KR101199214B1 - Bifacial Photovoltaic Localized Emitter Solar Cell and Method for Manufacturing Thereof - Google Patents

Abstract

The present invention forms a light receiving portion on the front and rear surfaces of the substrate, locally emitters and electrodes on the front light receiving portion of the substrate, locally formed base and electrodes on the rear light receiving portion of the substrate, emitters and electrodes, The present invention relates to a double-sided light receiving localized emitter solar cell having an auxiliary electrode layer formed between a base and an electrode, and a method of manufacturing the same. ; A first high concentration doped region of a second conductive impurity is locally formed on the upper portion of the substrate, and a first conductive type is formed on a portion of the upper portion of the substrate except for the formation portion of the first high concentration doped region of the second conductive impurity. A first high concentration doped region of an impurity is formed, and a second high concentration doped region of a first conductive impurity is locally formed in the lower portion of the substrate, and a second high concentration doped region of the first conductive impurity in the lower portion of the substrate. A second high concentration doped region of a second conductive impurity is formed in a portion other than the formation portion of the substrate, and a dielectric layer and an auxiliary electrode layer are sequentially stacked between the substrate and the front electrode and between the substrate and the back electrode, thereby forming a substrate. By increasing the light-receiving area, it absorbs even the sunlight reflected from the surface of the earth, which can increase the amount of solar light absorbed. It is to maximize the effect.

Description

Bilateral Photovoltaic Localized Emitter Solar Cell and Method for Manufacturing Thereof}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided light receiving type localized emitter solar cell and a method for manufacturing the same, and more particularly, to a double-sided light receiving type localized emitter solar cell in which an electrode is formed locally at a light receiving portion of a substrate.

The solar cell is a key element of photovoltaic power generation that converts sunlight directly into electricity, and is basically a diode composed of a p-n junction.

In the process of converting sunlight into electricity by solar cells, solar light is incident on the solar cells to generate electron-hole pairs inside the solar cells, and electrons move to n layers and holes move to p layers by the electric field. Thus, photovoltaic power is generated between the pn junctions, and when a load or a system is connected to both ends of the solar cell, current flows to generate power.

On the other hand, solar cells are classified into various types according to the shape of the light absorption layer or the impurity ions, which are pn junction layers. Examples of the light absorption layer include silicon (Si). The silicon substrate type used as the light absorption layer is divided into a thin film type which forms a light absorption layer by depositing silicon in a thin film form.

Looking at the general structure of the silicon substrate type of silicon-based solar cell as an example.

As illustrated in FIG. 1, a second conductive semiconductor layer 12, which is an emitter layer, is stacked on the first conductive semiconductor layer 11, and a finger bar or the upper surface of the second conductive semiconductor layer 12 is formed. A front electrode 14 having a pattern such as a bus bar is formed and a rear electrode 15 is provided on a lower surface of the first conductive semiconductor layer 11.

In this case, the first conductive semiconductor layer 11 and the second conductive semiconductor layer 12 are implemented on one silicon substrate 10, and the lower portion of the silicon substrate 10 is the first conductive semiconductor layer 11. The upper portion of the silicon substrate 10 is divided into the second conductive semiconductor layer 12, and a lower concentration doped region of the first conductive impurity for forming a backside electric field is formed below the first conductive semiconductor layer 11. The second conductive semiconductor layer 12 having (10-1) and the front electrode 14 formed on the upper surface thereof is optionally provided with a highly doped region 10-2 of the second conductive impurity.

Here, the highly doped region 10-1 of the first conductive impurity formed entirely under the first conductive semiconductor layer 11 may have a rear electric field having a higher energy barrier than that of the first conductive semiconductor layer 11. Since it is formed, the minority transporter 1 photogenerated by solar incidence in the first conductive semiconductor layer 11 is prevented from moving to the rear electrode 15.

Looking at the general manufacturing process of such a substrate-type silicon solar cell, first preparing a silicon substrate 10 of the first conductivity type, surface texturing of the prepared silicon substrate 10, doping impurity ion (Doping) of the second conductivity type The second conductive semiconductor layer 12 may be formed through diffusion, and the front electrode 14 and the rear electrode 15 may be formed.

Meanwhile, before the front electrode 14 and the back electrode 15 are formed, impurities including impurities such as a PSG (Phosphorus Silicate Glass) film or a BSG (Boron Silicate Glass) film formed on the surface of the substrate 10 by a diffusion process are formed. A cleaning process for removing an oxide film and a process for forming an anti-reflection film 13 on the second conductive semiconductor layer 12, and the like, to reduce contact resistance between the surface of the silicon substrate 10 and the front electrode 14. In order to form the second conductive semiconductor layer 12 corresponding to the portion where the front electrode 14 is to be formed, a highly doped region 10-2, that is, an emitter, of the second conductive impurity is selectively formed.

In addition, after the formation of the front electrode 14 and the rear electrode 15, a high concentration doped region 10-1 of the first conductive type impurity is entirely formed under the first conductive semiconductor layer 11 through a firing process. And forming a trench for disconnection of a predetermined depth along the circumference of the front surface of the substrate using a laser.

When the second conductive semiconductor layer 12 is formed, the silicon substrate 10 is immersed in a solution containing the second conductive impurity ions and subsequently subjected to a heat treatment process, thereby forming the second conductive impurity ions into a silicon substrate ( 10), the second conductive semiconductor layer is formed on the side of the substrate in addition to the upper portion of the silicon substrate 10. Thus, the second conductive semiconductor layer formed on the side of the substrate is the front electrode 14; Since the back electrode 15 is shorted to act as a factor of reducing photoelectric conversion efficiency of the solar cell, the front electrode 14 and the rear surface of the second conductive semiconductor layer formed on the side of the silicon substrate 10 are reduced. This is because it is necessary to interrupt the electrical connection between the electrodes 15.

