KR101890286B1 - Manufacturing method of bi-facial solar cell - Google Patents

Abstract

The present invention relates to a method of manufacturing a double-sided solar cell.
A method of manufacturing a double-sided solar cell according to the present invention is a method for manufacturing a double-sided solar cell, comprising the steps of: applying, on a first surface of a substrate having a first conductivity type, a first dopant paste containing an impurity of a second conductivity type opposite to the first conductivity type step; A second applying step of applying a second dopant paste containing a dopant of the first conductivity type to the second surface of the substrate; And diffusing the impurity of the first dopant paste to the first surface of the substrate to form an emitter portion on the first surface of the substrate and diffusing impurities of the second dopant paste to the second surface of the substrate, A diffusion step of forming an electric field portion; And an electrode forming step of forming a first electrode connected to the emitter section and a second electrode connected to the back electroluminescent part, wherein the diffusing step includes the step of forming the first dopant paste and the second dopant paste in the same Concentration emitter section having a first sheet resistance value higher than a sheet resistance value of the high concentration emitter section and the high concentration emitter section having a first sheet resistance value on the first surface of the substrate, and a low concentration emitter section having a second sheet resistance value higher than the sheet resistance value of the high concentration emitter section, A high concentration electric field having a sheet resistance value and a low concentration electric field portion having a second sheet resistance value higher than the sheet resistance value of the high concentration electric field portion are simultaneously formed.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing a double-

The present invention relates to a method of manufacturing a double-sided solar cell.

Recently, as energy resources such as oil and coal are expected to be depleted, interest in alternative energy to replace them is increasing, and solar cells that produce electric energy from solar energy are attracting attention.

Typical solar cells have a semiconductor portion that forms a p-n junction by different conductive types, such as p-type and n-type, and electrodes connected to semiconductor portions of different conductivity types, respectively.

When light is incident on such a solar cell, a plurality of electron-hole pairs are generated in the semiconductor portion, and the generated electron-hole pairs are separated into electrons and holes which are charged by the incident light and electrons are separated toward the n- And the holes move toward the p-type semiconductor portion. The transferred electrons and holes are collected by different electrodes connected to the n-type semiconductor portion and the p-type semiconductor portion, respectively, and electric power is obtained by connecting these electrodes with electric wires.

Recently, in order to increase the efficiency of such a solar cell, a double-sided solar cell having a structure in which light is incident on both the front and back sides of the semiconductor part is attracting attention.

It is an object of the present invention to provide a method of manufacturing a double-sided solar cell capable of further improving the efficiency of a manufacturing process.

A method of manufacturing a double-sided solar cell according to the present invention is a method for manufacturing a double-sided solar cell, comprising the steps of: applying, on a first surface of a substrate having a first conductivity type, a first dopant paste containing an impurity of a second conductivity type opposite to the first conductivity type step; A second applying step of applying a second dopant paste containing a dopant of the first conductivity type to the second surface of the substrate; And diffusing the impurity of the first dopant paste to the first surface of the substrate to form an emitter portion on the first surface of the substrate and diffusing impurities of the second dopant paste to the second surface of the substrate, A diffusion step of forming an electric field portion; And an electrode forming step of forming a first electrode connected to the emitter section and a second electrode connected to the back electroluminescent part, wherein the diffusing step includes the step of forming the first dopant paste and the second dopant paste in the same Concentration emitter section having a first sheet resistance value higher than a sheet resistance value of the high concentration emitter section and the high concentration emitter section having a first sheet resistance value on the first surface of the substrate, and a low concentration emitter section having a second sheet resistance value higher than the sheet resistance value of the high concentration emitter section, A high concentration electric field having a sheet resistance value and a low concentration electric field portion having a second sheet resistance value higher than the sheet resistance value of the high concentration electric field portion are simultaneously formed.

Here, the first dopant paste is applied on the first region of the first surface of the substrate, the high concentration emitter portion is formed in the first region of the first surface of the substrate by the impurity diffusion of the first dopant paste, The low concentration emitter portion may be formed in the second region except for the first region.

At this time, the first region of the first surface of the substrate to which the first dopant is applied may overlap with the pattern of the first electrode.

Also, the second dopant paste is applied on the first area of the second surface of the substrate, the high concentration electric field portion is formed in the first area of the second surface of the substrate by the impurity diffusion of the second dopant paste, The low concentration electric field portion may be formed in the second region except the first region.

At this time, the first region of the second surface of the substrate to which the second dopant is applied may overlap the pattern of the second electrode.

Further, in the diffusion step, impurities of the first dopant paste and impurities of the second dopant paste can be diffused in an inert gas atmosphere.

Further, in the diffusion step, a substrate having a first dopant paste on the first surface of the substrate and a second dopant paste on the second surface of the substrate is disposed in the diffusion chamber in a plurality, and each of the plurality of substrates has a first surface May be arranged to face each other, or the second side of the substrate may face each other.

At this time, the distance between each substrate closest to each other among the plurality of substrates may be between 1.5 mm and 3 mm.

