CN109449257B - Post-hydrogenation treatment method for amorphous film and preparation method for silicon heterojunction solar cell - Google Patents

Abstract

The invention provides a post-hydrogenation treatment method of an amorphous film and a preparation method of a silicon heterojunction solar cell, wherein the post-hydrogenation treatment method comprises the following steps: providing an amorphous film to be processed and placing the amorphous film into a reaction chamber provided with a hot wire; and introducing reaction gas into the reaction chamber, catalytically decomposing the reaction gas by the hot wire to generate at least hydrogen atoms, and thermally radiating the amorphous film to be treated so as to diffuse the hydrogen atoms into the amorphous film to be treated, thereby realizing the post-hydrogenation treatment of the amorphous film to be treated. According to the post-hydrogenation treatment method of the amorphous film, atomic hydrogen is diffused into the film in the amorphous film treatment process under the hot wire thermal radiation condition, and the defect state density such as dangling bonds in the film is reduced.

Description

Post-hydrogenation treatment method for amorphous film and preparation method for silicon heterojunction solar cell

Technical Field

The invention belongs to the technical field of semiconductor structure preparation, and particularly relates to a post-hydrogenation treatment method of an amorphous film and a silicon heterojunction solar cell preparation method based on the post-hydrogenation treatment method.

Background

In a solar cell device, the short-range order and the long-range disorder of an amorphous structure cause the defects of difficult control of the preparation process, high density of dangling bonds and other defect states, so that the research on the regulation and control of the amorphous silicon thin film structure based on the preparation and treatment processes is a hot spot of industrial research. In addition, the hydrogenated amorphous silicon material is widely used in devices such as thin film transistors and solar cells due to properties such as direct optical band gap and adjustable energy band.

The chemical vapor deposition method is the most commonly used method for preparing amorphous silicon thin films in solar cells, and currently, the research on the structure of the amorphous silicon thin film, particularly the structure of a hydrogenated amorphous silicon thin film, in the method is mainly carried out by changing deposition parameters such as the flow ratio of gas, the temperature of a chamber, the pressure, the power and the like. The long silicon-silicon bond angles in the amorphous silicon are irregularly distributed, and a large number of defect states exist. The adjustment of material structure performance (such as hydrogen content and mass density) and the like can be realized by adjusting deposition process parameters, but due to the existence of dangling bonds in the material and the like, the passivation performance of the solar cell and the transport capacity of carriers are difficult to improve. At present, the subsequent processing of the amorphous silicon thin film mainly includes technical means such as high-temperature annealing and plasma processing, however, these technical means can damage the original structure of the material while improving the defect density of the material, which affects the improvement of the solar cell efficiency.

Therefore, it is necessary to provide a post-hydrogenation treatment method, a solar cell manufacturing method and a solar cell to solve the above technical problems in the prior art.

Disclosure of Invention

In view of the above disadvantages of the prior art, an object of the present invention is to provide a post-hydrogenation treatment method for an amorphous thin film and a method for preparing a silicon heterojunction solar cell based on the post-hydrogenation treatment method, which are used to solve the problems in the prior art that the density of defects such as dangling bonds in the amorphous thin film is high, the damage to the thin film structure during the treatment process of the thin film defects is improved, the passivation effect of the solar cell is affected, and the like.

To achieve the above and other related objects, the present invention provides a post-hydrotreating method for an amorphous thin film, the post-hydrotreating method comprising at least:

providing an amorphous film to be processed, and placing the amorphous film to be processed in a reaction chamber provided with a hot wire; and introducing reaction gas into the reaction chamber, wherein the hot wire catalytically decomposes the reaction gas to generate at least hydrogen atoms, and thermally radiates the amorphous film to be treated, so that the hydrogen atoms are diffused into the amorphous film to be treated, and the post-hydrogenation treatment of the amorphous film to be treated is realized.

As an alternative of the present invention, the amorphous film to be treated includes a hydrogenated amorphous silicon film; the reaction gas comprises hydrogen; the amorphous film to be processed is formed on a substrate, and the substrate comprises any one of a crystalline silicon substrate and a quartz glass substrate.

As an alternative of the present invention, the reaction chamber comprises a reaction chamber of a hot filament chemical vapor deposition system, the hot filament comprises a hot filament in the hot filament chemical vapor deposition system; the process for preparing the amorphous film to be treated comprises any one of hot wire chemical vapor deposition, plasma chemical vapor deposition, photochemical vapor deposition and liquid silicon printing.

As an alternative of the present invention, a preset temperature is provided in the reaction chamber, and the preset temperature is between 50 ℃ and 250 ℃; in the action process of the hot wire, the temperature of the hot wire is between 1500 ℃ and 2000 ℃; the action time of the hot wire is between 1min and 5 min; the vacuum degree in the reaction chamber is between 1Pa and 10 Pa.

As an alternative of the invention, the distance between the hot wire and the upper surface of the amorphous film to be treated is between 5cm and 15 cm; the temperature of the upper surface of the amorphous film to be processed is between 100 and 200 ℃.