Looking at the movement of the minority transporter (1) during photovoltaic power generation in such a general solar cell, for example, when the first conductivity type is p-type, the second conductivity type is n-type, as the solar light enters the first conductive semiconductor The electrons, which are the minority carriers 1 generated in the layer 11, move toward the front surface of the silicon substrate 10 on which the second conductive semiconductor layer 12, that is, the emitter layer, is formed. At this time, the hole which is the majority carrier 2 is moved toward the rear side of the silicon substrate 10.

In such a general solar cell, the impurity doping concentration in the depth direction is highest at the top and decreases toward the bottom, and accordingly, the conduction band is lowered toward the top in the energy band structure. Since the semiconductor layer 12, that is, the emitter layer, is formed on the entire light-receiving surface of the silicon substrate 10, the minority transport photogenerated in the first conductive semiconductor layer 11 by the depth energy band structure of the emitter layer. The self moves along the emitter layer, and in particular, moves along the surface of the silicon substrate 10 above the emitter layer adjacent to the anti-reflection film 13 and is collected by the front electrode 14.

However, since the surface area of the silicon substrate 10, which is the movement path of the minority transporter 1, is a high density of defects in which a large number of crystal defects and impurities exist, the minority transporter 1 has such a conventional solar cell. There is a fear that it may be easily lost by recombination before being collected by the front electrode 14.

Furthermore, in the conventional solar cell, since the front electrode 14 having a large line width W within a range of 100 µm to 140 µm must be formed on the front surface of the silicon substrate 10, that is, the light receiving surface, it is sufficient to maintain the light receiving rate. In order to secure the light-receiving surface of the area, the distance d between the front electrodes 14 is formed very large within 1800 μm to 2300 μm, so that the minority carriers 1 generated in the first conductive semiconductor layer 11 are silicon. Since the distance to the front electrode 14 along the surface portion of the substrate 10 becomes longer, the minority transporter 1 may be recombined and lost on the surface of the silicon substrate 10 before being collected by the front electrode 14. The possibility increases.

That is, the conventional solar cell has a problem in that the photoelectric conversion efficiency is low due to its high recombination rate of the minority transporter 1 photogenerated in the silicon substrate 10.

In addition, in the conventional solar cell, when the number of the front electrodes 14 is reduced in order to secure the light receiving surface of the silicon substrate 10, the distance d between the front electrodes 14 becomes larger, so that the silicon substrate 10 is formed. As the minority carrier recombination rate at the surface is further increased, it is difficult to improve the light receiving rate of the solar cell, and thus, there is a problem in that the efficiency of the solar cell is also difficult to increase.

In addition, in the conventional solar cell, due to its structure, a metallic back electrode 15 is formed on the rear surface of the substrate 10 as a whole, the manufacturing cost is high, and solar light reflected from the ground surface cannot be absorbed at all. have.

In addition, a conventional solar cell requires a complicated process procedure such as a cleaning process for removing an oxide film and an insulation process for forming a trench for disconnection, and thus, a manufacturing period and a manufacturing cost are high.

The present invention has been made to solve the above-described problems, the light-receiving portion is formed on the front and rear surfaces of the substrate, the emitter and the electrode is formed locally on the front light-receiving portion of the substrate, local to the rear light-receiving portion of the substrate The present invention provides a double-sided light-receiving localized emitter solar cell having a base and an electrode, an auxiliary electrode layer formed between an emitter and an electrode, and a base and an electrode, and a method of manufacturing the same.

In addition, the present invention forms a doped region of a conductive impurity having a polarity opposite to the conductivity type of the emitter in the front light receiving portion of the substrate except the emitter formation region, and the base of SUMMARY OF THE INVENTION An object of the present invention is to provide a double-sided light receiving localized emitter solar cell in which a doped region of a conductive impurity having a polarity opposite to that of a conductive type is formed, and a method of manufacturing the same.

A solar cell according to an embodiment of the present invention for achieving the above object includes a first conductive substrate of silicon material having a front electrode and a rear electrode at the top and bottom; A first high concentration doped region of a second conductive impurity is locally formed on the upper portion of the substrate, and a first conductive type is formed on a portion of the upper portion of the substrate except for the formation portion of the first high concentration doped region of the second conductive impurity. A first high concentration doped region of an impurity is formed, and a second high concentration doped region of a first conductive impurity is locally formed in the lower portion of the substrate, and a second high concentration doped region of the first conductive impurity in the lower portion of the substrate. A second high concentration doped region of the second conductive impurity is formed in a portion except for the formation region of the dielectric layer, and a dielectric layer and an auxiliary electrode layer are sequentially stacked between the substrate and the front electrode and between the substrate and the back electrode, respectively.

Here, the first high concentration doped region of the first conductivity type impurity is formed on the upper layer of the substrate so as not to contact the first high concentration doped region of the second conductivity type impurity and the front electrode, It is desirable to prevent substrate top surface movement.

In addition, the second high concentration doped region of the second conductive impurity is formed in the lower layer of the substrate so as not to contact the second high concentration doped region of the first conductive impurity and the back electrode, the photo-generated multiple carriers It is desirable to prevent substrate bottom surface movement.

