Preparation method of microcrystalline silica film layer, heterojunction solar cell and preparation method of heterojunction solar cell
By combining high-frequency and very high-frequency RF frequency in the PECVD process cavity to control the process gas composition and flow rate, the problems of denseness and dark decay of the microcrystalline silicon oxide film layer are solved, and the stability of film formation and heterojunction battery efficiency of high-quality film layers is achieved.
Patent Information
- Application Number
- CN202411886540.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-20
- Publication Date
- 2025-04-15
AI Technical Summary
In the prior art, the microcrystalline silicon oxygen film layer is not dense enough due to the high CO2 flow during the production process, and there are holes and defects, which are easily invaded by oxygen in air or water vapor, resulting in decay of the film layer performance and the photoelectric conversion efficiency of heterojunction batteries, resulting in dark decay.
By setting the high-frequency and VHF RF frequency in the PECVD process cavity, combined with appropriate high-frequency and VHF power, the process gas composition and flow rate, including SiH4, H2, PH3 and CO2, ensure that the volume ratio of PH3 to SiH4 is between 1% and 10% and the volume ratio of CO2 to SiH4 is between 20% and 100% to form a high-quality microcrystalline silicon oxide film layer.
It effectively improves the film formation quality of the microcrystalline silicon oxygen film layer, reduces pores and defect states, reduces dark decay phenomenon, and significantly improves the photoelectric conversion efficiency stability of heterojunction solar cells.
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Figure CN119824397A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of photovoltaic manufacturing, and in particular to a method for preparing a microcrystalline silicon oxygen film layer, a heterojunction solar cell and a method for preparing the same. Background Art
[0002] Heterojunction cells use microcrystalline silicon oxygen film as the cell window layer structure, which helps to increase the optical band gap of the microcrystalline N layer, enhance light transmittance, and improve the current and photoelectric conversion efficiency of the cell. At present, the industry's microcrystalline silicon oxygen film usually uses very high frequency (including 27M, 40M and 60MHZ) to increase the deposition rate of microcrystalline N. The higher the frequency, the faster the electron oscillation, the higher the plasma concentration, and the faster the deposition rate. In the process of making microcrystalline silicon oxygen film, CO2 is usually used as a source of oxygen. Usually, as the CO2 flow rate increases, the light transmittance increases, and the cell efficiency increases. However, too high a CO2 flow rate will cause the film to be not dense enough, with holes and defect states, and the film quality is poor, which is easily invaded by oxygen in the air or water vapor. The invasion of oxygen will cause the film performance to decay, thereby causing the photoelectric conversion efficiency of the heterojunction cell to decrease. This phenomenon of increasing efficiency decline over time is called dark decay.
[0003] Therefore, how to provide a method for preparing a microcrystalline silicon oxide film layer, a heterojunction solar cell and a preparation method thereof to improve the film forming quality of the microcrystalline silicon oxide film layer and effectively improve the dark decay phenomenon has become a technical problem that needs to be solved urgently in the industry. Summary of the invention
[0004] In view of the above problems in the prior art, the present invention proposes a method for preparing a microcrystalline silicon oxide film layer, comprising the following steps:
[0005] The single crystal silicon wafer on which the intrinsic amorphous silicon is deposited is fed into the PECVD process chamber;
[0006] The PECVD process chamber is evacuated and its pressure is stabilized at 1-10 mbar;
[0007] The RF frequency input into the PECVD process chamber is set to two frequencies, high frequency and very high frequency, the input high frequency power is set to 50-2500 watts, and the input very high frequency power is set to 2000-10000 watts;
[0008] Stabilize the temperature of the PECVD process chamber at 160-230 degrees Celsius;
[0009] Introducing process gas into the PECVD process chamber, wherein the process gas includes SiH4, H2, PH3 and CO2, wherein the volume ratio of PH3 to SiH4 is 1%-10%, and the volume ratio of CO2 to SiH4 is 20%-100%; and
[0010] A microcrystalline silicon oxide film layer with a predetermined thickness is deposited on the intrinsic amorphous silicon surface of the single crystal silicon wafer over a predetermined deposition time.
[0011] In one embodiment, the ratio of O element to Si element in the microcrystalline silicon oxide film is 5-80%.
[0012] In one embodiment, the flow rate range of SiH4 in the process gas is 100 sccm-1000 sccm, the flow rate range of H2 is 20000 sccm-300000 sccm, the flow rate range of PH3 is 10 sccm-100 sccm, and the flow rate range of CO2 is 20 sccm-1000 sccm.
