scholarly journals Structural Controlling of Highly-Oriented Polycrystal 3C-SiC Bulks via Halide CVD

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 390 ◽  
Author(s):  
Zhiying Hu ◽  
Dingheng Zheng ◽  
Rong Tu ◽  
Meijun Yang ◽  
Qizhong Li ◽  
...  
Keyword(s):  
Total Pressure ◽  
Molten Aluminum ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Deposition Mechanism ◽  
Growth Orientation ◽  
Vacuum Atmosphere ◽  
Columnar Grains ◽  
Surface Morphologies ◽  
Wetting Behaviors

Highly-oriented polycrystal 3C-SiC bulks were ultra-fast fabricated via halide chemical vapor deposition (CVD) using tetrachlorosilane (SiCl4) and methane (CH4) as precursors. The effects of deposition temperature (Tdep) and total pressure (Ptot) on the orientation and surficial morphology were investigated. The results showed that the growth orientation of 3C-SiC columnar grains was strongly influenced by Tdep. With increasing Tdep, the columnar grains transformed from <111>- to <110>-oriented. The arrangement of <111>-oriented columnar grains was controlled by Ptot. Lotus-, turtle-, thorn-, and strawberry-like surface morphologies were naturally contributed by different arrangements of <111>-oriented grains, and the deposition mechanism was discussed. The wetting behaviors of CVD-SiC samples by molten aluminum were also examined at 1173 K in a high vacuum atmosphere.

Low Temperature Synthesis of the Carbon Micro Materials

2017 ◽  
Vol 730 ◽  
pp. 327-332 ◽  
Author(s):  
Si Eun An ◽  
Sung Hoon Kim
Keyword(s):  
Low Temperature ◽  
Total Pressure ◽  
Carbon Materials ◽  
Chemical Vapor ◽  
Injection Time ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
Entire Surface ◽  
Surface Morphologies ◽  
Head Area

The formation of the carbon microcoils could be achieved under the low temperature (550°C). Ni powders were used as the catalyst on the alumina substrate. C2H2 was used as a source gas and a few amount of SF6 gas were used as an additive gas under the thermal chemical vapor deposition system. The surface morphologies of as-grown carbon materials at the low temperature (550°C) were also investigated according to the total pressure and the injection time of SF6 flow. At 80Torr and 10min injection time of SF6 flow, the carbon microcoils were highly developed on the entire surface of the sample. The lower or higher total pressure and the longer injection time of SF6 flow deteriorated the formation of CMCs. The head area of the carbon microcoils was closely investigated and the growth mode for the initiation of the carbon microcoils at the low temperature was suggested.

Effect of Pressures on the Chemical Vapor Deposition of BN Using Borazine

2011 ◽  
Vol 214 ◽  
pp. 588-592
Author(s):  
Jun Sheng Li ◽  
Chang Rui Zhang ◽  
Bin Li ◽  
Feng Cao ◽  
Si Qing Wang
Keyword(s):  
Chemical Vapor Deposition ◽  
Boron Nitride ◽  
Surface Structure ◽  
Vapor Deposition ◽  
Total Pressure ◽  
Chemical Vapor ◽  
Xrd Analysis ◽  
Composition And Structure ◽  
Single Precursor ◽  
Surface Morphologies

Boron nitride coatings have been prepared by chemical vapor deposition using borazine as single precursor at 900 °C. The effect of the total pressure on the surface morphologies of the coatings was investigated. For low total pressures (≤ 3 kPa), the deposits presents a compact pebble-like surface structure. However, when high total pressures (> 3 kPa) were used, the surface of the coatings presents a loose grain-like feature. When the total pressure increases up to 12 kPa, the coatings shows a porous surface structure. The composition and structure of the deposited coatings were investigated by means of FTIR and XRD analysis. It shows that the coatings have a structure of turbostratic boron nitride.

Kinetics of Chemical Vapor Deposition of Sic Between 750 and 850°C at 1 Bar Total Pressure

1991 ◽  
Vol 250 ◽  
Author(s):  
Dieter Neuschütz ◽  
Farzin Salehomoum
Keyword(s):  
Deposition Rate ◽  
Total Pressure ◽  
Reaction Rate ◽  
Chemical Vapor ◽  
Deposition Mechanism ◽  
Reaction Orders ◽  
Si Content ◽  
Boundary Reaction ◽  
Phase Boundary Reaction ◽  
Kinetics Of

AbstractThe deposition rate from mixtures of methyltrichlorosilane (MTS), hydrogen and methane was measured thermogravimetrically using a hot wall vertical reactor and planar SiC substrates. Below 850 °C and at sufficiently high gas velocities, the rate of the phase boundary reaction could be determined. In the absence of CH4 and at H2 :MTS=55, Si was deposited together with SiC. Addition of CH4 lowered the Si content, pure SiC being deposited at CH4 :MTS above 10. The deposition rate j in the range 750 to 850 °C follows the equation with E(Si) = 160 and E(SiC) = 300 kJ/mol. Reaction mechanisms are presented to account for the observed reaction orders with respect to MTS. Between 900 and 970 °C, the reaction rate decreased with temperature indicating a change in the deposition mechanism.

scholarly journals Annealing Condition Effects on the Structural Properties of FePt Nanoparticles Embedded in MgO via Pulsed Laser Deposition