As an alternative of the present invention, the preparation of the to-be-treated amorphous thin film and the post-hydrogenation treatment performed on the to-be-treated amorphous thin film are completed in the same reaction chamber, wherein the reaction chamber is subjected to an exhaust treatment after the to-be-treated amorphous thin film is formed and before the reaction gas is introduced, so that the post-hydrogenation treatment is performed in a single hydrogen atom atmosphere.

As an alternative of the present invention, after the post-hydrogenation treatment is performed on the amorphous thin film to be treated, the method further comprises: and alternately performing the steps of depositing an amorphous film and performing the post-hydrogenation treatment on the deposited amorphous film.

The invention also provides a preparation method of the silicon heterojunction solar cell, which comprises the step of preparing the window layer, wherein the window layer is obtained by processing through the post-hydrogenation treatment method in any scheme.

As an alternative of the present invention, the method for preparing a silicon heterojunction solar cell includes the following steps:

1) providing a crystalline silicon substrate, wherein the crystalline silicon substrate is provided with a first surface and a second surface which are opposite;

2) forming a first passivation layer on the first surface, and forming an n-type doped layer on the first passivation layer, wherein the first passivation layer and the n-type doped layer form the window layer, and at least one of the first passivation layer and the n-type doped layer is subjected to the post-hydrogenation treatment;

3) forming a second passivation layer on the second surface, and forming a p-type doping layer on the second passivation layer; and

4) and respectively forming transparent conductive films on the surface of the n-type doped layer and the surface of the p-type doped layer, and preparing a metal grid line on the transparent conductive films.

As described above, the post-hydrogenation treatment method and the solar cell manufacturing method of the present invention have the following advantageous effects: the invention provides a post-hydrogenation treatment method of an amorphous film, which can reduce the density of defect states such as dangling bonds in the film by diffusing atomic hydrogen into the film in the process of treating the amorphous film (such as a hydrogenated amorphous silicon film) under the thermal radiation condition of a hot wire.

Drawings

Fig. 1 is a schematic diagram illustrating an amorphous film to be processed in a post-hydrogenation process of an amorphous film according to a first embodiment of the invention.

Fig. 2 is a schematic structural diagram of an amorphous film to be processed formed on a substrate during post-hydrogenation processing of the amorphous film according to a first embodiment of the present invention.

Fig. 3 is a schematic diagram showing the arrangement of the structural positions during the post-hydrogenation treatment of the amorphous thin film according to the first embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating the decomposition of the reaction gas during the post-hydrogenation treatment of the amorphous thin film according to the first embodiment of the present invention.

Fig. 5 is a diagram illustrating the processing of an amorphous film to be processed in the post-hydrogenation processing of the amorphous film according to the first embodiment of the present invention.

Fig. 6 is a flow chart of a manufacturing process for manufacturing a silicon heterojunction solar cell according to the second embodiment of the present invention.

Fig. 7 shows a schematic structural diagram of a silicon heterojunction solar cell prepared in the second embodiment of the present invention.

Description of the element reference numerals

100 amorphous film to be processed

101 substrate

200 reaction chamber

201 hot wire structure

202 reaction gas

203 hydrogen atom

204 chemical vapor deposition tray

205 inlet pipe

206 exhaust pipe

207 current source

300 silicon atoms

301 chemical bond

302 hanging key

400 crystal silicon substrate

401 first surface

402 second surface

403 first passivation layer

404 second passivation layer

405 n-type doped layer

406 p-type doped layer

407. 408 transparent conductive film

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

Please refer to fig. 1 to 7. It should be noted that the drawings provided in the present embodiment are only schematic and illustrate the basic idea of the present invention, and although the drawings only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation, the form, quantity and proportion of the components in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.

The first embodiment is as follows:

as shown in fig. 1 to 5, the present invention provides a post-hydrogenation treatment method for an amorphous thin film, comprising the steps of:

providing an amorphous film 100 to be processed, and placing the amorphous film 100 to be processed in a reaction chamber 200 provided with a hot wire 201; and introducing reaction gas into the reaction chamber 200, wherein the hot wire 201 catalytically decomposes the reaction gas to generate at least hydrogen atoms, and thermally radiates the to-be-treated amorphous film 100, so that the hydrogen atoms are diffused into the to-be-treated amorphous film 100, thereby realizing the post-hydrogenation treatment of the to-be-treated amorphous film 100.

As shown in fig. 1-2, in the post-hydrogenation treatment method of the amorphous film of the present invention, an amorphous film 100 to be treated is provided first;

the to-be-processed amorphous film 100 is provided by way of example as being formed on a substrate 101, and in an alternative example, the substrate 101 includes any one of crystalline silicon and quartz glass.

Specifically, firstly, an amorphous film 100 to be processed, which needs to be subjected to post-hydrogenation treatment, is provided or prepared, and of course, the amorphous film 100 to be processed may be an existing structure that has already been prepared, or may be a newly prepared structure, and is not particularly limited, and in addition, the amorphous film 100 to be processed may be a single-layer material layer, or may be a stacked structure formed by multiple material layers. In an example, the to-be-processed amorphous film 100 is preferably formed on a substrate 101, wherein the material of the substrate 101 may be crystalline silicon or quartz glass, and the substrate 101 may also be a structural layer including other prepared device structures, may be a single-layer structural layer or a stacked structural layer, which is not limited herein.

