Solar cell and method for manufacturing the same

Abstract

The present application relates to the field of photovoltaic technology, and in particular to a solar cell and a method for preparing the same. The method for preparing the solar cell comprises the following steps: forming a passivation film on a silicon substrate; using a chemical vapor deposition chamber to decompose a gas containing hydrogen and doping elements, allowing the decomposed active particles to act on the passivation film and the silicon substrate, doping hydrogen and doping elements into the passivation film to form a passivation doped film, and doping elements on the side of the silicon substrate close to the passivation film to form a silicon doping layer with a thickness of 1nm to 50nm, wherein the thickness of the silicon doping layer is less than the thickness of the silicon substrate. The above method can form an internal electric field between the film and the crystalline silicon, and this electric field can effectively reduce the recombination of carriers (electrons and holes) near the interface, and cooperate with the hydrogen passivation effect of the passivation doped amorphous silicon film, which can improve the photoelectric conversion efficiency of the battery and reduce energy loss, thereby improving the performance of the device.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to a solar cell and a method for preparing the same. Background Art

[0002] Solar cells, also known as photovoltaic cells, are devices that convert sunlight energy directly into electrical energy. They are based on the photoelectric effect, which is when sunlight shines on semiconductor materials, electron-hole pairs are generated, and the electron-hole pairs are separated, thereby generating current. Solar cells are usually composed of multiple layers of materials, and the passivation film occupies one of the layers. The provision of a passivation film is beneficial to reduce the charge recombination loss on the surface of the cell and improve the photoelectric conversion efficiency of the cell.

[0003] Traditional passivation films usually use the following two post-treatment methods to improve the passivation effect: one is to perform electrical injection, optical injection, annealing and other treatments on the existing film with a large amount of hydrogen content; the other is to introduce additional hydrogen into the passivation film, including hydrogen atmosphere annealing, hydrogen plasma treatment, etc., to saturate the dangling bonds on the silicon surface through hydrogenation treatment and reduce the interface state density. The above two methods have limited effect on improving the passivation performance. Summary of the invention

[0004] Based on this, the first aspect of the present application provides a method for preparing a solar cell, and its technical solution is as follows:

[0005] A method for preparing a solar cell comprises the following steps:

[0006] forming a passivation film on a silicon substrate;

[0007] A gas containing hydrogen and doping elements is decomposed in a chemical vapor deposition chamber, and the active particles obtained by the decomposition act on the passivation film and the silicon substrate, hydrogen and doping elements are doped into the passivation film to form a passivation doped film, and doping elements are doped into a side of the silicon substrate close to the passivation film to form a silicon doping layer with a thickness of 1nm to 50nm, wherein the thickness of the silicon doping layer is less than the thickness of the silicon substrate.

[0008] The second aspect of the present application provides a solar cell, and its technical solution is as follows:

[0009] A solar cell is prepared by the preparation method as described above.

[0010] Compared with the traditional solution, this application has the following beneficial effects:

[0011] After forming a passivation film on a silicon substrate, the present application decomposes a gas containing hydrogen and doping elements, and the decomposed active particles act on the passivation film and the silicon substrate, while doping elements are doped into the passivation film, the side of the silicon substrate close to the passivation film is doped with doping elements to form a silicon doping layer with a thickness of 1nm to 50nm. Under the above method, an internal electric field can be formed between the film and the crystalline silicon. This electric field can effectively reduce the recombination of carriers (electrons and holes) near the interface, and cooperate with the hydrogen passivation effect of the passivation doped amorphous silicon film, which can improve the photoelectric conversion efficiency of the battery and reduce energy loss, thereby improving the performance of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present application and to more completely understand the present application and its beneficial effects, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0013] Figure 1 Schematic diagram of decomposing PH3 in a hot wire chemical vapor deposition chamber;

[0014] Figure 2 is a schematic structural diagram of a solar cell according to one embodiment;

[0015] Figure 3 is a schematic structural diagram of a solar cell according to Example 2;

[0016] Figure 4 is a schematic structural diagram of a solar cell according to Example 3;

[0017] Figure 5 The phosphorus doping amount of Example 1 varies with the test depth. DETAILED DESCRIPTION

[0018] The present application will be further described in detail below in conjunction with specific embodiments. The present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thoroughly understood.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0020] the term

[0021] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0022] In the present application, "plurality", "multiple", "multiple times", "plurality", etc., unless otherwise specified, refer to a number greater than 2 or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0023] In the present application, “several” means at least one, such as one, two, etc., unless otherwise clearly defined.

