Mass Spectrometric Study of Laser-Induced Chemical Vapor Deposition of Gold

1987 ◽  
Vol 101 ◽  
Author(s):  
Toivo T. Kodas ◽  
Paul B. Comita
Keyword(s):  
Surface Temperature ◽  
Reaction Rate ◽  
Chemical Vapor ◽  
Mass Spectrometric Study ◽  
Reaction Products ◽  
Quadrupole Mass ◽  
Product Concentration ◽  
Ion Laser ◽  
Phase Sensitive ◽  
Argon Ion

ABSTRACTA modulated surface temperature technique was used to study the surface chemical reactions occurring during the laser-assisted deposition of gold from dimethyl gold hexafluoroacetylacetonate. An argon ion laser was chopped and used to modulate the surface temperature on an area roughly 1 mm in diameter on an alumina substrate. Reactant and products of the photothermal reaction were sampled through an orifice located at the center of the deposit and were then introduced directly into a quadrupole mass filter. Since the reactant concentration at the surface decreased when the laser turned on while the product concentration at the surface increased when the laser turned on, modulating the surface reaction rate and employing phase-sensitive detection allowed the identification of reaction products.

Silicon Growth Rate Enhancement Using Trisilane in a Laser Direct-Writing Technique

1995 ◽  
Vol 397 ◽  
Author(s):  
S. Boughaba ◽  
G. Auvert
Keyword(s):  
Surface Temperature ◽  
Gas Pressure ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Multilayered Structures ◽  
Deposition Rates ◽  
Micron Size ◽  
Ion Laser ◽  
Silicon Growth ◽  
Argon Ion

ABSTRACTAn argon-ion laser based direct-writing technique was used to deposit micron-size silicon lines from the decomposition of silane (SiH4) and trisilane (Si3H8) gases. The substrates used were 0.1 μrn polysilicon/1 μ.m silicon dioxide/<100> monosilicon multilayered structures. The vertical silicon deposition rate was investigated as a function of the laser-induced surface temperature and gas pressure. For temperatures ranging between 1000 and 1410 °C, the pressure was varied in the range 5-250 mbar and 0.1-30 mbar for SiH4 and Si3H8, respectively. For both gases, three growth regimes could be distinguished according to precursor pressure. The deposition rates achieved using trisilane are far higher than those obtained with silane in spite of the use of a reduced gas pressure range. For a laser-induced surface temperature of 1300 °C and a precursor pressure of 10 mbar, the deposition rates achieved using SiH4 and Si3H8 are, respectively, 0.42 and 20 μ.m/s, representing an enhancement factor of 50 with the later.

Laser-Induced Dry Etching of GaAs with High Aspect Ratio

1991 ◽  
Vol 236 ◽  
Author(s):  
Cheon Lee ◽  
Hirokazu Sayama ◽  
Susumu Namba ◽  
Mikio Takai
Keyword(s):  
Aspect Ratio ◽  
Electron Spectroscopy ◽  
Laser Power ◽  
Chemical Compositions ◽  
Reaction Products ◽  
Scan Speed ◽  
Ion Laser ◽  
Etched Surface ◽  
Argon Ion ◽  
Scattering Measurement

AbstractLaser-induced thermochemical reactions have been investigated for GaAs in a CCl2F2 gas ambient using an argon-ion laser. The chemical compositions of the reaction products deposited on the etched groove were measured by Auger electron spectroscopy (AES). The conditions of laser power, scan speed, and CC12F2 gas pressure under which the etching reaction occurs without deposition of the residue were clarified. High etching rates up to 267 μm/s and an aspect ratio of 4.5 have been achieved by a single scan of a laser beam. Microprobe photoluminescence and Raman scattering measurement were carried out on the etched surface to characterize damage induced by this processing.

Fabrication and Testing of a Novel Microelectromechnical Device for the Study of Boiling Bubble Dynamics

2003 ◽  
Author(s):  
Saeed Moghaddam ◽  
Kenneth T. Kiger ◽  
Jean-Marc Henriette ◽  
Michael Ohadi
Keyword(s):  
Surface Temperature ◽  
High Speed ◽  
Sensor Array ◽  
Bubble Dynamics ◽  
Ccd Camera ◽  
Ion Laser ◽  
Net Flux ◽  
Argon Ion ◽  
The Heat Transfer Coefficient ◽  
Wall Surface Temperature