As an example, the to-be-treated amorphous film 100 includes a hydrogenated amorphous silicon film.

In an alternative example, the hydrogenated amorphous silicon thin film includes at least one of an intrinsic hydrogenated amorphous silicon thin film and an n-type doped hydrogenated amorphous silicon thin film.

Specifically, this example provides a specific structure of the to-be-processed amorphous film 100, that is, the hydrogenated amorphous silicon film adopts a hydrogenated amorphous silicon film, and then the post-hydrogenation process of the present invention is performed, so that defects in the amorphous film can be more significantly improved, and in addition, preferably, the hydrogenated amorphous silicon film selects an intrinsic hydrogenated amorphous silicon film or an n-type hydrogenated amorphous silicon film, and of course, may also be a stacked structure formed by the intrinsic hydrogenated amorphous silicon film and the n-type hydrogenated amorphous silicon film, where in such a structure, when performing subsequent post-hydrogenation, more silicon hydrogen bonds are favorably generated, and other ineffective doping chemical bonds are not easily introduced, so that lattice distortion of an original structure is not easily caused, and the original defects of the amorphous film are more favorably reduced, and the device performance is more favorably improved.

As an example, the thickness of the to-be-treated amorphous thin film 100 is less than 50 nm.

As an example, the process for preparing the to-be-treated amorphous film 100 includes any one of hot filament chemical vapor deposition, plasma chemical vapor deposition, photochemical vapor deposition, and liquid silicon printing.

Specifically, in this example, the thickness of the to-be-processed amorphous thin film 100 is less than 50nm, preferably less than 40nm, and may be 35nm, 30nm, 10nm, and the like, and at such a thickness, the effect of subsequent post-hydrogenation treatment is significant, which is beneficial to obtaining a device structure with smaller defect density and more stable performance. In addition, the preparation process of the to-be-processed amorphous film 100 includes any one of Hot Wire Chemical Vapor Deposition (HWCVD), plasma chemical vapor deposition (PECVD), photochemical vapor deposition (Photo-CVD), and liquid silicon printing, but is not limited thereto.

Next, as shown in fig. 3, the to-be-processed amorphous film 100 is placed in a reaction chamber 200 provided with a hot wire 201; as an example, the reaction chamber 200 includes a reaction chamber of a hot filament chemical vapor deposition system, and the hot filament 201 includes a hot filament of the hot filament chemical vapor deposition system.

The material of the hot wire 201 is selected from an alloy of tungsten, tantalum, molybdenum, etc., but not limited thereto.

Specifically, the amorphous film 100 to be processed is placed in a reaction chamber 200 to perform a subsequent post-hydrogenation process, preferably, the post-hydrogenation process is performed in a Hot Wire Chemical Vapor Deposition (HWCVD) system, when the HWCVD system is adopted, the reaction chamber 200 is a reaction chamber of the HWCVD system, the hot wire structure is a hot wire of the HWCVD system, and the material of the hot wire structure 201 includes, but is not limited to, the above materials.

In addition, the post-hydrogenation treatment process of the invention is completed based on the hot wire 201, and the hot wire 201 has high energy content and high diffusion rate compared with other processes, such as a plasma chemical vapor deposition system, a plasma chemical vapor deposition system and the like, of decomposed hydrogen atoms, and causes defects of etching damage to a film structure, hole generation and the like. In addition, the amorphous film to be processed is placed in the reaction chamber 200 with the hot wire 201, the hot wire 201 not only can play a role in catalytically decomposing reaction gas and heating the sample (the amorphous film 100 to be processed), but also can be kept in the environment in the reaction chamber 200, and hydrogen diffuses into the amorphous film to be processed, so that hydrogen atoms keep a relatively high diffusion rate under the action of heat.

Finally, as shown in fig. 3 to 5, a reaction gas 202 is introduced into the reaction chamber 200, wherein the hot wire 201 catalyzes and decomposes the reaction gas to generate at least hydrogen atoms 203, and performs thermal radiation on the amorphous film 100 to be processed, so that the hydrogen atoms 203 are diffused into the amorphous film 100 to be processed, thereby implementing post-hydrogenation treatment on the amorphous film 100 to be processed.

Specifically, as shown in fig. 3, in an example, the to-be-processed amorphous film 100 is disposed on the chemical vapor deposition tray 204, and the reaction gas 202 is introduced into the reaction chamber 200 through the gas inlet pipe 205, wherein the reaction gas 202 may be a gas containing hydrogen (such as silane and phosphine), and in a preferred embodiment, a single hydrogen gas is selected, so that other atoms (silicon atoms, phosphorus atoms, etc.) are not introduced into the to-be-processed amorphous film, thereby reducing or even avoiding a change in thickness and structure of the to-be-processed amorphous film, effectively stabilizing properties of the to-be-processed amorphous film, further using the to-be-processed amorphous film in a device, and ensuring stability of the device and no contamination by other atoms. In addition, in one example, the reacted gases, as well as other impurity gases and the like, may be exhausted from the reaction chamber via an exhaust pipe 206.

