Transamination in Pulsed DC-Plasma Enhanced CVD Of Ti(C,N) From TDMAT

1999 ◽  
Vol 564 ◽  
Author(s):  
J. P. A. M. Driessen ◽  
A. D. Kuypers ◽  
J. Schoonman
Keyword(s):  
Gas Phase ◽  
Phase Particle ◽  
Hydrogen Plasma ◽  
Similar Process ◽  
Process Conditions ◽  
Pure Hydrogen ◽  
High Quality ◽  
Dc Plasma ◽  
Thermal Cvd ◽  
Pulsed Dc

AbstractFavourable gas-phase conditions for deposition of Ti(C,N) from tetrakis(dimethylamine)titanium (TDMAT) in a pulsed DC-plasma have been determined, making use of mass spectroscopy. Decomposition of TDMAT in a pure hydrogen plasma results in the favourable cleavage of dimethylamine from TDMAT but prevents the formation of Ti(C,N) due to the lack of nitrogen and carbon. Addition of N2 to the hydrogen plasma results in the formation of NHx (l<x<4), opening possible transamination pathways. Transamination plays an important role in thermal CVD processes and results in high quality TiN layers. However, an undesired side-effect is the gas-phase particle formation under the conditions used here, possibly due to TDMAT - N2 interactions. The depletion of TDMAT by interaction with nitrogen in a H2(85%) - N2(15%) plasma proceeds in a mechnistic step with a rate constant of k = 4.7 × 10−14 cm3 mol−1sec. Results were compared with those obtained from using ammonia under similar process conditions, and with results from thermal CVD. Seemingly high quality Ti(C,N) coatings were deposited at temperatures between 200°C and 425°C on steel and glass with this simple and, therefore, interesting set-up.

Aspects of Gas Phase Chemistry During Chemical Vapor Deposition of Ti-Si-N Thin Films With Ti(NMe2)4 (TDMAT), NH3, and SiH4

1999 ◽  
Vol 606 ◽  
Author(s):  
Carmela Amato-Wierda ◽  
Edward T. Norton ◽  
Derk A. Wierda
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Gas Phase ◽  
Vapor Deposition ◽  
Molecular Beam ◽  
Chemical Vapor ◽  
Similar Process ◽  
Process Conditions ◽  
Gas Phase Chemistry ◽  
Phase Chemistry

AbstractSilane activation, predominantly in the gas phase, has been observed during the chemical vapor deposition of Ti-Si-N thin films using Ti(NMe2)4, tetrakis(dimethylamido)titanium, silane, and ammonia at 450°C, using molecular beam mass spectrometry. The extent of silane reactivity was dependent upon the relative amounts of Ti(NMe2)4and NH3. Additionally, each TDMAT molecule activates multiple silane molecules. Ti-Si-N thin films were deposited using similar process conditions as the molecular beam experiments, and RBS and XPS were used to determine their atomic composition. The variations of the Ti:Si ratio in the films as a function of Ti(NMe2)4 and NH3 flows were consistent with the changes in silane reactivity under similar conditions.

Reactivity Trends in the Gas Phase Addition of Acetylene to N-protonated Aryl Radical Cations

2020 ◽  
Author(s):  
Oisin Shiels ◽  
P. D. Kelly ◽  
Cameron C. Bright ◽  
Berwyck L. J. Poad ◽  
Stephen Blanksby ◽  
...  
Keyword(s):  
Gas Phase ◽  
Ion Trap ◽  
Radical Cations ◽  
Rate Coefficients ◽  
Similar Process ◽  
Ion Molecule Reactions ◽  
Aromatic Radicals ◽  
Polycyclic Aromatic ◽  
Gas Phase Ion ◽  
Type Radical

<div> <div> <div> <p>A key step in gas-phase polycyclic aromatic hydrocarbon (PAH) formation involves the addition of acetylene (or other alkyne) to σ-type aromatic radicals, with successive additions yielding more complex PAHs. A similar process can happen for N- containing aromatics. In cold diffuse environments, such as the interstellar medium, rates of radical addition may be enhanced when the σ-type radical is charged. This paper investigates the gas-phase ion-molecule reactions of acetylene with nine aromatic distonic σ-type radical cations derived from pyridinium (Pyr), anilinium (Anl) and benzonitrilium (Bzn) ions. Three isomers are studied in each case (radical sites at the ortho, meta and para positions). Using a room temperature ion trap, second-order rate coefficients, product branching ratios and reaction efficiencies are reported. </p> </div> </div> </div>

scholarly journals Hydrogenated amorphous carbon thin films deposition by pulsed DC plasma enhanced by electrostatic confinement

