TWI488324B - Solar cell, module comprising the same, method of manufacturing the same and method of manufacturing dielectric layer of the same - Google Patents

Description

Solar cell, module thereof, method of manufacturing the same, and method of manufacturing the same

The invention relates to a solar cell, a module thereof and a related manufacturing method thereof, in particular to a twinned solar cell, a module thereof, a manufacturing method thereof and a method for manufacturing the dielectric layer.

In the known twinned solar cell, since the germanium material of the substrate has a dangling bond, thereby forming a trap of the carrier, the carrier recombination rate is increased and the photoelectric conversion efficiency is lowered, so In the prior art, a passivation layer made of a dielectric material is formed on the substrate to passivate the surface of the substrate to reduce the number of dangling bonds and improve photoelectric conversion efficiency.

The passivation layer material is, for example, tantalum nitride or tantalum oxide, wherein the tantalum oxide passivation layer is usually formed by plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD) or high temperature thermal oxidation, wherein thermal oxidation is performed. The method is to raise the substrate to a high temperature of 900 ° C or higher, and then pass water vapor and oxygen to grow the oxide layer. However, the disadvantages of the above various methods are slow process speed, long process time and high production cost. In addition, the process temperature of the above method is high, for example, PECVD can reach 400 ° C or more, so that the doping element of the emitter layer on the battery substrate is easily diffused into the passivation layer of the yttrium oxide, thereby affecting the passivation layer of the yttrium oxide. The quality and passivation function.

Accordingly, an object of the present invention is to provide a method for producing a dielectric layer of a solar cell having a high process speed and a low production cost, and a method for producing a solar cell.

Another object of the present invention is to provide a solar cell and a module thereof which have good film quality, good passivation effect, and good photoelectric conversion efficiency.

Therefore, the method for fabricating a dielectric layer of a solar cell of the present invention comprises: providing a substrate having a surface and being made of a semiconductor material, the surface of the substrate being wetted by a solution in a non-immersed manner, and heating the substrate, and The heating temperature is not less than the boiling temperature of the solution, wherein the boiling temperature of the solution is not more than 338 ° C, so that a surface of the substrate is wetted by the solution to form a dielectric layer, so that an anti-reflection is formed above the dielectric layer. Floor.

The method for manufacturing a solar cell of the present invention comprises: providing a substrate having a surface and a semiconductor material, the surface of the substrate is formed with an emitter layer, and an n-type or p-type germanium semiconductor material is further formed on the substrate. The germanium semiconductor material is removed and a first solution remains on the surface of the substrate. The substrate is placed in a heating environment, the heating environment is not less than the boiling temperature of the first solution, wherein the boiling temperature of the first solution is not more than 338 ° C, thereby leaving the first surface of the substrate A dielectric layer is formed at the solution to form an anti-reflective layer over the dielectric layer.

The solar cell of the present invention comprises: a first conductivity type substrate, a ruthenium oxide layer, and an electrode disposed on the substrate. The substrate of the first conductivity type includes a second conductivity type emitter layer disposed at a surface thereof. The ruthenium oxide layer is on the surface of the substrate, and the ratio of the positive trivalent to the positive monovalent intensity of the 2p orbital spectrum of the ruthenium atom in the ruthenium oxide layer is less than 1.

The solar cell module of the present invention comprises: a first plate and a second plate disposed opposite to each other, a plurality of solar cells as described above, and a packaging material . The solar cells are connected and arranged between the first plate and the second plate. The encapsulant is located between the first plate and the second plate and is wrapped around the solar cells.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments.

Referring to FIG. 1 and FIG. 2, a preferred embodiment of the solar cell module of the present invention comprises: a first plate 1 and a second plate 2 disposed opposite to each other and connected to the first plate 1 and A solar cell 3 between the second plate 2 and a package 4 between the first plate 1 and the second plate 2 and wrapped around the solar cells 3. In addition, two or more package materials 4 may be used for module packaging of the solar cell.