Specifically, as shown in fig. 3, in an example, the hot wire 201 is energized based on a current source 207, after the energization, the hot wire 201 catalytically decomposes the reaction gas 202 to generate hydrogen atoms 203, and on the other hand, after the energization, the hot wire 201 generates thermal radiation, so that the temperature of the amorphous film 201 to be processed and the entire reaction chamber 200 is increased, at this time, the hydrogen atoms 203 diffuse into the amorphous film 100 to be processed, and the hydrogen atoms 203 are combined with the original dangling bonds 302, as shown in fig. 5, so that the dangling bonds can be passivated, the density of the dangling bonds can be reduced, and the defects in the original amorphous film 100 to be processed can be reduced, and meanwhile, in the above processing process, the density of the material defects can be improved without damaging the original structure of the material.

As an example, the reaction chamber 200 has a predetermined temperature therein, and the predetermined temperature is between 50 ℃ and 250 ℃.

As an example, the vacuum degree in the reaction chamber 200 is between 1Pa and 10 Pa.

Specifically, in the post-hydrogenation treatment process, the temperature of the reaction chamber 200 is between 50 ℃ and 250 ℃, preferably between 100 ℃ and 200 ℃, preferably, the temperature is an optimal scheme obtained by monitoring the optimized hot wire treatment process, and within the temperature range, the temperature is favorable for reducing or even eliminating structural changes of the treatment process to the original film due to the annealing effect, and the hydrogen atom diffusion rate is moderate, so that the damage to the original structure of the film in the diffusion process is favorably reduced or even eliminated, and the obtained treated structural performance is relatively stable. In addition, "between …" of the present invention means a numerical range including two endpoints.

In addition, the degree of vacuum in the reaction chamber 200 is between 1Pa and 10Pa, preferably between 3Pa and 7Pa, so as to be beneficial to ensure that the concentration of hydrogen atoms in the reaction chamber is high enough to facilitate the diffusion of the hydrogen atoms into the amorphous film to be processed.

By way of example, the hot wire 201 has a hot wire temperature between 1500 ℃ and 2000 ℃.

As an example, the temperature of the hot wire 201 is adjusted by adjusting any one of the current and the power of the hot wire 201.

Specifically, in the process of performing the post-hydrogenation treatment on the hot wire 201, the temperature of the hot wire 201 is between 1500 ℃ and 2000 ℃, preferably between 1600 ℃ and 1800 ℃, so as to ensure that the catalytic decomposition reaction occurs on the surface of the hot wire structure, so that hydrogen-containing molecules can be decomposed into hydrogen atoms, and in addition, the temperature of the hot wire 201 can be adjusted by the current or power flowing through the hot wire, which, of course, can also be other adjustable factors, and is not limited thereto.

As an example, the distance between the hot wire 201 and the upper surface of the to-be-processed amorphous thin film 100 is between 5cm and 15cm, where the upper surface refers to a surface of the to-be-processed amorphous thin film 100 on a side close to the hot wire 201.

As an example, the temperature of the upper surface of the to-be-treated amorphous thin film 201 is between 100 ℃ and 200 ℃, wherein the upper surface refers to the surface of the to-be-treated amorphous thin film 100 on the side close to the hot wire 201.

As an example, the time of the hot wire 201 is between 1min and 5 min.

Specifically, the distance between the hot wire 201 and the to-be-processed amorphous film 100 is between 5cm and 15cm, preferably between 8cm and 12cm, the thermal radiation effect of the decomposition process of the hot wire 201 on the original sample (to-be-processed amorphous film) is equivalent to annealing the film (to-be-processed amorphous film), and the distance between the hot wire 201 and the film is selected to be larger than 5cm, so that the change of the basic structure of the film caused by overhigh temperature of the film is favorably alleviated, the distance between the hot wire 201 and the film is selected to be smaller than 15cm, and the average free path of hydrogen atoms is considered, so that the hydrogen atoms are further favorably diffused into the film. The temperature of the upper surface of the amorphous film to be processed is controlled. In addition, the diffusion depth of the atomic hydrogen into the hydrogenated amorphous silicon film can be controlled by parameters such as the flow rate of hydrogen gas, the air pressure of the chamber, the processing time and the like in the processing process, and preferably, for the amorphous silicon film with the thickness of 0-50 nanometers, the processing time is usually 1-5 minutes, and the background vacuum degree of the reaction chamber is 1-10 Pa.

Further, the temperature of the surface of the to-be-processed amorphous film 201 exposed in the reaction chamber 200 is preferably controlled to be between 100 ℃ and 200 ℃, and the temperature of the upper surface of the to-be-processed amorphous film 201 is preferably controlled to be between 120 ℃ and 150 ℃, so that the structure of the to-be-processed film is not damaged, and the diffusion stroke of hydrogen atoms is favorably ensured.

As an example, the preparation of the to-be-treated amorphous film 100 and the post-hydrogenation treatment process for the to-be-treated amorphous film are provided in the same reaction chamber, wherein, in a preferred embodiment, the reaction chamber is subjected to an exhaust treatment after the to-be-treated amorphous film 100 is formed and before the reaction gas 202 is introduced, so that the post-hydrogenation treatment is performed in a single hydrogen atom atmosphere.