The first high concentration doped region of the first conductive impurity is formed in a structure stacked on an upper surface of the substrate so as not to contact the first high concentration doped region of the second conductive impurity and the front electrode. It is desirable to prevent the substrate top surface movement of the generated minority carriers.

The second high concentration doped region of the second conductive impurity is formed in a structure stacked on a lower surface of the substrate so as not to contact the second high concentration doped region of the first conductive impurity and the back electrode. It is desirable to prevent the substrate bottom surface movement of the resulting multiple carriers.

In this case, the first high concentration doped region of the first conductivity type impurity and the second high concentration doped region of the second conductivity type impurity may be each composed of a heavy doped amorphous silicon (a-Si) thin film.

The dielectric layer may be formed on portions of the upper and lower surfaces of the substrate except for regions in which the first high concentration doped region of the second conductive impurity and the high concentration doped region of the first conductive impurity are formed.

The auxiliary electrode layer may be formed to be stacked on the dielectric layer while directly contacting the first high concentration doped region of the second conductive impurity and the second high concentration doped region of the first conductive impurity or contacting the seed layer via a seed layer. It is preferable to be.

The auxiliary electrode layer is preferably made of a transparent conductive oxide film.

As such, the dielectric layer and the auxiliary electrode layer preferably serve as an anti-reflective coating (ARC).

Further, the first high concentration doped region of the second conductive impurity and the second high concentration doped region of the first conductive impurity are preferably formed in a line or dot pattern having regular or irregular line width and spacing.

In this case, the front electrode is preferably formed in a direction parallel or perpendicular to the pattern of the high concentration doped region of the second conductive impurity.

In addition, the back electrode may be formed in a direction parallel to or perpendicular to the pattern of the highly doped region of the first conductivity type impurity.

On the other hand, the method for manufacturing a double-sided light receiving localized emitter solar cell according to an embodiment of the present invention, preparing a substrate of the first conductive type; Forming a first heavily doped region of a first conductive impurity locally in an upper layer of the substrate; Forming a second heavily doped region of a second conductive impurity locally in the underlying layer of the substrate; Forming a dielectric layer on top and bottom of the substrate; The dielectric layer formed on the upper and lower portions of the substrate is locally removed through a laser doping process, and the first high concentration of the second conductive impurity is locally formed on the upper layer of the substrate so as not to contact the first high concentration doped region of the first conductive impurity. Forming by exposing a doped region, and locally exposing a second high concentration doped region of a first conductive impurity to a lower layer of the substrate so as not to contact the second high concentration doped region of the second conductive impurity; An auxiliary electrode layer is formed on and under the substrate so as to be stacked on the dielectric layer while contacting the first high concentration doped region of the second conductive impurity formed in the upper layer of the substrate and the second high concentration doped region of the first conductive impurity formed in the lower layer of the substrate. Depositing; It is preferable to include a step of forming a front electrode and a back electrode on the surface of the auxiliary electrode layer.

On the other hand, the method for manufacturing a double-sided light receiving localized emitter solar cell according to another embodiment of the present invention, preparing a substrate of the first conductive type; Forming a first heavily doped region of a first conductive impurity locally on an upper surface of the substrate; Forming a second highly doped region of a second conductive impurity locally under the bottom surface of the substrate; Forming a dielectric layer on top and bottom of the substrate; The dielectric layer formed on the upper and lower portions of the substrate is locally removed through a laser doping process, and the first high concentration of the second conductive impurity is locally formed on the upper layer of the substrate so as not to contact the first high concentration doped region of the first conductive impurity. Forming by exposing a doped region, and locally exposing a second high concentration doped region of a first conductive impurity to a lower layer of the substrate so as not to contact the second high concentration doped region of the second conductive impurity; An auxiliary electrode layer is formed on and under the substrate so as to be stacked on the dielectric layer while contacting the first high concentration doped region of the second conductive impurity formed in the upper layer of the substrate and the second high concentration doped region of the first conductive impurity formed in the lower layer of the substrate. Depositing; It is preferable to include a step of forming a front electrode and a back electrode on the surface of the auxiliary electrode layer.

The forming of the first high concentration doped region of the first conductive impurity may include patterning an amorphous silicon (a-Si) thin film doped with a first conductive impurity on an upper surface of the substrate. It is preferable to make.

The forming of the second high concentration doped region of the second conductive impurity may include patterning an amorphous silicon (a-Si) thin film heavily doped with the second conductive impurity under a lower surface of the substrate. It is preferable to make it.

The depositing of the auxiliary electrode layer may include depositing a seed layer that lowers a contact resistivity to directly contact the heavily doped region of the second conductive impurity and the heavily doped region of the first conductive impurity. It is preferred to include a step.

According to the double-sided light receiving type localized emitter solar cell according to the present invention and a method of manufacturing the same, by forming a light receiving portion on the front and rear surfaces of the substrate, the light receiving portion of the substrate is increased to absorb even the sunlight reflected from the ground surface to absorb the sunlight. This can increase, thereby maximizing the efficiency of the solar cell.

In addition, according to the double-sided light receiving type localized emitter solar cell and a method of manufacturing the same according to the present invention, the emitter and the electrode are locally formed on the front light receiving portion of the substrate, but not on the front light receiving portion of the substrate except the emitter formation region. By forming a doped region of a conductive impurity having a polarity opposite to that of the emitter, and forming an auxiliary electrode layer between the emitter and the electrode, the recombination rate of the minority carriers that are generated in the substrate and collected by the electrode is reduced. It can increase the lifespan of minority transporters and maximize the photoelectric conversion efficiency of solar cells by safely delivering photogenerated minority transporters to the electrodes regardless of the electrode pattern type such as line width, number and spacing of electrodes. Reduce the line width and number of electrodes to be formed in the light receiving portion of the substrate, maximize the distance between the electrodes, An electrode pattern may be formed to maximize the light receiving surface of the substrate, thereby maximizing the light receiving rate of the solar cell, thereby increasing the efficiency of the solar cell.