[0024] In this application, "optionally", "optional" and "optional" refer to optional, that is, to any one of the two parallel schemes of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0025] In this application, in the "first aspect", "second aspect", "third aspect", "fourth aspect", etc., the terms "first", "second", "third", "fourth", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0026] In the present application, when referring to a numerical interval (i.e., a numerical range), unless otherwise specified, the optional numerical distribution within the above numerical interval is deemed to be continuous and includes the two numerical endpoints of the numerical range (i.e., the minimum value and the maximum value), and every numerical value between the two numerical endpoints.

[0027] The temperature parameters in this application, unless otherwise specified, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0028] A first aspect of the present application provides a method for preparing a solar cell. In one embodiment, the method for preparing a solar cell comprises the following steps:

[0029] forming a passivation film on a silicon substrate;

[0030] A gas containing hydrogen and doping elements is decomposed in a chemical vapor deposition chamber, and the active particles obtained by the decomposition act on the passivation film and the silicon substrate, hydrogen and doping elements are doped into the passivation film to form a passivation doped film, and doping elements are doped into a side of the silicon substrate close to the passivation film to form a silicon doping layer with a thickness of 1nm to 50nm, wherein the thickness of the silicon doping layer is less than the thickness of the silicon substrate.

[0031] After forming a passivation film on a silicon substrate, the present application decomposes a gas containing hydrogen and doping elements, and the decomposed active particles act on the passivation film and the silicon substrate, while doping elements are doped into the passivation film, the side of the silicon substrate close to the passivation film is doped with doping elements to form a silicon doping layer with a thickness of 1nm to 50nm. Under the above method, an internal electric field can be formed between the film and the crystalline silicon. This electric field can effectively reduce the recombination of carriers (electrons and holes) near the interface, and cooperate with the hydrogen passivation effect of the passivation doped amorphous silicon film, which can improve the photoelectric conversion efficiency of the battery and reduce energy loss, thereby improving the performance of the device.

[0032] Optionally, the silicon substrate is an N-type crystalline silicon substrate, which serves as the main body of the solar cell and provides an electron transmission path. It can be understood that before forming the passivation film on the silicon substrate, the steps of cleaning, texturing, and then cleaning the silicon substrate are also included.

[0033] The thickness of the silicon doped layer is 1 nm to 50 nm. For example, the thickness of the silicon doped layer is 1 nm, 10 nm, 20 nm, 30 nm, 40 nm, or 50 nm. The thickness of the silicon doped layer is relatively small, and is formed by the doping elements entering a portion of the silicon substrate while the passivation doped film is formed.

[0034] Optionally, the content of the doping element at any depth of the silicon doping layer is 1×10 16 / cm 3 ~1×10 20 / cm 3 For example, the content of the doping element at any depth of the silicon doping layer is 1×10 16 / cm 3 , 1×10 17 / cm 3 , 1×10 18 / cm 3 , 1×10 19 / cm 3 or 1×10 20 / cm 3 .

[0035] Optionally, the content of the doping element at any depth of the passivation doped film is between 1×10 16 / cm 3 ~1×10 20 / cm 3 For example, the content of the doping element at any depth of the passivation doping film is 1×10 16 / cm 3 , 1×10 17 / cm 3 , 1×10 18 / cm 3 , 1×10 19 / cm 3 , 3×10 19 / cm 3 or 1×10 20 / cm 3 .

[0036] The silicon doped layer contains doping elements, the passivation doped film contains hydrogen and doping elements, the doping elements of the silicon doped layer are the same as the doping elements of the passivation doped film, and are selected from at least one of P, As, Sb, Bi, B, Al, Mg, Ga, In and Se.

