Plasma Etching Techniques for Solar Cell Production

A method for preparing solar cells that enables efficient copper seed layer formation for gate electrode deposition. The method involves depositing a protective gas plasma in a controlled hydrogen environment to create a thin copper seed layer on a transparent conductive film, followed by a second copper layer deposition. This sequential process enables the formation of a uniform copper seed layer suitable for subsequent gate electrode deposition, significantly improving the efficiency and quality of solar cell fabrication.

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Plasma etching method using heptafluoropropyl methyl ether (HFE-347mcc3) and heptafluoroisopropyl methyl ether (HFE-347mmy) as etchant gases, achieving high aspect ratio etching while maintaining selectivity. The method employs a bias voltage-controlled plasma environment, where the etchant gas mixture is supplied to the plasma chamber along with argon gas. The HFE-347mcc3 and HFE-347mmy mixtures are vaporized and introduced into the plasma chamber, where they interact with the plasma to enhance etching performance. The etching process enables the formation of high-aspect-ratio structures through anisotropic etching, with improved selectivity compared to conventional fluorocarbon-based etching methods.

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A method for preparing solar cells that significantly enhances etching speed and reduces etching time for transparent conductive layers. The method employs a novel acid concentration strategy that maintains a controlled concentration of etching agents while achieving higher etching rates compared to conventional wet etching methods. The controlled acid concentration enables precise control over etching conditions, particularly for difficult-to-etch transparent conductive layers, while minimizing etching liquid usage and volatilization. The method enables rapid etching of transparent conductive layers, enabling faster solar cell production.

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Selective etching of silicon oxide films using a plasma etching process that combines a fluorocarbon gas with an oxidant like oxygen. The process employs a halogenated hydrocarbon gas and a C4F6O3 gas in a controlled ratio, with the fluorocarbon gas forming active species in the plasma while the oxidant provides reactive oxygen species. This dual-gas approach enables precise control of sidewall etch rates while maintaining selective etching of the silicon oxide film.

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Method to improve the efficiency of heterojunction solar cells by treating the intrinsic amorphous silicon (a-Si) layer with hydrogen plasma multiple times during deposition. After forming each layer of a-Si, hydrogen plasma treatment is performed before continuing with the next layer. This step is repeated multiple times during the deposition of the entire a-Si stack. The hydrogen plasma treatment improves carrier transport in the a-Si layers, which increases solar cell efficiency.

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Etching silicon-based films using a novel plasma-enhanced etching process that combines multiple etching cycles with plasma treatment. The process involves preparing a substrate with the target film, then repeatedly applying etchant gas followed by plasma treatment to expose the substrate. This approach enhances etch uniformity and surface quality by addressing the film's chemical and physical properties.

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Copper seed layer processing method and solar cell preparation method to improve the conductivity and tensile strength of copper electrode grid lines in solar cells. The method involves partially oxidizing the copper seed layer on the solar cell substrate before electroplating the copper grid lines. The oxidation is done using plasma treatment. This improves the contact between the copper grid and the seed layer, reducing defects and voids. It also reduces oxide formation during electroplating, which improves grid conductivity.

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Method to improve uniformity of plasma processing for semiconductor devices like solar cells. The method involves doping hydrogen gas into the plasma processing chamber during deposition of thin films like aluminum oxide. The hydrogen improves thickness uniformity of the deposited film across the wafer. It can be added as an auxiliary gas along with the reactant and carrier gases. The hydrogen can be in excited state provided by a remote plasma generator.

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A plasma etching method for high-aspect-ratio silicon structures using a fluorocarbon-free etchant. The method employs a mixed gas containing argon and 1,1,2,2-tetrafluoroethylenetriethanol as the etchant, which achieves superior etching characteristics compared to conventional perfluorocarbon-based etchants. The etchant is generated through a plasma process where the mixed gas is introduced into a plasma chamber containing an etchant source. The plasma etching process enables the formation of high-aspect-ratio structures with minimal fluorocarbon film deposition, while maintaining high etch rates and selectivity.