In addition, the solar cell manufacturing method may further include forming a dielectric layer on at least one of the emitter portion and the back surface electric portion between the diffusion step and the electrode formation step.

At this time, the dielectric layer may include at least one of a silicon nitride (SiNx) film, a silicon oxide (SiOx) film, a silicon nitride oxide (SiNxOy) film and an aluminum oxide (AlOx) film.

In addition, the step of forming the dielectric layer may include forming a silicon nitride (SiNx) film on the emitter portion when the substrate is p-type and the emitter portion is n-type. Forming an aluminum oxide (AlOx) film on a silicon nitride (SiNx) film formed on the emitter portion and on a backside field portion; And forming a silicon nitride (SiNx) film on the aluminum oxide (AlOx) film formed on the rear electric field portion.

In addition, the step of forming the dielectric layer may include forming a silicon nitride (SiNx) film on the rear electric field portion when the substrate is n-type and the emitter portion is p-type. Forming an aluminum oxide (AlOx) film on a silicon nitride (SiNx) film and an emitter portion formed on the rear electric field; And a silicon nitride (SiNx) film on an aluminum oxide (AlOx) film formed on the emitter portion.

Here, the high concentration emitter portion is 20? / Sq. To 80 Ω / sq., And the low concentration emitter section has a sheet resistance of 80 Ω / sq. To 150 Ω / sq. It can have a sheet resistance value.

Also, the high-concentration electric field portion has a resistance of 20? / Sq. To 80? / Sq., And the low concentration electric field portion has a sheet resistance of 80? / Sq. To 150 Ω / sq. It can have a sheet resistance value.

A method of manufacturing a double-sided solar cell according to the present invention includes forming a high-concentration emitter portion and a low-concentration emitter portion on a first surface of a substrate in a single heat treatment process in the same chamber, forming a high- The manufacturing process of the double-sided solar cell having more excellent efficiency can be further simplified.

1 and 2 are views for explaining an example of a double-sided solar cell according to the present invention.
3A to 3I are views for explaining an example of a method of manufacturing a double-sided solar cell.
4A to 4F are views for explaining another example of a method of manufacturing a double-sided solar cell.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out 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 order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

In the drawings, the thicknesses are enlarged to clearly indicate layers and regions. 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. Conversely, when a part is "directly over" another part, it means that 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.

1 and 2 are views for explaining an example of a double-sided solar cell according to the present invention.

Hereinafter, a solar cell according to an embodiment of the present invention will be described with reference to the accompanying drawings.

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

1 and 2, a double-sided solar cell 1 according to an embodiment of the present invention includes a substrate 110, an emitter section 120, a back surface field (BSF) 130, The first electrode 140, and the second electrode 150, and may further include a dielectric layer 160,

Here, the dielectric layers 160 and 170 may be omitted, but they are more advantageous for improving the efficiency of the double-sided solar cell 1, and therefore, the case where the dielectric layers 160 and 170 are included will be described below as an example.

In the double-sided solar cell 1 according to the present invention, the first electrode 140 is formed on the first surface of the substrate 110, and the second electrode 150 is formed on the second surface of the substrate 110, Sided solar cell 1 that produces electricity from light incident on the first surface of the substrate 110 and the second surface of the substrate 110.

The substrate 110 may have a first conductivity type, for example a p-type conductivity type, and such a substrate 110 may comprise crystalline silicon or polycrystalline silicon. Impurities such as boron (B), gallium, indium, and the like are doped to the substrate 110 when the substrate 110 has a p-type conductivity type. Alternatively, however, the substrate 110 may be of the n-type conductivity type. Impurities of pentavalent elements such as phosphorus (P), arsenic (As), and antimony (Sb) may be doped to the substrate 110 when the substrate 110 has an n-type conductivity type.

The first and second surfaces of the substrate 110 may be textured to have a textured surface that is an uneven surface. 1, only the edge portion of the substrate 110 is shown as a textured surface, but substantially the entire first and second sides of the substrate 110 have a textured surface, The emitter section 120 located on the surface of the substrate 110 and the rear electric section 130 located on the second surface of the substrate 110 also have an uneven surface.

At this time, the textured surface may be formed by wet etching or dry etching. At this time, the width and height of the concavities and convexities formed may vary depending on the etching method.

The light incident on the first surface and the rear surface of the substrate 110 is reflected by the texturing surface having a plurality of irregularities by a plurality of irregularities formed on the surface of the substrate 110, . As a result, the amount of light reflected from the first and second surfaces of the substrate 110 decreases and the amount of light incident into the substrate 110 increases.

The emitter portion 120 is formed on the first surface of the first conductive type semiconductor substrate 110, as shown in FIGS. 1 and 2, and is of a second conductive type opposite to the first conductive type, for example, , an n-type conductive type impurity may be located within the first surface of the substrate 110 as an area doped to the substrate 110. [ Thus, the emitter portion 120 of the second conductivity type forms a p-n junction with the substrate 110.