[0013] In one embodiment, the volume ratio of PH3 to SiH4 is 3%-8%, the volume ratio of CO2 to SiH4 is 60%-80%, and the volume ratio of H2 to SiH4 is 180-250.
[0014] In one embodiment, the pressure for depositing the microcrystalline silicon oxide film is 3-8 mbar, the predetermined deposition time is 100-400 seconds, the deposition temperature is 180-220 degrees Celsius, and the predetermined thickness is 10-30 nanometers.
[0015] In one embodiment, the deposition rate of the microcrystalline silicon oxide film is The crystallization rate of the microcrystalline silicon oxide thin film layer is between 20% and 60%.
[0016] In one embodiment, the very high frequency includes 27 MHz, 40 MHZ and 60 MHZ, and the high frequency includes 2 MHz and 13.56 MHz.
[0017] In one embodiment, the microcrystalline silicon oxide thin film is deposited on the light incident side of the heterojunction solar cell made of the single crystal silicon wafer.
[0018] The present invention also provides a method for preparing a silicon-based heterojunction solar cell, including the method for preparing the above-mentioned microcrystalline silicon oxygen film layer.
[0019] The present invention also provides a silicon-based heterojunction solar cell, comprising a single crystal silicon wafer, and also comprising a first intrinsic amorphous silicon layer, a microcrystalline silicon oxide film layer, a first transparent conductive film and a first electrode formed in sequence on the light incident surface of the single crystal silicon wafer, and also comprising a second intrinsic amorphous silicon layer, a P-type microcrystalline silicon thin film layer, a second transparent conductive film and a second electrode formed in sequence on the backlight surface of the single crystal silicon wafer, characterized in that the microcrystalline silicon oxide film layer is formed by any of the above-mentioned methods for preparing the microcrystalline silicon oxide film layer.
[0020] Compared with the prior art which uses very high frequency and has too high oxygen concentration, resulting in holes and defective film quality in the microcrystalline silicon oxygen film layer, which is easy to produce dark decay phenomenon, the preparation method of the microcrystalline silicon oxygen film layer of the present invention firstly sends a single crystal silicon wafer deposited with intrinsic amorphous silicon into a PECVD process chamber; then evacuates the PECVD process chamber and stabilizes its pressure at 1-10 mbar; then sets the RF frequency input to the PECVD process chamber to two frequencies, high frequency and very high frequency, and sets the input high frequency power to 50-2500 watts. The input VHF power is set to 2000-10000 watts; then the temperature of the PECVD process chamber is stabilized at 160-230 degrees Celsius; then process gas is introduced into the PECVD process chamber, the process gas includes SiH4, H2, PH3 and CO2, wherein the volume ratio of PH3 to SiH4 is 1%-10%, and the volume ratio of CO2 to SiH4 is 20%-100%, and finally a microcrystalline silicon oxygen film layer of a predetermined thickness is deposited on the intrinsic amorphous silicon surface of the single crystal silicon wafer after a predetermined deposition time. The present invention can effectively improve the film quality of the microcrystalline silicon oxygen film layer and effectively improve the dark decay phenomenon. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The above features and advantages of the present invention can be better understood after reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings. In the drawings, the components are not necessarily drawn to scale, and components with similar related properties or features may have the same or similar reference numerals.
[0022] Figure 1 It is a schematic diagram of the composition structure of an embodiment of the method for preparing a microcrystalline silicon oxide film layer of the present invention. DETAILED DESCRIPTION
[0023] The following specific embodiments illustrate the implementation of the present invention, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this implementation. On the contrary, the purpose of introducing the invention in conjunction with the implementation is to cover other options or modifications that may be extended based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will include many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description.
[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0025] In addition, the terms "upper", "lower", "left", "right", "top", "bottom", "horizontal" and "vertical" used in the following description should be understood as the directions shown in the paragraph and the related drawings. Such relative terms are only used for the convenience of description and do not mean that the device described therein must be manufactured or operated in a specific direction, and therefore should not be understood as limiting the present invention.
[0026] It is understood that although the terms "first", "second", "third", etc. may be used herein to describe various components, regions, layers and / or parts, these components, regions, layers and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers and / or parts. Therefore, the first component, region, layer and / or part discussed below may be referred to as a second component, region, layer and / or part without departing from some embodiments of the present invention.