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 131
Author(s):  
Tingting Xiao ◽  
Qi Yang ◽  
Jian Yu ◽  
Zhengwei Xiong ◽  
Weidong Wu
Keyword(s):  
Pulsed Laser Deposition ◽  
Room Temperature ◽  
High Vacuum ◽  
Pulsed Laser ◽  
Annealing Process ◽  
Ultra High Vacuum ◽  
Laser Deposition ◽  
Fept Nanoparticles ◽  
Annealing Conditions ◽  
Vacuum Atmosphere

FePt nanoparticles (NPs) were embedded into a single-crystal MgO host by pulsed laser deposition (PLD). It was found that its phase, microstructures and physical properties were strongly dependent on annealing conditions. Annealing induced a remarkable morphology variation in order to decrease its total free energy. H2/Ar (95% Ar + 5% H2) significantly improved the L10 ordering of FePt NPs, making magnetic coercivity reach 37 KOe at room temperature. However, the samples annealing at H2/Ar, O2, and vacuum all showed the presence of iron oxide even with the coverage of MgO. MgO matrix could restrain the particles’ coalescence effectively but can hardly avoid the oxidation of Fe since it is extremely sensitive to oxygen under the high-temperature annealing process. This study demonstrated that it is essential to anneal FePt in a high-purity reducing or ultra-high vacuum atmosphere in order to eliminate the influence of oxygen.

Early Growth in the Chemical Vapor Deposition of Tin and TiC and Monitoring by Laser Scattering

1989 ◽  
Vol 168 ◽  
Author(s):  
Max Klein ◽  
Bernard Gallois
Keyword(s):  
Pyrolytic Graphite ◽  
Chemical Vapor ◽  
Early Growth ◽  
Columnar Growth ◽  
Laser Scattering ◽  
Fine Grained ◽  
Steady Rate ◽  
Columnar Grains ◽  
State Growth

AbstractThe early growth of chemically vapor deposited TiN and TiC coatings on pyrolytic graphite was studied in the kinetic- and mass transport-controlled regimes. While steady-state growth of these coatings results in columnar grains, such morphologies do not originate at the substrate/coating interface. Rather, TiC deposition begins on the substrate as fine grains less than 100 nm in diameter. Early TiN growth occurs in layers of 50 nm grains. In both cases, early fine-grained growth occurs at a lower rate than the linear, steady rate observed for columnar growth. A laser scattering technique has been developed as a tool for characterizing early growth through surface roughness. This noncontact method can be used as an in-situ diagnostic to detect changes in the surface of the growing deposit.

Challenge to 200 mm 3C-SiC Wafers Using SOI

2005 ◽  
Vol 483-485 ◽  
pp. 205-208 ◽  
Author(s):  
Motoi Nakao ◽  
Hirofumi Iikawa ◽  
Katsutoshi Izumi ◽  
Takashi Yokoyama ◽  
Sumio Kobayashi
Keyword(s):  
Cross Section ◽  
Vapor Deposition ◽  
Seed Layer ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Average Thickness ◽  
Entire Region ◽  
Transmission Electron ◽  
Good Crystallinity

200 mm wafer with 3C-SiC/SiO2/Si structure has been fabricated using 200 mm siliconon- insulator (SOI) wafer. A top Si layer of 200 mm SOI wafer was thinned down to approximately 5 nm by sacrificial oxidization, and the ultrathin top Si layer was metamorphosed into a 3C-SiC seed layer using a carbonization process. Afterward, an epitaxial SiC layer was grown on the SiC seed layer with ultra-high vacuum chemical vapor deposition. A cross-section transmission electron microscope indicated that a 3C-SiC seed layer was formed directly on the buried oxide layer of 200 mm wafer. The epitaxial SiC layer with an average thickness of approximately 100 nm on the seed was recognized over the entire region of the wafer, although thickness uniformity of the epitaxial SiC layer was not as good as that of SiC seed layer. A transmission electron diffraction image of the epitaxial SiC layer showed a monocrystalline 3C-SiC(100) layer with good crystallinity. These results indicate that our method enables to realize 200 mm SiC wafers.

Ultra-high vacuum chemical vapor deposition and in situ characterization of titanium oxide thin films

1991 ◽  
Vol 6 (9) ◽  
pp. 1913-1918 ◽  
Author(s):  
Jiong-Ping Lu ◽  
Rishi Raj
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Titanium Oxide ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Titanium Isopropoxide ◽  
Ultra High Vacuum

Chemical vapor deposition (CVD) of titanium oxide films has been performed for the first time under ultra-high vacuum (UHV) conditions. The films were deposited through the pyrolysis reaction of titanium isopropoxide, Ti(OPri)4, and in situ characterized by x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). A small amount of C incorporation was observed during the initial stages of deposition, through the interaction of precursor molecules with the bare Si substrate. Subsequent deposition produces pure and stoichiometric TiO2 films. Si–O bond formation was detected in the film-substrate interface. Deposition rate was found to increase with the substrate temperature. Ultra-high vacuum chemical vapor deposition (UHV-CVD) is especially useful to study the initial stages of the CVD processes, to prepare ultra-thin films, and to investigate the composition of deposited films without the interference from ambient impurities.

Homoepitaxy of Ge on ozone-treated Ge (1 0 0) substrate by ultra-high vacuum chemical vapor deposition

2019 ◽  
Vol 507 ◽  
pp. 113-117 ◽  
Author(s):  
Jiaqi Wang ◽  
Limeng Shen ◽  
Guangyang Lin ◽  
Jianyuan Wang ◽  
Jianfang Xu ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum
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