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Deposition of Organosilicon-Plasma Coating onto Fine Graphite Micropowder with a Downstream Tubular PECVD Reactor
摘要： Fine graphite micropowder was processed in a downstream tubular reactor to perform a fast and homogeneous plasma-enhanced chemical vapor deposition of an organosilicon-plasma coating onto the powder surface. As a single process run results in the deposition of a non-continuous coating, consisting of a nanoparticle distribution, on the powder surface, the powder was repeatedly reprocessed until a continuous coating was obtained. The coating was imaged with focused ion-beam scanning electron microscopy and chemically characterized with Raman spectroscopy and X-ray photoelectron spectroscopy. The assessment of the powder flowability was also performed to investigate the roughness of the coated surface. The chemical characterization indicated that the coating is composed of amorphous hydrogenated silicon carbide with a little oxygen contamination.
关键词： PECVD,FIB-SEM,Micropowders,XPS
更新于2025-11-21 11:20:42
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Dependence of Mechanical Stresses in Silicon Nitride Films on the Mode of Plasma-Enhanced Chemical Vapor Deposition
摘要： Films of silicon nitride SiNx, obtained by plasma-enhanced chemical vapor deposition from the monosilane SiH4 and ammonia NH3 gases, are widely used in microelectronics and micro- and nanoelectromechanical systems. Residual mechanical stresses and film composition are important characteristics for many applications. The properties of SiNx films, particularly mechanical stresses and composition, depend largely on the conditions of production, e.g., the ratio of the reacting gas flow rates, the composition of the gas mixture, the power and frequency of the plasma generator, and the temperature and pressure during deposition. Despite the great volume of works on the subject, data regarding the dependence of the properties and composition of SiNx films on the conditions of production remain sparse. This work considers the effect the ratio of the reacting gas flow rates has on the mechanical stresses and composition of silicon nitride films SiNx obtained by plasma-enhanced chemical vapor deposition from gaseous mixtures of SiH4 monosilane and NH3 ammonia using low-frequency plasma. It is found that when the ratio of the gas flow rates of SiH4 and NH3 is raised from 0.016 to 0.25, the compressive mechanical stresses are reduced by 31%, the stoichiometric coefficient falls from 1.40 to 1.20, the refractive index rises from 1.91 to 2.08, the concentration of N–H bonds is reduced by a factor of 7.4, the concentration of Si–H bonds grows by a factor of 8.7, and the concentration of hydrogen atoms is reduced by a factor of 1.5. These results can be used for the controlled production of SiNx films with such specified characteristics as residual mechanical stresses, refractive index, stoichiometric coefficient, and the concentration of hydrogen-containing bonds.
关键词： mechanical stresses,optical profilometry,films of PECVD silicon nitride SiNx,IR Fourier spectroscopy
更新于2025-11-14 15:18:02
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Rapid Thermal Process for Crystallization Silicon Nitride Films
摘要： Synthesis and characterisation of silicon nanocrystals (Si NCs) materials are carried out. We investigated the morphological and structural Si NCs embedded in the silicon nitride (SiNx) matrix. The study has been carried out on thin ?lms thermally annealed at high temperature by rapid thermal annealing after deposition at 380°C by plasma-enhanced chemical vapour deposition. Our study evidenced the existence of an Si NCs embedded on the SiNx matrix. This has been proven by Raman spectra and high-resolution transmission electron microscopy (HR-TEM). A sharp peak at a frequency of 515 cm?1 ascribed to the transverse optical (TO) mode becomes broader and makes a symmetric shoulder on the higher frequency side with an increase in the annealing temperature. HR-TEM analyses have demonstrated that Si NCs having a mean radius ranging between 3 and 5 nm. This con?rms the a-SiN phase transition to the c-SiN phase by the formation of silicon NCs.