Specifically, in an example, the deposition forming apparatus for the film 100 to be processed and the post-hydrogenation are selected to be completed in the same reaction chamber, for example, both the deposition forming apparatus and the post-hydrogenation are implemented by using a hot filament chemical vapor deposition system, which can save the process cycle and simplify the process, preferably, after the amorphous film to be processed is formed, the exhaust process is performed, so that the reaction chamber does not contain gases (such as silicon source gas, doping gas, etc.) containing elements other than hydrogen elements, i.e., when the post-hydrogenation process and the deposition process of the sample (amorphous film to be processed) are continuously performed, the silicon source gas and the doping gas except for hydrogen elements are exhausted from the chamber after the deposition of the sample, and then the sample processing is performed in a pure hydrogen atmosphere, as an example, for the exhaust process, the apparatus is automatically controlled, and the exhaust valve is controlled by monitoring the gas content in the reaction chamber, specifically, only a period of time (several minutes, such as 3-5 minutes) is set after deposition, the chamber is kept in a vacuum state in the period of time, the equipment can automatically exhaust the gas in the chamber to reach a high vacuum state (such as 0.01-0.05 Pa), and then hydrogen is introduced for subsequent treatment.

As an example, after the post-hydrogenation treatment is performed on the to-be-treated amorphous thin film 100, the method further includes: and alternately performing the steps of depositing an amorphous film and performing the post-hydrogenation treatment on the deposited amorphous film. In an optional embodiment, the material of the amorphous film deposited alternately and the material of the provided amorphous film to be processed are the same, so that an amorphous film of a single material subjected to multiple post-hydrogenation treatments can be provided based on the method of this embodiment.

Specifically, in this example, a manner of forming a stacked amorphous structure is provided, that is, a manner of "thin film deposition-post-hydrogenation treatment" is cyclically performed, for example, to form an amorphous silicon thin film with a thickness of 50nm, the specific method is to deposit 10nm amorphous silicon, perform hydrogenation treatment after heating wire, and so on until an amorphous structure with a required thickness and subjected to hydrogenation treatment after multiple times is formed, the thickness of the amorphous film is selected according to actual requirements, and is not particularly limited, so that a laminated amorphous structure with excellent performance is obtained, preferably, the same material is selected for each layer of the amorphous film to be processed, and then a uniform and stable laminated amorphous structure is obtained, and compared with an untreated amorphous film of the same thickness and an amorphous film subjected to one-time post-hydrogenation treatment, the laminated amorphous structure has fewer defects and more excellent performance.

In addition, the invention also provides an amorphous film structure based on post-hydrogenation treatment, the amorphous film structure is preferably prepared by adopting the post-hydrogenation treatment method of the invention, the amorphous film structure comprises the amorphous film subjected to post-hydrogenation treatment, after the post-hydrogenation treatment, dangling bonds in the amorphous film are combined with hydrogen atoms generated in the post-hydrogenation treatment process to form silicon-hydrogen bonds, so that the defect density in the film is reduced, and the original basic structure of the amorphous film is not damaged.

To further illustrate the beneficial effects of the present invention, a specific preferred example is provided, in which a hydrogenated amorphous silicon film is first deposited on a crystalline silicon or glass substrate by a hot filament chemical vapor deposition system, hydrogen is then introduced into the evacuated chamber after the deposition is finished, and then the deposited sample is treated by irradiation of a high temperature hot filament. The processing technology of the amorphous silicon film prepared by adopting the hot wire chemical vapor deposition technology can be continuously carried out with the subsequent preparation technology, and the films prepared by other technologies are put into a hot wire chemical vapor deposition chamber for processing after the preparation is finished. Specifically, when the substrate is a single crystal silicon wafer prepared by the floating zone method or the czochralski method, the surface oxide layer removing treatment is usually carried out for 2 minutes in a hydrofluoric acid solution with a concentration of 2% before the amorphous silicon film is deposited. In addition, the temperature of the reaction chamber in the post-hydrogenation treatment process is kept at 50-250 ℃, the temperature of the electrified hot wire can be adjusted through current or power and kept at 1500-2000 ℃, and it should be noted that the current is preferably set to be the highest when the hot wire decomposes hydrogen, the temperature is also the highest at the moment, the heating effect on the chamber is most obvious, after the decomposition of the hot wire is finished, the current is usually gradually reduced (cannot be suddenly reduced to 0 ampere), the diffusion of hydrogen atoms to the film still exists at the moment, but the heat radiation effect of the hot wire is weakened, and the temperature of the chamber is also reduced; before the hot wire decomposes the hydrogen, the heat radiation effect on the chamber is always present and gradually strengthened, and the temperature of the chamber is increased.