[0037] Optionally, the hydrogen content in the passivation doped film is 1wt% to 30wt%. For example, the hydrogen content in the passivation doped film is 1wt%, 5wt%, 10wt%, 20wt%, and 30wt%. Through the coordination of the field passivation of the doped element and the chemical passivation of hydrogen passivation, the photoelectric conversion efficiency of the battery can be improved and the energy conversion loss can be reduced, which is conducive to expanding the application of ultra-thin film passivation in different types of batteries. For example, heterojunction solar cells, HBC solar cells, etc.

[0038] Optionally, the passivation film comprises amorphous silicon or oxide. Optionally, the oxide is selected from AlO X , VO X 、MoO X , HfO X and TiO X One or more of the .

[0039] Optionally, the thickness of the passivation film is 1nm~15nm. For example, the thickness of the passivation film is 1nm, 5nm, 10nm, and 15nm. The thickness of the passivation film is relatively small. If the process gas is ionized by a plasma enhanced chemical vapor deposition (PECVD) method, which has a high plasma energy, it is easy to damage the passivation film, not only failing to play the role of passivating the hanging bond, but also destroying the Si-H bond. The hot wire chemical vapor deposition (HWCVD) method or the inductively coupled chemical deposition (ICPCVD) method catalytically decomposes the ionized process gas more gently, is not easy to damage the passivation film, and will not destroy the Si-H bond. Optionally, the chemical vapor deposition chamber is provided by a hot wire chemical vapor deposition device or an inductively coupled chemical vapor deposition device.

[0040] Optionally, the gas containing hydrogen and doping elements is selected from at least one of PH3, B2H5, H2 / He / doping element mixed gas and H2 / N2 / doping element mixed gas, wherein H2 / He / doping element mixed gas refers to a mixed gas of H2, He and doping elements, and H2 / N2 / doping element mixed gas refers to a mixed gas of H2, N2 and doping elements.

[0041] Taking the catalytic decomposition of PH3 in a hot wire chemical vapor deposition chamber as an example, see Figure 1 , a silicon substrate 01 with a passivation film 02 is placed in a hot wire chemical vapor deposition chamber 30, with the side where the passivation film 02 is located facing the direction of the hot wire 301, and a heater 302 is arranged on the side where the silicon substrate 01 is located. PH3 gas is introduced into the chamber 30 through a gas pipeline 303, and the PH3 gas will decompose on the surface of the high-temperature hot wire 301. The decomposed particle groups act on the passivation film 02 and the silicon substrate 01, first diffuse into the inside of the passivation film 02, and further diffuse to the silicon substrate 01, and hydrogen and doping elements are doped into the passivation film 02 to form a passivation doped film, and doping elements are doped into a part of the silicon substrate 01 to form a silicon doping layer with a thickness less than that of the silicon substrate 01. The passivation doped film and the silicon doping layer are as described above, and will not be repeated here.

[0042] It can be understood that the diffusion of hydrogen and doping elements can be controlled by controlling the pressure, process time, and temperature.

[0043] Optionally, the pressure of the chemical vapor deposition chamber is 0.01 mbar to 1 mbar. For example, the pressure of the chemical vapor deposition chamber is 0.01 mbar, 0.05 mbar, 0.1 mbar, 0.5 mbar, or 1 mbar.

[0044] Optionally, the active particles act on the passivation film and the silicon substrate for 1 min to 15 min. For example, the active particles act on the passivation film and the silicon substrate for 1 min, 5 min, 10 min, or 15 min.

[0045] Optionally, the surface temperature of the hot wire 301 is between 1200°C and 2500°C.

[0046] When ionizing a gas containing hydrogen and doping elements in an inductively coupled chemical deposition chamber, the electrode temperature can be controlled in the range of 5°C to 400°C, so that the gas decomposes in the electrode area and then enters the passivation film and the silicon substrate through the action of electric field coupling.