2014 ◽  
Vol 258 ◽  
pp. 219-224 ◽  
Author(s):  
S.M.M. Dufrène ◽  
F. Cemin ◽  
M.R.F. Soares ◽  
C. Aguzzoli ◽  
M.E.H. Maia da Costa ◽  
...  
Keyword(s):  
Thin Films ◽  
Amorphous Carbon ◽  
Dc Plasma ◽  
Hydrogenated Amorphous Carbon ◽  
Pulsed Dc ◽  
Electrostatic Confinement ◽  
Carbon Thin Films ◽  
Hydrogenated Amorphous

scholarly journals Fabrication and Particle Size Control of Oxide Nanoparticles by Gas Phase Reaction Assisted with DC Plasma

2007 ◽  
Vol 44 (6) ◽  
pp. 447-452 ◽  
Author(s):  
Akira Watanabe ◽  
Motoharu Fujii ◽  
Masayoshi Kawahara ◽  
Takehisa Fukui ◽  
Kiyoshi Nogi
Keyword(s):  
Particle Size ◽  
Gas Phase ◽  
Size Control ◽  
Oxide Nanoparticles ◽  
Phase Reaction ◽  
Dc Plasma ◽  
Gas Phase Reaction ◽  
Particle Size Control

Comparative Study of GaN Growth Process by MOVPE

1999 ◽  
Vol 572 ◽  
Author(s):  
Jingxi Sun ◽  
J. M. Redwing ◽  
T. F. Kuech
Keyword(s):  
High Temperature ◽  
Comparative Study ◽  
Gas Phase ◽  
Residence Time ◽  
Gas Flow ◽  
Flow Sheet ◽  
Flow Zone ◽  
High Quality ◽  
Phase Temperature ◽  
High Temperature Gas

ABSTRACTA comparative study of two different MOVPE reactors used for GaN growth is presented. Computational fluid dynamics (CFD) was used to determine common gas phase and fluid flow behaviors within these reactors. This paper focuses on the common thermal fluid features of these two MOVPE reactors with different geometries and operating pressures that can grow device-quality GaN-based materials. Our study clearly shows that several growth conditions must be achieved in order to grow high quality GaN materials. The high-temperature gas flow zone must be limited to a very thin flow sheet above the susceptor, while the bulk gas phase temperature must be very low to prevent extensive pre-deposition reactions. These conditions lead to higher growth rates and improved material quality. A certain range of gas flow velocity inside the high-temperature gas flow zone is also required in order to minimize the residence time and improve the growth uniformity. These conditions can be achieved by the use of either a novel reactor structure such as a two-flow approach or by specific flow conditions. The quantitative ranges of flow velocities, gas phase temperature, and residence time required in these reactors to achieve high quality material and uniform growth are given.

Structuring of Silicon Wafer Surfaces on the Sub-100 nm Scale by Hydrogen Plasma Treatments

2003 ◽  
Vol 788 ◽  
Author(s):  
R. Job ◽  
Y. Ma ◽  
A. G. Ulyashin
Keyword(s):  
Hydrogen Plasma ◽  
Structural Defects ◽  
Process Conditions ◽  
Force Microscopy ◽  
Czochralski Silicon ◽  
Atomic Force ◽  
Nano Structures ◽  
Plasma Treatments ◽  
The Impact ◽  
Wafer Surfaces

ABSTRACTHydrogen plasma treatments applied on standard Czochralski silicon (Cz Si) wafers cause a structuring of the surface regions on the sub-100 nm scale, i.e. a thin ‘nano-structured’ Si layer is created up to a depth of ∼ 150 nm. The formation of the ‘nano-structures’ and their evolution in dependence on the process conditions was studied. The impact of post-hydrogenation annealing on the morphology of the structural defects was studied up to 1200 °C. The H-plasma treated and annealed samples were analyzed at surface and sub-surface regions by scanning electron microscopy (SEM), atomic force microscopy (AFM), and μ-Raman spectroscopy.