[0027] See also Figure 1 , which is a schematic diagram of the process of preparing the microcrystalline silicon oxide film layer of the present invention. Figure 1 As shown, the method for preparing the microcrystalline silicon oxide film layer first performs step S100, where a single crystal silicon wafer deposited with intrinsic amorphous silicon is introduced into a PECVD process chamber.
[0028] Then proceed to step S110 to evacuate the PECVD process chamber and stabilize its pressure at 1-10 mbar.
[0029] Then proceed to step S120, set the RF frequency input to the PECVD process chamber to high frequency and very high frequency, set the input high frequency power to 50-2500 watts, and set the input very high frequency power to 2000-10000 watts. The very high frequency includes 27 MHZ, 40 MHZ and 60 MHZ, and the high frequency includes 2 MHz and 13.56 MHz. The input high frequency and very high frequency are input to the same PECVD process chamber after a matcher, and frequency mixing is achieved in the PECVD process chamber.
[0030] Then proceed to step S130 to stabilize the temperature of the PECVD process chamber at 160-230 degrees Celsius.
[0031] Then proceed to step S140, introducing process gas into the PECVD process chamber, wherein the process gas includes SiH4, H2, PH3 and CO2, wherein the volume ratio of PH3 to SiH4 is 1%-10%, and the volume ratio of CO2 to SiH4 is 20%-100%.
[0032] The flow rate of SiH4 in the process gas ranges from 100sccm to 1000sccm, the flow rate of H2 ranges from 20000sccm to 300000sccm, the flow rate of PH3 ranges from 10sccm to 100sccm, and the flow rate of CO2 ranges from 20sccm to 1000sccm. The volume ratio of PH3 to SiH4 is 3% to 8%, the volume ratio of CO2 to SiH4 is 60% to 80%, and the volume ratio of H2 to SiH4 is 180-250.
[0033] Then proceed to step S150, depositing a microcrystalline silicon oxide film layer of a predetermined thickness on the intrinsic amorphous silicon surface of the single crystal silicon wafer after a predetermined deposition time. The microcrystalline silicon oxide film layer is deposited on the light-incident side of the heterojunction solar cell made of the single crystal silicon wafer. The pressure for depositing the microcrystalline silicon oxide film layer is 3-8 millibars (mbar), the predetermined deposition time is 100-400 seconds (s), the deposition temperature is 180-220 degrees Celsius (℃), and the predetermined thickness is 10-30 nanometers (nm). The ratio of O element to Si element in the microcrystalline silicon oxide film layer is 5-80%. The deposition rate for depositing the microcrystalline silicon oxide film layer is The crystallization rate of the microcrystalline silicon oxide film layer is between 20% and 60%.
[0034] When 40MHZ is selected for VHF and 13.56MHz is selected for HF, the mechanism of mixed frequency is as follows: 40MHZ is used as the main working frequency to form a high-concentration plasma and quickly deposit a microcrystalline silicon oxide film layer; 13.56MHz is used as an auxiliary working frequency, which is mainly used to bombard the film during the film formation process, reduce the voids inside the film, and form a dense microcrystalline silicon oxide film layer. The combination of 13.56MHz and 40MHZ can deposit a dense, high-quality microcrystalline silicon oxide film layer quickly. The dense, high-quality microcrystalline silicon oxide film layer can block the erosion of water vapor in the atmosphere and reduce the dark decay caused by high CO2 flow.
[0035] First embodiment:
[0036] The preparation method of the microcrystalline silicon oxide film layer in this embodiment firstly sends a single crystal silicon wafer deposited with intrinsic amorphous silicon into a PECVD process chamber; then the PECVD process chamber is evacuated and its pressure is stabilized at 3-8 mbar; then the RF frequency input to the RF electrode in the PECVD process chamber is set to two frequencies of 40 MHZ and 13.56 MHz, the input high frequency power is set to 50-2500 watts, and the input very high frequency power is set to 2000-10000 watts; then the temperature of the PECVD process chamber is stabilized at 200-220 degrees Celsius; then process gas is introduced into the PECVD process chamber, and the process gas includes SiH4, H2, PH3 and CO2, wherein the volume ratio of PH3 to SiH4 is 3%-8%, and the volume ratio of CO2 to SiH4 is 200-2500 watts. The volume ratio of H2 to SiH4 is 60%, the volume ratio of H2 to SiH4 is 180-250, the flow rate range of SiH4 in the process gas is 500sccm-1000sccm, the flow rate range of H2 is 60000sccm-80000sccm, the flow rate range of PH3 is 50sccm-100sccm, and the flow rate range of CO2 is 150sccm-300sccm; finally, a microcrystalline silicon oxygen film layer of a predetermined thickness is deposited on the intrinsic amorphous silicon surface of the single crystal silicon wafer after a predetermined deposition time, the ratio of O element to Si element in the microcrystalline silicon oxygen film layer is 5-80%, the predetermined deposition time is 300 seconds, the deposition temperature is 200-220 degrees Celsius, the thickness of the deposited microcrystalline silicon oxygen film layer is 20-30 nanometers, and the deposition rate of the deposited microcrystalline silicon oxygen film layer is The crystallization rate of the microcrystalline silicon oxide film layer is between 20% and 60%.