Due to the built-in potential difference caused by the pn junction between the substrate 110 and the emitter section 120, the electron-hole pairs generated by the light incident on the substrate 110 are electrically coupled with electrons Electrons move to the n-type and holes move to the p-type. Accordingly, when the substrate 110 is p-type and the emitter section 120 is n-type, the separated holes move toward the back surface of the substrate 110, and the separated electrons move toward the emitter section 120.

Since the emitter layer 120 forms a pn junction with the substrate 110, when the substrate 110 has an n-type conductivity type, the emitter layer 120 has a p-type conductivity type . In this case, the separated electrons move toward the back surface of the substrate 110, and the separated holes move toward the emitter section 120.

When the emitter section 120 has an n-type conductivity type, the emitter section 120 can be formed by doping an impurity of a pentavalent element into the substrate 110. Conversely, when the emitter section 120 has a p-type conductivity type, May be formed by doping an impurity of the element into the substrate 110. [

The emitter layer 120 may be formed by diffusing an impurity of the second conductivity type into the substrate 110.

The backside electrical section 130 may be located on the second side of the substrate 110 and may include regions of the same conductivity type as the substrate 110 that are heavily doped than the substrate 110, .

Due to the difference in impurity concentration between the first conductive region of the substrate 110 and the rear electric field 130, a potential barrier is formed, thereby hindering electron movement toward the rear electric field 130, which is the direction of the hole movement Thereby facilitating hole transfer to the rear electric field 130. Accordingly, the amount of charges lost due to the recombination of electrons and holes at the back surface and the vicinity of the substrate 110 is reduced, and the movement of the desired charge (e.g., hole) is accelerated to increase the amount of charge transfer to the first electrode 140 .

The dielectric layers 160 and 170 may be located on at least one of the emitter portion 120 and the backside electrical portion 130. For example, it may be located only on the emitter section 120, or may be located only on the rear electric section 130.

Or both on emitter portion 120 and on backside electrical portion 130, as shown in Figures 1 and 2.

The dielectric layers 160 and 170 may include at least one of a silicon nitride film (SiNx), a silicon oxide film (SiOx), a silicon nitride oxide film (SiNxOy), an amorphous silicon (a-Si: H), and an aluminum oxide film .

In addition, the dielectric layers 160 and 170 may be formed of one layer, or may be formed of a plurality of layers, as shown in FIG. 1 and FIG.

For example, when the substrate 110 is an n-type and the emitter section 120 is a p-type, the 160A layer of the dielectric layers 160 and 170 directly contacting the emitter section 120 is electrically connected to the emitter section 120 (AlOx), and the 170A layer in contact with the 160A layer in the dielectric layers 160 and 170 may be formed of a silicon nitride film (SiNx).

In addition, the 170B layer in contact with the lower surface of the rear electric part 130 of the dielectric layers 160 and 170 may be formed of a silicon nitride film (SiNx) in consideration of the charge characteristics with the substrate 110, The 160B layer may be formed of an aluminum oxide film (AlOx).

Here, the silicon oxide film (SiOx) and the silicon nitride oxide film (SiNxOy) having the same charge characteristics as the silicon nitride film (SiNx) may be used instead of the silicon oxide film (SiNx) layer in the 170A layer and the 170B layer.

When the substrate 110 is of the p-type and the emitter 120 is of the n-type, the 160A layer of the dielectric layers 160 and 170 directly contacting the emitter layer 120 contacts the emitter layer 120, A silicon nitride film (SiNx) may be formed in consideration of charge characteristics, and the 170A layer in contact with the 160A layer in the dielectric layers 160 and 170 may be formed of an aluminum oxide film (AlOx).

The 170B layer in contact with the bottom of the rear electric portion 130 of the dielectric layers 160 and 170 may be formed of an aluminum oxide film (AlOx) in consideration of the charge characteristics with the substrate 110, The 160B layer may be formed of a silicon nitride film (SiNx).

In addition, the dielectric layers 160 and 170 may include hydrogen (H), which may cause defects such as dangling bonds mainly present on the surface of the substrate 110 and its vicinity, A passivation function is performed to reduce the loss of charges moving toward the surface of the substrate 110 due to the defects so as to reduce the charges accumulated on the surface of the substrate 110 or near the substrate 110 due to defects Can be reduced.

For example, in FIGS. 1 and 2, 160A directly contacting the emitter portion 120 and 170B contacting directly below the backside electrical portion 130 may perform a passivation function.

Also, using the refractive index difference of the dielectric layers 160 and 170, the 170A layer and the 160B layer in the dielectric layers 160 and 170 in FIGS. 1 and 2 may function as an anti-reflection film.

The first electrode 140 is located on the first surface of the substrate 110 as shown in FIGS. 1 and 2, and may be connected to the emitter section 120.

The first electrode 140 includes a plurality of front finger electrodes 141 and a plurality of front bus bars 142 connected to the plurality of front finger electrodes 141.

A plurality of front finger electrodes 141 are electrically and physically connected to the emitter section 120 and are spaced apart from each other and extend in a predetermined direction. A plurality of front finger electrodes 141 collects charges, for example, electrons, which have migrated toward the emitter section 120.

