Design and Deposition of Infrared Antireflection Protection Film on Magnesium Fluoride Substrate for 3~5 μm

2014 ◽  
Vol 609-610 ◽  
pp. 94-99
Author(s):  
Lin Li ◽  
Da Xing Wang ◽  
Xiu Hua Fu ◽  
Dong Mei Liu ◽  
Yang Kou
Keyword(s):  
Flow Rate ◽  
Deposition Temperature ◽  
Gas Flow ◽  
Ion Beam ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Magnesium Fluoride ◽  
Infrared Band ◽  
Key Words Magnesium ◽  
Protection Coating

The infrared antireflection protection film is designed and deposited on magnesium fluoride substrate for 3~5 μm. The multilayer antireflection film is designed and prepared by ion beam assisted electron-beam deposition. After repeated experiments, the absorption peak of SiO2 is found at 3000nm,using MgF2 and SiO2 as the low-index materials to reduce the absorption. The coating structure is Sub|1.46H1.37L2.19H1.45L2.49M|Air. DLC (diamond-like carbon) protection coating is deposited by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD). Through contrast tests, the best deposition process is obtained (the butane flow rate is 5sccm/s, deposition temperature is 80°C) by setting deposition time as invariant, the reaction gas flow rate and deposition temperature as variables. Meanwhile the problem of associativity between antireflection film and DLC protection coating is solved by adding a Si transition layer. The result shows that the average transmittance of this film in 3~5μm is 95.5%, and this film can withstands harsh environment tests. Key words: Magnesium fluoride substrate; Antireflection protection film; 3~5 μm infrared band Document Code: A Article ID: DIO

Growth Mechanism and Dislocation Characterization of Silicon Carbide Epitaxial Films

2006 ◽  
Vol 911 ◽  
Author(s):  
Govindhan Dhanaraj ◽  
Yi Chen ◽  
Hui Chen ◽  
William M Vetter ◽  
Hui Zhang ◽  
...  
Keyword(s):  
Screw Dislocation ◽  
Flow Rate ◽  
Growth Rates ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Epitaxial Layers ◽  
Gas Flow Rate ◽  
Carrier Gas ◽  
Carrier Gas Flow

AbstractSiC homo-epitaxial layers were grown in a chemical vapor deposition process using silicon tetrachloride and propane precursors with hydrogen as a carrier gas. Growth rates were found to increase as temperatures increased at high carrier gas flow rate, while at lower carrier gas flow rate growth rates were observed to decrease as temperature increased. Based on the equilibrium model, “thermodynamically controlled growth” accounts for the growth rate reduction. The grown epitaxial layers were characterized using various techniques. Reduction in the threading screw dislocation (SD) density in the epilayers was observed. Suitable models were developed for explaining the reduction in the screw dislocation density as well as the conversion of basal plane dislocations (BPD) into threading edge dislocations (TED).

Deposition Mechanism of Tungsten Silicide Films by Low Pressure CVD

1990 ◽  
Vol 181 ◽  
Author(s):  
Jae H. Sone ◽  
Hyeong J. Kim
Keyword(s):  
Mass Transfer ◽  
Deposition Rate ◽  
Flow Rate ◽  
Deposition Temperature ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Low Pressure ◽  
Deposition Mechanism ◽  
Si Substrates ◽  
Si Content

ABSTRACTWSix thin films were deposited on SiO2/Si substrates by Low Pressure Chemical Vapor Deposition (LPCVD) using WF6 and SiH4 gases. The deposition mechanism has been studied by measuring the thickness, resistivity and composition of the films by varying deposition temperature and gas flow rate at a constant total reactant gas pressure. Below 300°C, the surface chemical reaction was the rate-limiting process and the deposition rate increased exponentially with temperature having a thermal activation energy of 3.2 kcal/mol. Meanwhile, above 300°C the reaction was governed by the mass transfer step in the gas. The deposition rate in this range is insensitive to the deposition temperature but shows dependence of the flow rate of reactant gases. AES and RBS analyses were performed to determine the stoichiometry of WSix thin film. The Si content in film gradually increased as the deposition temperature increased. The resistivity of as-deposited WSix film has dependence on both deposition temperature and Si/W ratio, and exponentially increased with a moderate slope. However, temperature insensitive behavior of resistivity appeared in the mass transfer controlled region. Such resistivity changes with temperature were discussed with the Si/W ratio and the microstructure of films.