[0037] The efficiency attenuation of the heterojunction solar cell formed by the first embodiment after 720 hours is only 0.4%, which is significantly improved compared with the efficiency attenuation of 1% of the heterojunction solar cell in the prior art with the RF frequency set to 40 MHZ after 720 hours.
[0038] Second embodiment:
[0039] The preparation method of the microcrystalline silicon oxide film layer in this embodiment firstly sends a single crystal silicon wafer deposited with intrinsic amorphous silicon into a PECVD process chamber; then the PECVD process chamber is evacuated and its pressure is stabilized at 3-8 mbar; then the RF frequency input to the RF electrode in the PECVD process chamber is set to two frequencies of 40MHZ and 13.56MHz, the input high frequency power is set to 50-2500 watts, and the input very high frequency power is set to 2000-10000 watts; then the temperature of the PECVD process chamber is stabilized at 200-220 degrees Celsius; then process gas is introduced into the PECVD process chamber, and the process gas includes SiH4, H2, PH3 and CO2, wherein the volume ratio of PH3 to SiH4 is 3%-8%, and the volume ratio of CO2 to SiH4 is 2.5%. The volume ratio is 100%, the volume ratio of H2 to SiH4 is 180-250, the flow rate range of SiH4 in the process gas is 500sccm-1000sccm, the flow rate range of H2 is 60000sccm-80000sccm, the flow rate range of PH3 is 50sccm-100sccm, and the flow rate range of CO2 is 175sccm-350sccm; then, a microcrystalline silicon oxide film layer of a predetermined thickness is deposited on the intrinsic amorphous silicon surface of the single crystal silicon wafer after a predetermined deposition time, the ratio of O element to Si element in the microcrystalline silicon oxide film layer is 5-80%, the predetermined deposition time is 300 seconds, the deposition temperature is 200-220 degrees Celsius, the thickness of the deposited microcrystalline silicon oxide film layer is 20-30 nanometers, and the deposition rate of the deposited microcrystalline silicon oxide film layer is The crystallization rate of the microcrystalline silicon oxide film layer is between 20% and 60%.
[0040] The efficiency attenuation of the heterojunction solar cell formed by the second embodiment after being placed for 720 hours is only 0.44%, which is significantly improved compared with the efficiency attenuation of 2% of the heterojunction solar cell in the prior art after being placed for 720 hours.
[0041] The present invention also provides a method for preparing a silicon-based heterojunction solar cell, comprising: Figure 1 The preparation method of the microcrystalline silicon oxygen film layer.
[0042] The present invention further provides a silicon-based heterojunction solar cell, comprising a single-crystal silicon wafer, a first intrinsic amorphous silicon layer, a microcrystalline silicon oxide film layer, a first transparent conductive film and a first electrode formed in sequence on a light-incident surface of the single-crystal silicon wafer, and a second intrinsic amorphous silicon layer, a P-type microcrystalline silicon thin film layer, a second transparent conductive film and a second electrode formed in sequence on a backlight surface of the single-crystal silicon wafer, wherein the microcrystalline silicon oxide film layer is formed by Figure 1 The microcrystalline silicon oxide film layer is formed by the preparation method.
[0043] In summary, the preparation method of the microcrystalline silicon oxide film layer of the present invention firstly sends a single crystal silicon wafer deposited with intrinsic amorphous silicon into a PECVD process chamber; then the PECVD process chamber is evacuated and its pressure is stabilized at 1-10 mbar; then the RF frequency input into the PECVD process chamber is set to two frequencies, high frequency and very high frequency, the input high frequency power is set to 50-2500 watts, and the input very high frequency power is set to 2000-10000 watts; then the temperature of the PECVD process chamber is stabilized at 160-230 degrees Celsius; then process gas is introduced into the PECVD process chamber, the process gas includes SiH4, H2, PH3 and CO2, wherein the volume ratio of PH3 to SiH4 is 1%-10%, and the volume ratio of CO2 to SiH4 is 20%-100%, and finally a microcrystalline silicon oxide film layer of a predetermined thickness is deposited on the intrinsic amorphous silicon surface of the single crystal silicon wafer after a predetermined deposition time. The present invention can effectively improve the film-forming quality of the microcrystalline silicon oxide film layer and effectively improve the dark decay phenomenon.