[0047] Optionally, when the active particles act on the passivation film and the silicon substrate, the temperature of the passivation film and the silicon substrate is 25-250° C. Compared with the traditional high-temperature passivation treatment at a temperature higher than 300° C., the present application can complete the passivation at a relatively low temperature, and ensure the combination of hydrogen and dangling bonds, ensure the passivation quality, and is suitable for low-temperature battery processes.

[0048] The above method performs non-destructive, low-temperature hydrogenation treatment on the passivation film on the silicon substrate. By using non-destructive technologies such as hot wire chemical vapor deposition (HWCVD) and inductively coupled chemical vapor deposition (ICPCVD), the gas containing hydrogen and doping elements is decomposed into active particles (where the active particles do not include charged or uncharged free radicals including hydrogen and doping elements. For example, PH3 is decomposed into free radicals including H, P, PH, and PH2). These active particles then enter the passivation film through diffusion or under the acceleration of electric field coupling, increase the hydrogen content in the film and dope the passivation film at the same time, improve the chemical passivation and field passivation properties of the passivation film, and at the same time, the doping elements further enter the silicon substrate to form a thinner silicon doping layer to enhance the field passivation effect. Compared with traditional PECVD treatment, the above method has no plasma bombardment damage, the ion energy can be independently controlled, there is no damage to the silicon substrate and the passivation film, and the process temperature is low, which is particularly suitable for post-processing of ultra-thin passivation films in low-temperature battery systems.

[0049] Optionally, after taking out the passivation doped film and the silicon doped layer from the chamber of the chemical vapor deposition equipment, the method further includes forming other film layers on the passivation doped film to prepare a solar cell. The preparation of the specific film layers depends on the type of solar cell, and the types of solar cells used in the above method include but are not limited to heterojunction solar cells, HBC solar cells, etc.

[0050] The second aspect of the present application provides a solar cell, which is prepared by the preparation method as described above, see Figure 2, is a schematic diagram of the structure of a solar cell according to an embodiment, wherein the solar cell 100 comprises a silicon substrate 11, a silicon doping layer 12 and a passivation doping film 13, wherein the silicon doping layer 12 is located on the silicon substrate 11, and the passivation doping film 13 is located on the silicon doping layer 12, wherein the portion of the silicon matrix doped with doping elements is the silicon doping layer 12, and the portion not doped with doping elements is the silicon substrate 11. Under the above structure, an internal electric field can be formed between the film and the crystalline silicon, and this electric field can effectively reduce the recombination of carriers (electrons and holes) near the interface, and cooperate with the hydrogen passivation effect of the passivation doping film, which can improve the photoelectric conversion efficiency of the battery, reduce energy loss, and improve the performance of the device.

[0051] Optionally, the thickness of the passivation doped film is 1nm~15nm. For example, the thickness of the passivation doped film is 1nm, 5nm, 10nm, 15nm. The thickness of the passivation doped film is small, and it uses a gentle hot wire chemical vapor deposition (HWCVD) method or an inductively coupled chemical deposition (ICPCVD) method to catalytically decompose or ionize the process gas, and completes the element doping and hydrogen treatment under low temperature (25~250°C) conditions, which is suitable for low-temperature battery systems, and the hot wire chemical vapor deposition (HWCVD) method or the inductively coupled chemical deposition (ICPCVD) method is gentle, and the damage to the thinner passivation doped film is small.

[0052] The following is further described in conjunction with specific embodiments and comparative examples. The raw materials involved in the following specific embodiments and comparative examples, unless otherwise specified, can all be commercially available, the instruments used, unless otherwise specified, can all be commercially available, and the processes involved, unless otherwise specified, are all routinely selected by those skilled in the art.

[0053] Example 1

[0054] This embodiment provides a passivation method, the steps are as follows:

[0055] Step 1: Clean, texturize, and clean the N-type crystalline silicon substrate, and form an intrinsic amorphous silicon (a-Si:H(i)) film with a thickness of 15 nm on one surface thereof.