关键词： SiNx,RTA,PECVD,Si NCs
更新于2025-09-23 15:23:52
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AlGaN/GaN MIS-HEMT with PECVD SiNx, SiON, SiO2 as Gate Dielectric and Passivation Layer
摘要： Three different insulator layers SiNx, SiON, and SiO2 were used as a gate dielectric and passivation layer in AlGaN/GaN metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMT). The SiNx, SiON, and SiO2 were deposited by a plasma-enhanced chemical vapor deposition (PECVD) system. Great differences in the gate leakage current, breakdown voltage, interface traps, and current collapse were observed. The SiON MIS-HEMT exhibited the highest breakdown voltage and Ion/Ioff ratio. The SiNx MIS-HEMT performed well in current collapse but exhibited the highest gate leakage current density. The SiO2 MIS-HEMT possessed the lowest gate leakage current density but suffered from the early breakdown of the metal–insulator–semiconductor (MIS) diode. As for interface traps, the SiNx MIS-HEMT has the largest shallow trap density and the lowest deep trap density. The SiO2 MIS-HEMT has the largest deep trap density. The factors causing current collapse were confirmed by Photoluminescence (PL) spectra. Based on the direct current (DC) characteristics, SiNx and SiON both have advantages and disadvantages.
关键词： interface traps,MISHEMT,gallium nitride,PECVD,current collapse,dielectric layer
更新于2025-09-23 15:22:29
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Structural characterization and emission properties of phosphorus-doped NCD films
摘要： Phosphorus-doped NCD films were grown on n-type silicon substrate by plasma-enhanced CVD with H2, CH4, and PH3 gas mixture for cold cathode application. The structure properties were characterized by Raman spectroscopy with a green laser of 532 nm at room temperature, scanning electron microscope, transmission electron microscope, and electron energy-less spectroscopy. Grown films show a good conductivity and have a typical structure with a combination of sp3 diamond gains with size around 20-100 nm and sp2 grain boundaries. The electron emission properties were characterized as comparing with single crystal, NCD film, and tip-array NCD. The tip-array NCD shows good emission properties with lower threshold electric filed and higher saturation current.
关键词： Structural characterization,Nano crystal diamond (NCD),PECVD,electron emitter,Phosphorus doping
更新于2025-09-23 15:21:21
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Deposition of boron-doped nanocrystalline silicon carbide thin films using H2-Ar mixed dilution for the application on thin film solar cells
摘要： Hydrogen-argon mixed dilution has been applied for the deposition of boron-doped nanocrystalline silicon carbide (nc-SiCx) thin films. The variations of structural, compositional, electrical and optical properties with the varying H2/Ar ratio are systemically investigated through various characterizations. It is shown that by using H2-Ar mixed dilution for deposition, B-doped nc-SiCx thin film possessing both wide optical band gap (~2.22 eV) and high conductivity (~1.9 S/cm) can be obtained at the H2/Ar flow ratio of 360/140. In addition, the B-doped nc-SiCx thin films are fabricated as the window layers of a-Si thin film solar cells, and the highest conversion efficiency (8.13%) is obtained when applying the window layer with the largest optical band gap energy.
关键词： PECVD,solar cell,B-doping,thin film,silicon carbide
更新于2025-09-23 15:21:01
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Insights into the Role of Plasma in Atmospheric Pressure Chemical Vapor Deposition of Titanium Dioxide Thin Films
摘要： In this work, the effect of plasma on the chemistry and morphology of coatings deposited by Atmospheric Pressure Plasma Enhanced Chemical Vapor Deposition (AP-PECVD) is investigated. To do so, plasma deposited amorphous titanium dioxide (TiO2) thin films are compared to thin films deposited using Atmospheric Pressure Chemical Vapor Deposition (AP-CVD) not involving the use of plasma. We focus here on the effect and the interest of plasma in the AP-PECVD process over AP-CVD for low substrate temperature deposition. The advantages of AP-PECVD over AP-CVD are often suggested in many articles however no direct evidence of the role of the plasma for TiO2 deposition at atmospheric pressure was reported. Hence, herein, the deposition via both methods is directly compared by depositing coatings with and without plasma using the same CVD reactor. Through the control of the plasma parameters, we are able to form low carbon coatings at low temperature with a deposition rate twice faster than AP-CVD, clearly showing the interest of plasma. Plasma enhanced methods are promising for the deposition of coatings at industrial scale over large surface and at high rate.