Further, the reaction chamber does not contain gases (such as silicon source gas, doping gas and the like) except hydrogen elements, the high-temperature hot wire decomposes the hydrogen into hydrogen atoms, the distance between the surface of the hot wire and the surface of the film to be processed is 10 cm, and the temperature of the surface of the sample is 100-200 ℃. Therefore, hydrogen atoms decomposed by the hot wire are diffused into the deposited hydrogenated amorphous silicon film under the action of heat radiated by the hot wire to form a silicon-hydrogen chemical bond so as to passivate a dangling bond in the amorphous film, and the defect concentration in the hydrogenated amorphous silicon film is effectively reduced. The hydrogen atoms can be diffused into the film body material with the whole depth by adjusting parameters such as processing time and the like. In the treatment process, atomic hydrogen has no etching effect on the film and no silicon atom is introduced, so that the original silicon atom grid structure is not changed, and the mass density, the thickness and the like of the material are not influenced. Wherein, the characteristic parameters of the hydrogenated amorphous silicon thin film prepared conventionally and the hydrogenated amorphous silicon thin film subjected to the atomic hydrogen post-treatment in this example are shown in table 1.

TABLE 1

Wherein, the parameters in table 1 are obtained by testing an elliptical polarization spectrometer and a Fourier transform infrared spectrometer, and the size (such as 6nm) in the table is the thickness of the sample. As can be seen from the table, the optical band gap and the hydrogen content of the hydrogenated amorphous silicon thin film subjected to the atomic hydrogen post-treatment in this example are significantly optimized.

Example two:

as shown in fig. 6 to 7, the present invention further provides a method for manufacturing a silicon heterojunction solar cell structure, wherein the silicon heterojunction solar cell is preferably manufactured based on the to-be-processed amorphous thin film processed by the post-hydrogenation method of the present invention, and the method for manufacturing the silicon heterojunction solar cell structure includes a step of manufacturing a window layer, and the window layer is obtained by processing the window layer by the post-hydrogenation method according to any one of the first embodiment.

Specifically, the invention further provides a method for preparing a silicon heterojunction solar cell structure, in the solar cell heterostructure, a window layer comprises intrinsic and n-type doped amorphous thin film materials, and the amorphous thin film materials are subjected to post-hydrogenation treatment in the first embodiment, so that the treated window layer materials have a higher optical band gap and a lower defect state density, wherein in the energy band theory, energy levels corresponding to dangling bonds exist in a band gap, which is called a gap state, and the environment of each dangling bond in the material is different, so that the energy is different, so that a state (non-single energy) with continuously distributed energy is formed in the band gap, after treatment, the dangling bonds are saturated, the gap state density is reduced, so that the measured optical band gap is widened, and therefore, the characteristics of good passivation performance and good light transmission performance are achieved, the substrate is used as a crystalline silicon substrate in the silicon heterojunction solar cell, and the window layer is arranged on the basis of the semiconductor substrate and is formed on the semiconductor substrate.

The invention also provides a preparation method of the silicon heterojunction solar cell structure, wherein the silicon heterojunction solar cell is preferably prepared on the basis of the post-hydrogenation treated amorphous film to be treated, and the preparation method comprises the following steps:

1) providing a crystalline silicon substrate 400 (e.g., an n-type crystalline silicon substrate) having a first surface 401 and a second surface 402 opposite to each other;

2) forming a first passivation layer 403 on the first surface 401, and forming an n-type doped layer (back field) 405 on the first passivation layer 403, where the first passivation layer 403 and the n-type doped layer 405 form the window layer, and at least one of the first passivation layer 403 and the n-type doped layer 405 is subjected to the post-hydrogenation treatment;

3) forming a second passivation layer 404 on the second surface 402, and forming a p-type doped layer (emitter) 406 on the second passivation layer 404; and

4) transparent conductive films 407 and 408 are formed on the surface of the n-type doped layer 405 and the surface of the p-type doped layer 406, respectively, and metal gate lines (not shown) are formed on the transparent conductive films (407/408) to form the silicon heterojunction solar cell structure.

In other examples, the crystalline silicon substrate 400 may be a p-type crystalline silicon substrate, and when the crystalline silicon substrate 400 is a p-type crystalline silicon wafer, the n-type doped layer serves as an emitter and the p-type doped layer serves as a back field.

Specifically, the present invention further provides a method for manufacturing a silicon heterojunction solar cell structure, in the silicon heterojunction solar cell structure, at least one of the first passivation layer 403 and the n-type doped layer 405 is manufactured by the manufacturing method according to any one of the embodiments, that is, at least one of the two is subjected to a post-hydrogenation treatment, preferably, both of the two include an amorphous silicon material layer, and both of the two are used as a window layer of a solar cell and are subjected to a post-hydrogenation treatment process. Therefore, the processed window layer material has the characteristics of high optical band gap and low defect state density, and has the characteristics of good passivation performance and good light transmission performance, wherein in the energy band theory, the energy level corresponding to the dangling bond exists in the band gap, which is called gap state, and the environment of each dangling bond in the material is different, so that the energy is different, so that a state (non-single energy) with continuously distributed energy is formed in the band gap, after the processing, the dangling bond is saturated, and the gap state density is reduced, so that the measured optical band gap is widened, and the characteristics of good passivation performance and good light transmission performance are achieved.