A plurality of front bus bars 142 are electrically and physically connected to the emitter section 120 and extend in a direction parallel to the plurality of front finger electrodes 141.

At this time, the plurality of front bus bars 142 are located on the same layer as the plurality of front finger electrodes 141 and are electrically and physically connected to the corresponding front finger electrodes 141 at the intersections of the front finger electrodes 141 .

1, the plurality of front finger electrodes 141 have a stripe shape extending in the horizontal or vertical direction, and the plurality of front bus bars 142 are arranged in a stripe shape extending in the vertical or horizontal direction Shape so that the first electrode 140 is located in a lattice form on the first surface of the substrate 110. [

A plurality of front bus bars 142 collect the charge moving from the portion of the contacted emitter portion 120 as well as the charge collected and moved by the plurality of front finger electrodes 141.

Each front bus bar 142 has to collect the electric charges collected by the plurality of intersecting front finger electrodes 141 and move them in a desired direction so that the width of each front bus bar 142 is equal to the width of each front finger electrode 141 Width.

The plurality of front bus bars 142 are connected to an external device to output collected electric charges (e.g., electrons) to an external device.

The plurality of front finger electrodes 141 and the plurality of front bus bars 142 of the first electrode 140 are formed of at least one conductive material such as silver (Ag).

In FIG. 1, the number of the front finger electrodes 141 and the front bus bars 142 located on the substrate 110 is only an example, and may be changed in some cases.

The second electrode 150 includes a plurality of rear finger electrodes 151 and a plurality of rear bus bars 152 connected to the plurality of rear finger electrodes 151 in the same manner as the first electrode 140. The second electrode 150 is in contact with the rear electric part 130 disposed on the second surface of the substrate 110 through the protective films 160 and 170. Thus, May be formed in the same pattern as the first electrode 140.

The second electrode 150 may include silver (Ag), which is the same material as the first electrode 140, or may include a conductive material such as aluminum (Al).

The second electrode 150 collects charge, for example, holes, moving from the rear electric field 130 side.

The second electrode 150 is in contact with the rear electric part 130 which is maintained at a higher impurity concentration than the substrate 110. The substrate 110, that is, the rear electric part 130 and the second electrode 150, The charge transfer efficiency from the substrate 110 to the second electrode 150 is improved.

The operation of the double-sided solar cell 1 according to this embodiment having such a structure is as follows.

The first surface of the double-sided solar cell 1 is irradiated with light and is incident on the emitter section 120 which is a semiconductor part and the substrate 110 through the transparent electrode layer 125 and is disposed outside the solar cell module 1 When light is reflected by a reflector or the like and light is irradiated to the second surface of the solar cell 1 and light is incident on the rear electric unit 130 and the substrate 110, electron-hole pairs are generated in the semiconductor unit due to light energy do.

These electron-hole pairs are separated from each other by the pn junction of the substrate 110 and the emitter section 120, and the electrons and the holes are separated from each other by, for example, the emitter section 120 having the n-type conductivity type and the p- Type substrate 110, respectively. The electrons moved toward the emitter section 120 are collected by the plurality of front finger electrodes 141 and the plurality of front bus bars 142 and travel along the plurality of front bus bars 142, Holes are collected by the rear finger electrodes 151 and the plurality of rear bus bars 152 through the rear electric unit 130 and moved along the plurality of rear bus bars 152. [ When the front bus bar 142 and the rear bus bar 152 are connected to each other by a wire, a current flows and is used as electric power from the outside.

In the double-sided solar cell 1, the double-sided solar cell 1 according to the present invention may include the emitter section 120 including the high concentration emitter section 120H and the low concentration emitter section 120L, The rear electric power unit 130 may include a high-concentration electric field unit 130H and a low-concentration electric field unit 130L.

More specifically, the emitter section 120 containing impurities of the second conductivity type has a low sheet resistance value having a second sheet resistance value higher than that of the high concentration emitter section 120H having the first sheet resistance value and the sheet resistance value of the high concentration emitter section 120H Emitter portion 120L.

Here, the first sheet resistance value of the high concentration emitter section 120H is 20? / Sq. And 80 Ω / sq., And the second sheet resistance value of the low concentration emitter section 120L is 80 Ω / sq. To 150 Ω / sq. It can have a sheet resistance value.

The high concentration emitter section 120H may be formed in a first region where the emitter section 120 and the first electrode 140 are in contact with the first electrode 140 in the first surface of the substrate 110 The low concentration emitter layer 120L is formed on the first surface of the substrate 110 in a second region other than the first region described above, that is, the first electrode 140 is not formed on the first surface of the substrate 110 Lt; / RTI > region.

Therefore, the pattern shape of the high concentration emitter section 120H may be the same as the arrangement of the plurality of front finger electrodes 141 and the plurality of front bus bars 142 of the first electrode 140.

