Detection of SiH3 radicals and cluster formation in a highly H2 diluted SiH4 VHF plasma by means of time resolved cavity ring down spectroscopy

2006 ◽  
Vol 910 ◽  
Author(s):  
Takehiko Nagai ◽  
Arno H. M. Smets ◽  
Michio Kondo
Keyword(s):  
Growth Rate ◽  
Cluster Formation ◽  
Film Surface ◽  
Growth Conditions ◽  
Time Resolved ◽  
Cavity Ringdown ◽  
Plasma Ignition ◽  
Diffusion Controlled ◽  
Kinetics Of ◽  
Main Growth

AbstractThe spatial distribution of the SiH3 radicals between the electrodes of a hydrogen diluted silane VHF plasma under thin film hydrogenated microcrystalline silicon (μc-Si:H) growth conditions has been measured using the time resolved cavity ringdown (τ-CRD) absorption spectroscopy technique. The μc-Si:H growth rate is estimated from the measured spatial SiH3 profiles using a simple model based upon diffusion controlled flux of SiH3 radicals to the electrode surface, where the SiH3 can react with the film surface. The calculated value of μc-Si:H growth rate roughly agrees with the value of the experimentally determined growth rate. This agreement implies that the SiH3 radical is the main growth contributor to the μc-Si:H growth. Furthermore, the τ-CRD reveals the growth kinetics of the clusters in the plasma by light scattering at these clusters on time scales of 1 s after the plasma ignition.

Preparation and characterization of epitaxial iron oxide films

1998 ◽  
Vol 13 (7) ◽  
pp. 2003-2014 ◽  
Author(s):  
Y. Gao ◽  
Y. J. Kim ◽  
S. A. Chambers
Keyword(s):  
Growth Rate ◽  
Iron Oxide ◽  
Oxygen Plasma ◽  
Film Surface ◽  
Surface Region ◽  
Growth Conditions ◽  
Epitaxial Films ◽  
Pure Phase ◽  
Iron Oxide Films

Well-ordered, pure-phase epitaxial films of FeO, Fe3O4, and γ–Fe2O3 were prepared on MgO(001) by oxygen-plasma-assisted MBE. The stoichiometries of these thin films were controlled by varying the growth rate and oxygen partial pressure. Selective growth of γ–Fe2O3 and α–Fe2O3 was achieved by controlling the growth conditions in conjunction with the choice of appropriate substrates. Growth of the iron oxide epitaxial films on MgO at ≥350 °C is accompanied by significant Mg outdiffusion. The FeO(001) film surface exhibits a (2 × 2) reconstruction, which is accompanied by a significant amount of Fe3+ in the surface region. Fe3O4 (001) has been found to reconstruct to a structure. γ–Fe23 (001) film surface is unreconstructed.

Influence of oxygen partial pressure on the kinetics of YBa2Cu3O7−x formation

1994 ◽  
Vol 9 (2) ◽  
pp. 275-285 ◽  
Author(s):  
V. Milonopoulou ◽  
K.M. Forster ◽  
J.P. Formica ◽  
J. Kulik ◽  
J.T. Richardson ◽  
...  
Keyword(s):  
X Ray Diffraction ◽  
Decomposition Products ◽  
Time Resolved ◽  
X Ray ◽  
Formation Kinetics ◽  
Dimensional Diffusion ◽  
Diffusion Controlled ◽  
Gas Atmosphere ◽  
Kinetics Of

The YBa2Cu3O7−x formation kinetics from a spray-roasted precursor powder containing Y2O3, BaCO3, and CuO was followed via in situ, time-resolved x-ray diffraction as a function of gas atmosphere and temperature. In inert atmospheres, BaCO3 and CuO form BaCu2O2 which subsequently reacts with Y2O3 to form YBa2Cu3O6. However, YBa2Cu3O6 decomposes at temperatures exceeding 725 °C with Y2BaCuO5 being one of the decomposition products. In oxidizing atmospheres, YBa2Cu3O7−x formation involves the BaCuO2. At high temperatures (800–840 °C), oxygen increases the yield of YBa2Cu3O6. A nuclei growth model assuming two-dimensional, diffusion-controlled growth with second-order nucleation rate fits the experimental data.

Time-resolved Cavity Ringdown Spectroscopy as a Monitoring Technique of Nanoparticles in Pulsed VHF Plasmas

2007 ◽  
Vol 989 ◽  
Author(s):  
Takehiko Nagai ◽  
Arno H. M. Smets ◽  
Michio Kondo
Keyword(s):  
Time Scales ◽  
Rayleigh Scattering ◽  
Mie Scattering ◽  
Nano Particles ◽  
Initial Growth ◽  
Time Resolved ◽  
Cavity Ringdown ◽  
Plasma Ignition ◽  
Cavity Loss ◽  
Small Constant