The first plate 1 and the second plate 2 are not particularly limited in implementation, and a plate made of glass or plastic may be used, and the plate on the side of the light receiving surface of the battery must be permeable to light. In the case of a double-sided light-receiving solar cell, both the first plate 1 and the second plate 2 must be permeable to light. The material of the encapsulant 4 is, for example, a light transmissive ethylene vinyl acetate copolymer (EVA) or other related materials that can be used for solar cell module packaging.

The solar cells 3 are electrically connected through soldering wires (not shown). The configurations of the solar cells 3 are the same, and only one of them will be described below as an example.

The solar cell 3 includes a substrate 31 of a first conductivity type, a ruthenium oxide layer (SiO _x ) 32, an anti-reflection layer 33, and an electrode 34 disposed on the substrate 31.

The substrate 31 of the first conductivity type of the present embodiment is a germanium substrate and includes a second conductivity type emitter layer 312 disposed on a surface 311 thereof. The first conductivity type and the second conductivity type refer to a conductive form of a semiconductor material, one of which is a p-type and the other of which is an n-type. In the present embodiment, the n-type substrate 31 is matched with the p-type emitter layer 312. As an example, of course, the conductive form of both can be reversed when implemented. In general, yttrium-doped phosphorus provides an n-type material, and yttrium-doped boron provides a p-type material.

The material of one of the substrate 31 and the emitter layer 312 of the present invention may be germanium doped boron. The ratio of the average concentration of boron in the yttrium oxide layer 32 to the average concentration of boron at a depth of 10 nm below the surface 311 of the substrate 31 (corresponding to the inside of the emitter layer 312) is less than 2. Since the solubility of boron in cerium oxide is greater than that in cerium, and the process temperature of the cerium oxide layer of the conventional battery is too high, a considerable amount of boron enters the cerium oxide layer. However, the above ratio of the present invention is lower than the above ratio of the known battery, mainly because the present invention produces the yttrium oxide layer 32 in a relatively low temperature process (the method of the present invention will be described later), so that the yttrium oxide can be effectively reduced. The boron content in layer 32 further enhances the quality and passivation of the yttria layer 32.

On the other hand, the material of one of the substrate 31 and the emitter layer 312 of the present invention may be germanium doped phosphorus, and the average concentration of phosphorus in the tantalum oxide layer 32 and the depth of the surface 311 of the substrate 31 The ratio of the average phosphorus concentration at 10 nm is less than 0.16, wherein the above ratio is less than 1 because the solubility of phosphorus in cerium oxide is less than that in cerium. The process of the present invention can also reduce the proportion of phosphorus entering the ruthenium oxide layer 32, The above ratio is lower than the above ratio of the known battery, thereby improving the quality and passivation effect of the ruthenium oxide layer 32.

The yttrium oxide layer 32 is located on the surface 311 of the substrate 31 for passivating the surface 311 to reduce the presence of dangling bonds and carrier traps, thereby helping to reduce the surface recombination rate of the carrier and improve the photoelectric conversion efficiency. The ratio of the positive trivalent (Si ³⁺ ) to the positive monovalent (Si ⁺ ) intensity of the 2p orbital spectrum of the germanium atom in the cerium oxide layer 32 of the present invention is less than 1. Since the more the content of Si ³⁺ represents the more the dangling bonds, the present invention effectively reduces the content of Si ³⁺ , indicating that the yttrium oxide layer 32 does achieve a good passivation effect. The 2p orbital spectrum is measured by X-ray photoelectron spectroscopy (XPS).

The thickness of the ruthenium oxide layer 32 is preferably from 0.5 nm to 10 nm, more preferably from 1 nm to 3 nm, most preferably from 1.5 nm. The yttrium oxide layer 32 having the above thickness provides a better passivation effect.