The thickness T120L of the low concentration emitter section 120L may be smaller than the thickness T120H of the high concentration emitter section 120H. Therefore, it is possible to prevent a shunt in which the first electrode 140 and the substrate 110 are in contact with each other in the high concentration emitter section 120H which is in direct contact with the first electrode 140, Concentration emitter portion 120L formed on the surface of the emitter portion 120, that is, the second region, on which no impurity is formed, the amount of the impurity is relatively small, so that the loss of charge can be minimized. Therefore, the efficiency of the solar cell 1 can be further improved.

Next, the rear electric field 130 contains impurities of the first conductivity type as opposed to the emitter 120, and may have the same sheet resistance value, pattern shape, and formed thickness as the emitter layer 120.

More specifically, the backside electrical section 130 includes a high concentration electrical section 130H having a first sheet resistance value and a low concentration electrical section 130L having a second sheet resistance value higher than the sheet resistance value of the high concentration electrical section 130H .

Here, the first sheet resistance value of the high-concentration electric field section 130H is 20? / Sq. And the second sheet resistance value of the low concentration electric field 130L may be 80? / Sq. To 150 Ω / sq. It can have a sheet resistance value.

Here, the high-concentration electric field portion 130H is formed in the first region of the substrate 110 in which the second electrode 150 is formed and the rear electric portion 130 and the second electrode 150 are in contact with each other And the low concentration electric field 130L is formed on the second surface of the substrate 110 except for the first region, that is, the second electrode 150 is formed on the second surface of the substrate 110 Or the like.

Therefore, the pattern shape of the high-concentration electric field 130H may be the same as the arrangement of the finger electrode 151 and the rear bus bar 152 of the second electrode 150. [

In addition, the thickness T130L of the low-concentration electric field portion 130L may be smaller than the thickness T130H of the high-concentration electric field portion 130H. Therefore, it is possible to prevent a shunt that the second electrode 150 and the substrate 110 are in contact with each other in the high-concentration electric field portion 130H which is in direct contact with the second electrode 150, The amount of impurities is relatively small when moving along the low-concentration electric field portion 130L formed on the surface of the rear electric section 130 where the light-emitting section 130 is not formed, that is, the second region. Therefore, the efficiency of the solar cell 1 can be further improved.

As described above, in the double-sided solar cell 1 according to the present invention, not only the emitter section 120 but also the rear electric section 130 have regions with different concentration differences, thereby maximizing the efficiency of the solar cell 1 can do.

3A to 3I are diagrams for explaining an example of a method of manufacturing the double-sided solar cell shown in Figs. 1 and 2 described above.

First, as shown in FIG. 3A, a substrate 110 of a first conductivity type is prepared. At this time, the surface of the substrate 110 may be textured to form a plurality of irregularities.

Here, the first conductive type may be a p-type conductive type or an n-type conductive type, as described in FIGS. 1 and 2.

Accordingly, when the substrate 110 has a p-type conductivity type, the substrate 110 may contain an impurity of a trivalent element such as boron (B), gallium, indium, etc. Alternatively, the substrate 110 may contain an impurity of a pentavalent element such as phosphorus (P), arsenic (As), antimony (Sb) or the like.

Hereinafter, a case where the substrate 110 has a p-type conductivity type will be described as an example.

Next, as shown in FIG. 3B, a first dopant paste 120P containing an impurity of a second conductivity type opposite to the first conductivity type is applied to the first surface of the substrate 110 of the first conductivity type . Here, the second conductivity type means the opposite of the first conductivity type.

Therefore, when the substrate 110 has a p-type conductivity type, the first dopant paste 120P may contain an impurity of a pentavalent element, and when the substrate 110 has an n-type conductivity type, 1 dopant paste 120P may contain an impurity of a trivalent element.

3A, the first dopant paste 120P shown in FIG. 3B includes phosphorus (P), arsenic (As), antimony (Sb), and the like. ), And the like.

The first dopant paste 120P may be applied to the first region of the substrate 110 in the same manner as the pattern of the first electrode 140, as described above. In other words, it may be applied in the same pattern overlapping the patterns of the front finger electrode 141 and the front bus bar 142 to be formed on the first area of the first surface of the substrate 110.

Therefore, when the pattern of the first electrode 140 has a lattice-like pattern, the first dopant paste 120P can also be applied in a lattice pattern.

Next, as shown in FIG. 3C, a second dopant paste 130P is applied to the second surface of the substrate 110 with an impurity of the first conductivity type. Accordingly, the second dopant paste 130P may contain the same impurity as the substrate 110, such as boron (B), gallium, indium, or the like.

The second dopant paste 130P may be applied to the first region of the second surface of the substrate 110 in the same manner as the pattern of the second electrode 150, as described above. That is, the same pattern that overlaps the pattern of the rear finger electrode 151 and the rear bus bar 152 to be formed on the first area of the second side of the substrate 110.

Therefore, when the pattern of the second electrode 150 has a lattice pattern, the second dopant paste 130P can also be applied in a lattice pattern.