AbstractTime-resolved cavity ringdown (τ-CRD) spectroscopy has been applied to monitor the sylil (SiH3) radicals and nano-particles in pulsed very high frequency (VHF) silane (SiH4)/hydrogen (H2) plasmas under microcrystalline silicon (μc-Si:H) deposition conditions. After the plasma ignition, a small constant cavity loss (~100 ppm) on timescales smaller than ~1 s has been observed, whereas on time scales larger than ~1 s after plasma ignition, an additional cavity loss is observed. By variation of the wavelength of the CRD laser pulse, we demonstrate that the cavity loss on time scales smaller than ~1 s reflects the SiH3 absorption. On time scales larger than ~1 s, the additional cavity loss corresponds to the loss of light due to mainly scattering at the nano-particles. Under the conditions studied, the light scattering at nano-particles can be described by Rayleigh scattering during its initial growth. After ~ 2.5 s, the cavity loss reflects the transition of the scattering mechanism from dominant Rayleigh to dominant Mie-scattering. These results are discussed in terms of nano-particles growing in time and further confirmed by additional scanning electron microscopy analyses on the nano-particles created in the plasma pulse.

Study of MBE ZnSe Growth Using Rheed Oscillations

1989 ◽  
Vol 145 ◽  
Author(s):  
Francoise S. Turco ◽  
M.C. Tamargo
Keyword(s):  
Growth Rate ◽  
Quantitative Study ◽  
Growth Parameters ◽  
Growth Conditions ◽  
High Energy ◽  
Growth Mechanisms ◽  
Mbe Growth ◽  
Wide Range ◽  
Main Growth

AbstractReflection high energy electron diffraction (RHEED) intensity oscillations are often used to investigate in situ the growth of III-V materials by molecular beam epitaxy (MBE). In this work, we have used RHEED oscillations to perform a quantitative study of the growth mechanisms of ZnSe, a II-VI semiconductor.Our experiments illustrate that the RHEED pattern of ZnSe is far less intense than that of III-V materials grown by MBE, and no specular spot is observed over a wide range of growth conditions. We have, however, been able to record up to 25 oscillations allowing a quantitative study of the growth of ZnSe by MBE. Thus we have used RHEED oscillations to make an in situ systematic study of the influence of the three main growth parameters (substrate temperature and Zn or Se impinging fluxes) on the ZnSe growth rate. We observed that the variation of the ZnSe growth rate is due to a non unity sticking coefficient of both Zn and Se species at the interface in the standard growth conditions used. Our observations can be described using a thermodynamic model and enable us to control the desired growth conditions. Our work demonstrates the utility of RHEED oscillations to understand the MBE growth mechanisms of II-VI compounds.

scholarly journals Two dimensional diffusion-controlled triplet–triplet annihilation kinetics

2019 ◽  
Vol 10 (32) ◽  
pp. 7633-7640 ◽  
Author(s):  
Grégoire C. Gschwend ◽  
Morgan Kazmierczak ◽  
Astrid J. Olaya ◽  
Pierre-François Brevet ◽  
Hubert H. Girault
Keyword(s):  
Harmonic Generation ◽  
Second Harmonic ◽  
Molecular Crowding ◽  
Two Dimensional ◽  
Time Resolved ◽  
Dimensional Diffusion ◽  
Diffusion Controlled ◽  
Kinetics Of ◽  
Annihilation Reaction ◽  
Triplet Triplet Annihilation

We show with time-resolved second harmonic generation and molecular mechanics simulations that the kinetics of a two-dimensional triplet–triplet annihilation reaction at the liquid–liquid interface is affected by molecular crowding.

Comparison of the Growth Kinetics of Oxides Grown in Tungsten-Halogen and Water Cooled Arc Lamp Systems

1987 ◽  
Vol 92 ◽  
Author(s):  
C.A. Paz de Araujo ◽  
J.C. Gelpey ◽  
Y.P. Huang ◽  
R. Kwor
Keyword(s):  
Growth Rate ◽  
Thermal Oxidation ◽  
Growth Kinetics ◽  
Dwell Time ◽  
Growth Conditions ◽  
Ambient Conditions ◽  
Wafer Temperature ◽  
System Bias ◽  
Lamp System ◽  
Kinetics Of

ABSTRACTRapid thermal oxidation of silicon has been performed in a tungsten-halogen system (AG-410) and a water-wall arc lamp system (Eaton ROA-400). Growth kinetics of the oxides are studied with particular attention to ramp-up ambient conditions, dwell time, maximum wafer temperature and difference in activation energies. These parameters are characterized using ellipsometry in order to measure system bias with respect to growth rate and breakdown. Experiments were designed to identify the differences in the initial enhanced growth conditions, and their effect on growth kinetics during the dwell cycle.

In situ Time-Resolved Small-Angle X-ray Scattering Reveals the Formation Kinetics of Polyelectrolyte Complex Micelles

2019 ◽  
Author(s):  
Hao Wu ◽  
Jeffrey Ting ◽  
Siqi Meng ◽  
Matthew Tirrell
Keyword(s):  
Small Angle ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Polyelectrolyte Complex ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Kinetics Of ◽  
Ray Scattering

We have directly observed the <i>in situ</i> self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

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