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Plasma CVD (plasma + cvd)

Distribution by Scientific Domains

Polymers and Materials Science	50%

Selected Abstracts

Effect of deposition temperature on the properties of thin polymer films deposited by plasma-enhanced CVD using cyclo-hexa-hydrocarbons as monomers

ELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 4 2010
Kazunori Moriki
Abstract Plasma CVD is a candidate technology for the fabrication of optical polymer waveguides. It can deposit a film on any surface geometry and any substrate material at a temperature under 200 °C in a vacuum process. It also provides good thickness controllability and uniformity of the deposition film. In the present study, the effects of the deposition temperature on film properties, specifically the refractive index, deposition rate, and molecular structure, are discussed. The refractive index decreases as the deposition temperature rises. The logarithm of the deposition rate increases with the reciprocal of the temperature and the gradient of the deposition rate depends on the relative abundance of double bonds in the monomer source. The gradient does not change when CF4 is used instead of Ar as the gas mixed into the plasma, although the deposition rate increases by a factor of about five. We speculate that the deposition rate increases due to the increase in the abundance precursors produced by the presence of CF4 in the plasma and due to an increased abundance of dangling bonds on the surface of the deposition film caused by F radicals. We further speculate that the precursors incorporated into the polymer are selected on the substrate by the density of adsorption sites and the adsorption energy. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(4): 27,35, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10171 [source]

Very High Yield Growth of Vertically Aligned Single-Walled Carbon Nanotubes by Point-Arc Microwave Plasma CVD,

CHEMICAL VAPOR DEPOSITION, Issue 3 2005
F. Zhong
A very high yield, selective growth of dense, vertically aligned single-walled carbon nanotubes (SWNTs) has been demonstrated for the first time on Si substrates with a sandwich-like coating structure of Al2O3/Fe/Al2O3 at a low (600,°C) temperature by point-arc microwave plasma CVD. The SWNT film thickness increases continuously with the growth time, suggesting an almost unlimited life time for the catalyst. A film thickness of 420,,m, and production yield of SWNTs to catalyst of about 770,000,% can be achieved within 2,h. [source]

Characterization of microcrystalline Si films deposited at low temperatures with high rates by atmospheric-pressure plasma CVD

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010
K. Ouchi
Abstract Low-temperature and high-rate depositions of hydrogenated microcrystalline silicon (,c -Si:H) films are investigated using stable plasma excited at atmospheric pressure (AP) by supplying 150-MHz very high-frequency (VHF) power. VHF power density, H2/SiH4 ratio and plasma gap are varied as parameters under a fixed substrate temperature (Tsub) of 220 ,C. Increasing VHF power density and H2/SiH4 ratio is primarily important for the sufficient decomposition of source gas molecules, improving both deposition rate and film property. In addition, the plasma gap is found to be another crucial parameter in the deposition process using AP-VHF plasma. Numerical analyses on the temperature distribution around the plasma region have revealed that the steady-state surface temperature of the glass substrate becomes approximately 100 ,C higher than the back surface temperature (Tsub), which is caused by the moderate surface heating effect of the AP-VHF plasma. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Investigation of structural properties of high-rate deposited SiNx films prepared at low temperatures (100,300 °C) by atmospheric-pressure plasma CVD

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010
Y. Yamaguchi
Abstract We have investigated the structural properties of silicon nitride (SiNx) films deposited at low temperatures (100,300 °C with very high rates (>50 nm/s) in atmospheric-pressure He/H2/SiH4/NH3 plasma excited by a 150 MHz very high-frequency (VHF) power using a cylindrical rotary electrode. For this purpose, SiNx films are prepared on Si(001) wafers varying NH3/SiH4 ratio, H2 concentration in the plasma and substrate temperature (Tsub). Infrared absorption spectroscopy is used to analyze the bonding configurations of Si, N and H atoms in the films. It is shown that by decreasing NH3/SiH4 ratio or increasing H2 concentration, Si,N and Si,H bond densities increase, while N,H bond density decreases. A reasonably good-quality film showing a BHF etching rate of 28 nm/min and a refractive index of 1.81 is obtained at Tsub = 300 °C despite the very high deposition rate of 166 nm/s. However, it is found that the decrease in Tsub causes the deterioration of film quality. Further surface excitation by increasing VHF power and/or H2 concentration together with the optimization of other deposition parameters will be needed to form high-quality SiNx films with high rates at lower temperatures (Tsub , 100 °C). (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Low Temperature Growth of Photoactive Titania by Atmospheric Pressure Plasma

PLASMA PROCESSES AND POLYMERS, Issue 9 2009
John L. Hodgkinson
Abstract Atmospheric pressure glow discharge plasma CVD was used to deposit thin films of titania at 200,°C using two different precursors. The resulting films were characterised using techniques including XPS, RBS and XRD. It was established that annealing at temperatures as low as 275,°C produced crystalline films that were photocatalytically active. When annealed at 300,°C the photoactivity was greater than that of commercially available "self-cleaning" titania films. The effects of the different precursors, annealing times and temperatures on the crystallinity and photoactivity are discussed. [source]