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Plasma etching method using pentafluoropropanol (PFP) with low global warming potential, replacing conventional perfluorocarbon (PFC) gas. The method employs a PFP/argon gas mixture in an etching chamber, where the PFP vaporizes and generates plasma. The plasma density is enhanced through electropositive Ar addition, enabling isotropic etching of target surfaces. The PFP/argon mixture maintains a controlled ratio of 2:3 to 1:9, ensuring optimal etching conditions for silicon oxide thin films.

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Selective plasma etching of silicon oxide films using a novel gas mixture that improves etch selectivity and prevents shoulder collapse in spacers. The method employs a fluorocarbon-hydrofluoric acid gas mixture for plasma etching, with specific ratios of fluorocarbon and hydrofluoric acid gases. The fluorocarbon gas enhances surface passivation, while the hydrofluoric acid gas selectively etches the silicon oxide film. The fluorocarbon-hydrofluoric acid gas mixture provides superior etch selectivity compared to conventional fluorocarbon-hydrofluoric acid gas mixtures, particularly in the critical shoulder region of spacers. This approach enables reliable etching of silicon oxide films without compromising spacer integrity.

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Enhancing the etching rate of silicon nitride films in plasma processing by combining iodine heptafluoride (IF7) plasma with an inert gas. The method utilizes a plasma generated by converting IF7 into plasma to etch the silicon nitride film simultaneously with the formation of a silicon oxide film. The IF7 plasma provides high etch rates for the silicon nitride, while the oxide film acts as a sacrificial mask. This approach enables simultaneous etching of both silicon nitride and silicon oxide films at elevated etch rates.

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Plasma etching method using a low-GWP etchant that enables high aspect ratio etching in semiconductor devices. The method employs a hydrofluoroether gas, HFE-347, with a global warming potential (GWP) lower than traditional perfluorocarbon (PFC) gases. The etchant is supplied in a mixed gas composition of 3:2 to 1:4 heptafluoroisopropyl methyl ether (CF3CH(CH2)2CH2OEt) and argon, with flow rates in the 9:1 to 7:3 ratio. The etchant selectively etches silicon oxide or silicon nitride structures with diameters greater than 10 times their depths, enabling the formation of high-aspect-ratio holes.

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Etching of silicon-based films using a novel plasma etching process that enhances selectivity through controlled fluorine incorporation. The process employs a temperature-controlled plasma etching environment where the substrate temperature is maintained below -40°C. This temperature condition enables the formation of a plasma containing hydrogen and fluorine, which selectively etches silicon-based films while selectively degrading fluorine-containing compounds. The plasma composition can be optimized to achieve improved selectivity between silicon oxide and silicon films.

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Plasma etching method using perfluoropropylcarbinol (PPC) as a low-GWP discharge gas for high-aspect-ratio silicon oxide structures. The method employs PPC as a precursor to form a stable gas phase, which enhances plasma density and surface chemistry. PPC vaporizes in the chamber, generating a stable PPC-argon mixture that enables efficient etching of silicon oxide thin films through enhanced ion bombardment. The PPC-argon mixture is optimized with a flow ratio of 2:3 to 1:9, maintaining optimal etching conditions for high-aspect-ratio etching.

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Plasma etching method using PIPVE (perfluoroisopropyl vinyl ether) with low global warming potential for high-aspect-ratio silicon etching. The method employs a PIPVE vaporizer followed by a discharge gas containing the vaporized PIPVE and argon. The plasma is generated by applying a bias voltage to the substrate, with the PIPVE serving as a precursor to fluorine-containing species. The plasma etches the target material through ion bombardment, resulting in anisotropic etching with improved selectivity and uniformity compared to conventional PFC-based etching.

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A novel etching method for photovoltaic cells that enables the removal of the silicon-arsenic (a-Si) transition layer through enhanced physical etching without replacing etching gases or equipment. The method employs reactive ion etching (RIE) with chlorine and sulfur hexafluoride as the etching gas, which generates reactive plasma that selectively targets and breaks through the transition layer. This approach addresses the conventional challenge of removing the transition layer through dry etching without damaging the underlying silicon.