[0056] Step 2: Place the N-type crystalline silicon substrate with the a-Si:H(i) film in the HWCVD chamber, with the side where the a-Si:H(i) film is located facing the direction of the hot wire, and a heater is arranged at the side where the N-type crystalline silicon substrate is located. PH3 gas is introduced into the chamber through a gas pipeline, and the PH3 gas is decomposed on the surface of the high-temperature hot wire. The decomposed active particles act on the a-Si:H(i) film and the N-type crystalline silicon substrate, first diffuse into the inside of the a-Si:H(i) film, and further diffuse to the N-type crystalline silicon substrate, and hydrogen and doping elements are doped into the a-Si:H(i) film to form a 15nm thick passivation doped amorphous silicon film, and doping elements are doped into a part of the N-type crystalline silicon substrate to form a 10nm thick silicon doping layer. In the chamber, the temperature of the heater and the heating wire is controlled to make the temperature of the a-Si:H(i) film and the N-type crystalline silicon substrate 250°C.

[0057] Example 2

[0058] This embodiment provides a method for preparing a heterojunction solar cell. Figure 3 The structure shown, the steps are as follows:

[0059] Step 1: Clean, texturize, and clean the N-type crystalline silicon substrate, and form an intrinsic amorphous silicon (a-Si:H(i)) film with a thickness of 10 nm on the front side thereof.

[0060] Step 2: Place the N-type crystalline silicon substrate with the a-Si:H(i) film on the front side in the HWCVD chamber, with the side where the a-Si:H(i) film is located facing the direction of the hot wire, and a heater is provided at the side where the N-type crystalline silicon substrate is located. B2H5 gas is introduced into the chamber through a gas pipeline, and the B2H5 gas is decomposed on the surface of the high-temperature hot wire. The decomposed active particles act on the a-Si:H(i) film and the N-type crystalline silicon substrate, first diffuse into the inside of the a-Si:H(i) film, and further diffuse to the N-type crystalline silicon substrate, and hydrogen and doping elements are doped into the a-Si:H(i) film to form a first passivation doped amorphous silicon film 13A with a thickness of 10nm, and doping elements are doped into a part of the N-type crystalline silicon substrate to form a first silicon doping layer 12A with a thickness of 10nm. In the chamber, the temperature of the heater and the heating wire is controlled to make the temperature of the a-Si:H(i) film and the N-type crystalline silicon substrate 250°C.

[0061] Step 3: Take out the intermediate product obtained in step 2 from the HWCVD chamber, and form an intrinsic amorphous silicon (a-Si:H(i)) film with a thickness of 10 nm on the back side of the N-type crystalline silicon substrate.

[0062] Step 4: Place the intermediate product with the a-Si:H(i) film on the back side in the HWCVD chamber, with the side where the a-Si:H(i) film is located facing the direction of the hot wire, and the side where the N-type crystalline silicon substrate is located is provided with a heater. PH3 gas is introduced into the chamber through a gas pipeline, and the PH3 gas is decomposed on the surface of the high-temperature hot wire. The decomposed active particles act on the a-Si:H(i) film and the N-type crystalline silicon substrate, first diffuse into the inside of the a-Si:H(i) film, and further diffuse to the N-type crystalline silicon substrate, and hydrogen and doping elements are doped into the a-Si:H(i) film to form a second passivation doped amorphous silicon film 13B with a thickness of 10nm, and doping elements are doped into a part of the N-type crystalline silicon substrate to form a second silicon doping layer 12B with a thickness of 10nm, and the remaining N-type crystalline silicon substrate without doping elements is used as the silicon substrate 11. In the chamber, the temperature of the heater and the heating wire is controlled to make the temperature of the a-Si:H(i) film and the N-type crystalline silicon substrate 250°C.

[0063] Step 5: Form a first doped amorphous silicon (nc-Si:H(n)) film 14A on the first passivation doped amorphous silicon film 13A, form a TCO 15A on the nc-Si:H(n) film 14A, and form a first metal electrode 16A on the TCO 15A; form a second doped amorphous silicon (nc-Si:H(p)) film 14B on the second passivation doped amorphous silicon film 13B, form a TCO 15B on the nc-Si:H(p) film 14B, and form a second metal electrode 16B on the TCO 15B, to obtain a heterojunction solar cell 100.

