On the oxidation resistance of superhard Ti–Si–C–N coatings

2008 ◽  
Vol 23 (9) ◽  
pp. 2420-2428 ◽  
Author(s):  
Yan Guo ◽  
Shengli Ma ◽  
Kewei Xu ◽  
Tom Bell ◽  
Xiaoying Li ◽  
...  
Keyword(s):  
Grain Size ◽  
Chemical Vapor Deposition ◽  
Oxidation Resistance ◽  
Vapor Deposition ◽  
Silicon Content ◽  
Oxidation Behavior ◽  
Oxidation Process ◽  
Chemical Vapor ◽  
Surface Morphologies ◽  
The Relationship

The oxidation behavior of three types of plasma-enhanced chemical vapor deposition (PECVD) processed Ti–Si–C–N coatings with silicon content ranging from 4.3 to 11.6 at.% has been investigated at high temperatures. Systematic characterization was conducted to study the evolution of composition, phase constituents, hardness, surface morphologies, microstructures, and grain size during oxidation. A two-stage oxidation process was observed between 700 and 1000 °C for all three coatings. Experimental results indicate that a superhardness of 40 GPa can be maintained up to 700, 800, and 850 °C for 4.3, 7.4, and 11.6 at.% Si coatings, respectively; the dual-phased 7.4 and 11.6 at.% Si coatings show a better oxidation resistance than the single-phased 4.3 at.% Si coating. On the basis of the results, a mechanism is proposed to explain the relationship between the nanostructure and oxidation behavior.

Quantitative Modelling of Nucleation Kinetics in Experiments for Poly-Si Growth on Sio2 by Hot-Wire Chemical Vapor Deposition

2001 ◽  
Vol 664 ◽  
Author(s):  
Maribeth Swiatek ◽  
Jason K. Holt ◽  
Harry A. Atwater
Keyword(s):  
Activation Energy ◽  
Grain Size ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Nucleation Density ◽  
Hot Wire ◽  
Nucleation Kinetics ◽  
Temperature Dependent ◽  
Cluster Density

ABSTRACTWe apply a rate-equation pair binding model of nucleation kinetics [1] to the nucleation of Si islands grown by hot-wire chemical vapor deposition on SiO2 substrates. Previously, we had demonstrated an increase in grain size of polycrystalline Si films with H2 dilution from 40 nm using 100 mTorr of 1% SiH4 in He to 85 nm with the addition of 20 mTorr H2. [2] This increase in grain size is attributed to atomic H etching of Si monomers rather than stable Si clusters during the early stages of nucleation, decreasing the nucleation density. Atomic force microscopy (AFM) measurements show that the nucleation density increases sublinearly with time at low coverage, implying a fast nucleation rate until a critical density is reached, after which grain growth begins. The nucleation density decreases with increasing H2 dilution (H2:SiH4), which is an effect of the etching mechanism, and with increasing temperature, due to enhanced Si monomer diffusivity on SiO2. From temperature-dependent measurements, we estimate the activation energy for surface diffusion of Si monomers on SiO2 to be 0.47 ± 0.09 eV. Simulations of the temperature-dependent supercritical cluster density lead to an estimated activation energy of 0.42 eV ± 0.01 eV and a surface diffusion coefficient prefactor of 0.1 ± 0.03 cm2/s. H2-dilution-dependent simulations of the supercritical cluster density show an approximately linear relationship between the H2 dilution and the etch rate of clusters.

Te Induced AlAs/GaAs Superlattice Mixing

1988 ◽  
Vol 126 ◽  
Author(s):  
P. Mel ◽  
S. A. Schwarz ◽  
T. Venkatesan ◽  
C. L. Schwartz ◽  
E. Colas
Keyword(s):  
Mass Spectrometry ◽  
Activation Energy ◽  
Diffusion Coefficient ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Secondary Ion Mass Spectrometry ◽  
Chemical Vapor ◽  
Temperature Range ◽  
The Relationship ◽  
Secondary Ion

ABSTRACTTe enhanced mixing of AlAs/GaAs superlattice has been observed by secondary ion mass spectrometry. The superlattice sample was grown by organometallic chemical vapor deposition and doped with Te at concentrations of 2×1017 to 5×1018 cm−.3 In the temperature range from 700 to 1000 C, a single activation energy for the Al diffusion of 2.9 eV was observed. Furthermore, it has been found that the relationship between the Al diffusion coefficient and Te concentration is linear. Comparisons have been made between Si and Te induced superlattice mixing.

