Effect of CS2 Flow Rate on the Formation of Aligned Carbon Microcoils

2019 ◽  
Vol 947 ◽  
pp. 40-46
Author(s):  
Hyun Ji Kim ◽  
Sung Hoon Kim
Keyword(s):  
Flow Rate ◽  
Vapor Deposition ◽  
Rate Ratio ◽  
Chemical Vapor ◽  
Regular Structure ◽  
Flow Rate Ratio ◽  
Total Flow ◽  
Total Flow Rate ◽  
Flow Rates ◽  
Thermal Chemical Vapor Deposition

The formation of aligned carbon microcoils could be achieved using C2H2 as a source gas and CS2 as an incorporated additive gas under thermal chemical vapor deposition system. To elucidate the ratio of C2H2/CS2 for the formation of the aligned carbon microcoils, the CS2 flow rate was first manipulated under the identical C2H2 flow rate (500sccm) condition. The formation and the alignment of carbon microcoils could be only achieved under the ratio of C2H2/CS2 = 33.3 condition, namely the flow rates of CS2 = 15sccm and C2H2= 500sccm. The total flow rate of the used gases was varied under the identical C2H2/CS2 flow rate ratio (33.3) condition. The C2H2 flow rate was manipulated under the identical CS2 flow rate (15sccm) condition. It was found that the formation and the alignment of carbon microcoils could be only achieved under the condition of 15sccm of CS2 flow rate in the range of 200 ~ 500sccm of C2H2 flow rate, regardless of the flow rate ratio of C2H2/CS2 and the total flow rate. The crystal structure of the well-aligned CMCs reveals the increase in the (002) peak in XRD spectrum for the aligned carbon microcoils, indicating the existence of the more regular structure in the aligned carbon microcoils. Based on these results, the cause for the formation of the aligned carbon microcoils only in the case of the CS2 flow rate = 15sccm with the imaginary pictures for the flow rate ratio of C2H2/CS2 just above the substrate were proposed.

Thin Oxynitride Films Prepared by Low Pressure Rapid Thermal Chemical Vapor Deposition

1993 ◽  
Vol 303 ◽  
Author(s):  
P.K. Mclarty ◽  
W.L. Hill ◽  
X.L Xu ◽  
J.J. Wortman ◽  
G.S. Harris
Keyword(s):  
Chemical Vapor Deposition ◽  
Nitrogen Content ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Low Pressure ◽  
Flow Rate Ratio ◽  
Thermal Chemical Vapor Deposition ◽  
Rate Ratios ◽  
Post Deposition

ABSTRACTThin silicon oxynitride (Si-O-N) films have been deposited using low pressure rapid thermal chemical vapor deposition (RTCVD) with silane (SiH4), nitrous oxide (N2O), and ammonia (NH3) as the reactive gases. Structural analysis coupled with a study of deposition conditions indicate that an increase in NH3/N2O flow rate ratios leads to an increased N/O atomic ratio and a decreased Si-O-N deposition rate. Thin film (55-75A) polySi/Si-N-O/Si capacitors and transistors were fabricated for NH3/N2O flow rate ratios from 20% to 100%. Some of the films were subjected to a post deposition anneal at 950°C for 15 seconds in both argon and oxygen. Capacitance voltage measurements indicate a mid-gap interface trap density of ≤ 6 × 1010 eV−1cm−2 for all the films independent of both nitrogen content and post deposition annealing conditions. The transconductance was studied as a function of NH3/N2O flow rate ratio and decreasing peak gm values but improved high field degradation was observed for increased nitrogen content. This is consistent with previous work on nitrided oxides and suggests that the films are under tensile stress. Hot carrier stress at maximum substrate current was performed with the Si-O-N films displaying larger threshold voltage shifts when compared to furnace SiO2 indicating the possible existence of hydrogen related traps.

Growth of Rhombohedral B12P2 Thin Films on 6H-SiC(0001) By Chemical Vapor Deposition

2003 ◽  
Vol 799 ◽  
Author(s):  
Peng Lu ◽  
J. H. Edgar ◽  
J. Pomeroy ◽  
M. Kuball ◽  
H. M. Meyer ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Flow Rate ◽  
Growth Rates ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Flow Rate Ratio ◽  
Good Surface ◽  
Boron Phosphide ◽  
Moderate Growth

ABSTRACTThe parameters necessary to deposit oriented rhombohedral boron phosphide (B12P2) thin films on on-axis Si-face 6H-SiC(0001) substrates by chemical vapor deposition are reported. Ultra high purity BBr3 and PBr3 were used as reactants, with hydrogen as the carrier gas. The BBr3 to PBr3 flow rate ratio was adjusted to obtain good surface morphology of the B12P2 films. BBr3 to PBr3 ratios in the range of 1 to 1.5 produced smooth surfaces and moderate growth rates of 10μm/hr. Higher growth rates were obtained by increasing the BBr3 flow rate, but the surfaces became very rough. The c-axis of the B12P2 film was aligned with the c -axis of the substrate at temperatures between 1650°C-1700°C. The surface morphologies were investigated by SEM and the crystalline properties of the films were characterized by XRD and Raman spectroscopy.