3 (a), impurities of the first dopant paste 120P are diffused to the first surface of the substrate 110, and the emitter portion 120 is formed on the first surface of the substrate 110 And the impurities of the second dopant paste 130P are diffused to the second surface of the substrate 110 to form the rear surface electric conductor 130 on the second surface of the substrate 110. [ At this time, the impurities of the first dopant paste 120P applied to the first surface of the substrate 110 and the impurities of the second dopant paste 130P applied to the second surface of the substrate 110 are the same in the same chamber And is simultaneously diffused by the heat treatment process.

3E, the first surface of the substrate 110 has a second sheet resistance value higher than that of the high concentration emitter section 120H having the first sheet resistance value and the sheet resistance value of the high concentration emitter section 120H The low concentration emitter section 120L and the low concentration conductive section 130H having the second sheet resistance value higher than the sheet resistance value of the high concentration electric field section 130H and the high concentration electric field section 130H having the first sheet resistance value are formed on the second surface of the substrate 110 130L can be simultaneously formed.

At this time, impurities of the first dopant paste 120P and impurities of the second dopant paste 130P are simultaneously diffused by the same heat treatment process in the same chamber, as shown in FIG. 3D (a) The impurity of the first dopant paste 120P and the impurity of the second dopant paste 120P in the inert gas atmosphere have to be formed on the first surface of the emitter layer 120 and the second surface of the substrate 110, It is possible to diffuse impurities of the impurity 130P. For example, the diffusion can proceed in an N ₂ gas atmosphere, and the diffusion temperature at this time may be approximately 900 ° C to 950 ° C.

In order to improve the process time and the efficiency of the process in the diffusion process, the first dopant paste 120P, the substrate (not shown) The substrate 110 on which the second dopant paste 130P is applied may be disposed on the second surface of the diffusion chamber 110 in a plurality of diffusion chambers.

As shown in FIG. 3D, each of the plurality of substrates 110 may be disposed such that the first surfaces of the substrates 110 face each other, or the second surfaces of the substrates 110 face each other . That is, for example, as shown in FIG. 3D, a first dopant paste 120P is applied to the first surface and a second dopant paste 130P is applied to the second surface of the substrate 110 The first dopant paste 120P is coated on the substrates 110a and 110b so that the surfaces coated with the second dopant paste 130P are opposed to each other on the substrates 110a and 110b and the first dopant paste 120P is coated on the substrates 110b and 110c So that the surfaces face each other.

This allows the emitter section 120 and the rear electric section 130 to be more stably disposed so that the respective impurities of the first dopant paste 120P and the second dopant paste 130P diffuse, .

At this time, the interval DW between the substrates 110 closest to each other among the plurality of substrates 110 may be between 1.5 mm and 3 mm.

The impurity of the first dopant paste 120P and the impurity of the second dopant paste 130P are simultaneously diffused so that the emitter portion 120 and the substrate (not shown) are formed on the first surface of the substrate 110, 110 are formed on the second surface.

At this time, since the substrate 110 is p-type, the emitter section 120 becomes n-type and the rear electric section 130 becomes p +.

3E, a high concentration emitter section 120H is formed in the first region of the first surface of the substrate 110, to which the first dopant paste 120P is applied, by the impurity diffusion of the first dopant paste 120P. And the low concentration emitter layer 120L may be formed in the second region of the first surface of the substrate 110 except for the first region, that is, the region where the first dopant paste 120P is not applied.

Therefore, since the first electrode 140 is formed in the first region of the first surface of the substrate 110 by a subsequent process, the pattern in which the high concentration emitter portion 120H is formed is formed in a pattern of the first electrode 140 And the low concentration emitter layer 120L may be formed in a region where the first electrode 140 is not formed.

Here, the high concentration emitter section 120H has a resistance of 20? / Sq. And 80 Ω / sq., And the low concentration emitter section 120L has a sheet resistance of 80 Ω / sq. To 150 Ω / sq. It can have a sheet resistance value.

As shown in FIG. 3E, by the impurity diffusion of the second dopant paste 130P, a high concentration electric field 130H is formed in the first region of the second surface of the substrate 110, to which the second dopant paste 130P is applied And a low concentration electric field portion 130L may be formed in a second region of the second surface of the substrate 110 excluding the first region, that is, a region where the second dopant paste 130P is not applied.

Accordingly, since the second electrode 150 is formed in the first region of the second surface of the substrate 110 by a subsequent process, the pattern in which the high-concentration electric field portion 130H is formed is formed in a pattern of the second electrode 150 And the low concentration electric field portion 130L may be formed in an area where the second electrode 150 is not formed.

Here, the high-concentration electric field portion 130H has a resistance value of 20? / Sq. And the low concentration electric field portion 130L has a sheet resistance of 80? / Sq. To 150 Ω / sq. It can have a sheet resistance value.

Next, the method may further include forming the dielectric layers 160 and 170 shown in FIGS. 1 and 2 on at least one of the emitter portion 120 and the rear electric portion 130 before forming the electrode.