Accurate estimation of DLC thin film hardness using genetic programming

2020 ◽  
Vol 111 (6) ◽  
pp. 453-462
Author(s):  
Ranjan Kumar Ghadai ◽  
Kanak Kalita
Keyword(s):  
Thin Film ◽  
Genetic Programming ◽  
Flow Rate ◽  
Deposition Temperature ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Symbolic Regression ◽  
Accurate Estimation ◽  
Hydrogen Flow ◽  
Film Hardness

Abstract In the current research, diamond-like carbon thin films are deposited on silicon substrates by plasma-enhanced chemical vapor deposition. The effect of argon-C2H2 flow rate, hydrogen flow rate and deposition temperature on the thin film hardness is investigated. Morphology of the DLC films is investigated by scanning electron microscopy and atomic force microscopy, while the nano-hardness is investigated using nanoindentation. Raman spectroscopy is used for the characterization of the structural properties of the film. A metamodel of the DLC deposition process with argon- C2H2 flow rate, H2 flow rate and deposition temperature as the regressor variables and coating hardness as the response is built by using a novel symbolic regression approach. A state-of-the-art machine learning approach - genetic programming (GP) - is used for the symbolic regression. By carefully evaluating the performance of the current GP metamodel against a classical RSM (response surface methodology) metamodel, it is seen that the GP significantly outperforms RSM.

The Effect of Inoculum in the Preparation of Fermented Tapioca for Nanotechnology Applications Based on FT-IR Studies

2013 ◽  
Vol 667 ◽  
pp. 534-537
Author(s):  
M.Z. Nuraini ◽  
S. Aishah ◽  
S.F. Nik ◽  
Mohamad Rusop
Keyword(s):  
Carbon Nanotubes ◽  
Gas Flow ◽  
Deposition Time ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Ir Studies ◽  
Multi Walled Carbon Nanotubes ◽  
Ft Ir ◽  
Walled Carbon Nanotubes ◽  
Ft Ir Spectroscopy

Fermented tapioca which is a new starting material was used as a carbon precursor. Carbon nanotubes (CNTs) were deposited on silicon wafer (Si) by Thermal Chemical Vapor Deposition (TCVD). The gas flow of Argon (Ar) was constant at 70 bubbles per minute and 20 minutes of deposition time. Before the deposition process, silicon was coated with Nickel using spin coater. Various parameters such as amount of inoculums have been studied. Chemical functional groups of carbon nanotubes were characterized using FT-IR Spectroscopy. The FT-IR result shows peaks attributed to multi–walled carbon nanotubes (MWCNT) vibration modes.

Influences of deposition temperature, gas flow rate and ZrC content on the microstructure and anti-ablation performance of CVD-HfC-ZrC coating

2021 ◽  
Vol 47 (1) ◽  
pp. 556-566
Author(s):  
Jincui Ren ◽  
Errong Feng ◽  
Yulei Zhang ◽  
Jian Zhang ◽  
Donghai Ding ◽  
...  
Keyword(s):  
Flow Rate ◽  
Deposition Temperature ◽  
Gas Flow ◽  
Gas Flow Rate ◽  
Zrc Coating

Effects of Reaction Conditions on MoS2 Thin Film Formation Synthesized by Chemical Vapor Deposition using Organic Precursor

MRS Advances ◽  
2016 ◽  
Vol 2 (29) ◽  
pp. 1533-1538 ◽  
Author(s):  
S. Ishihara ◽  
Y. Hibino ◽  
N. Sawamoto ◽  
T. Ohashi ◽  
K. Matsuura ◽  
...  
Keyword(s):  
Thin Film ◽  
Chemical Vapor Deposition ◽  
Low Temperature ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Film Formation ◽  
Chemical Vapor ◽  
Gas Flow Rate ◽  
Axis Orientation

ABSTRACTMolybdenum disulfide (MoS2) thin films were fabricated by two-step chemical vapor deposition (CVD) using (t-C4H9)2S2 and the effects of temperature, gas flow rate, and atmosphere on the formation were investigated in order to achieve high-speed low-temperature MoS2 film formation. From the results of X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) investigations, it was confirmed that c-axis orientation of the pre-deposited Mo film has a significant involvement in the crystal orientation after the reaction low temperature sulfurization annealing and we successfully obtained 3 nm c-axis oriented MoS2 thin film. From the S/Mo ratios in the films, it was revealed that the sulfurization reaction proceeds faster with increase in the sulfurization temperature and the gas flow rate. Moreover, the sulfurization under the H2 atmosphere promotes decomposition reaction of (t-C4H9)2S2, which were confirmed by XPS and density functional theory (DFT) simulation.