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Method for optimizing heterojunction solar cells through controlled hydrogen plasma treatment during thin film deposition. The process involves plasma etching the intrinsic silicon layer before deposition of the conductive silicon layer, followed by hydrogen plasma treatment during film formation. This approach enables precise control over film thickness variations during deposition, which can lead to improved conversion characteristics and reduced batch-to-batch variability in solar cells.

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A method for achieving high-efficiency solar cells through a single-chamber process that eliminates interface contaminants. The method employs controlled plasma treatment of the photovoltaic unit's interface regions between layers, specifically the p-n junction interface. The treatment process selectively reacts with contaminants present at this interface, effectively removing them from the chamber while maintaining the unit's electrical performance. This approach enables the production of high-efficiency solar cells without the need for separate chamber cleaning steps, achieving comparable efficiency levels as conventional multi-chamber processes.

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Etching silicon-containing films using a plasma processing apparatus that employs a novel fluorine-based gas mixture. The apparatus generates plasma through a CF4-H2-IF6 mixture, which is supplemented with an additive gas containing fluorine. The CF4 component provides the base plasma, while the IF6 component enhances the etching process by reducing fluorine binding energy. This approach enables improved etching performance of silicon-containing films in plasma processing applications.

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Plasma-curing of light-receiving surfaces for solar cells enhances performance and stability through a novel fabrication process. The process involves growing a phosphorous-doped oxide layer and an anti-reflective coating (ARC) layer in a plasma-enhanced chemical vapor deposition (PECVD) tool. The ARC layer is formed directly on the phosphorous-doped oxide layer, eliminating the need for intermediate layers. Plasma-induced radiation during the ARC deposition process creates a protective layer that prevents hot electron injection across the interface, thereby reducing interface wear and degradation. The plasma-cured solar cell exhibits improved front surface field (FSF) performance, enhanced UV stability, and enhanced overall solar cell efficiency compared to conventional methods.

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A plasma etching method for multi-component materials that achieves uniform surface finish and controlled processing while maintaining low processing costs. The method employs controlled plasma generation conditions where the etching rates of each component material are matched, enabling consistent surface quality throughout the material. The plasma etching process is optimized for multi-component materials like RS-SiC, where conventional single-component etching approaches often result in uneven surface quality and processing issues. The controlled plasma conditions achieve uniform etching rates across all component materials while maintaining processing efficiency.

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A process for etching silicon wafers that combines a pretreatment step with an F2-containing gas etching process, enabling improved etch rates and reduced reflection characteristics in photovoltaic applications. The pretreatment step uses an HF-containing gas mixture to modify the silicon surface before etching with F2-containing gas, while the F2-containing gas etches the modified surface. This combined approach enables enhanced etch properties and reduced reflection characteristics compared to conventional F2-based etching methods.

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A plasma texturing method for crystalline solar cells that achieves improved surface roughness without the need for chlorine gas. The method employs a process gas mixture containing N2 (95-99%), NF3 (0.5-3%), O2 (0.2-1%), and H2 (0.2-1%) in a heated crystalline solar cell. The process gas is optimized to achieve the best reflectance at 600-1000 nm. When the H2 gas is discharged, it increases plasma density through electron excitation, effectively creating micro-textured surface features that enhance solar reflectance. This approach enables high-quality solar cell texturing without the need for traditional chlorine-based plasma processing.

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Safe and controllable RIE texturing process for solar silicon wafers that eliminates the need for hazardous gases like SF6 and 02. The process employs a unique pipeline system that provides both gas supply and SiCL4 for the reaction chamber, with the gas mixture ionized by plasma glow discharge. This configuration enables controlled reaction conditions while minimizing the need for hazardous chemicals.