An array of 44 resistance temperature sensors with a radial resolution of 35 μm was fabricated around a re-entrant cavity (3 μm mouth diameter) on a thin silicon diaphragm with the intended purpose of obtaining highly resolved spatial and temporal measurements of the wall surface temperature during the boiling process. An Argon ion laser beam was used to provide a constant net flux of thermal energy to the backside of the diaphragm underneath the cavity and sensor area. This microsystem initiates and grows a single bubble at the center of the radial sensor array; all while the temperature variation underneath the bubble region during growth, departure, and rewetting is being measured with a frequency of 10 kHz. A high-speed CCD camera capable of taking over 3700 pictures per second is used to monitor the growth rate and departure process of the bubble from the surface, and correlated with the surface temperature measurement. The resulting temperature data can then be used to calculate the variation of the heat transfer coefficient under the bubble during the process of growth, departure, and rewetting. This experimental study provided unique experimental data to evaluate varieties of theories and speculations about the dynamics of bubbling at a microscale level. The focus of the current paper is on the details of the apparatus development and fabrication.

Surface Studies of Laser Processing of W on GaAs from WF6

1991 ◽  
Vol 236 ◽  
Author(s):  
M. Tabbal ◽  
A. Lecours ◽  
R. Izquierdo ◽  
M. Meunier ◽  
A. Yelon
Keyword(s):  
Photoelectron Spectroscopy ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Process Window ◽  
Laser Chemical Vapor Deposition ◽  
Laser Illumination ◽  
Ion Laser ◽  
Spectroscopy Studies ◽  
Argon Ion

AbstractLaser Chemical Vapor Deposition of tungsten on GaAs from WF6 using a focused cw scanning argon-ion laser beam has been investigated. Lines have been produced using different mixtures of WF6:H2 and WF6:SiH4 and in some cases, without any reducing gas. Depositions are found to occur within a narrow process window, and are difficult to reproduce. In order to understand this process, we have performed surface analysis on GaAs samples exposed to WF6. X-Ray Photoelectron Spectroscopy studies on the interaction between WF6 and GaAs in the absence of laser illumination show that fluorinated tungsten compounds are present on the GaAs surface. Furthermore, the existence of a chemical reaction leading to the formation of GaF3 at the surface and to a loss of the stoichiometry of the substrate surface is detected. Possible mechanisms, and the effects of these reactions on the deposition process are discussed.

Decomposition of peroxobenzoic acid in benzene catalyzed by transition metal 2,4-pentanedionates

1984 ◽  
Vol 49 (3) ◽  
pp. 673-679 ◽  
Author(s):  
Pavel Lederer ◽  
Eva Mácová ◽  
Josef Vepřek-Šiška
Keyword(s):  
Transition Metal ◽  
Reaction Rate ◽  
Reaction Products ◽  
Acid Decomposition ◽  
Analogous Experiment ◽  
Catalytic Effects

The decomposition of peroxobenzoic acid in benzene was studied, and catalytic effects of Fe(III), Mn(III), Co(II), Co(III), and Cr(III) on the reaction rate and the composition of the reaction mixture were investigated. An analogous experiment carried out in perdeuterobenzene and determination of the distribution of deuterium in the reaction products provided evidence for the participation of the solvent in peroxobenzoic acid decomposition.

Kinetics of carbon monoxide methanation on a Ni/SiO2 catalyst

1990 ◽  
Vol 55 (7) ◽  
pp. 1678-1685
Author(s):  
Vladimír Stuchlý ◽  
Karel Klusáček
Keyword(s):  
Carbon Monoxide ◽  
Reaction Rate ◽  
Catalyst Activity ◽  
Adsorbed Hydrogen ◽  
Reaction Products ◽  
Co Methanation ◽  
Molar Ratios ◽  
Rate Determining Step ◽  
Higher Temperature ◽  
Kinetics Of

Kinetics of CO methanation on a commercial Ni/SiO2 catalyst was evaluated at atmospheric pressure, between 528 and 550 K and for hydrogen to carbon monoxide molar ratios ranging from 3 : 1 to 200 : 1. The effect of reaction products on the reaction rate was also examined. Below 550 K, only methane was selectively formed. Above this temperature, the formation of carbon dioxide was also observed. The experimental data could be described by two modified Langmuir-Hinshelwood kinetic models, based on hydrogenation of surface CO by molecularly or by dissociatively adsorbed hydrogen in the rate-determining step. Water reversibly lowered catalyst activity and its effect was more pronounced at higher temperature.

