KR101135590B1 - Solar cell and method for manufacturing the same - Google Patents

Solar cell and method for manufacturing the same Download PDF

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Publication number
KR101135590B1
KR101135590B1 KR1020090084046A KR20090084046A KR101135590B1 KR 101135590 B1 KR101135590 B1 KR 101135590B1 KR 1020090084046 A KR1020090084046 A KR 1020090084046A KR 20090084046 A KR20090084046 A KR 20090084046A KR 101135590 B1 KR101135590 B1 KR 101135590B1
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South Korea
Prior art keywords
substrate
rear
passivation layer
solar cell
surface
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KR1020090084046A
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Korean (ko)
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KR20110026238A (en
Inventor
양현진
이헌민
지광선
최원석
최정훈
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엘지전자 주식회사
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Priority to KR1020090084046A priority Critical patent/KR101135590B1/en
Priority claimed from CN 201010535062 external-priority patent/CN102044579B/en
Priority claimed from CN201010540778.3A external-priority patent/CN102074599B/en
Publication of KR20110026238A publication Critical patent/KR20110026238A/en
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/50Photovoltaic [PV] energy

Abstract

The present invention relates to a solar cell. The solar cell includes a substrate, a front electric field portion located at an incident surface of the substrate, at least one emitter portion located at a rear surface of the substrate, at least one first electrode electrically connected to the at least one emitter portion, And at least one second electrode positioned on a rear surface of the substrate and electrically connected to the substrate. In this case, the substrate and the at least one emitter portion form a heterojunction. As such, since the front electric field is located on the incident surface of the solar cell, the recombination rate of charges is reduced at the incident surface of the substrate, thereby improving the efficiency of the solar cell.
Solar cell, back electrode, front electric field, passivation, protective film, heterojunction

Description

SOLAR CELL AND METHOD FOR MANUFACTURING THEREOF {SOLAR CELL AND METHOD FOR MANUFACTURING THE SAME}

The present invention relates to a solar cell and a method of manufacturing the same.

Recently, as the prediction of depletion of existing energy sources such as oil and coal is increasing, interest in alternative energy to replace them is increasing. Among them, solar cells are producing electric energy from solar energy, and are attracting attention because they are rich in energy resources and have no problems with environmental pollution.

A typical solar cell includes a substrate and an emitter layer made of semiconductors of different conductive types, such as p-type and n-type, and electrodes connected to the substrate and the emitter, respectively. At this time, p-n junction is formed in the interface of a board | substrate and an emitter part.

When light is incident on the solar cell, a plurality of electron-hole pairs are generated in the semiconductor, and the generated electron-hole pairs are separated into electrons and holes charged by the photovoltaic effect, respectively, and the electrons and holes are n-type. Move toward the semiconductor and the p-type semiconductor, for example toward the emitter portion and the substrate, collected by electrodes electrically connected to the substrate and the emitter portion, and connected to the wires to obtain power.

At this time, on the emitter unit and the substrate, a plurality of electrodes electrically connected to the emitter unit and the substrate are positioned to collect charges moved to the substrate and the emitter unit, respectively, to be moved to a load connected to the outside.

However, in this case, since the electrode is positioned not only on the surface of the substrate on which light is not incident, but also on the surface on which the light is incident, that is, on the emitter portion formed on the incident surface, the incident area of the light is reduced, thereby decreasing the efficiency of the solar cell.

Accordingly, in order to increase the incident area of light, a solar cell having a back contact structure has been developed in which both electrodes for collecting electrons and holes are located on the back of the substrate.

The technical problem to be achieved by the present invention is to improve the efficiency of the solar cell.

A solar cell according to an aspect of the present invention includes a substrate of a first conductivity type, a front electric field portion located on an incident surface of the substrate, and at least a second conductivity type located on a rear surface of the substrate and opposite to the first conductivity type. One emitter portion, at least one first electrode electrically connected to the at least one emitter portion, and at least one second electrode positioned on a rear surface of the substrate and electrically connected to the substrate; The substrate and the at least one emitter portion form a heterojunction.

The solar cell according to the above feature may further include at least one rear electric field part positioned between the substrate and the at least one second electrode.

The solar cell according to the above feature may further include a rear passivation layer on the back of the substrate.

The rear passivation layer may be located between the at least one emitter unit and the at least one rear field unit, and the rear passivation layer may be formed of a silicon oxide layer or a silicon nitride layer.

The rear passivation layer may be located on the entire rear surface of the substrate, wherein the back passivation layer may be formed of one of amorphous silicon, silicon oxide, or silicon nitride.

The rear passivation layer may include a first rear passivation layer positioned between the substrate, the at least one emitter unit and the at least one rear electric field unit, and a second rear passivation layer located between the at least one emitter unit and the at least one rear electric field unit. A rear passivation layer may be included, and the first rear passivation layer and the second rear passivation layer may be formed of different materials.

The first rear protective layer may be made of a conductive material, and the second rear protective layer may be made of an insulating material.

