that the first intrinsic amorphous layer 21, the first doped amorphous layer 31, the second intrinsic amorphous layer 22 and the second doped amorphous layer 32 are formed in different coating chambers, respectively. In addition, in the process of plating the four amorphous silicon layers, before the corresponding amorphous silicon layers are plated, the temperature and the pressure of the related plating chamber need to reach preset values, the temperature is usually 180 ℃, and the pressure is controlled to be 30-200 pa.

In order to optimize the passivation effect of the first and second intrinsic

amorphous layers

21 and 22 on the single crystal silicon substrate 10, in the specific manufacturing process of the first and second intrinsic

amorphous layers

21 and 22, when SiH4 diluted with H2 is introduced, the dilution ratio of H2/SiH4 may be adjusted, so that the first and second intrinsic

amorphous layers

21 and 22 have multiple intrinsic films with different characteristics, and the dilution ratio of H2/SiH4 is usually in the range of 5-250.

The above shows only the preparation manner in which the first intrinsic amorphous layer 21 and the second intrinsic amorphous layer 22 are all made of intrinsic amorphous silicon, and it can be understood that in other embodiments of the present invention, the intrinsic films of the first intrinsic amorphous layer 21 and the second intrinsic amorphous layer 22 may also be intrinsic amorphous silicon oxide or intrinsic amorphous silicon carbide. And in particular will not be described further herein.

When the first doped amorphous layer 31 and the second doped amorphous layer 32 are fabricated, CO2 or CH4 may be introduced into the corresponding plating chamber, so that the first doped amorphous layer 31 and the second doped amorphous layer 32 are made of amorphous silicon oxide or amorphous silicon carbide. More specifically, reference is made to the following.

In fabricating the first doped amorphous film 301, SiH4, H2, and a first type dopant gas are introduced into the vacuum chamber.

When the doped amorphous silicon oxide film, the doped amorphous silicon carbide film or the doped amorphous silicon carbide/doped amorphous silicon oxide composite film 302 is manufactured: if the film layer is a doped amorphous silicon oxide film, introducing SiH4, H2, CO2 and a first type of doping gas into a vacuum chamber; if the film layer is a doped amorphous silicon carbide film, introducing SiH4, H2, CH4 and a first type of doping gas into a vacuum chamber; if the film layer is a doped amorphous silicon carbide/doped amorphous silicon oxide composite film, SiH4, H2, CO2, CH4 and a first type of doping gas are simultaneously introduced into a vacuum chamber to form the composite film, or at least one layer of doped amorphous silicon oxide and at least one layer of doped amorphous silicon carbide are separately deposited to form the composite film. The utility model discloses in, doping amorphous silicon oxide film, doping amorphous silicon carbide film or doping amorphous silicon carbide/doping amorphous silicon oxide complex film 302 can increase the optical band gap of heterojunction solar cell photic surface rete, increases the printing opacity, can promote the optical property of battery.

When it is desired to fabricate the second doped amorphous film 303, SiH4, H2, and a first type of dopant gas are introduced into the vacuum chamber.

In fabricating the third doped amorphous film 304 and the fourth doped amorphous film 305, SiH4, H2, and a second-type dopant gas are introduced into the vacuum chamber. The difference is that the doping concentration of the second type dopant gas when the third doped amorphous film 303 is formed is smaller than that when the fourth doped amorphous film 304 is formed.

It should be understood that the above references to the first type of dopant gas refer to one of a PH3 (phosphine) gas and a B2H6 (diborane) gas, and the second type of dopant gas refer to the other of a PH3 (phosphine) gas and a B2H6 (diborane) gas.

It should be understood that although the present description refers to embodiments, not every embodiment contains only a single technical solution, and such description is for clarity only, and those skilled in the art should make the description as a whole, and the technical solutions in the embodiments can also be combined appropriately to form other embodiments understood by those skilled in the art.

The above list of details is only for the practical implementation of the present invention, and they are not intended to limit the scope of the present invention, and all equivalent implementations or modifications that do not depart from the technical spirit of the present invention should be included in the scope of the present invention.

Claims

1. A heterojunction solar cell, comprising:

2. The heterojunction solar cell of claim 1, wherein the thickness of the first amorphous film and the second amorphous film on the light receiving surface is less than or equal to the thickness on the backlight surface.