[0064] Example 3

[0065] This embodiment provides a method for preparing a HBC solar cell. Figure 4 The structure shown, the steps are as follows:

[0066] Step 1: Clean, texture, and clean the N-type crystalline silicon substrate, and form an aluminum oxide (AlO) layer with a thickness of 10 nm on one side of the substrate. X )film.

[0067] Step 2: AlO X The N-type crystalline silicon substrate of the film is placed in the HWCVD chamber, and the AlO X The side where the film is located faces the direction of the hot wire, and the side where the N-type crystalline silicon substrate is located is separated by a heater. PH3 gas is introduced into the chamber through a gas pipeline. The PH3 gas is decomposed on the surface of the high-temperature hot wire. The decomposed active particles act on the AlO X Thin film and N-type crystalline silicon substrate, first diffuse into AlO X The film is further diffused into the N-type crystalline silicon substrate, and the AlO XHydrogen and doping elements are doped into the film to form a 10nm thick passivation doped film 23, and doping elements are doped into a part of the N-type crystalline silicon substrate to form a 10nm thick silicon doping layer 22. The remaining N-type crystalline silicon substrate not doped with doping elements is used as a silicon substrate 21. In the chamber, the temperature of the heater and the heating wire is controlled to make AlO X The temperature of the film and the N-type crystalline silicon substrate is 250°C.

[0068] Step 3, an anti-reflection film 24 is formed on the passivation doped film 23, and intrinsic amorphous silicon 251, n-doped amorphous silicon 252, a conductive oxide layer 253 and a metal electrode 254 are sequentially formed in the N-type conductive region on the other side of the silicon substrate 21; intrinsic amorphous silicon 261, p-doped amorphous silicon 262, a conductive oxide layer 263 and a metal electrode 264 are sequentially formed in the p-type conductive region to obtain the HBC battery 200.

[0069] Comparative Example 1

[0070] This comparative example provides a method for preparing a heterojunction solar cell, which is basically the same as Example 2, except that: a gas containing hydrogen is decomposed in a chemical vapor deposition chamber, and the gas does not contain doping elements. Steps 2 and 4 are as follows:

[0071] Step 2: Place the N-type crystalline silicon substrate with the a-Si:H(i) film on the front side in the HWCVD chamber, with the side where the a-Si:H(i) film is located facing the direction of the hot wire, and a heater is provided on the side where the N-type crystalline silicon substrate is located. H2 gas is introduced into the chamber through a gas pipeline, and the H2 gas is decomposed on the surface of the high-temperature hot wire. The decomposed active particles act on the a-Si:H(i) film and the N-type crystalline silicon substrate, diffuse into the a-Si:H(i) film, and dope hydrogen into the a-Si:H(i) film to form a hydrogen-passivated amorphous silicon film with a thickness of 10nm. In the chamber, control the temperature of the heater and the heating wire to make the temperature of the a-Si:H(i) film and the N-type crystalline silicon substrate 250°C.

[0072] Step 4: Place the intermediate product with the a-Si:H(i) film on the back in the HWCVD chamber, with the side where the a-Si:H(i) film is located facing the direction of the hot wire, and the side where the N-type crystalline silicon substrate is located is provided with a heater. H2 gas is introduced into the chamber through a gas pipeline, and the H2 gas is decomposed on the surface of the high-temperature hot wire. The decomposed active particles act on the a-Si:H(i) film and the N-type crystalline silicon substrate, diffuse into the a-Si:H(i) film, and hydrogen is doped into the a-Si:H(i) film to form a hydrogen-passivated amorphous silicon film with a thickness of 10nm. In the chamber, the temperature of the heater and the heating wire is controlled to make the temperature of the a-Si:H(i) film and the N-type crystalline silicon substrate 250°C.