Plasma Enhanced Chemical Vapor Deposition of Silicon Sulfide and Phosphorus Sulfide thin Films

1994 ◽  
Vol 346 ◽  
Author(s):  
R.K. Shibao ◽  
V.I. Srdanov ◽  
M. Hay ◽  
H. Eckert
Keyword(s):  
Thin Films ◽  
Nuclear Magnetic Resonance ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Rate Ratio ◽  
Chemical Vapor ◽  
Flow Rate Ratio ◽  
Structural Studies ◽  
Melt Quenching ◽  
Quenching Method

ABSTRACTAmorphous SiSx:H (x ∼ 2) films have been synthesized from H2S and SiH4 precursors using a remote plasma enhanced chemical vapor deposition apparatus. Structural studies by solid state nuclear magnetic resonance (NMR) and Raman scattering reveal that the atomic environments in these materials are similar to those observed in melt-quenched silicon sulfide glasses, and are characterized by corner- and edge-shared SiS4/2 tetrahedra. Compared to these glasses, however, the films show consistently higher fractions of corner-sharing S1S4/2 tetrahedra. The ratio of corner- to edge sharing tetrahedra and the Si:S ratio can be influenced by the H2S/S1H4 flow rate ratio during deposition. Thus, PECVD opens up wider opportunities for structural tailoring of amorphous silicon sulfide materials than currently possible by means of the melt-quenching method. Preliminary data for the PECVD synthesis of phosphorus sulfide is also presented.

scholarly journals Material Structure and Mechanical Properties of Silicon Nitride and Silicon Oxynitride Thin Films Deposited by Plasma Enhanced Chemical Vapor Deposition

Surfaces ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 59-72 ◽  
Author(s):  
Zhenghao Gan ◽  
Changzheng Wang ◽  
Zhong Chen
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Silicon Nitride ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Silicon Oxynitride ◽  
Flow Rates ◽  
Silicon Nitride Films

Silicon nitride and silicon oxynitride thin films are widely used in microelectronic fabrication and microelectromechanical systems (MEMS). Their mechanical properties are important for MEMS structures; however, these properties are rarely reported, particularly the fracture toughness of these films. In this study, silicon nitride and silicon oxynitride thin films were deposited by plasma enhanced chemical vapor deposition (PECVD) under different silane flow rates. The silicon nitride films consisted of mixed amorphous and crystalline Si3N4 phases under the range of silane flow rates investigated in the current study, while the crystallinity increased with silane flow rate in the silicon oxynitride films. The Young’s modulus and hardness of silicon nitride films decreased with increasing silane flow rate. However, for silicon oxynitride films, Young’s modulus decreased slightly with increasing silane flow rate, and the hardness increased considerably due to the formation of a crystalline silicon nitride phase at the high flow rate. Overall, the hardness, Young modulus, and fracture toughness of the silicon nitride films were greater than the ones of silicon oxynitride films, and the main reason lies with the phase composition: the SiNx films were composed of a crystalline Si3N4 phase, while the SiOxNy films were dominated by amorphous Si–O phases. Based on the overall mechanical properties, PECVD silicon nitride films are preferred for structural applications in MEMS devices.

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.

scholarly journals Role of Arsenic Hexagonal growth-suppression on a Cubic GaNAs Growth using Metalorganic Chemical Vapor Deposition

2000 ◽  
Vol 5 (S1) ◽  
pp. 223-229 ◽  
Author(s):  
S. Yoshida ◽  
T. Kimura ◽  
J. Wu ◽  
J. Kikawa ◽  
K. Onabe ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Photoluminescence Intensity ◽  
Flow Rates ◽  
Surface Morphologies ◽  
Metalorganic Chemical

The hexagonal domain suppression-effects in cubic-GaNAs grown by metalorganic chemical-vapor deposition (MOCVD) is reported. A thin buffer layer (20 nm) was first grown on a substrate at 853 K using trimethylgallium and dimethylhydrazine (DMHy), and GaNAs samples were grown at different AsH3 flow rates (0 ∼ 450 μmol/min) at 1193 K. As a result, three types of surface morphologies were obtained: the first was a smooth surface (AsH3 = 0 μmol/min); the second was a mirrorlike surface having small and isotropic grains (AsH3 : 45 ∼ 225 μmol/min ); and the third involved three-dimensional surface morphologies (above 450 μmol/min of AsH3 flow rate). Furthermore, it was confirmed using X-ray diffraction that the mixing ratio of hexagonal GaNAs in cubic GaNAs decreased with an increase of the AsH3 flow rate. We could obtain GaNAs having a cubic component of above 85% at AsH3 flow rates above 20 μmol/min. Therefore, the MOCVD growth method using AsH3 and DMHy was mostly effective for suppressing hexagonal GaNAs. It was observed that the photoluminescence intensity of GaNAs was decreased with increase of arsine flow rate.

The Aligned Carbon Microcoils Having the Straight Type Overall Geometry

2016 ◽  
Vol 689 ◽  
pp. 43-47
Author(s):  
Gi Hwan Kang ◽  
Sung Hoon Kim
Keyword(s):  
Chemical Vapor Deposition ◽  
Crystal Structures ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Regular Structure ◽  
Growth Mode ◽  
Thermal Chemical Vapor Deposition

The aligned carbon microcoils having the straight type overall geometry could be obtained using C2H2/H2 as source gases and SF6 as an incorporated additive gas under the thermal chemical vapor deposition system. Their morphologies and crystal structures were investigated and compared with the randomly grown carbon microcoils having the coil or twist type overall geometry. We could observe the enhancement of the (002) peak in XRD spectra of the aligned carbon microcoils indicating the existence of the more regular structure in the aligned carbon microcoils. The aligned carbon microcoils were formed as a bundle shape, while the randomly grown carbon microcoils were appeared as an individual shape. The systematic growth mode for the developing aspect of the aligned carbon microcoils was proposed.

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