3. The heterojunction solar cell of claim 2, wherein the thicknesses of the first amorphous film and the second amorphous film on the light receiving surface and the back light surface are 6-21nm and 6-30nm, respectively.

4. The heterojunction solar cell of any of claims 1 to 3, wherein the thickness of the first intrinsic amorphous layer and the second intrinsic amorphous layer on the light receiving surface is less than or equal to the thickness on the backlight surface.

5. The heterojunction solar cell of claim 4, wherein the thickness of the first intrinsic amorphous layer and the second intrinsic amorphous layer on the light receiving surface is 3-6nm, and the thickness on the backlight surface is 3-10 nm.

6. The heterojunction solar cell of any of claims 1 to 3, wherein the thickness of the first doped amorphous layer and the second doped amorphous layer on the light receiving surface side is less than or equal to the thickness on the backlight surface side.

7. The heterojunction solar cell of claim 6, wherein the thickness of the first doped amorphous layer and the second doped amorphous layer on the light receiving surface side is 3-15nm, and the thickness of the first doped amorphous layer and the second doped amorphous layer on the backlight surface side is 3-20 nm.

8. The heterojunction solar cell of claim 1, 2 or 3, wherein the first doped amorphous layer and the second doped amorphous layer sequentially comprise a first doped amorphous silicon film and a doped amorphous silicon oxide film, a doped amorphous silicon carbide film or a doped amorphous silicon carbide/doped amorphous silicon oxide composite film on the surface of the first doped amorphous silicon film, from the backlight surface to the light receiving surface.

9. The heterojunction solar cell of claim 8, wherein the first doped amorphous layer and the second doped amorphous layer on the light-receiving surface further comprise a second doped amorphous silicon film on the surface of the doped amorphous silicon oxide film, the doped amorphous silicon carbide film or the doped amorphous silicon carbide/doped amorphous silicon oxide composite film.

10. The heterojunction solar cell of claim 1, 2 or 3, wherein the first doped amorphous layer and the second doped amorphous layer sequentially comprise a third doped amorphous silicon film and a fourth doped amorphous silicon film on the surface of the third doped amorphous silicon film and with a doping concentration higher than that of the third doped amorphous silicon film, from the light receiving surface to the backlight surface.

11. The heterojunction solar cell of claim 1, 2 or 3, wherein the thickness of the region where the first and second intrinsic amorphous layers extend to cover the side is not less than 1 nm.

12. The heterojunction solar cell of claim 1, 2 or 3, wherein the first and second intrinsic amorphous layers each comprise at least two intrinsic films disposed one on top of the other.

13. The heterojunction solar cell of claim 12, wherein the layer of intrinsic film of the first intrinsic amorphous layer and/or the second intrinsic amorphous layer furthest from the single crystal silicon substrate is an intrinsic amorphous silicon oxide film.

14. The heterojunction solar cell of claim 1, 2 or 3, wherein one of the first and second doped amorphous layers on the light receiving surface side is an n-type doped amorphous layer, and one of the first and second doped amorphous layers on the backlight surface side is a p-type doped amorphous layer.

15. The heterojunction solar cell of claim 14, wherein the first and second transparent conductive film layers are disposed on the light receiving surface and comprise a first TCO film attached to the surface of the n-type doped amorphous layer and a second TCO film attached to the surface of the first TCO film and having a smaller mass fraction of doped oxide than the mass fraction of doped oxide in the first TCO film.

16. The heterojunction solar cell of claim 15, wherein the first and second transparent conductive film layers on the light receiving surface further comprise a third TCO film attached to the surface of the second TCO film and having a higher mass fraction of doped oxide than the second TCO film.

17. The heterojunction solar cell of claim 14, wherein the first and second transparent conductive film layers on the back light side comprise a fourth TCO film attached to the surface of the p-type doped amorphous layer and a fifth TCO film attached to the surface of the fourth TCO film and having a mass fraction of doped oxide greater than the mass fraction of doped oxide in the fourth TCO film.

18. The heterojunction solar cell of claim 1, 2 or 3, wherein the thickness of the first transparent conductive film layer and the second transparent conductive film layer on the light receiving surface is less than or equal to the thickness of the first transparent conductive film layer and the second transparent conductive film layer on the backlight surface.

19. The heterojunction solar cell of claim 1, 2 or 3, wherein one of the first and second transparent conductive film layers covers a region of the second doped amorphous layer corresponding to the side surface.