The first rear passivation layer may be made of amorphous silicon, and the second rear passivation layer may be made of silicon oxide or silicon nitride.

The thicknesses of the first rear protective layer and the second rear protective layer may be different from each other.

The thickness of the first rear protective film may be smaller than the thickness of the second rear protective film.

The first electrode and the second electrode are nickel (Ni), copper (Cu), silver (Ag), aluminum (Al), tin (Sn), zinc (Zn), indium (In), titanium (Ti), At least one conductive material selected from the group consisting of gold (Au) and combinations thereof.

Preferably, the substrate is made of crystalline silicon, and the at least one emitter part is made of amorphous silicon.

The solar cell according to the above feature may further include a front passivation layer positioned on the front field part, and further include an antireflection layer positioned on the front passivation layer.

According to another aspect of the present invention, there is provided a method of manufacturing a solar cell, including: forming a front electric field on an incident surface of a substrate of a first conductivity type; Forming at least one emitter portion having a second conductivity type opposite to the substrate type and having a material different from the substrate, forming at least one rear electric field portion over the back surface of the substrate, and over the at least one emitter portion; Forming a first electrode and a second electrode on the at least one rear electric field.

The substrate may be made of crystalline silicon, and the at least one emitter part may be made of amorphous silicon.

The front electric field part may be made of amorphous silicon, a silicon oxide film, or a silicon nitride film.

The forming of the rear passivation layer may include stacking the rear passivation layer on the entire rear surface of the substrate, wherein the at least one emitter unit and the at least one rear electric field unit may be positioned on the rear passivation layer, respectively.

The forming of the rear passivation layer may include: stacking a first rear passivation layer on a rear surface of the substrate, exposing a portion of the substrate by etching a portion of the first rear passivation layer; Stacking a rear protective film; and etching the second rear protective film stacked on the first rear protective film to expose the first rear protective film, wherein the at least one emitter portion and the at least one second second protective film are exposed. An electric field portion may be positioned over the first back passivation material.

The first rear passivation layer may be made of amorphous silicon, and the second rear passivation layer may be made of silicon oxide or silicon nitride.

The forming of the rear passivation layer may include stacking a rear passivation layer on the entire rear surface of the substrate and exposing a portion of the backside of the substrate by etching a portion of the rear passivation layer, wherein the at least one emitter portion and the at least one The second electric field may be located on the rear surface of the exposed substrate.

The method of manufacturing a solar cell according to the above feature may further include forming a texturing surface on the incident surface of the substrate.

The forming of the texturing surface may include forming an etch stop layer on a rear surface of the substrate, etching the surface of the substrate to form a texturing surface on the incident surface of the substrate, and removing the etch stop layer. have.

The method of manufacturing a solar cell according to the above feature may further include forming an anti-reflection film on the front field part.

According to a feature of the present invention, since the front electric field is located at the incident surface of the solar cell, the recombination rate of the charge is reduced at the incident surface of the substrate, thereby improving the efficiency of the solar cell.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a layer, film, region, plate, or the like is referred to as being "on" another portion, it includes not only the case directly above another portion but also the case where there is another portion in between. On the contrary, when a part is "just above" another part, there is no other part in the middle. Also, when a part is formed as "whole" on the other part, it means not only that it is formed on the entire surface (or the front surface) of the other part but also not on the edge part.

Next, a solar cell and a manufacturing method thereof according to an embodiment of the present invention will be described with reference to the accompanying drawings.

First, a solar cell according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2.

1 is a partial perspective view of a solar cell according to an exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view of the solar cell illustrated in FIG. 1 taken along line II-II.

1 and 2, a solar cell 1 according to an embodiment of the present invention is referred to as a surface of a substrate 110 and a substrate 110 to which light is incident (hereinafter, referred to as a “front surface”). The front surface field (FSF) 171 positioned above, the front passivation layer 191 positioned on the front field pass 171, the antireflection layer 130 positioned on the front passivation layer 191, and light A plurality of rear protective layers 192 and rear protective layers 192 positioned on a surface of the substrate 110 facing the front surface of the substrate 110 without being incident (hereinafter, referred to as a “rear surface”). A plurality of back surface fields (BSFs) 172 located on the emitter portion 120, the rear passivation layer 192, and spaced apart from the plurality of emitter portions 120, and the plurality of emitter portions 120. The plurality of first electrodes 141 and the plurality of second electrodes 142 positioned on the plurality of rear electric field parts 172 are included.

The substrate 110 is a semiconductor substrate made of silicon of a first conductivity type, for example, an n-type conductivity type. At this time, the silicon is crystalline silicon such as monocrystalline silicon or polycrystalline silicon. When the substrate 110 has an n-type conductivity type, the substrate 110 may contain impurities of pentavalent elements such as phosphorus (P), arsenic (As), and antimony (Sb). Alternatively, the substrate 110 may be of a p-type conductivity type and may be made of a semiconductor material other than silicon. When the substrate 110 has a p-type conductivity type, the substrate 110 may contain impurities of trivalent elements such as boron (B), gallium (Ga), and indium (In).