关键词： AP-PECVD,TiO2 thin films,Atmospheric Pressure Chemical Vapor Deposition,Atmospheric Pressure Plasma Enhanced Chemical Vapor Deposition,plasma,AP-CVD,low substrate temperature deposition
更新于2025-09-23 15:21:01
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Protective Properties of a Microstructure Composed of Barrier Nanostructured Organics and SiOx Layers Deposited on a Polymer Matrix
摘要： The SiOx barrier nanocoatings have been prepared on selected polymer matrices to increase their resistance against permeation of toxic substances. The aim has been to find out whether the method of vacuum plasma deposition of SiOx barrier nanocoatings on a polyethylene terephthalate (PET) foil used by Aluminium Company of Canada (ALCAN) company (ALCAN Packaging Kreuzlingen AG (SA/Ltd., Kreuzlingen, Switzerland) within the production of CERAMIS? packaging materials with barrier properties can also be used to increase the resistance of foils from other polymers against the permeation of organic solvents and other toxic liquids. The scanning electron microscopy (SEM) microstructure of SiOx nanocoatings prepared by thermal deposition from SiO in vacuum by the Plasma Assisted Physical Vapour Deposition (PA-PVD) method or vacuum deposition of hexamethyldisiloxane (HMDSO) by the Plasma-enhanced chemical vapour deposition (PECVD) method have been studied. The microstructure and behavior of samples when exposed to a liquid test substance in relation to the barrier properties is described.
关键词： CERAMIS?,polymeric matrix,barrier material,permeation,nanocoating of SiOx,SorpTest,PVD,PECVD,plasma deposition,PA-PVD
更新于2025-09-23 15:21:01
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Intrinsic Sub-Nanocrystalline Silicon Thin Films: Active Layer for Solar Cells
摘要： The study presents the typical aspects of silicon thin films in terms of growth under variation of applied power using Radio frequency Plasma Enhanced Chemical Vapor Deposition technique (RF-PECVD). The corresponding material found to maintain the typical properties of amorphous nature without compensating the structural modification in terms of crystallinity and has been defined as a material having the “sub-nanocrystalline phase”. Characterizations like, UV-Visible spectroscopy, Photoluminescence and Temperature dependent conductivity was used to effectively map the structural details along with electrical and optical properties. The optical bandgap of the films found to be vary from 1.77 eV to 1.99 eV with typical photoresponse variations in the range 103 to 101. At 30 W applied power, the transition regime observed with the formation of sub-nanocrystallites. The analysis of such phase reveals the superior optoelectronic properties. This article suggests the suitability of sub-nanocrystalline silicon thin films to replace hydrogenated amorphous silicon in various applications.
关键词： Nc-Si:H/μc-Si:H,Thin film,PECVD,Sub-nanocrystalline phase,Conductivity
更新于2025-09-23 15:19:57
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In-situ phosphorus-doped polysilicon prepared using rapid-thermal anneal (RTA) and its application for polysilicon passivated-contact solar cells
摘要： A rapid thermal anneal (RTA) is used to crystallize the plasma-enhanced chemical vapor deposition (PECVD) deposited hydrogenated amorphous silicon (a-Si:H) thin film to form the phosphorus-doped polysilicon passivated contact in tunnel oxide passivated contact (TOPCon) solar cells. The effects of annealing temperature, annealing time, cooling time, and the polysilicon thickness on the surface passivation are investigated. The primary advantage of the RTA is reducing the whole crystallization period to ~15 min, shorter than the conventional tube-furnace annealing period of >60 min. We find that the RTA is a robust method to prepare high-quality polysilicon passivated contact without introducing blistering when the thickness of the a-Si:H is less than 40 nm. The optimized RTA process leads to an implied open-circuit voltage (iVoc) of 712 mV and a single-sided dark saturation current density (J0,s) of 12.5 fA/cm2 in the as-annealed state, which is inferior to the surface passivation of the controlled one prepared by a tube furnace annealing. Fortunately, a subsequent Al2O3 capping hydrogenation improves the iVoc and J0,s to 727 mV and 4.7 fA/cm2, respectively. The champion conversion efficiency of 23.04% (Voc ? 679.0 mV, Jsc ? 41.97 mA/cm2 and FF ? 80.86%) is achieved, which demonstrates the effectiveness of RTA for preparing a high-efficiency polysilicon passivated-contact solar cell.
关键词： Rapid thermal anneal (RTA),Polysilicon passivated contact,c-Si,Solar cell,PECVD,TOPCon
更新于2025-09-23 15:19:57