In addition, according to the double-sided light receiving localized emitter solar cell according to the present invention and a method for manufacturing the same, the base and the electrode are locally formed on the rear light receiving portion of the substrate, but the base of the base on the rear light receiving portion of the substrate By forming a doped region of a conductive impurity having a polarity opposite to that of the conductive type, and forming an auxiliary electrode layer between the base and the electrode, the front and rear surfaces of the substrate can be formed in the same structure, so that the high temperature process during solar cell manufacturing is possible. The occurrence of bowing is reduced, which can minimize the breakage rate of the substrate during the manufacturing process of the solar cell using a thin thickness substrate, and reduces the manufacturing cost by not forming a metallic electrode on the back of the substrate as a whole. There is a saving effect.

Further, according to the present invention, the double-sided light receiving type localized emitter solar cell and the manufacturing method thereof do not need to perform a cleaning process for removing an oxide film or an insulation process for forming a disconnection trench, thereby simplifying the process procedure. The manufacturing period can be shortened, and manufacturing cost can be reduced.

1 is a cross-sectional view showing the structure of a typical solar cell.
Figure 2 is a plan view of a double-sided light receiving localized emitter solar cell according to an embodiment of the present invention.
3 is a cross-sectional view of the double-sided light receiving localized emitter solar cell according to AA ′ in FIG. 2;
Figure 4 is a process flow chart for explaining a method for manufacturing a double-sided light receiving localized emitter solar cell according to an embodiment of the present invention.
5 to 11 are cross-sectional views illustrating a method of manufacturing a double-sided light receiving type localized emitter solar cell according to an embodiment of the present invention.
12 is a cross-sectional view illustrating a method of manufacturing a double-sided light receiving localized emitter solar cell according to another embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail with respect to a double-sided light receiving localized emitter solar cell and a manufacturing method according to a preferred embodiment of the present invention.

2 to 3, a double-sided light receiving type localized emitter solar cell according to an embodiment of the present invention has a first conductive type of silicon material having a front electrode 14 and a rear electrode 15 disposed on upper and lower sides thereof. Wherein the first high concentration doped region 10-2 of the second conductive impurity is locally formed on the substrate 10, and the second conductive type of the upper portion of the substrate 10 is formed. A first high concentration doped region 10-3 of the first conductive type impurity is formed in a portion except for a portion where the first high concentration doped region 10-2 of the impurity is formed, between the substrate 10 and the front electrode 14. The dielectric layer 20 and the auxiliary electrode layer 30 are stacked in this order, and a second high concentration doped region 10-4 of the first conductive type impurity is locally formed under the substrate 10. In the lower part of 10), the second high concentration of the second conductive impurities is located at the portions except for the formation portion of the second high concentration doped region 10-4 of the first conductive impurities. FIG doped region (10-5) is formed, it has a substrate 10 and rear electrode 15 of the dielectric layer 21 and the auxiliary electrode layer 31 sequentially stacked structure between. Here, the first conductivity type may be n type or p type, hereinafter, the first conductive type is p type, and the second conductive type is n type.

The first high concentration doped region 10-2 of the second conductive type impurity is formed in the upper layer of the substrate 10 to form a pn junction in the substrate 10, whereby a minority carrier (1) photogenerated by solar incidence 1 It is possible to generate a potential difference in the substrate 10 by enabling the movement of), and serves to reduce the contact resistance between the metallic front electrode 14 and the interface between the substrate 10.

The first heavily doped region 10-2 of the second conductive type impurity is formed in a dot pattern having a regular size and spacing on the upper layer of the substrate 10 as shown in FIG. As shown in (b) of FIG. 2, the upper layer of the substrate 10 is preferably formed with a line pattern having a regular line width and spacing, but a dot pattern having an irregular size and spacing, or an irregular line width and spacing. It may also be formed in a line pattern having a. That is, the first heavily doped region 10-2 of the second conductive type impurity may be formed in the upper layer portion of the substrate 10 in various forms without restriction of the pattern shape. However, the first high concentration doped region 10-2 of the second conductive type impurity may have a narrow interval (for example, 450 μm or more to reduce the moving distance of the minority transporter 1 photogenerated in the substrate 10). It is preferably formed to have an appropriate width (for example, about 20 to 40 ㎛) with a width of about 2300㎛).

Meanwhile, the first high concentration doped region 10-3 of the first conductivity type impurity may not be in contact with the first high concentration doped region 10-2 of the second conductivity type impurity and the front electrode 14. It is formed in the upper layer, and prevents the surface movement of the substrate 10 of the photo-generated minority transporter (1).

That is, the first high concentration doped region 10-3 of the first conductivity type impurity is formed to alternate with the first high concentration doped region 10-2 of the second conductivity type impurity on the substrate 10 at a predetermined interval. It is preferable to be.

As a result, the minority carriers 1 generated in the substrate 10 approach the upper surface of the substrate 10 by the electric field generated by the first heavily doped region 10-3 of the first conductivity type impurity. If not, the shortest distance to the first high concentration doped region 10-2 of the second conductivity type impurity may be moved to the front surface through the first high concentration doped region 10-2 of the second conductivity type impurity and the auxiliary electrode layer 30. By being collected by the electrode 14, the surface recombination rate is significantly reduced compared to the conventional.