This substrate 100 has a textured surface whose surface is textured and is an uneven surface.

The front field part 171 formed on the front surface of the substrate 110 is made of crystalline silicon such as amorphous silicon or polycrystalline silicon, and impurities of the same conductivity type as the substrate 110 are contained at a higher concentration than the substrate 110. Part, for example n + part.

Therefore, a potential barrier is formed due to the difference in the impurity concentration between the substrate 110 and the front surface electric field unit 171, thereby preventing hole movement toward the front surface of the substrate 110, thereby recombining electrons and holes near the surface of the substrate 110. To reduce extinction.

The front passivation layer 191 disposed on the front field part 171 converts an unstable bond such as a dangling bond, which exists near the surface of the substrate 110, into a stable bond, thereby forming an unstable bond of the substrate 110. It reduces the charges traveling towards the front, for example the disappearance of electrons.

The front passivation layer 191 is made of a silicon oxide layer (SiOx), a silicon nitride layer (SiNx), amorphous silicon, or the like.

The anti-reflection film 130 disposed on the passivation layer 191 is made of a silicon nitride film (SiNx), a silicon oxide film (SiOx), or the like. The anti-reflection film 130 reduces the reflectivity of light incident on the solar cell 1 and increases the selectivity of a specific wavelength region, thereby increasing the efficiency of the solar cell 1. In the present embodiment, the anti-reflection film 130 may have a single film structure but may have a multilayer film structure such as a double film, and may be omitted as necessary.

The rear passivation layer 192 disposed on the rear surface of the substrate 110 is formed of a silicon oxide layer (SiOx), a silicon nitride layer (SiNx), amorphous silicon, or the like, similar to the front passivation layer 191, and is located near the surface of the substrate 110. By changing the unstable bond present in the stable bond, the electrons moved toward the rear of the substrate 110 is reduced to disappear by the unstable bond.

The rear passivation layer 192 has a thickness such that charges moved to the rear surface of the substrate 110 may pass through the rear passivation layer 192 and move to the plurality of rear electric field parts 172 or the emitter parts 120. In this embodiment, one example of the thickness of the rear passivation layer 192 may be about 1 to 10 nm.

The plurality of emitter portions 120 disposed on the rear passivation layer 192 have a second conductivity type, for example, a p-type conductivity type, which is opposite to the conductivity type of the substrate 110, and has a semiconductor different from that of the substrate 110. For example, it consists of amorphous silicon. Accordingly, the emitter unit 120 forms a hetero junction as well as a p-n junction with the substrate 110.

As shown in FIG. 1, the plurality of emitter portions 120 are spaced apart from each other and extend in a direction determined substantially in parallel.

When the plurality of emitter portions 120 have a p-type conductivity type, the emitter portion 120 may include impurities of trivalent elements such as boron (B), gallium (Ga), indium (In), and the like. On the contrary, when the plurality of emitter portions 120 have an n-type conductivity type, impurities of a pentavalent element such as phosphorus (P), arsenic (As), and antimony (Sb) may be included.

The plurality of backside electric fields 172 positioned on the rear surface of the substrate 110 are separated from the plurality of emitter portions 120 and extend in the same direction as the plurality of emitter portions 120 substantially parallel to each other. Thus, as shown in FIGS. 1 and 2, the plurality of emitter portions 120 and the plurality of rear electric field portions 171 are alternately positioned on the rear surface of the substrate 110.

The plurality of rear electric field parts 172 is made of amorphous silicon or crystalline silicon, similar to the front electric field part 171, and an impurity part in which impurities of the same conductivity type as the substrate 110 are contained at a higher concentration than the substrate 110, For example n + parts.

As a result, a potential barrier is formed due to the difference in the impurity concentration between the substrate 110 and the plurality of rear electric field parts 172, and thus the holes passing through the rear passivation layer 192 are formed in the same manner as the front electric field part 171. Since movement toward the second electrode 142 is prevented, the amount of electrons and holes recombined and extinguishes in the vicinity of the plurality of second electrodes 142 is reduced.

As such, an electron-hole pair, which is a charge generated by light incident on the substrate 110 due to a built-in potential difference due to a pn junction formed between the substrate 110 and the plurality of emitter portions 120. Is separated into electrons and holes, electrons move toward n-type and holes move toward p-type. Therefore, when the substrate 110 is n-type and the plurality of emitter portions 120 are p-type, the separated holes move through the rear passivation layer 192 toward each emitter portion 120 and the separated electrons form the back passivation layer ( It penetrates through the 192 and moves toward the plurality of backside electric fields 172 having higher impurity concentration than the substrate 110.

Since each emitter portion 120 forms a pn junction with the substrate 110, unlike the present embodiment, when the substrate 110 has a p-type conductivity type, the emitter portion 120 has an n-type conductivity type. Have In this case, the separated electrons move toward the plurality of emitter units 120 through the rear passivation layer 192, and the separated holes move toward the plurality of rear electric field units 172 through the rear passivation layer 192.

