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  • 1
    Electronic Resource
    Electronic Resource
    Initial stages of AlN thin-film growth on alumina using trimethylamine alane and ammonia precursors (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 5385-5390 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A novel precursor combination, trimethylamine alane (TMAA) and ammonia (NH3), has been investigated for the low-temperature chemical vapor-deposition of AlN thin films. The initial stages of AlN growth on alumina powder substrates were studied by Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy. Upon exposure of TMAA to the alumina surface at 300 K, infrared data show the presence of molecular trimethylamine alane on the surface. NH3 reacts with the TMAA derivatized surface at 300 K, removing all of the trimethylamine, and leaving a four-coordinate -NH2- species bound to aluminum in extended networks. Concurrently, the population of alane on the surface is greatly reduced as a result of reaction with NH3 to form -NH2- and liberate H2. Subsequent exposure of TMAA leads to reaction with the surface -NH2- species and the further adsorption of TMAA. These reactions continue to propagate following additional alternating exposures of NH3 and TMAA, although with decreasing efficiency. The efficiency is increased if the processing is carried out at 400 K. X-ray photoelectron spectroscopy results confirm the formation of AlN after repeated cyclic exposure/processing at substrate temperatures as low as 400 K but not at 300 K.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.355693
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  • 2
    Electronic Resource
    Electronic Resource
    Chemisorption of trimethylaluminum and ammonia on silica: mechanisms for the formation of aluminum-nitrogen bonds and the elimination of methyl groups bonded to aluminum (1991)
    s.l. : American Chemical Society
    Chemistry of materials 3 (1991), S. 953-960 
    Details
    ISSN: 1520-5002
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/cm00017a035
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  • 3
    Electronic Resource
    Electronic Resource
    Mechanistics of early stage growth of aluminum nitride (AlN) on alumina: TMAl [trimethylaluminum] and ammonia (1993)
    s.l. : American Chemical Society
    Chemistry of materials 5 (1993), S. 391-395 
    Details
    ISSN: 1520-5002
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/cm00027a025
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  • 4
    Electronic Resource
    Electronic Resource
    Mechanistics of early stage growth of aluminum nitride on alumina. 2. TMAl and ammonia (1993)
    s.l. : American Chemical Society
    Chemistry of materials 5 (1993), S. 1814-1818 
    Details
    ISSN: 1520-5002
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/cm00036a020
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  • 5
    Electronic Resource
    Electronic Resource
    A simple fast pulse gas valve using a dynamic pressure differential as the primary closing mechanism (1993)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1410-1413 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: In this article we describe a simple fast pulse gas valve developed for use in a plasma discharge experiment. The valve delivers 1017–1019 molecules per pulse varied by changing the voltage on the electromagnetic driver power supply. Valve pulse widths are observed to be less than 300 μs full width at half maximum with a rise time of less than 100 μs resulting in a maximum gas flow rate of ∼1022 molecules per second. An optical transmission technique was used to determine the mechanical opening and closing characteristics of the valve piston. A fast ionization gauge (FIG) was used for diagnosis of the temporal character of the gas pulse while the total gas throughput was determined by measuring the change in pressure per pulse in a small test chamber with a convectron tube gauge. Calibration of the FIG was accomplished by comparing the net change in pressure in a large chamber as measured by the FIG to the net change in pressure in a small test chamber as measured by the convectron tube gauge.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1144053
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  • 6
    Electronic Resource
    Electronic Resource
    Potassium-assisted, facile oxidation of Si3N4 thin films (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 2066-2073 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: X-ray photoelectron spectroscopy (XPS) was used to investigate potassium-assisted, facile oxidation of silicon nitride (Si3 N4 ) thin films on Si(100) substrates. The nitride films, 0.8–2.5 nm thick, were grown by heating the Si(100) crystal in hydrazine. Potassium (K) deposited onto the Si3 N4 surface at room temperature in a background of oxygen resulted in the formation of potassium peroxide (K2 O2 ) overlayers. Annealing the sample at 975 K for only 60 s decomposed the K2 O2 overlayer, desorbed K from the surface, and efficiently oxidized the underlying substrate. The XPS Si(2p) spectra indicate formation of silicon oxynitride on the surface. In the early stages of oxidation, up to 100% of the oxygen originally deposited as K2 O2 , was converted to silicon oxynitride after annealing. The enhanced oxidation rate under these conditions, relative to direct thermal oxidation, is attributed to the large concentration of reactive oxygen on the surface when the K2 O2 thermally decomposes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.345594