The yttrium oxide layer 32 contains boron or phosphorus because the doping elements in the emitter layer 312 also diffuse into the yttrium oxide layer 32. In addition, the ruthenium oxide layer 32 inevitably contains sulfur, chlorine, iron, sodium, and because the yttrium oxide layer 32 can be formed by using an acid, an alkali solution or an inorganic or organic solution or a mixture thereof. Among them, because the purity of these chemical solutions is not absolutely pure, usually there will be more sulfur, chlorine, iron, sodium and other components, so that the concentration of sulfur and chlorine in the yttrium oxide layer 32 will be greater than 50ppm. The concentration of iron and sodium will be greater than 5 ppm. However, when the present embodiment is wetted with water, the concentration of sulfur and chlorine in the ruthenium oxide layer 32 will be less than 50 ppm, and the concentration of iron and sodium will be less than 5 ppm, sulfur, chlorine, iron, The content of sodium is small, that is, the impurities are less, and the quality and passivation function of the ruthenium oxide layer 32 can be avoided.

In addition, the surface 311 of the substrate 31 of the present embodiment refers to a light receiving surface, and the yttrium oxide layer 32 is disposed on the emitter layer 312, that is, on the light receiving surface, but is not limited thereto. The ruthenium oxide layer 32 may be disposed on the back surface of the substrate 31 or may be disposed on the light receiving surface and the back surface at the same time. In addition, the design of the ruthenium oxide layer 32 of the present invention can also be applied to a double-sided light-emitting battery.

The anti-reflective layer 33 is disposed on the yttrium oxide layer 32. The material of the anti-reflective layer 33 includes tantalum nitride (SiN _x ), and may also cooperate with the yttrium oxide layer 32 to passivate and repair the surface 311 of the substrate 31. In particular, when the thickness of the yttria layer 32 is sufficiently thin, for example, at 1.5 nm, hydrogen (H) in the anti-reflective layer 33 of the tantalum nitride can penetrate the yttrium oxide layer 32 to impart a passivation effect to the surface 311. That is, the anti-reflection layer 33 has an anti-reflection function and helps to increase the incident amount of light, and may have a passivation effect. Preferably, the anti-reflection layer 33 has a thickness of 45 nm to 95 nm.

The electrode 34 of the present embodiment may include a first electrode portion 341 electrically connected to the surface 311 of the substrate 31 through the anti-reflection layer 33 and the yttria layer 32, and a first surface disposed on the back surface of the substrate 31. Two electrode portions 342. The function of the electrode 34 is to transfer the electrical energy generated by the battery to the outside.

Referring to Figures 3, 4 and 5, a preferred embodiment of the method of fabricating a solar cell of the present invention comprises:

(1) Step 61: providing the substrate 31 having the surface 311, and then forming the emitter layer 312 at the surface 311 by a diffusion process of phosphorus or boron, At the same time, the surface of the substrate 31 other than the surface 311 is formed with an n-type or p-type germanium semiconductor material 35 due to a diffusion process, and the conductivity and material of the germanium semiconductor material 35 are combined with the emitter layer. Similarly to 312, the germanium semiconductor material 35 is typically n-type phosphorous glass (PSG) or p-type boron germanium glass (BSG). In general, the back side of the substrate 31 will only have the germanium semiconductor material 35 near the periphery, depending on the diffusion process and equipment used.

(2) Step 62: Removing the germanium semiconductor material 35, this step is also referred to as an isolation process, and is mainly wet etching with a solution of HF, NH ₄ F or a mixture thereof to remove the germanium semiconductor material 35. Since the isolation process is a known technique and is not an improvement of the present invention, it will not be described in detail. Then, the substrate 31 is washed with a first solution, and the first solution is left on the surface 311. The first solution may include water, deionized water (DI Water) and other solutions for cleaning. By. The first solution may be selected from the group consisting of water (including DI Water), hydrogen peroxide solution, nitric acid solution, sulfuric acid solution, phosphoric acid solution, hydrogenated ammonia solution, hydrochloric acid solution, ozone solution, boric acid solution, acetic acid solution, and the like. The group formed by the combination. This embodiment washes the substrate 31 with water. The boiling point temperature of the first solution is not more than 338 °C.