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Method for manufacturing crystalline silicon-based solar cells with integrated intrinsic silicon and conductive silicon layers. The method involves plasma treatment of the intrinsic silicon layer to enhance passivation and interface quality, followed by the formation of conductive silicon layers. The plasma treatment introduces hydrogen gas during the intrinsic silicon layer formation, which is then used to passivate the surface while forming the intrinsic silicon layer. The conductive silicon layers are formed through conventional CVD processes. The plasma treatment process enables uniform film thickness control and passivation across the substrate, particularly in regions with high substrate density.

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Method for manufacturing high-efficiency heterojunction solar cells by optimizing hydrogen plasma treatment of intrinsic silicon films during CVD process. The method involves hydrogen plasma treatment of the intrinsic silicon film before forming the secondary intrinsic silicon film, followed by CVD formation of the secondary film at high hydrogen dilution ratios. This approach ensures uniform film thickness and quality across multiple batches, particularly beneficial in high-volume production where batch-to-batch variations are common. The hydrogen plasma treatment before film formation improves the intrinsic silicon film's passivation and interface quality, while the high hydrogen dilution ratio during secondary film formation enables precise control over film thickness.

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Selective etching of silicon oxide using a novel plasma etching gas that achieves high selectivity and short atmospheric lifetime. The gas contains fluorocarbons with 3-4 carbon atoms, containing bromine and/or ether bonds, with specific bromine-to-carbon and hydrogen-to-fluorine ratios. This gas enables precise control over etching selectivity and environmental performance compared to conventional fluorocarbons.

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Treatment of perovskite solar cells using water and oxygen plasma to enhance hole transport layer performance and improve perovskite layer crystallinity. The treatment involves applying low-temperature plasma discharge through water and oxygen, which rapidly addresses the perovskite photoactive layer's crystallization issues while maintaining hole transport layer functionality. The treatment enables significant improvements in open circuit voltage, short circuit current density, and efficiency stability, with the perovskite layer's crystallinity enhanced through controlled plasma processing.

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Dry etching process for crystalline silicon solar cells that utilizes a low-concentration alkali solution to remove damaged surface layers while preserving minority carrier lifetime. The process employs dry etching to create textured surface features, followed by a controlled removal of damaged regions using a low-concentration alkali solution to restore the surface structure. This approach enables the creation of textured surfaces while maintaining carrier lifetime through precise control over etching conditions.

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Improved surface treatment of hydrogenated amorphous silicon (h-Si:H) films in silicon heterojunction solar cells through a novel plasma-based approach. The treatment method combines hydrogen plasma cleaning with nitrogen or ammonia plasma treatment to enhance surface passivation and interface defect reduction. This approach addresses the limitations of traditional hydrogen plasma treatment alone by combining the physical cleaning capabilities of nitrogen or ammonia plasma with the chemical passivation capabilities of hydrogen plasma. The treatment enables effective removal of surface contaminants and saturation of dangling bonds, resulting in improved interface quality and reduced interface recombination.

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A plasma etching method and device that improves groove shape and deposition control in etching processes. The method employs a novel mask design with a specially optimized oxygen-COS-Cl2 gas plasma etching system that creates precise groove profiles. The mask features a tapered sidewall angle that enables controlled deposition of the etched film, while the etching process creates a uniform profile across the groove width. This approach addresses the conventional issue of vertical sidewall profiles in etching, particularly in silicon-based films, by promoting a controlled deposition pattern that naturally forms a cone-shaped profile.

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Plasma multi-tip nanostructured solar cells that enhance photocurrent through electromagnetic field enhancement of surface plasmons. The cells feature a composite structure layer comprising a multi-tip metal nanostructure and a light absorption layer, where the multi-tip structure is arranged in a nano-star or double-tower configuration. The composite layer is deposited on a substrate using surface evaporation, followed by the deposition of a positive electrode layer through vacuum evaporation of aluminum-doped zinc oxide. The multi-tip structure in the composite layer enhances light absorption and surface plasmon coupling, thereby increasing the solar cell's photoelectric conversion efficiency.