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  • 7
    Electronic Resource
    Electronic Resource
    The University of Washington polarized ion source : International conference on ion sources (1990)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 445-447 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A colliding-beam polarized ion source has been in operation for nuclear physics experiments at the University of Washington tandem-linac facility since late 1987. Thermal beams of polarized atomic hydrogen or deuterium are ionized by charge exchange in collisions with a collinear, fast, neutral cesium beam. Negative ions are extracted, and the polarization symmetry axis is precessed to any desired direction in a crossed-field spin precessor. The design of the cesium-beam system differs from previous sources in that magnetic deflection and focusing are used, and beams of several milliamperes at energies of 40 keV are produced. The source is controlled by a microprocessor-based system which is connected via fiber-optic links to the main linac-control and data-acquisition computers. To date, currents of 1 μA and polarizations in excess of 90% have been produced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1141268
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  • 8
    Electronic Resource
    Electronic Resource
    Beat wave excitation of electron plasma waves in a toroidal magnetized plasma (1992)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 4 (1992), S. 1920-1926 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Electrostatic waves are driven in a toroidal plasma by counterpropagating microwave beams with a difference in frequency approximately equal to the electron plasma frequency. Energetic electrons are detected when the phase velocity of the electrostatic waves are 3ve〈 vph 〈 7ve, where ve is the electron thermal velocity. Experiments are performed in the Davis Diverted Torus (DDT) [Bull. Am. Phys. Soc. 33, 2049 (1988)] operating in a high repetition rate (15 Hz), low-density (7×107–2×109 cm−3) mode with only a toroidal magnetic field (∼110 G). The microwaves are triggered 30 μsec after the pulsed discharge ends. At this time the energetic electrons have left the system and the velocity distribution is Maxwellian (Te ∼ 1 eV). The microwaves have tunable frequencies over the range 8.5–9.5 GHz, and peak powers ∼180 kW (400 nsec). Bounded plasma modes are excited when the electron cyclotron frequency is larger than the electron plasma frequency. Direct measurements of the wave vector have been made with a double probe antenna, from which the dispersion relation of the electrostatic wave can be obtained. The electron distribution is measured with an electrostatic energy analyzer. The electron velocity distribution function is found to be constant over an interval that extends well beyond the phase velocity of the wave.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.860044
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  • 9
    Electronic Resource
    Electronic Resource
    A reexamination of the chemisorption of trimethylaluminum on silica (1991)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 95 (1991), S. 4453-4463 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100164a054
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  • 10
    Electronic Resource
    Electronic Resource
    Validating cylindrical Langmuir probe techniques (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 31-36 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Several methods for estimating the plasma potential and density using cylindrical Langmuir probes are compared to the self-consistent solutions of the Vlasov–Poisson equations calculated by Laframboise (J. G. Laframboise, Ph. D. dissertation, University of Toronto, 1966). Measurements are made during the decay of a magnetic-field-free plasma in which the mean-free path of the electron is shorter than the dimensions of the vacuum vessel (the electrons, therefore, have a Maxwellian velocity distribution). The measurements are made in a parameter range in which exact analytical solutions do not exist for the ion and electron saturation currents, 0.5≤R/λDe≤5, where R is the probe radius and λDe is the electron Debye length (kTe/4πne2)1/2. An iterative procedure is used to fit the data at probe voltages both above and below the plasma potential while constraining the curves to be continuous at the plasma potential. The measured curves could be represented extremely well by the numerical results. It is therefore assumed that the plasma parameters used to fit the numerical results to the measurements are correct. The systematic errors which result from using several analysis techniques which assume R/λDe(very-much-less-than)1 are also presented, and it is shown that empirical corrections to these errors can be described which compensate for the finite probe radius.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1142743
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