(3) Step 63: The substrate 31 is placed in a heating environment. In this embodiment, the heating environment is implemented by providing a heating carrier 5, that is, the substrate 31 is placed on the heating load. The heating carrier 5 is, for example, a heater or other similar instrument or device having a heating function, and the front surface of the heating carrier 5 has a screen 51, at least one temperature control member 52, and the like. The substrate 31 is a heating plate or a heating platform placed on the heater on. In this embodiment, before the substrate 31 is placed, the heating carrier 5 has been preheated to 100 ° C or higher, that is, the preheating is not less than the first solution remaining on the surface 311 (this embodiment) For example, the boiling temperature of water). Of course, if the first solution used for cleaning and wetting is different, the boiling temperature will be different. For example, when pure sulfuric acid is used, the boiling temperature is 338 ° C, so the heating temperature is also 338 ° C.

Preheating the heating carrier 5 helps to bake the substrate 31 at a relatively uniform temperature, and the surface 311 is oxidized by means of the heat baking, so that the first solution remains on the surface 311. A dielectric layer is formed, the type of dielectric layer comprising an oxide layer, such as the yttria layer 32 mentioned above. In the present embodiment, the time for heating the substrate 31 is about 2 minutes. Then, the substrate 31 is cooled, and then the substrate 31 is removed from the heating carrier 5.

In addition, when the substrate 31 is placed on the heating carrier 5, it may be directly contacted with heating or indirectly heated. For example, the heating carrier 5 may be provided with some top supporting members (not shown). The top support members jack up the substrate 31 for air heating. Of course, in the selection of the heat source, a heat source such as baking, UV lamp, infrared lamp or/and hot air can also be used as a synchronous combination for heating.

(4) Step 64: depositing the anti-reflection layer 33 on the ruthenium oxide layer 32 by means of PECVD plating or the like, and forming the electrode 34 by screen printing or vacuum plating.

Further, before the substrate 31 is placed on the heating carrier 5, a surface of the substrate 31 may be provided in a non-immersed manner. A second solution of moisture is used to wet the surface 311. The non-immersing means comprises wetting the surface 311 by the second solution in any manner of spraying and coating, the non-immersing means that the substrate 31 is not completely immersed in the second solution. The second solution may be the same as or different from the first solution, and the second solution may be selected from the group consisting of water (including DI Water), hydrogen peroxide solution, nitric acid solution, sulfuric acid solution, phosphoric acid solution, hydrogenated ammonia solution, hydrochloric acid solution, An ozone solution, a boric acid solution, an acetic acid solution, and a combination of the above, and the second solution has a boiling temperature of not more than 338 °C. By this step, the surface 311 of the substrate 31 is more wetted, and the above-mentioned acidic solution or water coverage helps to oxidize the surface 311 to form the yttrium oxide layer 32 (i.e., the dielectric layer).

In addition, the step of providing the second solution containing moisture on the surface 311 in a non-immersing manner may be performed after the substrate 31 is placed on the heating carrier 5, that is, when the substrate 31 is subjected to The second solution may be sprayed or coated on the surface 311 while being heated or baked. Alternatively, the second solution may be provided on the surface 311 in a non-immersed manner before and after the substrate 31 is placed on the heating carrier 5. Alternatively, the second solution may be applied by immersion before and after the substrate 31 is placed on the heating carrier 5. Alternatively, the substrate 31 can be selectively provided with the second solution by immersion/non-immersion or non-immersion/immersion before and after the placement.

It should be noted that, in the implementation of the present invention, the ruthenium oxide layer 32 may be disposed adjacent to the light-receiving surface of the battery, may be disposed on the back surface, or may be disposed on the light-receiving surface and the back surface. Therefore, when manufacturing, it can be designed according to the needs. The first solution remains and is wetted with the second solution on any surface of the substrate 31 that needs to be wetted to form a ruthenium oxide layer 32 at a predetermined location. Although the function of the first solution of the present embodiment is to clean the substrate 31, the first solution remains on the substrate 31 to have the function of wetting the substrate 31.