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Enhancing solar cell efficiency through surface modification of protective substrates using plasma treatment. The process involves introducing a plasma gas mixture containing fluorinated gases (CxFy) or hydrocarbons (CxHy) to create a polymer coating on the substrate surface. The plasma treatment creates a thin, hydrophobic polymer layer that reduces reflected light and enhances self-cleaning properties of the substrate. The treatment apparatus can be integrated into existing solar cell manufacturing processes, eliminating the need for substrate replacement.

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A method for producing high-efficiency solar cells using copper oxide (CuO) as the semiconductor material. The method involves a novel approach to CuO formation through controlled hydrogen plasma treatment of the copper substrate surface. The treatment, performed in a reduced-pressure plasma environment, selectively forms cuprous oxide (CuO) while preserving the copper substrate. This approach enables the formation of CuO layers with controlled composition and thickness, which are then used as the solar cell's semiconductor material. The treatment process eliminates the need for conventional oxidation steps, allowing for the formation of Schottky junctions between the CuO and copper layers. The resulting solar cells achieve high conversion efficiencies comparable to traditional silicon-based solar cells while maintaining the benefits of copper oxide as the semiconductor material.

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A plasma-based method for creating textured surfaces on aluminum-doped zinc oxide (AZO) thin-film solar cells. The method employs a controlled plasma etching process that combines physical etching with chemical reactions to achieve precise texture formation on AZO surfaces. The plasma generates active particles that physically etch the surface while chemically reacting with it, enabling the creation of textured patterns with controlled dimensions and uniformity. This approach enables high-precision texture control while minimizing environmental impact compared to traditional wet etching methods.

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Method for optimizing solar cell performance by controlling the interface between the rear electrode and light absorption layer in CZTS-based thin-film solar cells. The method employs plasma treatment of the rear electrode surface to suppress selenium diffusion, thereby enhancing interface quality and preventing electrical degradation. The plasma treatment is performed at controlled conditions (temperature and pressure) and duration, allowing precise control over the diffusion barrier formation. This approach enables the creation of high-quality light absorption layers while maintaining electrical performance characteristics.

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A process for improving the deposition of thin films in heterojunction solar cells by enhancing step coverage through a novel plasma-assisted atomic layer deposition (PAD) technique. The process involves depositing a first intrinsic amorphous germanium layer on the front surface of the solar cell, followed by a plasma-assisted PAD of an auxiliary P-type amorphous germanium layer on the front surface. This creates a P-type intrinsic amorphous germanium layer on the front surface, which is then followed by a plasma-assisted PAD of an N-type intrinsic amorphous germanium layer on the back surface. This multi-layered approach significantly improves the step coverage of subsequent film deposition steps in heterojunction solar cells.

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Etching photovoltaic solar cells using a novel alkaline-based approach that improves polishing efficiency and reduces environmental impact. The process involves removing the back surface of the silicon substrate through a pretreatment step, followed by etching using a potassium hydroxide solution. The alkaline solution enhances the etching process by creating a more uniform and controlled chemical environment, resulting in superior polishing characteristics that enhance long-wave absorption in photovoltaic cells.

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Vapor-phase etching and texturing of polycrystalline silicon wafers for solar cells using chemical reactions between corrosive gases and silicon. The method enables high-quality etching and texturing of polycrystalline silicon wafers through chemical reactions, achieving better than current mixed acid solution etching and superior anti-reflective properties. The process eliminates the need for expensive and complex RIE technology, while providing precise control over surface texture and anti-reflectivity.

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A plasma doping system for solar cells that achieves uniform doping across large areas without the need for specialized equipment like laser doped systems. The system employs a plasma source that generates atmospheric pressure plasma through corona discharge, which is then directed towards the solar cell wafer through a specially designed electrode structure. The plasma is generated by a power supply unit that provides a controlled DC voltage, while the electrode structure is designed to maintain a stable plasma environment. The system eliminates the need for high-temperature furnaces and laser equipment, while maintaining high doping rates and uniformity.