On the other hand, the second high concentration doped region 10-4 of the first conductivity type impurity is formed in the lower layer of the substrate 10 to form a high-low junction in the substrate 10, thereby generating a small number of carriers photogenerated by solar light incident At the same time to prevent the rear side movement of (1), it serves to facilitate the movement of the plurality of carriers (2) collected by the rear electrode (15).

The second high concentration doped region 10-4 of the first conductive impurity may be formed in the same pattern as the first high concentration doped region 10-2 of the second conductive impurity in the lower layer of the substrate 10. . For example, as shown in FIG. 2, the lower layer of the substrate 10 is formed in a dot pattern having a regular size and spacing, or the lower layer of the substrate 10 is formed in a line pattern having a regular line width and spacing. Although preferably, the pattern may be formed as a dot pattern having an irregular size and spacing, or a line pattern having an irregular line width and spacing. That is, the second high concentration doped region 10-4 of the first conductivity type impurity may also be formed in the lower layer of the substrate 10 in various forms without restriction of the pattern form.

Meanwhile, the second high concentration doped region 10-5 of the second conductive impurity may not be in contact with the second high concentration doped region 10-4 of the first conductive impurity and the back electrode 15. It is formed in the lower layer, to prevent the surface movement of the substrate 10 of the photo-generated majority carrier (2).

That is, the second high concentration doped region 10-5 of the second conductive impurity is formed to alternate with the second high concentration doped region 10-4 of the first conductive impurity at a lower portion of the substrate 10. It is preferable to be.

As a result, the multiple carriers 2 generated in the substrate 10 approach the lower surface of the substrate 10 by an electric field generated by the second heavily doped region 10-5 of the second conductive impurity. If not, the shortest distance is moved to the second high concentration doped region 10-4 of the first conductivity type impurity so as to be rearward through the second high concentration doped region 10-4 of the first conductivity type impurity and the auxiliary electrode layer 31. The electrode 15 is collected.

In addition, the first high concentration doped region 10-2 of the second conductivity type impurity has a higher doping concentration than the second high concentration doped region 10-5 of the second conductivity type impurity, and The high concentration doped region 10-4 is preferably formed to have a higher doping concentration than the first high concentration doped region 10-3 of the first conductivity type impurity. For example, when the first heavily doped region 10-2 of the second conductive impurity is composed of n ++ region, the second heavily doped region 10-5 of the second conductive impurity is composed of n + region, When the second high concentration doped region 10-4 of the first conductive impurity is formed of a p ++ region, the first high concentration doped region 10-3 of the first conductive impurity may be formed of a p + region.

On the other hand, the dielectric layers 20 and 21 are formed of the first heavily doped region 10-2 of the second conductive impurities and the second heavily doped region 10-4 of the first conductive impurities in the upper and lower surfaces of the substrate 10. It is formed at the site except for the forming site of.

The dielectric layers 20 and 21 may be formed of silicon oxide (SiO ₂ ), aluminum oxide (AlO ₃ ), titanium oxide (TiO ₂ ), silicon nitride (Si ₃ N ₄ ), or the like. It acts as a front passivation.

Meanwhile, the auxiliary electrode layer 30 formed on the substrate 10 is stacked on the dielectric layer 20 while directly contacting the first heavily doped region 10-2 of the second conductive impurity. In this case, the auxiliary electrode layer 30 is disposed on the dielectric layer 20 while contacting the high concentration doping region 10-2 of the second conductivity type impurity formed locally on the upper layer of the substrate 10 via the seed layer 20-1. It is preferable to stack.

In addition, the auxiliary electrode layer 31 formed under the substrate 10 may be formed under the dielectric layer 21 while directly contacting the second high concentration doped region 10-4 of the first conductive impurity. In this case, the auxiliary electrode layer 31 contacts the second high concentration doped region 10-4 of the first conductivity type impurity locally formed in the lower layer of the substrate 10 while contacting the seed layer 21-1 via the dielectric layer 21. It is preferred to be stacked below).

The auxiliary electrode layers 30 and 31 are photogenerated inside the substrate 10 such that the minority carriers 1 collected through the first high concentration doped region 10-2 of the second conductive type impurity have a front electrode 14. A travel path capable of moving by moving up to) and a plurality of transporters 2 collected through the second high concentration doping region 10-4 of the first conductivity type impurity can move to the rear electrode 15 by moving. It is composed of a material to provide, for example, it may be made of a transparent conductive oxide film (TCO).

As described above, the dielectric layers 20 and 21 and the auxiliary electrode layers 30 and 31 are formed to have predetermined thicknesses in consideration of refractive indices, respectively, to prevent light reflection loss of the front and rear light receiving portions of the substrate 10. : Anti-Reflective Coating.

In addition, since the front electrode 14 may collect the minority transporter 1 through the auxiliary electrode layer 30 stacked on the entire upper surface of the substrate 10, the front electrode 14 is locally formed on the upper layer of the substrate 10. It is not necessary to pattern the pattern so as to correspond to the formation position of the first heavily doped region 10-2 of the second conductivity type impurity, so that it does not correspond to the formation position of the first heavily doped region 10-2 of the second conductivity type impurity. The auxiliary electrode layer 30 may be formed in various patterns on the upper surface of the auxiliary electrode layer 30, and the rear electrode 15 may not correspond to the formation position of the second high concentration doped region 10-4 of the first conductivity type impurity. It may be formed in various patterns on the lower surface of the). Of course, if necessary, the front electrode 14 may be patterned on the auxiliary electrode layer 30 so as to correspond to the formation position of the first high concentration doped region 10-2 of the second conductivity type impurity. The back electrode 15 may be patterned under the auxiliary electrode layer 31 to correspond to the formation position of the second high concentration doped region 10-4 of the first conductivity type impurity.