[0073] Comparative Example 2

[0074] This comparative example provides a method for preparing an HBC solar cell, which is basically the same as Example 3, except that: a gas containing hydrogen is decomposed in a chemical vapor deposition chamber, and the gas does not contain doping elements. Step 2 is as follows:

[0075] Step 2: AlO X The N-type crystalline silicon substrate of the film is placed in the HWCVD chamber, and the AlO X The side where the film is located faces the direction of the hot wire, and the side where the N-type crystalline silicon substrate is located is separated by a heater. H2 gas is introduced into the chamber through a gas pipeline. The H2 gas decomposes on the surface of the high-temperature hot wire, and the decomposed active particles act on the AlO X Thin film and N-type crystalline silicon substrate, diffused into AlO X Inside the film, in AlO X Hydrogen is doped into the film to form a hydrogen passivation film with a thickness of 10nm. In the chamber, the temperature of the heater and the heating wire is controlled to make the AlO X The temperature of the film and the N-type crystalline silicon substrate is 250°C.

[0076] test

[0077] Project 1: Testing the content of doping element P in the silicon doped layer and the passivation doped amorphous silicon film obtained in step 2 of Example 1. Figure 5 ,from Figure 5 It can be seen that after the HWCVD chamber decomposes PH3 in the undoped a-Si:H(i) and N-type crystalline silicon substrates, many activated doped P elements can be seen in the passivation doped amorphous silicon film and part of the silicon substrate. The maximum concentration of doped elements in the passivation doped amorphous silicon film can be higher than 1×10 19 / cm 3 These doping can effectively improve the field effect passivation of a-Si:H film. With the change of test depth, the content of doping elements in the passivation doped amorphous silicon film is between 1×10 16 / cm 3 ~1×10 20 / cm 3 In the range of 1×10 16 / cm 3 ~1×10 17 / cm 3 within the range.

[0078] Project 2: IV characteristics test was performed on the solar cells of Example 2, Example 3, Comparative Example 1 and Comparative Example 2. The test results are shown in Table 1.

[0079] Table 1

[0080]

[0081] It can be seen that the passivation doping method of the present application can improve the photoelectric conversion efficiency of the battery.

[0082] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0083] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A method for preparing a solar cell, characterized in that: The following steps are involved: forming a passivation film on a silicon substrate, wherein the passivation film comprises amorphous silicon; Decomposing a gas containing hydrogen and doping elements in a chemical vapor deposition chamber, allowing the decomposed active particles to act on the passivation film and the silicon substrate, doping hydrogen and doping elements into the passivation film to form a passivation doped film, and doping doping elements on a side of the silicon substrate close to the passivation film to form a silicon doping layer with a thickness of 1 nm to 50 nm, wherein the thickness of the silicon doping layer is less than the thickness of the silicon substrate; A TCO is formed on the passivation doped film.

2. The method for preparing a solar cell according to claim 1, characterized in that: Includes at least one of the following features: (1) The content of the doping element at any depth of the silicon doping layer is within 1×10 16 / cm 3 ~1×10 20 / cm 3 between; (2) The content of the doping element at any depth of the passivation doping film is within 1×10 16 / cm 3 ~1×10 20 / cm 3 between.

3. The method for preparing a solar cell according to claim 1, characterized in that: The doping element is selected from at least one of P, As, Sb, Bi, B, Al, Mg, Ga, In and Se.

4. The method for preparing a solar cell according to claim 1, characterized in that: The hydrogen content in the passivation doped film is 1 wt% to 30 wt%.

5. The method for preparing a solar cell according to any one of claims 1 to 4, characterized in that: The thickness of the passivation film is 1 nm to 15 nm.

6. The method for preparing a solar cell according to claim 5, characterized in that: The chemical vapor deposition chamber is provided by a hot wire chemical vapor deposition device or an inductively coupled chemical vapor deposition device.

7. The method for preparing a solar cell according to any one of claims 1 to 4, characterized in that: When the active particles act on the passivation film and the silicon substrate, the temperature of the passivation film and the silicon substrate is 25-250°C.

8. The method for preparing a solar cell according to any one of claims 1 to 4, characterized in that: The pressure of the chemical vapor deposition chamber is 0.01 mbar~1 mbar.

9. The method for preparing a solar cell according to any one of claims 1 to 4, characterized in that: The active particles act on the passivation film and the silicon substrate for 1 min to 15 min.

10. A solar cell, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 9.

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