[0044] The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to those skilled in the art, and the universal principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein. The above embodiments are provided to persons familiar with the art to implement or use the present invention, and persons familiar with the art may make various modifications or changes to the above embodiments without departing from the inventive concept of the present invention, and thus the scope of protection of the present invention is not limited by the above embodiments, but should be the maximum scope of the innovative features mentioned in the claims.
Claims
1. A method for preparing a microcrystalline silicon oxide film layer, characterized in that: The following steps are involved: The single crystal silicon wafer on which the intrinsic amorphous silicon is deposited is fed into the PECVD process chamber; The PECVD process chamber is evacuated and its pressure is stabilized at 1-10 mbar; The RF frequency input into the PECVD process chamber is set to two frequencies, high frequency and very high frequency, the input high frequency power is set to 50-2500 watts, and the input very high frequency power is set to 2000-10000 watts; Stabilize the temperature of the PECVD process chamber at 160-230 degrees Celsius; Introducing process gas into the PECVD process chamber, wherein the process gas includes SiH4, H2, PH3 and CO2, wherein the volume ratio of PH3 to SiH4 is 1%-10%, and the volume ratio of CO2 to SiH4 is 20%-100%; as well as A microcrystalline silicon oxide film layer with a predetermined thickness is deposited on the intrinsic amorphous silicon surface of the single crystal silicon wafer after a predetermined deposition time.
2. The method for preparing a microcrystalline silicon oxide film layer according to claim 1, characterized in that: The ratio of O element to Si element in the microcrystalline silicon oxide film is 5-80%.
3. The method for preparing a microcrystalline silicon oxide film layer according to claim 1 or 2, characterized in that: The flow range of SiH4 in the process gas is 100 sccm-1000 sccm, the flow range of H2 is 20000 sccm-300000 sccm, the flow range of PH3 is 10 sccm-100 sccm, and the flow range of CO2 is 20 sccm-1000 sccm.
4. The method for preparing a microcrystalline silicon oxide film layer according to claim 3, characterized in that: The volume ratio of PH3 to SiH4 is 3%-8%, the volume ratio of CO2 to SiH4 is 60%-80%, and the volume ratio of H2 to SiH4 is 180-250.
5. The method for preparing a microcrystalline silicon oxide film layer according to claim 3 or 4, characterized in that: The pressure for depositing the microcrystalline silicon oxide film is 3-8 mbar, the predetermined deposition time is 100-400 seconds, the deposition temperature is 180-220 degrees Celsius, and the predetermined thickness is 10-30 nanometers.
6. The method for preparing a microcrystalline silicon oxide film layer according to claim 3 or 4, characterized in that: The deposition rate of the microcrystalline silicon oxide film is The crystallization rate of the microcrystalline silicon oxide thin film layer is between 20% and 60%.
7. The method for preparing a microcrystalline silicon oxide film layer according to claim 3 or 4, characterized in that: The very high frequency includes 27 MHZ, 40 MHZ and 60 MHZ, and the high frequency includes 2 MHz and 13.56 MHz.
8. The method for preparing a microcrystalline silicon oxide film layer according to claim 1 or 2, characterized in that: The microcrystalline silicon oxide thin film is deposited on the light incident side of the heterojunction solar cell made of the single crystal silicon wafer.
9. A method for preparing a silicon-based heterojunction solar cell, characterized in that: A method for preparing a microcrystalline silicon oxide film layer comprising the steps of any one of claims 1 to 8.
10. A silicon-based heterojunction solar cell, comprising a single crystal silicon wafer, and further comprising a first intrinsic amorphous silicon layer, a microcrystalline silicon oxide film layer, a first transparent conductive film and a first electrode formed in sequence on a light incident surface of the single crystal silicon wafer, and further comprising a second intrinsic amorphous silicon layer, a P-type microcrystalline silicon thin film layer, a second transparent conductive film and a second electrode formed in sequence on a backlight surface of the single crystal silicon wafer, characterized in that: The microcrystalline silicon oxide film layer is formed by the method for preparing a microcrystalline silicon oxide film layer according to any one of claims 1 to 8.