For example, the front electrode 14 may be formed in a pattern such as a finger line shape, wherein the front electrode 14 has a narrow line width (W) of about 20 μm to 40 μm, and between electrodes of about 1800 μm to 2300 μm. It is formed to have a distance (d) or, if necessary, is formed to exceed 2300㎛ within a range that does not exceed the light receiving surface of the substrate 10, thereby ensuring a much wider light receiving surface than the light receiving surface of a typical solar cell. have. In addition, the front electrode 14 may be patterned in a direction parallel or orthogonal to the pattern of the first heavily doped region 10-2 of the second conductive impurity.

In addition, like the front electrode 14, the rear electrode 15 may also be formed in a pattern such as a finger line shape. In this case, the rear electrode 15 may have a narrow line width (W) of about 20 μm to 40 μm, and about 1800 μm to 2300 μm. It is formed to have an interval d between the electrodes of about within or is formed to exceed 2300㎛ within the range that does not exceed the light receiving surface of the substrate 10, if necessary, it is possible to ensure a wide light receiving surface. The back electrode 15 may be patterned in a direction parallel or perpendicular to the pattern of the second heavily doped region 10-4 of the first conductive impurity.

Hereinafter, a method of manufacturing a double-sided light receiving type localized emitter solar cell according to an embodiment of the present invention will be described.

First, as shown in FIG. 4, a first conductive silicon substrate 10 is prepared (S100).

In step S100, a saw damage etching process of etching the substrate 10 in a chemical manner is performed in order to remove a defective portion generated as a result of the cutting process of the substrate 10. At this time, it is preferable to etch the surface of the substrate 10 by a predetermined depth using a potassium hydroxide (KOH) solution or the like as an etching solution, and then wash using DIW (Deionized Water).

In addition, after the saw damage etching (Saw Damage Etching) process, a wet texturing process or a dry texturing process using an acid or alkaline (Alkaline), etc. are performed. The surface uneven structure of the substrate 10 formed by this texturing process is not shown in FIGS. 5 to 12 for the sake of simplicity.

In the state in which the substrate 10 is prepared through the above step S100, as shown in FIG. 5, the substrate 10 of the substrate 10 except for the portion where the first high concentration doped region 10-2 of the second conductivity type impurity is to be formed is formed. Locally doping the first conductivity type impurity on the upper part, especially the upper layer of the substrate 10, to form the first high concentration doped region 10-3 of the first conductivity type impurity, The second conductive dopant is locally heavy doped to the lower portion of the substrate 10, particularly the lower layer of the substrate 10, except for the portion where the second high concentration doped region 10-4 of the impurity is to be formed. A second heavily doped region 10-5 is formed (S110).

In step S110, an impurity ion implantation process, a laser doping, or a diffusion process using an impurity paste as a source may be performed. In this case, the diffusion barrier may or may not be used in the diffusion process.

The first high concentration doped region 10-3 of the first conductivity type impurity formed in the upper layer of the substrate 10 through step S110 may be formed of, for example, a p + region, and a small number of carriers may be formed in front of the substrate 10. It is responsible for forming an electric field to prevent the access of 1), the second high concentration doping region (10-5) of the second conductive impurities formed in the lower layer of the substrate 10 may be made of, for example, n + region. In addition, the rear surface of the substrate 10 serves to form an electric field for preventing the access of the plurality of transporters (2).

After the above step S110, as shown in FIG. 6, the dielectric layers 20 and 21 are formed on the front surface, that is, the front and rear surfaces of the substrate 10 by performing a heat treatment process or a deposition process (S120).

In the step S120, for example, the dielectric layers 20 and 21 formed of silicon nitride layers Si ₃ N ₄ are formed on upper and lower surfaces of the substrate 10 by performing a chemical vapor deposition process such as a plasma enhanced chemical vapor deposition (PECVD) process. can do.

Next to step S120, as shown in FIG. 7, the laser doping process is performed to locally remove the dielectric layers 20 and 21 formed on the surface of the substrate 10 and to remove the dielectric layer 20. Heavy doping the second conductive dopant on the upper layer of the substrate 10 corresponding to the first conductive dopant region 10-2 of the second conductive dopant on the upper layer of the substrate 10. The second conductive doped region 10-4 of the first conductive dopant is formed in the lower layer of the substrate 10 by doping the first conductive dopant under the substrate 10 corresponding to the portion where the dielectric layer 21 is removed. It is formed by locally exposing (S130).

The second high concentration doped region 10-2 of the second conductive type impurity formed in the upper layer portion of the substrate 10 through step S130 may be formed of, for example, a heavy doped n ++ region, and is formed on the front surface of the substrate 10. It is responsible for forming the electric field. In addition, the second high concentration doped region 10-4 of the first conductive type impurity formed in the lower layer of the substrate 10 may be formed of, for example, a heavy doped p ++ region, and forms an electric field on the rear surface of the substrate 10. Play a role.

After the above step S130, as shown in FIG. 8, the auxiliary electrode layers 30 and 31 are deposited on the upper and lower portions of the substrate 10 (S140).