Here, the dielectric layers 160 and 170 may include at least one of a silicon nitride (SiNx) film, a silicon oxide (SiOx) film, a silicon nitride oxide (SiNxOy) film, and an aluminum oxide (AlOx) film.

For example, when the substrate 110 is a p-type and the emitter section 120 is an n-type, considering the degradation characteristics of the emitter section 120 having a negative charge characteristic, as shown in FIG. 3F, A silicon nitride (SiNx) film 160A having positive (+) charge characteristics can be formed on the emitter section 120. [ Thus, a parasitic shunt that attracts the carrier can be prevented.

3G, an aluminum oxide (AlOx) film 170A having negative (-) charge characteristics is formed on a silicon nitride (SiNx) film 160a formed on the emitter section 120, AlOx) film 170B may be formed on the rear electric section 130. [

Thereafter, a silicon nitride (SiNx) film 160B may further be formed on the aluminum oxide (AlOx) film 170B formed on the rear electric section 130, as shown in FIG. 3H.

As described above, the dielectric layers 160 and 170 having the passivation function and the antireflection film function can be formed on the emitter layer 120 and the back electric layer 130, respectively.

Here, the formation order of the dielectric layers 160 and 170 can be variously changed in addition to the charge characteristics of the dielectric layers 160 and 170 and the charge characteristics of the emitter section 120 and the rear electric section 130. For example, an aluminum oxide (AlOx) film having (-) charge characteristics may be formed first on the rear electric conductor 130, and a silicon nitride (SiNx) film 160A, 160B ), A silicon oxide (SiOx) film, a silicon nitride oxide (SiNxOy) film, or the like may be used together.

Next, as shown in FIG. 3I, a first electrode 140 is formed on a first area of the first surface of the substrate 110 where the high concentration emitter section 120H is formed, and a first electrode 140 is formed on the second surface of the substrate 110, The second electrode 150 may be formed in the first region where the first electrode 130H is formed.

More specifically, a paste for forming the first electrode 140 is applied on the 170A dielectric layer on the first area where the high concentration emitter section 120H is formed on the first surface of the substrate 110, A paste for forming the second electrode 150 is applied and dried on the 160B dielectric layer on the first area where the high concentration electric field 130H is formed on the second surface of the first electrode 140, And the second electrode 150 penetrate the dielectric layers 160 and 170 so that the first electrode 140 is connected to the high concentration emitter section 120H and the second electrode 150 is connected to the high concentration electric field section 130H, As shown in FIG.

Although the case where the substrate is a p-type has been described above as an example, in the following Figs. 4A to 4F, the case where the substrate is n-type will be briefly described as an example, and redundant contents will be omitted.

As shown in FIG. 4A, when the substrate 110 'is of n-type, a first dopant paste 120P' having a p-type impurity may be applied to the first surface of the substrate 110 ' have. For example, the first dopant paste 120P 'may contain an impurity of a trivalent element such as boron (B), gallium, indium, and the like.

In addition, a second dopant paste 130P 'having the same n-type impurity as the substrate 110' may be applied to the second surface of the substrate 110 '. For example, the second dopant paste 130P 'may contain impurities of pentavalent elements such as phosphorus (P), arsenic (As), antimony (Sb), and the like.

Thereafter, the first dopant paste 120P 'applied to the first surface of the substrate 110' and the second dopant paste 130P 'applied to the second surface of the substrate 110' are injected into an inert gas atmosphere Can be simultaneously diffused by the same heat treatment process.

Here, the same method as described in Fig. 3D can be applied to the diffusion method.

Accordingly, as shown in FIG. 4B, the high-concentration emitter section 120H 'and the low-concentration emitter section 120L' formed on the first surface of the substrate 110 'are p-type, The high-concentration electric field 130H 'and the low-concentration electric field 130L' formed on the two surfaces can be simultaneously formed with n +.

Therefore, the emitter section 120 'including the high concentration emitter section 120H' and the low concentration emitter section 120L 'has positive charge characteristics and the high concentration electric field section 130H' and the low concentration electric field section 130L ' (-) charge characteristic of the back electromotive section 130 '.

Therefore, the step of forming the dielectric layer can be formed differently from that described in FIGS. 3F to 3H.

As a specific example, as shown in FIG. 4C, a p-type substrate 110 'having an n-type and an emitter portion 120' having positive (+) charge characteristics, a backside electrical portion 130 ' -) charge characteristics, the silicon nitride (SiNx) film 160B 'having (+) charge characteristics can be formed first on the rear electric section 130'.

4D, an aluminum oxide (AlOx) film 170B 'having (-) charge characteristics is formed on a silicon nitride (SiNx) film 160B' formed on the rear electric field portion 130 ' , An aluminum oxide (AlOx) film 170A 'may be formed on the emitter section 120'.

4E, a silicon nitride (SiNx) film 160A 'having (+) charge characteristics is formed on the aluminum oxide (AlOx) film 170A' formed on the emitter section 120 ' can do.

4F, a first electrode 140 connected to the emitter section 120 'and a second electrode 150 connected to the rear electric section 130' may be formed. Here, the method of forming the first electrode 140 and the second electrode 150 may be the same as that described with reference to FIG. 3I.