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Atmospheric pressure plasma selective doping system for solar cells enabling selective doping without laser or vacuum equipment. The system uses a power supply with a built-in gas distribution unit, a selective plasma generator with metal electrodes, and a tray for transferring solar cells. The generator applies corona discharge to selectively dope solar cells by generating a plasma jet through uniform gas distribution and precise electrode positioning.

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Low-temperature plasma treatment of fluorine-based polymer films for enhanced solar cell performance. The treatment creates a fluorinated surface layer with improved adhesion, water vapor barrier, and chemical resistance properties, while maintaining the film's mechanical integrity. The treatment achieves superior performance characteristics compared to conventional backsheet materials, including enhanced electrical insulation, weather resistance, and chemical resistance, with a specific focus on the backsheet layer.

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A plasma etching method for creating wide conductive patterns on substrates using plasma-induced energy sources. The method employs a controlled plasma exposure angle between 5° and 85° relative to the substrate surface, enabling the etching of larger areas per unit energy compared to conventional methods. This approach enables the creation of complex patterns on substrates like glass substrates with high transparency, while maintaining the film's electrical conductivity. The method can be applied to various conductive films including transparent conductive oxides (TCOs) and metal oxides.

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A method for enhancing solar cell efficiency through controlled etching of crystalline silicon substrates using microwave-assisted vapor etching. The process involves generating steam vapor through microwave heating, which is then used to vaporize etching solution containing nitric acid and hydrofluoric acid. The vaporized solution is directed through silicon fluoride membranes to etch the substrate surface, creating a thin film that enhances reflectance reduction and doping efficiency. The process enables precise control over etching conditions through microwave vapor generation, allowing for optimized etching parameters while minimizing solution waste.

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Laser etching method for thin-film solar cells that enables both power generation and light transmission. The method employs a 532nm laser that passes through the glass substrate and front electrode, creating precise lines on the semiconductor layer and back electrode. This enables the formation of multiple sub-cells with both electrical functionality and optical transparency, meeting the requirements of building-integrated photovoltaic (BIPV) systems.

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High-efficiency solar cells produced through plasma-enhanced chemical vapor deposition (PECVD) at high deposition rates achieve improved performance without compromising deposition energy. The process enables rapid deposition of photovoltaic layers while maintaining high deposition rates, typically above 3 angstroms per second. Annealing at elevated temperatures (155-250°C) between 5-10 minutes enhances defect reduction and electrical conductivity in the solar cells, resulting in higher efficiency compared to conventional PECVD methods. The annealing process specifically targets error zones adjacent to contact areas, creating conductive pathways. The combination of high deposition rates and optimized annealing conditions enables the production of high-efficiency solar cells using cost-effective deposition tools.

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A method for silicon wafer solar cell fabrication that integrates parasitic junction removal and emitter etch-back into a single process. The method employs a KOH—NaOCl solution for both etch-back and polishing, which simultaneously removes parasitic junctions while maintaining conformal etch-back on doped surfaces and non-conformal polishing on undoped surfaces. This integrated solution enables a streamlined process sequence with only four steps, including parasitic junction removal, emitter etch-back, polishing, and rear-side processing.

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Plasma etching of boron-doped amorphous carbon (BAC) using a mixed gas plasma system. The method employs a chlorine-oxygen gas plasma with elevated temperature (100°C) and specific pressure conditions to selectively etch BAC, while maintaining high selectivity. The plasma chemistry is optimized to prevent sidewall damage during etching, particularly at the interface with the silicon oxide layer. The etching process can be controlled through adjustments in oxygen supply and pressure, enabling controlled etching rates while maintaining selectivity.

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A method to enhance solar cell efficiency through controlled surface passivation and anti-reflective coating. The method involves selectively removing the existing dielectric passivation layer from the solar cell surface, either through localized plasma etching or controlled oxidation, before applying the anti-reflective layer. This creates a surface interface between the silicon substrate and the anti-reflective coating that is inherently less prone to charge accumulation and degradation. The selective removal of the existing passivation layer enables the formation of a uniform, controlled anti-reflective coating that enhances solar cell efficiency without compromising device performance.

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