The auxiliary electrode layer 30 deposited on the upper portion of the substrate 10 through the step S140 is directly connected to the first high concentration doped region 10-2 of the second conductive impurity locally exposed on the upper layer portion of the substrate 10. Deposited on dielectric layer 20 in contact. In addition, the auxiliary electrode layer 31 deposited on the lower portion of the substrate 10 may be in direct contact with the second high concentration doped region 10-4 of the first conductivity type impurity that is locally exposed on the upper portion of the substrate 10. 21) deposited to be laminated underneath.

In the step S140 described above, as shown in FIG. 9, the seed layers 20-1 and 21-1 which lower the specific resistance upon contact with the substrate 10 are heavily doped with the second conductive impurities. After depositing to directly contact the region 10-2 and the highly doped region 10-2 of the first conductivity type impurity, as shown in FIG. 10, the auxiliary electrode layers 30 and 31 are disposed on upper and lower portions of the substrate 10. By depositing the C), the seed layer 20-1 is contacted to the high concentration doped region 10-2 of the second conductive impurity that is locally exposed in the upper layer of the substrate 10, and the upper portion of the substrate 10 The auxiliary electrode layer 30 is deposited so as to be stacked on the formed dielectric layer 20, and the seed layer 21-1 is formed in the highly doped region 10-1 of the first conductivity type impurity that is locally exposed to the lower layer of the substrate 10. The auxiliary electrode layer 31 is deposited so as to be stacked under the dielectric layer 21 formed under the substrate 10 while contacting with each other.

After the above step S140, as shown in FIG. 11, the front electrode 14 is formed on the surface of the auxiliary electrode layer 30 stacked on the substrate 10 by performing a screen printing process. A back electrode 15 is formed on the surface of the auxiliary electrode layer 31 stacked below (S150).

When the front electrode 14 and the back electrode 15 are formed in step S150, the gaps d and d 'are widened to maximize the light receiving surface on the surface of the auxiliary electrode layers 30 and 31. After apply | coating the metal substance comprised including silver (Ag), aluminum (Al), etc., it is preferable to advance a baking process.

The double-sided light receiving localized emitter solar cell as shown in FIGS. 2 to 3 may be manufactured by the above-described steps S100 to S150.

Alternatively, in a state in which the substrate 10 is prepared through the above step S100, the first surface on the upper surface of the substrate 10 except for the portion where the first high concentration doped region 10-2 of the second conductivity type impurity is to be formed. A heavily doped amorphous silicon (a-Si) thin film patterned with a conductive impurity is formed under the lower surface of the substrate 10 except for a portion where the second high concentration doped region 10-4 of the first conductive impurity is to be formed. By patterning the amorphous silicon (a-Si) thin film heavily doped with the second conductive impurity, a first high concentration doped region 10-3 of the first conductive impurity is locally formed on the upper surface of the substrate 10. 12, locally forming a second high concentration doped region 10-5 of the second conductive impurity under the lower surface of the substrate 10, and then performing steps S120 to S150 as shown in FIG. 12. The first heavily doped region 10-3 of the first conductivity type impurity is the first heavily doped region 10 of the second conductivity type impurity. -2) and the second high concentration doped region 10-5 of the second conductive impurity is stacked on the upper surface of the substrate 10 so as not to contact the front electrode 14, and the second high concentration of the first conductive impurity A double-sided light receiving localized emitter solar cell having a structure laminated on the lower surface of the substrate 10 so as not to contact the doped region 10-4 and the back electrode 15 can be manufactured.

The double-sided light-receiving localized emitter solar cell and the manufacturing method thereof according to the present invention are not limited to the above-described embodiments, and may be variously modified within the range allowed by the technical idea of the present invention.

1: minority carrier 2: majority carrier
10 Substrate 10-1 Highly Doped Layer of First Conductive Impurity
10-2: first heavily doped region of the second conductivity type impurity
10-3: first high concentration doped region of the first conductivity type impurity
10-4: second high concentration doped region of the first conductivity type impurity
10-5: second heavily doped region of the second conductivity type impurity
11: first conductive semiconductor layer 12: second conductive semiconductor layer
13: antireflection film 14: front electrode
15: rear electrode 20, 21: dielectric layer
20-1, 21-1: seed layer 30, 31: auxiliary electrode layer

Claims (18)