A preferred embodiment of the method of fabricating a dielectric layer for a solar cell of the present invention is actually used to fabricate the hafnium oxide layer 32, and a summary of the dielectric layer process of the present invention is further provided herein. The method comprises the steps of: providing the substrate 31 having the surface 311, moisturizing the surface 311 of the substrate 31 with a solution in a non-immersed manner, and heating the substrate 31, and the heating temperature is not less than the boiling point of the solution. Temperature, and the boiling temperature of the solution is not more than 338 °C. This step assists in the reaction of the solution with the surface 311 to oxidize the surface 311 where it is wetted to form the yttria layer 32 (i.e., the dielectric layer). Here, the solution may refer to the first solution or the second solution, but is not limited thereto, as long as it is a solution which can be used to wet the substrate 311. The type of the solution used to wet the substrate 31 may be the kind of the first solution listed above.

Further, the order of the wetting step and the heating step is not limited, and the surface 31 of the substrate 31 may be wetted by the solution before the substrate 31 is heated. Alternatively, the substrate 31 may be heated first, and the surface 311 may be wetted by the solution. When the substrate 31 is heated, the heating carrier 5 may be preheated so that the temperature of the heating carrier 5 is not less than the boiling temperature of the solution, and the substrate 31 is placed on the heating carrier 5 for heating. Of course, it is also possible that the heating carrier 5 has not reached the boiling temperature of the solution. The substrate 31 is placed at a time, and the final heating temperature is still not less than the boiling temperature of the solution. Further, the heating carrier 5 does not have to be preheated first, and the substrate 31 may be placed on the heating carrier 5 and then heated. As apparent from the above description, the operation of placing the substrate 31 on the heating carrier 5 for heating can be performed before or after the temperature of the heating carrier 5 is not less than the boiling temperature of the solution.

It is worth mentioning that the time required for PECVD, ALD, and thermal oxidation (using a high temperature of 900 ° C or higher) using a 1.5 nm ruthenium oxide layer 32 includes a rise and fall temperature of 30 minutes and 90 minutes, respectively. The heating and baking method of the present invention takes only about several minutes, for example, less than 5 minutes, which can effectively shorten the processing time and reduce the production cost, and the process steps are simple and convenient. The heating and baking temperature of the present invention only needs to be equal to or greater than the boiling temperature of water or other wetting solution, so that the process temperature is low, and the proportion of the doping element of the emitter layer 312 diffusing into the yttrium oxide layer 32 can be lowered. At the same time, the proportion of other impurities in the yttrium oxide layer 32 is lowered, thereby producing a yttrium oxide layer 32 of good quality and good passivation effect, and the photoelectric conversion efficiency of the battery can be improved.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

1‧‧‧ first plate

2‧‧‧Second plate

3‧‧‧Solar battery

31‧‧‧Substrate

311‧‧‧ surface

312‧‧ ‧ emitter layer

32‧‧‧Oxide layer

33‧‧‧Anti-reflective layer

34‧‧‧ electrodes

341‧‧‧First electrode section

342‧‧‧Second electrode

35‧‧‧矽 Semiconductor materials

4‧‧‧Package

5‧‧‧heating vehicle

51‧‧‧ screen

52‧‧‧temperature control

61~64‧‧‧Steps

1 is a partial cross-sectional view showing a preferred embodiment of the solar cell module of the present invention; 2 is a schematic diagram of a solar cell of the solar cell module; FIG. 3 is a block flow diagram of a preferred embodiment of the method for fabricating the solar cell of the present invention; and FIG. 4 is a schematic flow chart of each step of the manufacturing method; And FIG. 5 is a schematic view showing a substrate placed on a heating carrier in the manufacturing method.