The plurality of first electrodes 141 positioned on the plurality of emitter portions 120 extend along the plurality of emitter portions 120 and are electrically connected to the plurality of emitter portions 120.

Each first electrode 141 collects electric charges, for example, holes moved toward the corresponding emitter unit 120.

The plurality of second electrodes 142 positioned on the plurality of rear electric field units 172 extend along the plurality of rear electric field units 172 and are electrically connected to the plurality of rear electric field units 172.

Each second electrode 142 collects charge, for example electrons, that move toward each backside field portion 172.

The first and second electrodes 141 and 142 may include nickel (Ni), copper (Cu), silver (Ag), aluminum (Al), tin (Sn), zinc (Zn), indium (In), and titanium. It may be made of at least one conductive material selected from the group consisting of (Ti), gold (Au), and combinations thereof, but may be made of other conductive metal materials other than the above.

In the solar cell 1 according to the present exemplary embodiment having the structure as described above, the plurality of first electrodes 141 and the plurality of second electrodes 142 are positioned on the rear surface of the substrate 110 to which light is not incident, and the substrate ( The solar cell 110 and the emitter unit 120 are made of different kinds of semiconductors, and the operation thereof is as follows.

When light is irradiated onto the solar cell 1 and sequentially passes through the anti-reflection film 130, the front passivation layer 191, and the front electric field part 171, and enters the substrate 110, the light is radiated from the substrate 110 by light energy. Electron-hole pairs occur. At this time, since the surface of the substrate 110 is a texturing surface, the light reflectivity on the entire surface of the substrate 110 is reduced, and incident and reflection operations are performed on the texturing surface to increase light absorption, thereby improving efficiency of the solar cell 1. do. In addition, the reflection loss of light incident on the substrate 110 by the anti-reflection film 130 is reduced, so that the amount of light incident on the substrate 110 is further increased.

These electron-hole pairs are separated from each other by the pn junction of the substrate 110 and the emitter portion 120 so that the holes move toward the emitter portion 120 having a p-type conductivity type, and the electrons form an n-type conductivity type. The electrons moved toward the rear electric field part 172, collected by the first electrode 141 and the second electrode 142, respectively, and moved toward the plurality of rear electric field parts 172 are transferred to the second electrode 142. Is collected by When the first electrode 141 and the second electrode 142 are connected with a conductive wire, a current flows, which is used as power from the outside.

In this case, since the passivation layers 192 and 191 are positioned not only on the rear surface of the substrate 110 but also on the front surface of the substrate 110, the surface of the substrate 110 may be formed due to unstable coupling existing near the front and rear surfaces of the substrate 110. The amount of charge lost in the vicinity is reduced, so that the efficiency of the solar cell 1 is improved.

In addition, since the electric field parts 172 and 171 containing high concentration of impurities of the same conductivity type as the substrate 110 are located not only on the rear surface of the substrate 110 but also on the front surface of the substrate 110. Hole movement to the back is obstructed. As a result, the electrons and holes are recombined and extinguished in the rear and front surfaces of the substrate 110, thereby reducing the efficiency of the solar cell 1.

Next, a method of manufacturing a solar cell according to an embodiment of the present invention will be described with reference to FIGS. 3A to 3G.

3A to 3G are flowcharts sequentially illustrating a method of manufacturing a solar cell according to an embodiment of the present invention.

Referring to FIG. 3A, first, an etch stop layer 170 made of a silicon oxide film (SiOx) or the like is stacked on a rear surface of a substrate 110 made of n-type single crystal or polycrystalline silicon.

3B, the front surface of the substrate 110 on which the etch stop layer 170 is not formed is etched using the etch stop layer 170 as a mask, and a plurality of protrusions are formed on the front surface of the substrate 110. To form a textured surface. In this case, when the substrate 110 is made of single crystal silicon, the surface of the substrate 110 is textured by using a base solution such as KOH, NaOH, TMAH, or the like. On the other hand, when the substrate 110 is made of polycrystalline silicon, the surface of the substrate 110 is textured by using an acid solution such as HF or HNO 3 .

Then, as shown in Figure 3c, the front surface of the substrate 110, which is a texturing surface by using a chemical vapor deposition method such as plasma enhanced vapor deposition (PECVD), such as amorphous silicon or polycrystalline silicon 171 is formed. During deposition, a material containing a pentavalent element such as phosphorus (P), for example, POCl 3 is injected into the process chamber, so that the front electric field part 171 has the same conductivity type as the substrate 110, but the substrate The front field unit 171 having a higher impurity concentration than 110 is completed.

Next, as shown in FIG. 3D, the front passivation layer 191 made of amorphous silicon is formed on the front field part 171 using PECVD or the like. In an alternative embodiment, the front passivation layer 191 may be made of silicon oxide (SiOx) or silicon nitride (SiNx). When the front passivation layer 191 is made of silicon oxide (SiOx), the front passivation layer 191 may be formed by thermal oxidation.