A first conductive substrate of silicon material having front and rear electrodes disposed on upper and lower parts thereof;
A first high concentration doped region of a second conductive impurity is locally formed on the upper portion of the substrate, and a first conductive type is formed on a portion of the upper portion of the substrate except for the formation portion of the first high concentration doped region of the second conductive impurity. A first high concentration doped region of impurities is formed,
A second high concentration doped region of the first conductive impurity is locally formed in the lower portion of the substrate, and a second conductive type is formed in a portion of the lower portion of the substrate except for the formation portion of the second high concentration doped region of the first conductive impurity. A second high concentration doped region of impurities is formed,
A dielectric layer and an auxiliary electrode layer are sequentially stacked between the substrate and the front electrode, and between the substrate and the back electrode, respectively.
The dielectric layer is formed on a portion of the upper and lower surfaces of the substrate except for a portion where the first high concentration doped region of the second conductive impurity and the high concentration doped region of the first conductive impurity are formed.
The auxiliary electrode layer may be formed to be stacked on the dielectric layer in direct contact with the first high concentration doped region of the second conductive impurity and the second high concentration doped region of the first conductive impurity, or by contacting a seed layer. A double-sided light receiving type localized emitter solar cell.
The method of claim 1,
The first high concentration doped region of the first conductive type impurity is
Double-sided light receiving type localization is formed on the upper layer of the substrate so as not to contact the first high concentration doped region of the second conductivity type impurity and the front electrode, to prevent the photo-generated minority carriers to move the upper surface of the substrate. Emitter solar cell.
The method of claim 2,
The second high concentration doped region of the second conductive impurity is
A double-sided light receiving type localization is formed in the lower layer of the substrate so as not to contact the second high concentration doped region of the first conductive type impurity and the back electrode, to prevent the surface movement of the substrate generated by the plurality of photo-generated carriers. Emitter solar cell.
The method of claim 1,
The first high concentration doped region of the first conductive type impurity is
It is formed in a structure laminated on the upper surface of the substrate so as not to contact the first high concentration doped region and the front electrode of the second conductive type impurities, characterized in that to prevent the movement of the upper surface of the substrate generated by the minority transporter Double sided light receiving localized emitter solar cell.
5. The method of claim 4,
The second high concentration doped region of the second conductive impurity is
It is formed in a structure laminated on the lower surface of the substrate so as not to contact the second high concentration doped region of the first conductivity type impurities and the back electrode, it characterized in that to prevent the movement of the lower surface of the substrate of a plurality of photo-generated carriers Double sided light receiving localized emitter solar cell.
The method according to claim 4 or 5,
The first high concentration doped region of the first conductive impurity and the second high concentration doped region of the second conductive impurity are
A double-sided light receiving localized emitter solar cell, each comprising a heavy doped amorphous silicon (a-Si) thin film.
delete delete The method of claim 1,
The auxiliary electrode layer,
A double-sided light receiving localized emitter solar cell comprising a transparent conductive oxide film.
10. The method of claim 9,
The dielectric layer and the auxiliary electrode layer,
A double-sided light receiving localized emitter solar cell, characterized in that it serves as an anti-reflective coating (ARC).
10. The method of claim 9,
The first high concentration doped region of the second conductivity type impurity and the second high concentration doped region of the first conductivity type impurity,
A double-sided light receiving localized emitter solar cell, characterized in that it is formed in a line or dot pattern with regular or irregular line widths and spacing.
The method of claim 11,
The front electrode,
And a second light-receiving localized emitter solar cell formed in a direction parallel or orthogonal to the pattern of the heavily doped region of the second conductive impurity.
The method of claim 11,
The back electrode,
The double-sided light receiving localized emitter solar cell of claim 1, wherein the light-concentrated localized emitter solar cell is formed in a direction parallel or orthogonal to the pattern of the heavily doped region of the first conductive impurity.
Preparing a substrate of a first conductivity type;
Forming a first heavily doped region of a first conductive impurity locally in an upper layer of the substrate;
Forming a second heavily doped region of a second conductive impurity locally in the underlying layer of the substrate;
Forming a dielectric layer on top and bottom of the substrate;
The dielectric layer formed on the upper and lower portions of the substrate is locally removed through a laser doping process, and the first high concentration of the second conductive impurity is locally formed on the upper layer of the substrate so as not to contact the first high concentration doped region of the first conductive impurity. Forming by exposing a doped region, and locally exposing a second high concentration doped region of a first conductive impurity to a lower layer of the substrate so as not to contact the second high concentration doped region of the second conductive impurity;
An auxiliary electrode layer is formed on and under the substrate so as to be stacked on the dielectric layer while contacting the first high concentration doped region of the second conductive impurity formed in the upper layer of the substrate and the second high concentration doped region of the first conductive impurity formed in the lower layer of the substrate. Depositing;
A method for manufacturing a double-sided light receiving localized emitter solar cell, comprising: forming a front electrode and a back electrode on a surface of the auxiliary electrode layer.
Preparing a substrate of a first conductivity type;
Forming a first heavily doped region of a first conductive impurity locally on an upper surface of the substrate;
Forming a second highly doped region of a second conductive impurity locally under the bottom surface of the substrate;
Forming a dielectric layer on top and bottom of the substrate;
The dielectric layer formed on the upper and lower portions of the substrate is locally removed through a laser doping process, and the first high concentration of the second conductive impurity is locally formed on the upper layer of the substrate so as not to contact the first high concentration doped region of the first conductive impurity. Forming by exposing a doped region, and locally exposing a second high concentration doped region of a first conductive impurity to a lower layer of the substrate so as not to contact the second high concentration doped region of the second conductive impurity;
An auxiliary electrode layer is formed on and under the substrate so as to be stacked on the dielectric layer while contacting the first high concentration doped region of the second conductive impurity formed in the upper layer of the substrate and the second high concentration doped region of the first conductive impurity formed in the lower layer of the substrate. Depositing;
A method for manufacturing a double-sided light receiving localized emitter solar cell, comprising: forming a front electrode and a back electrode on a surface of the auxiliary electrode layer.
16. The method of claim 15,
Forming the first high concentration doped region of the first conductive impurity,
And patterning a heavily doped amorphous silicon (a-Si) thin film having a first conductivity type impurity on the upper surface of the substrate.
17. The method of claim 16,
Forming the second high concentration doped region of the second conductive impurity,
And patterning an amorphous silicon (a-Si) thin film doped with a second conductive impurity beneath a lower surface of the substrate.
The method according to any one of claims 14 to 17,
Depositing the auxiliary electrode layer,
And depositing a seed layer that lowers the contact resistivity to directly contact the heavily doped region of the second conductive impurity and the heavily doped region of the first conductive impurity. Type localized emitter solar cell manufacturing method.

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