61~64‧‧‧Steps

Claims (13)

A method for manufacturing a dielectric layer of a solar cell, comprising: providing a substrate having a surface and being made of a semiconductor material, the surface of the substrate being wetted by a solution in a non-immersed manner, heating the substrate, and heating temperature is not It is smaller than the boiling temperature of the solution, wherein the boiling temperature of the solution is not more than 338 ° C, so that a surface of the substrate is wetted by the solution to form a dielectric layer, and an anti-reflective layer is formed on the dielectric layer. The method for producing a dielectric layer for a solar cell according to claim 1, wherein the solution is selected from the group consisting of water, hydrogen peroxide solution, nitric acid solution, sulfuric acid solution, phosphoric acid solution, hydrogenated ammonia solution, hydrochloric acid solution, An ozone solution, a boric acid solution, an acetic acid solution, and a combination of these. The method for producing a dielectric layer for a solar cell according to claim 1, wherein the step of moistening the surface of the substrate with the solution may be performed before or/or after heating the substrate. The method of manufacturing a dielectric layer for a solar cell according to any one of claims 1 to 3, wherein the non-immersion method comprises subjecting the surface of the substrate to the surface by spraying or coating. The solution is wetted. A method for manufacturing a solar cell, comprising: providing a substrate having a surface and a semiconductor material; the surface of the substrate is formed with an emitter layer, and an n-type or p-type germanium semiconductor material is further formed on the substrate, In addition to the germanium semiconductor material, and Depositing a first solution on the surface of the substrate; placing the substrate in a heating environment, the heating environment reaching not less than the boiling temperature of the first solution, wherein the boiling temperature of the first solution is not more than 338 ° C, thereby Forming a dielectric layer on the surface of the substrate where the first solution remains; and forming an anti-reflection layer over the dielectric layer. The method for manufacturing a solar cell according to claim 5, wherein before or after the substrate is placed in the heating environment, a second solution containing moisture is provided to the substrate in a non-immersed manner. The surface is wetted. The method for manufacturing a solar cell according to the sixth aspect of the invention, wherein the first solution and the second solution are selected from the group consisting of water, a hydrogen peroxide solution, a nitric acid solution, a sulfuric acid solution, a phosphoric acid solution, a hydrogenated ammonia solution, A group consisting of a hydrochloric acid solution, an ozone solution, a boric acid solution, an acetic acid solution, and a combination thereof. A solar cell produced by the method for manufacturing a solar cell according to claim 5, comprising: a substrate of a first conductivity type, comprising a second conductivity type emitter layer disposed at a surface thereof; A ruthenium oxide layer is disposed on the surface of the substrate, and a ratio of a positive trivalent to a positive valence of a 2p orbital spectrum of the ruthenium atom in the ruthenium oxide layer is less than 1; and an electrode is disposed on the substrate. According to the solar cell of claim 8, wherein the The thickness of the ruthenium oxide layer is 1 nm to 3 nm. The solar cell of claim 8, wherein the material of the substrate and the emitter layer is doped with boron, and the average concentration of boron in the tantalum oxide layer and the surface of the substrate The ratio of the average boron concentration at a depth of 10 nm is less than 2. The solar cell of claim 8, wherein the material of the substrate and the emitter layer is erbium doped phosphorus, and the average concentration of phosphorus in the ruthenium oxide layer and the surface of the substrate The ratio of the average phosphorus concentration at a depth of 10 nm is less than 0.16. The solar cell according to claim 8, wherein the concentration of sulfur and chlorine in the cerium oxide layer is less than 50 ppm, and the concentration of iron and sodium in the cerium oxide layer is less than 5 ppm. A solar cell module comprising: a first plate and a second plate disposed oppositely; and a plurality of solar cells according to any one of claims 8 to 12, wherein the solar cells are connected and arranged Between the first plate and the second plate; and a package material between the first plate and the second plate, and wrapped around the solar cells.