Laser Induced Etching for Generation of Si Nanocrystals and Spectroscopic Investigation of Morphology

2005 ◽  
Vol 23 ◽  
pp. 43-46
Author(s):  
H.S. Mavi ◽  
S. Rath ◽  
Arun Shukla
Keyword(s):  
Quantum Confinement ◽  
Silicon Nanocrystals ◽  
Laser Wavelength ◽  
Interconnected Network ◽  
Substrate Type ◽  
Argon Ion Laser ◽  
Si Nanocrystals ◽  
Ion Laser ◽  
Laser Induced Etching ◽  
Argon Ion

Laser-induced etching of silicon is used to generate silicon nanocrystals. The pore structure depends on the substrate type and etching laser wavelength. Porous silicon (PS) samples prepared by Nd:YAG laser (1.16 eV) etching of n-type substrate showed a fairly uniform and highly interconnected network of nearly circular pores separated by thin columnar boundaries, while no circular pits were produced by argon- ion laser (2.41 eV) etching under similar conditions. The size and size distribution of the nanocrystals are investigated by Raman and photoluminescence spectroscopies and analyzed within the framework of quantum confinement models.

A Current Conduction Mechanism in Laser Recrystallized Silicon Metal-Oxide-Semiconductor Transistors

1983 ◽  
Vol 23 ◽  
Author(s):  
Han-Sheng Lee
Keyword(s):  
Conduction Mechanism ◽  
Single Crystal Silicon ◽  
Silicon Films ◽  
Oxide Semiconductor ◽  
Silicon Substrates ◽  
Mos Transistors ◽  
Crystal Silicon ◽  
Ion Laser ◽  
Argon Ion ◽  
A Current

ABSTRACTN-channel MOS transistors were fabricated on silicon films that had been recrystallized by an argon ion laser at different power levels. These transistors showed electrical characteristics similar, but somewhat inferior to those devices fabricated on single crystal silicon substrates. These differences are attributed to the presence of trapping states at the grain boundaries of the crystallites in the recrystallized silicon. A coulombic scattering model is presented to explain these differences. In the case of films annealed at low laser power, an additional factor of nonuniform trap state distribution is invoked to explain device characteristics. This model provides an adequate explanation for the observed transport properties of transistors fabricated from recrystallized silicon films.

Electron temperatures in a segmented-metal argon-ion laser

1972 ◽  
Vol 5 (10) ◽  
pp. 1807-1814 ◽  
Author(s):  
A Maitland ◽  
J C L Cornish
Keyword(s):  
Argon Ion Laser ◽  
Ion Laser ◽  
Argon Ion

scholarly journals A large area diamond-based beam tagging hodoscope for ion therapy monitoring

2018 ◽  
Vol 170 ◽  
pp. 09005 ◽  
Author(s):  
M.-L. Gallin-Martel ◽  
L. Abbassi ◽  
A. Bes ◽  
G. Bosson ◽  
J. Collot ◽  
...  
Keyword(s):  
Detection Efficiency ◽  
Signal To Noise Ratio ◽  
Therapy Monitoring ◽  
Chemical Vapor ◽  
X Rays ◽  
Reaction Products ◽  
Large Area ◽  
Position Measurement ◽  
Set Up ◽  
Good Signal

The MoniDiam project is part of the French national collaboration CLaRyS (Contrôle en Ligne de l’hAdronthérapie par RaYonnements Secondaires) for on-line monitoring of hadron therapy. It relies on the imaging of nuclear reaction products that is related to the ion range. The goal here is to provide large area beam detectors with a high detection efficiency for carbon or proton beams giving time and position measurement at 100 MHz count rates (beam tagging hodoscope). High radiation hardness and intrinsic electronic properties make diamonds reliable and very fast detectors with a good signal to noise ratio. Commercial Chemical Vapor Deposited (CVD) poly-crystalline, heteroepitaxial and monocrystalline diamonds were studied. Their applicability as a particle detector was investigated using α and β radioactive sources, 95 MeV/u carbon ion beams at GANIL and 8.5 keV X-ray photon bunches from ESRF. This facility offers the unique capability of providing a focused (~1 μm) beam in bunches of 100 ps duration, with an almost uniform energy deposition in the irradiated detector volume, therefore mimicking the interaction of single ions. A signal rise time resolution ranging from 20 to 90 ps rms and an energy resolution of 7 to 9% were measured using diamonds with aluminum disk shaped surface metallization. This enabled us to conclude that polycrystalline CVD diamond detectors are good candidates for our beam tagging hodoscope development. Recently, double-side stripped metallized diamonds were tested using the XBIC (X Rays Beam Induced Current) set-up of the ID21 beamline at ESRF which permits us to evaluate the capability of diamond to be used as position sensitive detector. The final detector will consist in a mosaic arrangement of double-side stripped diamond sensors read out by a dedicated fast-integrated electronics of several hundreds of channels.

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