Subsequently, as shown in FIG. 3E, an antireflection film 130 made of a silicon nitride film (SiNx) or a silicon oxide film (SiOx) is formed on the front passivation film 191 by using chemical vapor deposition.

Next, as shown in FIG. 3F, the etch stop layer 170 formed on the rear surface of the substrate 110 is etched and removed.

Next, as shown in FIG. 3G, a rear passivation layer 192 is formed on the back side of the substrate 110 by chemical vapor deposition. The back passivation layer 192 is made of amorphous silicon, silicon oxide (SiOx), silicon nitride (SiNx), or the like.

Subsequently, as shown in FIG. 3H, a mask (not shown) having a plurality of openings is positioned on the rear passivation film 192, and amorphous silicon is laminated by PECVD to complete the plurality of emitter portions 120. When the plurality of emitter portions 120 are formed, a material including impurities of trivalent elements such as boron (B), for example, B 2 H 6 is injected into the process chamber, and thus the plurality of emitter portions 120 are formed. Contains a high concentration of impurities of a conductive type opposite to the substrate 110. As a result, a pn junction is formed between the substrate 110 and the plurality of emitter portions 120. In addition, since the substrate 110 and the plurality of emitter portions 120 are made of different semiconductor materials, the substrate 110 and the plurality of emitter portions 120 form heterojunctions.

In this case, the plurality of opening positions correspond to portions of the rear passivation layer 192 in which the plurality of emitter portions 120 are formed, and the plurality of openings expose portions of the rear passivation layer 192 in which the plurality of emitter portions 120 are formed. do.

Then, as shown in FIG. 3I, a mask (not shown) having a plurality of openings is positioned on the rear passivation layer 192, and then a plurality of backside electric fields are deposited by PECVD or the like. 172 is formed. In this case, since the rear electric field part 172 is formed by injecting POCl 3 containing impurity of pentavalent element such as phosphorus (P) into the process chamber, the plurality of rear electric field parts 172 are higher than the substrate 110. It becomes a p + region having a concentration.

In this case, the plurality of opening positions correspond to portions of the rear passivation layer 192 on which the plurality of rear electric field portions 172 are formed, and the plurality of openings are portions of the rear passivation layer 192 on which the plurality of rear electric fields 172 are formed. Expose

In this case, the order of forming the plurality of emitter units 120 and the plurality of rear electric field units 172 may be changed. In addition, after the photoresist film is deposited and a photo mask is placed thereon, the photoresist film of the portion where the plurality of emitters 120 and the plurality of rear electric field portions 172 are to be formed is exposed to expose the rear passivation film 192 of the desired portion. After the exposure, the emitter unit 120 and the rear electric field unit 172 are formed on the rear passivation layer 192 in various ways, such as by depositing the emitter unit 120 and the rear electric field unit 172 on the exposed portions, respectively. can do.

Next, as shown in FIG. 3J, a conductive film 160 containing a conductive material is disposed on the rear passivation layer 192, the plurality of emitter portions 120, and the plurality of backside electric fields 172, which are exposed using PECVD. Deposit. In an alternative embodiment, the conductive film 160 may be formed by applying a paste containing a conductive material by screen printing and then drying.

Then, a portion of the conductive film 160 is etched using a mask or the like to form a plurality of first electrodes 141 and a plurality of first electrodes formed on the plurality of emitter portions 120 and the plurality of rear electric field portions 172, respectively. 2 electrodes 142 are formed (see FIGS. 1 and 2).

In alternative embodiments, all of the films 171, 191, 130, 192, 120, 172, 141, 142 formed over the substrate 110 may be formed by physical vapor deposition, such as sputtering, as well as chemical vapor deposition, such as PECVD. It can be formed by physical vapor deposition.

As such, since the films formed on the substrate 110 are formed by a chemical vapor deposition method or a physical vapor deposition method performed at a low temperature of about 200 ° C., the manufacturing of the solar cell 1 is easy, and each film 171 may be formed at a high temperature. Since the phenomenon of the characteristics of 191, 130, 192, 120, 172, 141, and 142 deterioration is prevented, the efficiency of the solar cell 1 is improved.

Next, a solar cell 1a according to another embodiment of the present invention will be described with reference to FIGS. 4 and 5.

4 is a partial perspective view of a solar cell according to an exemplary embodiment of the present invention, and FIG. 5 is a cross-sectional view of the solar cell illustrated in FIG. 4 taken along the line V-V.

In the present embodiment, the same reference numerals are assigned to components that perform the same function as compared with the solar cell 1 shown in FIGS. 1 and 2, and detailed description thereof is also omitted.

The solar cell 1a shown in FIGS. 4 and 5 has a structure similar to that of the solar cell 1 shown in FIGS. 1 and 2.