Direct Nucleation of Crystalline SiGe on Substrates by Reactive Thermal CVD with Si2H6 and GeF4

1997 ◽  
Vol 467 ◽  
Author(s):  
Fumio Yoshizawa ◽  
Kunihiro Shiota ◽  
Daisuke Inoue ◽  
Jun-ichi Hanna
Keyword(s):  
Growth Rate ◽  
Gas Phase ◽  
Heterogeneous Nucleation ◽  
Homogeneous Nucleation ◽  
Film Growth ◽  
Early Stage ◽  
Gaseous Mixture ◽  
The Other ◽  
Thermal Cvd ◽  
Initial Deposition

ABSTRACTPolycrystalline SiGe (poly-SiGe) film growth by reactive thermal CVD with a gaseous mixture of Si2H6 and GeF4 was investigated on various substrates such as Al,Cr, Pt, Si, ITO, ZnO and thermally grown SiO2.In Ge-rich film growth, SEM observation in the early stage of the film growth revealed that direct nucleation of crystallites took place on the substrates. The nucleation was governed by two different mechanisms: one was a heterogeneous nucleation on the surface and the other was a homogeneous nucleation in the gas phase. In the former case, the selective nucleation was observed at temperatures lower than 400°C on metal substrates and Si, where the activation of adsorbed GeF4 on the surface played a major role for the nuclei formation, leading to the selective film growth.On the other hand, the direct nucleation did not always take place in Si-rich film growth irrespective of the substrates and depended on the growth rate. In a growth rate of 3.6nm/min, the high crystallinity of poly-Si0.95Ge0.05in a 220nm-thick film was achieved at 450°C due to the no initial deposition of amorphous tissue on SiO2 substrates.

Modified Physical Vapor Transport Growth of SiC - Control of Gas Phase Composition for Improved Process Conditions

2005 ◽  
Vol 483-485 ◽  
pp. 25-30 ◽  
Author(s):  
Peter J. Wellmann ◽  
Thomas L. Straubinger ◽  
Patrick Desperrier ◽  
Ralf Müller ◽  
Ulrike Künecke ◽  
...  
Keyword(s):  
Temperature Field ◽  
Phase Composition ◽  
Gas Phase ◽  
Growth Conditions ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Process Conditions ◽  
Growth Technique ◽  
Experimental Implementation ◽  
P Type

We review the development of a modified physical vapor transport (M-PVT) growth technique for the preparation of SiC single crystals which makes use of an additional gas pipe into the growth cell. While the gas phase composition is basically fixed in conventional physical vapor transport (PVT) growth by crucible design and temperature field, the gas inlet of the MPVT configuration allows the direct tuning of the gas phase composition for improved growth conditions. The phrase "additional" means that only small amounts of extra gases are supplied in order to fine-tune the gas phase composition. We discuss the experimental implementation of the extra gas pipe and present numerical simulations of temperature field and mass transport in the new growth configuration. The potential of the growth technique will be outlined by showing the improvements achieved for p-type doping of 4H-SiC with aluminum, i.e. [Al]=9⋅1019cm-3 and ρ<0.2Ωcm, and n-type doping of SiC with phosphorous, i.e. [P]=7.8⋅1017cm-3.

Pulsed-DC Electrospray for Biopolymer Particle Production

2009 ◽  
Vol 1239 ◽  
Author(s):  
Cho-Hui Lim ◽  
Kiersten R Schierbeek ◽  
Michael E Mullins
Keyword(s):  
Pulse Width ◽  
Particle Production ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Process Conditions ◽  
High Duty Cycle ◽  
Pulsed Dc ◽  
High Pulse ◽  
Long Pulse ◽  
Frequency Pulse

AbstractPLLA microparticles were successfully fabricated via pulsed-DC electrospray. In this study, we investigated the effect of the pulsed voltage characteristics (e.g. pulse frequency, pulse amplitude and pulse width) on the particle’s size. We found that pulse frequency, pulse amplitude, pulse width, and the combinations of these factors had a statistically significant effect on the particle’s size. The process conditions to obtain smaller particles with uniform shape and size are a low pulse frequency, high pulse amplitude, and long pulse width (or a high duty cycle).

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