Structural and Optical Properties of ZnO Nanotetrapods Deposited by Thermal Chemical Vapor Deposition with Different Gas Flow Rate

2015 ◽  
Vol 1109 ◽  
pp. 456-460
Author(s):  
Najwa Ezira Ahmed Azhar ◽  
Shafinaz Sobihana Shariffudin ◽  
Aimi Bazilah Rosli ◽  
A.K.S. Shafura ◽  
Mohamad Rusop
Keyword(s):  
Optical Properties ◽  
Chemical Vapor Deposition ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Gas Flow Rate ◽  
Structural And Optical Properties ◽  
Thermal Chemical Vapor Deposition ◽  
Yellow Orange

ZnO nanotetrapod with different oxygen flow rate was prepared by thermal chemical vapor deposition. We have successfully deposited ZnO nanotetrapod on synthesis Zn powder using double furnace with argon (Ar) and oxygen (O2) gas as source material. In this study, we report the effect of different gas flow rate (5 sccm to 15 sccm) on structural and optical properties of the ZnO nanotetrapod. The morphology of ZnO nanotetrapods were analyzed by field emission scanning electron microscope (FE-SEM). It exhibits the length of the nanotetrapods arm decrease with increased of flow rate and diameter of nanotetrapod in range 30 nm to 90 nm. The optical properties were determined through XRD and photoluminescence with 2θ (30o to 80o) and wavelength 350 nm to 620 nm respectively. PL spectra show that the UV emission centred at 380 nm while yellow-orange emission centred at 540 nm.

Deposition on SS 316 at Different Gas Flow Rates Using Thermal CVD

2012 ◽  
Vol 576 ◽  
pp. 594-597 ◽  
Author(s):  
Mohammad Asaduzzaman Chowdhury ◽  
Dewan Muhammad Nuruzzaman
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Deposition Rate ◽  
Flow Rate ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Gas Flow Rate ◽  
Flow Rates

A hot filament thermal chemical vapor deposition (CVD) reactor was used to deposit solid thin films on stainless steel 316 (SS 316) substrates at different flow rates of natural gas. The variation of thin film deposition rate with the variation of gas flow rate has been investigated experimentally. During experiment, the effect of gap between activation heater and substrate on the deposition rate has also been observed. Results show that deposition rate on SS 316 increases with the increase in gas flow rate. It is also observed that deposition rate increases with the decrease in gap between activation heater and substrate within the observed range. In addition, friction coefficient and wear rate of SS 316 sliding against SS 304 under different normal loads are also investigated before and after deposition. The experimental results reveal that improved friction coefficient and wear rate are obtained after deposition as compared to that of before deposition.

Aerosol-Assisted CVD of SnO2 Thin Films for the Room-Temperature Detection of Hydrogen Sulfide

2013 ◽  
Vol 543 ◽  
pp. 422-425
Author(s):  
Huan Liu ◽  
Min Li ◽  
Jiu Xiao Wan ◽  
Jun Zhao ◽  
Qiu Yun Fu ◽  
...  
Keyword(s):  
Thin Films ◽  
Gas Flow ◽  
Room Temperature ◽  
Gas Sensing ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Temperature Detection ◽  
Low Concentrations ◽  
Initial Resistance ◽  
Deposition Conditions

High-quality SnO2 thin-film materials capable of detecting H2S gas of low concentrations at room temperature was demonstrated in this paper. We employed aerosol-assisted chemical vapor deposition process for the deposition of SnO2 thin films on alumina substrates with pre-patterned electrodes. The gas-sensing performances of the films prepared under different deposition conditions were systematically compared and analyzed. When SnCl2·2H2O was used as the precursor, a response sensitivity of 98.4 toward 50 ppm of H2S at room temperature was achieved. At room temperatures, the resistance upon the H2S gas exposure could recover to 90% of the initial resistance of the sensor when the H2S gas flow was turned off.

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