That is, the solar cell 1a according to the present exemplary embodiment includes the substrate 110, the front electric field part 171 positioned on the front surface of the substrate 110, the front passivation layer 191 located on the front electric field unit 171, and the front surface. The anti-reflection film 130 positioned on the passivation layer 191, the rear passivation layer 1921 positioned on the rear side of the substrate 110, the plurality of emitter portions 120 and the plurality of rear electric field portions 172, and the plurality of emitter portions And a plurality of first electrodes 141 and a plurality of second electrodes 142 respectively positioned on the 120 and the plurality of backside electric fields 172.

However, unlike the solar cell 1 shown in FIGS. 1 and 2, in the solar cell 1a of the present embodiment, a plurality of emitter portions 120 and a plurality of rear electric field portions 172 are directly connected to the substrate 110. The rear protective layer 1921 is positioned on the rear surface of the substrate 110 except for a portion where the plurality of emitter portions 120 and the plurality of rear electric field portions 172 are formed. That is, the rear protective film 1921 is the same as the solar cell 1 shown in FIGS. 1 and 2 except that the rear protective layer 1921 is positioned only between the plurality of emitter portions 120 and the plurality of rear electric field portions 172.

In this case, the thickness of the rear passivation layer 1921 may be thicker than the rear passivation layer 192 illustrated in FIGS. 1 and 2, but is not limited thereto.

The rear passivation film 1921 converts an unstable bond into a stable bond in the same manner as the rear passivation film 192 of FIGS. 1 and 2 to reduce the amount of charge loss near the surface of the substrate 110. In addition, the rear passivation layer 1921 may reduce electric charge loss by preventing electric interference such as charge transfer between the adjacent emitter unit 120 and the rear electric field unit 172, and the light passing through the substrate 110 may be reduced. By reflecting the inside of the substrate 110, the amount of light lost to the outside is reduced.

A method of manufacturing the solar cell 1a according to the present embodiment will be described with reference to FIGS. 6A to 6D as well as FIGS. 3A to 3J.

6A to 6D are flowcharts sequentially illustrating a part of a manufacturing method of a solar cell according to another embodiment of the present invention.

3A through 3G, the front field 171, the front passivation layer 191, and the anti-reflection layer 130 are sequentially formed on the entire surface of the substrate 110, which is textured in the same manner as the method illustrated in FIGS. 3A to 3G. The rear passivation film 1921 is formed on the rear side of the substrate.

6A, a portion of the rear passivation layer 1921 is removed using a mask to expose a portion of the back side of the substrate 110. In this case, the exposed portion of the substrate 110 corresponds to the plurality of emitter portion forming portions and the plurality of backside electric field forming portions.

Then, similar to FIGS. 3H and 3I, a plurality of emitter portions 120 and a plurality of rear electric field portions 172 are formed on the exposed emitter portion forming portion and the exposed back field forming portion, respectively, using a mask. 6b and 6c. As a result, the plurality of emitter portions 120 and the plurality of rear electric field portions 172 directly contact the substrate 110.

Next, similar to FIG. 3J, after the conductive film 140 is formed on the rear surface of the substrate 110, a portion of the conductive film 140 is etched to emit a plurality of emitter portions 120 and a plurality of rear electric field portions 172. A plurality of first electrodes 141 and a plurality of second electrodes 142, respectively, are formed on the upper surface of the substrate (see FIGS. 4 and 5).

As described above, since the plurality of emitter portions 120 and the plurality of rear electric field portions 172 directly contact the rear surface of the substrate 110, the transfer rates of charges moving to the emitter portion 120 and the rear electric field portions 172, respectively. This improves, and the efficiency of the solar cell 1a is further improved than the solar cell 1 shown in FIG. 1 and FIG.

Next, a solar cell 1b according to still another embodiment will be described with reference to FIGS. 7 and 8.

7 is a partial perspective view of a solar cell according to still another embodiment of the present invention, and FIG. 8 is a cross-sectional view of the solar cell shown in FIG. 7 taken along the line VIII-VIII.

In the present embodiment, the same reference numerals are assigned to components that perform the same function as compared with the solar cell 1 shown in FIGS. 1 and 2, and detailed description thereof is also omitted.

The solar cell 1b illustrated in FIGS. 7 and 8 is similar to the solar cell 1 illustrated in FIGS. 1 and 2, and includes a front electric field 171, a front passivation layer 191, and The anti-reflection film 130 is sequentially positioned, and the rear passivation layers 192a and 192b disposed on the rear surface of the substrate 110, the plurality of emitter portions 120 and the plurality of rear sides located on the rear passivation layers 192a and 192b. The system unit 172 includes a plurality of first electrodes 141 and a plurality of second electrodes 142 respectively positioned on the emitter unit 120 and the plurality of rear electric field units 172.

However, unlike FIGS. 1 and 2, the solar cell 1b according to the present exemplary embodiment may include a first rear passivation layer 192a positioned between the substrate 110, the plurality of emitter portions 120, and the plurality of rear electric field portions 172. ) And other portions, that is, the rear passivation layers 192a and 192b having the second rear passivation layer 192b disposed between the plurality of emitter portions 120 and the plurality of rear electric field portions 172 and exposed.