As described above, the solar cell according to the present invention includes a first dopant paste 120P 'applied on a first surface of a substrate 110' and a second dopant paste 130P 'applied on a second surface of the substrate 110' The low concentration emitter section 120L 'and the high concentration emitter section 120H' are formed on the first surface of the substrate 110 'and the low concentration electric field section 130L' is formed on the second surface of the substrate 110 ' The high-concentration electric field 130H 'can be formed at the same time by a single heat treatment process, so that the step and time of the solar cell manufacturing process can be further shortened.

As shown in FIG. 3D (c), a plurality of substrates 110 'are simultaneously subjected to a heat treatment process to form a low-concentration emitter section 120L' and a high-concentration emitter section 120L 'on the first surface of each of the plurality of substrates 110' The low concentration electric field portion 130L 'and the high concentration electric field portion 130H' can be simultaneously formed on the second surface of each of the emitter portion 120H 'and the substrate 110' by a single heat treatment process, Can be further improved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of the right.

Claims (14)

Applying a first dopant paste of a second conductivity and a second dopant paste of a first conductivity to the first and second surfaces of the first conductive substrate, respectively;
A diffusion step of simultaneously heat-diffusing the first and second conductive pastes to form emitter portions and a rear surface electric field portion on the first and second surfaces of the substrate, respectively; And,
An electrode forming step of forming a first electrode connected to the emitter section and a second electrode connected to the rear electric section,
In the diffusion step, the first dopant paste and the second dopant paste are simultaneously thermally diffused to the first and second surfaces of the substrate,
Wherein the emitter portion includes a high concentration emitter portion having a first sheet resistance value formed in a first region coated with the first dopant paste and a second sheet resistance portion having a second sheet resistance higher than the first sheet resistance value formed in the second region except for the first region, Concentration emitter portion having a value of < RTI ID = 0.0 >
Wherein the rear surface electric field portion has a second sheet resistance higher than the first sheet resistance value formed between the high concentration electric field portion having the first sheet resistance value formed in the first region coated with the second dopant paste and the second region except for the first region, And a low-concentration electric field portion having a value of < RTI ID =
The high-concentration emitter portion, the low-concentration emitter portion, the high-concentration electric field portion, and the low-concentration electric field portion are all formed in the diffusion step,
In the diffusion step,
A plurality of substrates having first and second dopant pastes and second dopant pastes respectively disposed on the first and second surfaces of the substrate are disposed in the diffusion chamber,
Wherein the plurality of substrates are disposed so that first surfaces of the first dopant paste are opposed to each other and second surfaces of the second dopant paste are opposed to each other. delete The method of claim 1,
Wherein the first region to which the first dopant paste is applied overlaps the pattern of the first electrode. delete The method of claim 1,
Wherein the first region to which the second dopant paste is applied overlaps the pattern of the second electrode. The method of claim 1,
In the diffusion step
Wherein the impurity of the first dopant paste and the impurity of the second dopant paste are diffused in an inert gas atmosphere. delete The method of claim 1,
Wherein a distance between each of the substrates closest to each other among the plurality of substrates is between 1.5 mm and 3 mm. The method of claim 1,
Further comprising forming a dielectric layer on at least one of the emitter portion and the rear electrode portion between the diffusion step and the electrode formation step. The method of claim 9,
Wherein the dielectric layer comprises at least one of a silicon nitride film, a silicon oxide film, a silicon nitride oxide film, and an aluminum oxide film. The method of claim 9,
The step of forming the dielectric layer
If the substrate is a p-type and the emitter is n-type,
Forming a silicon nitride film on the emitter portion;
Forming an aluminum oxide film on the silicon nitride (SiNx) film formed on the emitter portion and on the rear surface electric field portion; And
Forming a silicon nitride film on the aluminum oxide film formed on the rear electric field portion;
Lt; RTI ID = 0.0 > 1, < / RTI > The method of claim 9,
The step of forming the dielectric layer
If the substrate is n-type and the emitter is p-type,
Forming a silicon nitride film on the rear electric field portion;
Forming an aluminum oxide film on the silicon nitride film formed on the rear electric field portion and on the emitter portion; And
Forming a silicon nitride film on the aluminum oxide film formed on the emitter portion;
Lt; RTI ID = 0.0 > 1, < / RTI > The method of claim 1,
The heavily doped emitter portion has a resistivity of 20 Ω / sq. To 80 < RTI ID = 0.0 > ohm / sq.
The low concentration emitter portion has a conductivity of 80 Ω / sq. To 150 Ω / sq. A method of manufacturing a double-sided solar cell having a sheet resistance value. The method of claim 1,
The high-concentration field portion has a thickness of 20 Ω / sq. To 80 < RTI ID = 0.0 > ohm / sq.
The low-concentration electric field portion has an electric conductivity of 80 Ω / sq. To 150 Ω / sq. A method of manufacturing a double-sided solar cell having a sheet resistance value.

Images