As an example, the first passivation layer 403 includes an intrinsic hydrogenated amorphous silicon layer, and the second passivation layer 404 includes an intrinsic hydrogenated amorphous silicon layer; the n-doped layer (e.g., as a back field) 405 comprises an n-type hydrogenated amorphous silicon layer and the p-doped layer (e.g., as an emitter) 406 comprises a p-type hydrogenated amorphous silicon layer.

As an example, the thickness of the first passivation layer 403 is between 4nm and 8nm, and the thickness of the second passivation layer 404 is between 4nm and 8 nm; the thickness of the n-type doped layer is 8 nm-12 nm, and the thickness of the p-type doped layer is 8 nm-12 nm.

Specifically, this example provides a specific structure of each material layer, wherein a hydrogenated amorphous silicon layer is used and then subjected to subsequent post-hydrogenation treatment, so as to further reduce defects in the amorphous structure and further improve the device performance, wherein the first passivation layer 403 includes an intrinsic hydrogenated amorphous silicon layer, the n-type doped layer 405 includes an n-type hydrogenated amorphous silicon layer, and when the above two options are performed, the intrinsic hydrogenated amorphous silicon layer is the intrinsic hydrogenated amorphous silicon layer subjected to post-hydrogenation treatment, or the n-type hydrogenated amorphous silicon layer is the n-type hydrogenated amorphous silicon layer subjected to post-hydrogenation treatment, or both of them are subjected to post-hydrogenation treatment. In addition, the intrinsic hydrogenated amorphous silicon layer subjected to post-hydrogenation treatment may be a laminated structure layer based on the same material formed in a cyclic mode of "thin film deposition-post-hydrogenation treatment", and the n-type hydrogenated amorphous silicon layer may be a laminated structure layer based on the same material formed in a cyclic mode of "thin film deposition-post-hydrogenation treatment".

In addition, as shown in fig. 7, the present invention further provides a silicon heterojunction solar cell structure, where the solar cell structure is preferably prepared by using the preparation method of the silicon heterojunction solar cell structure provided in this embodiment, and the silicon heterojunction solar cell structure includes:

a crystalline silicon substrate 400 having opposing first and second surfaces 401, 402;

a first passivation layer 403 and a second passivation layer 404 on the first surface 401 and the second surface 402, respectively;

an n-type doped layer (back field) 405 and a p-type doped layer (emitter) 406, the n-type back field layer being formed on the first passivation layer 403, the p-type emitter layer being formed on the second passivation layer 404, wherein at least one of the first passivation layer 403 and the n-type doped layer 405 comprises the semiconductor structure based on the post-hydrogenation process according to the first embodiment;

transparent conductive films 407 and 408 and metal gate lines, wherein the transparent conductive films are formed on the surface of the n-type doped layer and the surface of the p-type doped layer, and the metal gate lines are formed on the transparent conductive films.

In the solar cell heterostructure, at least one of the first passivation layer 403 and the n-type doped layer 405 is subjected to post-hydrogenation, preferably, both include amorphous silicon material layers, and are used as a window layer of a solar cell together, and both are subjected to post-hydrogenation, so that the processed window layer material has a higher optical band gap and a lower defect state density, and thus has the characteristics of good passivation performance and good light transmittance. When the crystalline silicon substrate 400 is selected as an n-type crystalline silicon substrate, the n-type doped layer serves as a back field, and the p-type doped layer serves as an emitter; when the p-type crystalline silicon wafer is selected as the crystalline silicon substrate 400, the n-type doped layer serves as an emission layer, and the p-type doped layer serves as a back field layer.

To further illustrate the effects of the present invention, a specific preferred example is provided, which provides a specific implementation method for improving the efficiency of an amorphous silicon/crystalline silicon heterojunction solar cell by using the post-hydrogenation treatment technology of the present invention, comprising: an n-type crystalline silicon substrate; an intrinsic hydrogenated amorphous silicon passivation layer (6 nanometers) and an n-type hydrogenated amorphous silicon doping layer (back field, 10 nanometers) are positioned on the upper surface of the crystalline silicon substrate; an intrinsic hydrogenated amorphous silicon passivation layer (6 nanometers) and a p-type hydrogenated amorphous silicon doping layer (an emitter, 12 nanometers) are positioned on the lower surface of the crystalline silicon substrate; transparent conductive films respectively positioned on the n-type back field layer and the p-type emitting layer; and metal grid lines respectively positioned on the surfaces of the transparent conductive films. As shown in fig. 6, the specific preparation sequence includes: firstly, etching and cleaning; and then carrying out amorphous silicon film deposition, wherein the amorphous silicon film deposition sequentially comprises the following steps: depositing i-type amorphous silicon on the back field side, performing hydrogenation treatment on the i-type amorphous silicon, depositing n-type amorphous silicon on the back field side, performing hydrogenation treatment on the n-type amorphous silicon, and depositing i-type and p-type amorphous silicon on the emitter side; then depositing a transparent conductive film; then, manufacturing a metal electrode; and finally, drying and sintering the battery. The post-hydrogenation treatment technology of the hydrogenated amorphous silicon film provided by the invention is applied to the deposition-treatment process of the n-type crystalline silicon heterojunction solar cell window layer (namely the n-type doped back field layer and the n-side intrinsic passivation layer) with the inverted structure. The processed window layer material has higher optical band gap and lower defect state density, thus having the characteristics of good passivation performance and good light transmission.