The first rear passivation layer 192a disposed between the substrate 110, the emitter unit 120, and the rear electric field unit 172 is made of a conductive material such as amorphous silicon, and the second rear passivation layer ( 192b is made of an insulating material such as silicon oxide film (SiOx) or silicon nitride film (SiNx).

As a result, the rate of change of converting an unstable bond present in the contact surface with the substrate 110 into a stable bond is improved, and the emitter unit 120 or the rear electric field unit 172 is controlled by the conductive property of the first rear passivation layer 192a. Since the amount of charge to be transferred increases, the charge transfer efficiency is improved, so that the efficiency of the solar cell 1b is further improved compared with the solar cell 1.

In the present embodiment, the first and second rear passivation layers 192a and 192b have the same thickness but may be different from each other. For example, the thickness of the second rear passivation layer 192b may be thicker than the thickness of the first rear passivation layer 192a. In this case, as described above with reference to FIGS. 4 and 5, electrical interference such as charge transfer between the adjacent emitter unit 120 and the rear electric field unit 172 is prevented by the second rear passivation layer 192b. The efficiency of the solar cell 1b is further improved.

The method of manufacturing the solar cell 1b according to the present embodiment will be described with reference to FIGS. 9A to 9D as well as FIGS. 3A to 3J.

9A to 9D are flowcharts sequentially illustrating a part of a manufacturing method of a solar cell according to still another embodiment of the present invention.

In the method of manufacturing the solar cell 1a according to the present exemplary embodiment, after depositing the first rear passivation layer 192a made of amorphous silicon on the back of the substrate (FIG. 9A), the part is etched to form the emitter part and the back electric field part. A first rear passivation layer 192a positioned at the formation portion is completed (FIG. 9B), and a second rear passivation layer (SiOx) or a silicon nitride layer is formed on the exposed substrate 110 and the first rear passivation layer 192a (FIG. 9B). Except for the process of completing the second rear passivation layer 192b by etching a portion after depositing 192b (FIG. 9C) (FIG. 9D), the detailed description is omitted. do.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

1 is a partial perspective view of a solar cell according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the solar cell illustrated in FIG. 1 taken along the line II-II.

3A to 3J are flowcharts sequentially illustrating a method of manufacturing a solar cell according to an embodiment of the present invention.

4 is a partial perspective view of a solar cell according to an embodiment of the present invention.

5 is a cross-sectional view of the solar cell illustrated in FIG. 4 taken along the line V-V.

6A to 6D are flowcharts sequentially illustrating a part of a manufacturing method of a solar cell according to another embodiment of the present invention.

7 is a partial perspective view of a solar cell according to another embodiment of the present invention.

8 is a cross-sectional view of the solar cell illustrated in FIG. 7 taken along the line VIII-VIII.

9A to 9D are flowcharts sequentially illustrating a part of a manufacturing method of a solar cell according to still another embodiment of the present invention.

* Description of the Drawing Symbols *

110: substrate 120 emitter part

130: antireflection films 141, 142: electrode

171, 172: electric field 191, 192, 1921, 192a, 192b: protective film

Claims (26)