Effect of the Field Oxidation Process on the Electrical Characteristics of 6500V 4H-SiC JBS Diodes

2020 ◽  
Vol 1014 ◽  
pp. 144-148
Author(s):  
Ling Sang ◽  
Jing Hua Xia ◽  
Liang Tian ◽  
Fei Yang ◽  
Rui Jin ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Oxide Layer ◽  
Vapor Deposition ◽  
Oxidation Process ◽  
Chemical Vapor ◽  
Oxide Thickness ◽  
Electrical Characteristics ◽  
Field Plate ◽  
Plate Length ◽  
Field Oxide

The effect of the field oxidation process on the electrical characteristics of 6500V 4H-SiC JBS diodes is studied. The oxide thickness and field plate length have an effect on the reverse breakdown voltage of the SiC JBS diode. According the simulation results, we choose the optimal thickness of the oxide layer and field plate length of the SiC JBS diode. Two different field oxide deposition processes, which are plasma enhanced chemical vapor deposition (PECVD) and low pressure chemical vapor deposition (LPCVD), are compared in our paper. When the reverse voltage is 6600V, the reverse leakage current of SiC JBS diodes with the field oxide layer obtained by LPCVD process is 0.7 μA, which is 60% lower than that of PECVD process. When the forward current is 25 A, the forward voltage of SiC JBS diodes with the field oxide layer obtained by LPCVD process is 3.75 V, which is 10% higher than that of PECVD process. There should be a trade-off between the forward and reverse characteristics in the actual high power and high temperature applications.

Rapid and mass-producible synthesis of high-crystallinity MoSe2 nanosheets by ampoule-loaded chemical vapor deposition

Nanoscale ◽  
2020 ◽  
Vol 12 (13) ◽  
pp. 6991-6999 ◽  
Author(s):  
Na Liu ◽  
Woong Choi ◽  
Hyeongi Kim ◽  
Chulseung Jung ◽  
Jeonghun Kim ◽  
...  
Keyword(s):  
Grain Size ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Rapid Growth ◽  
Chemical Vapor ◽  
High Crystallinity

Rapid growth of high-crystalline MoSe2 nanosheets with grain size of up to ∼100 μm and yield of milligrams per hour.

Chemical Vapor Deposition of Binary Metal Germanides

1990 ◽  
Vol 187 ◽  
Author(s):  
M.J. Hampden-Smith ◽  
J. Garvey ◽  
D. Lei ◽  
J.C. Huffman
Keyword(s):  
Thermal Decomposition ◽  
Grain Size ◽  
Chemical Vapor Deposition ◽  
Transition Metal ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Solution Model ◽  
Binary Metal ◽  
Decomposition Experiments

AbstractA series of transition metal substituted germacyclopent-3-ene compounds containing transition metal-germanium bonds have been prepared with supporting ligands which are designed to be easily removed either thermally or photochemically. In solution, model thermal decomposition experiments show that either the geramanium or the transition metal substituents may be removed, depending on the nature of the metal. Preliminary hot-wall CVD experiments using manganese and cobalt derivatives result in films with small grain size.

Effects of Process Parameters on Graphene Growth Via Low-Pressure Chemical Vapor Deposition

2020 ◽  
Vol 8 (3) ◽  
Author(s):  
Byoungdo Lee ◽  
Weishen Chu ◽  
Wei Li
Keyword(s):  
Grain Size ◽  
Chemical Vapor Deposition ◽  
Process Parameters ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
High Growth ◽  
Low Pressure ◽  
Large Set ◽  
Graphene Growth ◽  
Pressure Chemical

Abstract Graphene has attracted enormous research interest due to its extraordinary material properties. Process control to achieve high-quality graphene is indispensable for graphene-based applications. This research investigates the effects of process parameters on graphene quality in a low-pressure chemical vapor deposition (LPCVD) graphene growth process. A fractional factorial design of experiment is conducted to provide understanding on not only the main effect of process parameters, but also the interaction effect among them. Graphene quality including the number of layers and grain size is analyzed. To achieve monolayer graphene with large grain size, a condition with low CH4–H2 ratio, short growth time, high growth pressure, high growth temperature, and slow cooling rate is recommended. This study considers a large set of process parameters with their interaction effects and provides guidelines to optimize graphene growth via LPCVD focusing on the number of graphene layers and the grain size.

Aluminizing for TiAl turbocharger rotor by reduced pressure metal-organic chemical vapor deposition (RPMOCVD) and the efficiency of its oxidation resistance

1994 ◽  
Vol 9 (8) ◽  
pp. 1984-1989 ◽  
Author(s):  
Takakazu Suzuki ◽  
Hiroyuki Umehara ◽  
Haruki Hino
Keyword(s):  
Heat Treatment ◽  
Chemical Vapor Deposition ◽  
Oxidation Resistance ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Turbine Rotor ◽  
Organic Chemical ◽  
Reduced Pressure ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

A complex-shaped TiAl turbine rotor has been uniformly aluminized by a metal-organic chemical vapor deposition under reduced pressure (RPMOCVD), and a thick TiAl3 layer, which affects the oxidation resistance, can be formed on the surface by subsequent heat treatment. The oxidation resistance has been studied with an oxidation test at 1173 K for 760 ks in static air. The microstructure has been investigated by SEM, EPMA, AES, and XRD. A heat treatment at above 933 K, which is the melting point of Al, is required to enhance the oxidation resistance of TiAl. With increasing the surface roughness of TiAl, the formation of TiAl3 increases, and consequently the oxidation resistance is more improved.

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