In addition, the test results of the cells using the post-hydrogenation treatment of the present invention under standard conditions and the comparative solar cell window layer not treated by the technique of the present invention were also prepared by the same process, and the comparative results are shown in table 2.

TABLE 2

Table 2 it can be seen that the cells using the post-hydrotreating window layer had higher open circuit voltage (Voc), short circuit current density (Jsc), Fill Factor (FF), and conversion efficiency (Eff.) than the control cells. This indicates that the window layer material subjected to post-hydrogenation treatment has better light transmittance and carrier transport performance, which also fully proves the practicability of the technology of the invention.

In summary, the present invention provides a post-hydrogenation method for an amorphous thin film and a method for manufacturing a silicon heterojunction solar cell, the post-hydrogenation method comprising: providing an amorphous film to be processed, and placing the amorphous film to be processed in a reaction chamber provided with a hot wire; and introducing reaction gas into the reaction chamber, wherein the hot wire catalytically decomposes the reaction gas to generate at least hydrogen atoms, and thermally radiates the amorphous film to be treated, so that the hydrogen atoms are diffused into the amorphous film to be treated, and the post-hydrogenation treatment of the amorphous film to be treated is realized. Through the scheme, atomic hydrogen is diffused into the amorphous film (such as a hydrogenated amorphous silicon film) in the process of processing the amorphous film under the thermal radiation condition of a hot wire, so that the defect state density of dangling bonds and the like in the film is reduced. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims (8)

1. A post-hydrotreating method of an amorphous thin film, characterized by comprising at least:

providing an amorphous film to be processed, and placing the amorphous film to be processed in a reaction chamber provided with a hot wire; introducing reaction gas into the reaction chamber, wherein the hot wire catalytically decomposes the reaction gas to generate at least hydrogen atoms, and thermally radiates the amorphous film to be treated, so that the hydrogen atoms are diffused into the amorphous film to be treated, and the hydrogen atoms are diffused into the amorphous film to be treated and combined with the original suspension bond to realize post-hydrogenation treatment of the amorphous film to be treated, wherein the reaction chamber has a preset temperature which is between 50 and 250 ℃; the distance between the hot wire and the upper surface of the amorphous film to be processed is 5 cm-15 cm; the temperature of the upper surface of the amorphous film to be processed is between 100 and 150 ℃.

2. The post-hydrogenation treatment method of amorphous film according to claim 1, wherein the amorphous film to be treated comprises a hydrogenated amorphous silicon film; the reaction gas comprises hydrogen; the amorphous film to be processed is formed on a substrate, and the substrate comprises any one of a crystalline silicon substrate and a quartz glass substrate.

3. The post-hydrogenation treatment method for amorphous thin film according to claim 1, wherein the reaction chamber comprises a reaction chamber of a hot filament chemical vapor deposition system, and the hot filament comprises a hot filament in the hot filament chemical vapor deposition system; the process for preparing the amorphous film to be treated comprises any one of hot wire chemical vapor deposition, plasma chemical vapor deposition, photochemical vapor deposition and liquid silicon printing.

4. The post-hydrogenation treatment method of amorphous film according to claim 1, wherein the temperature of the hot wire is between 1500 ℃ and 2000 ℃ during the action of the hot wire; the action time of the hot wire is between 1min and 5 min; the vacuum degree in the reaction chamber is between 1Pa and 10 Pa.

5. The method of claim 1, wherein the preparation of the amorphous film to be processed and the post-hydrogenation of the amorphous film to be processed are performed in the same reaction chamber, and wherein the reaction chamber is exhausted after the amorphous film to be processed is formed and before the reaction gas is introduced, so that the post-hydrogenation is performed in a single hydrogen atom atmosphere.

6. The method for post-hydrotreating of an amorphous thin film according to any one of claims 1 to 5, characterized in that after the post-hydrotreating of the to-be-treated amorphous thin film, the method further comprises: and alternately performing the steps of depositing an amorphous film and performing the post-hydrogenation treatment on the deposited amorphous film.

7. A preparation method of a silicon heterojunction solar cell is characterized by comprising the step of preparing a window layer, wherein the window layer is obtained by being processed by the post-hydrogenation treatment method as claimed in any one of claims 1 to 6.

8. The method for preparing the silicon heterojunction solar cell as claimed in claim 7, comprising the steps of:

1) providing a crystalline silicon substrate, wherein the crystalline silicon substrate is provided with a first surface and a second surface which are opposite;

2) forming a first passivation layer on the first surface, and forming an n-type doped layer on the first passivation layer, wherein the first passivation layer and the n-type doped layer form the window layer, and at least one of the first passivation layer and the n-type doped layer is subjected to the post-hydrogenation treatment;

3) forming a second passivation layer on the second surface, and forming a p-type doping layer on the second passivation layer; and

4) and respectively forming transparent conductive films on the surface of the n-type doped layer and the surface of the p-type doped layer, and preparing a metal grid line on the transparent conductive films.

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