  1. A substrate having a first conductivity type and made of crystalline silicon,
    A front electric field part disposed on the front surface of the substrate and having the first conductivity type and made of amorphous silicon;
    A front protective film positioned on the front surface of the substrate,
    At least one emitter portion, which is located on the rear surface of the substrate opposite to the front surface, has a second conductivity type opposite to the first conductivity type and is made of amorphous silicon,
    At least one first electrode located on the at least one emitter portion and electrically connected to the at least one emitter portion, and
    At least one second electrode on the back surface of the substrate and electrically connected to the substrate
    Solar cell comprising a.
  2. In claim 1,
    And at least one backside field portion located between the substrate and the at least one second electrode, the first conductivity type and consisting of amorphous silicon.
  3. 3. The method of claim 2,
    And a rear passivation layer on the back of the substrate.
  4. 4. The method of claim 3,
    And the rear passivation layer is positioned on the rear surface of the substrate between the at least one emitter portion and the at least one rear electric field portion.
  5. In claim 4,
    The rear protective film is a solar cell consisting of a silicon oxide film or a silicon nitride film.
  6. 4. The method of claim 3,
    The rear protective layer is located on the entire rear surface of the substrate.
  7. In claim 6,
    The back passivation layer is a solar cell comprising one of amorphous silicon, silicon oxide film, and silicon nitride film.
  8. In claim 6,
    The rear protective film,
    A first rear passivation layer positioned over said backside of said substrate between said substrate and said at least one emitter portion and between said substrate and said at least one backside electric field portion, and
    A second rear passivation layer positioned on the rear side of the substrate between the at least one emitter portion and the at least one rear electric field portion,
    The first rear passivation layer and the second rear passivation layer are made of different materials.
  9. In claim 8,
    The first rear protective film is made of a conductive material and the second rear protective film is made of an insulating material.
  10. The method of claim 9,
    The first rear protective film is made of amorphous silicon, and the second rear protective film is made of a silicon oxide film or a silicon nitride film.
  11. In claim 8,
    The solar cell of claim 1, wherein the first rear passivation layer and the second rear passivation layer have different thicknesses.
  12. 12. The method of claim 11,
    The solar cell of claim 1, wherein the thickness of the first rear protective layer is smaller than the thickness of the second rear protective layer.
  13. The method according to any one of claims 1 to 12,
    The first electrode and the second electrode are nickel (Ni), copper (Cu), silver (Ag), aluminum (Al), tin (Sn), zinc (Zn), indium (In), titanium (Ti), A solar cell comprising at least one conductive material selected from the group consisting of gold (Au) and combinations thereof.
  14. delete
  15. delete
  16. In claim 1,
    The solar cell further comprises an anti-reflection film disposed on the front protective film.
  17. Forming a front surface electric field portion having a first conductivity type and made of amorphous silicon on a front surface of the substrate made of crystalline silicon,
    Forming a front protective film on the front surface of the substrate,
    Forming a rear passivation layer on a back side of the substrate opposite to the front side;
    Forming at least one emitter portion on the back surface of the substrate, the at least one emitter portion having a second conductivity type opposite to the first conductivity type and made of amorphous silicon,
    Forming at least one backside field portion having said first conductivity type and made of amorphous silicon on said backside of said substrate, and
    Forming a first electrode and a second electrode on the at least one emitter part and on the at least one rear electric field part, respectively
    Method for manufacturing a solar cell comprising a.
  18. delete
  19. delete
  20. The method of claim 17,
    The forming of the rear passivation layer includes stacking the rear passivation layer on the entire rear surface of the substrate,
    The at least one emitter portion and the at least one rear electric field portion are respectively located on the rear passivation layer.
     Method for manufacturing a solar cell.
  21. The method of claim 17,
    The back protective film forming step,
    Stacking a first rear protective film with a first material on a rear surface of the substrate,
    Etching a portion of the first rear protective layer to expose a portion of the substrate;
    Stacking a second rear passivation layer on the first rear passivation layer and the exposed substrate with a second material different from the first material; and
    Etching the second rear passivation layer stacked on the first rear passivation layer to expose the first rear passivation layer;
    Including,
    The at least one emitter portion and the at least one second electric field portion are positioned on the first rear passivation layer.
    Method for manufacturing a solar cell.
  22. The method of claim 21,
    The first material is made of amorphous silicon, and the second material is made of a silicon oxide film or a silicon nitride film.
  23. The method of claim 17,
    The back protective film forming step,
    Stacking a rear passivation layer on the entire rear surface of the substrate and etching a portion of the rear passivation layer to expose a portion of the rear surface of the substrate,
    The at least one emitter portion and the at least one second electric field portion are located on the rear surface of the exposed substrate.
    Method for manufacturing a solar cell.
  24. The method according to any one of claims 17 and 20 to 23,
    Forming a texturing surface on the front surface of the substrate.
  25. The method of claim 24,
    The texturing surface forming step,
    Forming an etch stop layer on the rear surface of the substrate;
    Etching the front surface of the substrate to form a texturing surface on the incident surface of the substrate, and
    Removing the etch stop layer
    Method for manufacturing a solar cell comprising a.
  26. The method according to any one of claims 17 and 20 to 23,
    The method of manufacturing a solar cell further comprising the step of forming an anti-reflection film on the front field.
KR1020090084046A 2009-09-07 2009-09-07 Solar cell and method for manufacturing the same KR101135590B1 (en)

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KR1020090084046A KR101135590B1 (en) 2009-09-07 2009-09-07 Solar cell and method for manufacturing the same
CN 201010535062 CN102044579B (en) 2009-09-07 2010-09-07 Solar cell
CN201010540778.3A CN102074599B (en) 2009-09-07 2010-09-07 Solar cell and method for manufacturing the same
EP10009287.3A EP2293351B1 (en) 2009-09-07 2010-09-07 Solar cell
DE202010018510.6U DE202010018510U1 (en) 2009-09-07 2010-09-07 Solar cell
EP10009286.5A EP2293350A3 (en) 2009-09-07 2010-09-07 Solar cell and method for manufacturing the same
US12/876,821 US8525018B2 (en) 2009-09-07 2010-09-07 Solar cell
US12/876,847 US9064999B2 (en) 2009-09-07 2010-09-07 Solar cell and method for manufacturing the same
US14/720,527 US9508875B2 (en) 2009-09-07 2015-05-22 Solar cell and method for manufacturing the same
US14/843,778 USRE46515E1 (en) 2009-09-07 2015-09-02 Solar cell
US15/276,884 US20170018663A1 (en) 2009-09-07 2016-09-27 Solar cell and method for manufacturing the same
US15/367,811 US20170084759A1 (en) 2009-09-07 2016-12-02 Solar cell and method for manufacturing the same
US15/640,956 USRE47484E1 (en) 2009-09-07 2017-07-03 Solar cell

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