The Influence of Magnetic Fields on the Properties of Amorphous Carbon Prepared by Plasma Deposition

1987 ◽  
Vol 98 ◽  
Author(s):  
R. H. Jarman ◽  
A. T. Howe
Keyword(s):  
Magnetic Field ◽  
Amorphous Carbon ◽  
Plasma Deposition ◽  
Protective Coatings ◽  
Carbon Films ◽  
Rf Discharge ◽  
Capacitively Coupled ◽  
Amorphous Carbon Films ◽  
Wide Range ◽  
Electrical Conductivities

ABSTRACTAmorphous carbon films exhibit a wide range of optical, electrical and mechanical properties which make them candidates for a number of applications such as protective coatings and insulators in electronic devices. We describe the effects of a magnetic field applied at the powered electrode in a capacitively coupled rf discharge on the optical and electrical properties of amorphous carbon films deposited on substrates mounted on both electrodes. In the case of substrates placed on the powered electrode, the film properties appear to be very sensitive to the magnetic field strength. At the highest magnetic field, the deposition rates are very much higher than those obtained in the absence of a magnetic field. The optical gap varies from 1.1 eV to 2.7 eV depending on the deposition conditions. The electrical conductivities of the films are very low and show a complex dependence on the applied electric field.

Influence of nitrogen and temperature on the plasma deposition of fluorinated amorphous carbon films

2002 ◽  
Vol 20 (4) ◽  
pp. 1210-1215 ◽  
Author(s):  
L. Valentini ◽  
J. M. Kenny ◽  
R. M. Montereali ◽  
L. Lozzi ◽  
S. Santucci
Keyword(s):  
Amorphous Carbon ◽  
Plasma Deposition ◽  
Carbon Films ◽  
Amorphous Carbon Films

The Relationship Between Emission Spectroscopy and Optical Properties of Amorphous Carbon Films

1987 ◽  
Vol 98 ◽  
Author(s):  
Richard M. Roth ◽  
Richard H. Jarman
Keyword(s):  
Optical Properties ◽  
Amorphous Carbon ◽  
Emission Spectroscopy ◽  
Carbon Films ◽  
Capacitively Coupled ◽  
Amorphous Carbon Films ◽  
Rf Glow Discharge ◽  
Discharge Parameters ◽  
The Relationship ◽  
Deposited Films

ABSTRACTEmission from CH and H radicals was monitored during the deposition of amorphous carbon films in a capacitively coupled rf glow discharge. Both the spectral and spatial distributions of the emission were studied. The relative intensity of the CH and H emission was found to be sensitive to changes in discharge parameters. Preliminary results indicate a correlation between the ratios of the CH to H emission intensities and the optical properties of the deposited films.

THE DETERMINATION OF SP3 FRACTION IN TETRAHEDRAL AMORPHOUS CARBON FILMS BY RAMAN AND X-RAY PHOTOELECTRON SPECTROSCOPY

2002 ◽  
Vol 16 (28n29) ◽  
pp. 4413-4417 ◽  
Author(s):  
DIHU CHEN ◽  
G. Y. JING ◽  
AIXIANG WEI
Keyword(s):  
Amorphous Carbon ◽  
Photoelectron Spectroscopy ◽  
Plasma Deposition ◽  
Carbon Films ◽  
Gaussian Peak ◽  
Xps Spectra ◽  
Raman Analysis ◽  
Amorphous Carbon Films ◽  
Tetrahedral Amorphous Carbon

Tetrahedral amorphous carbon films have been prepared by magnetic filtered plasma deposition system. The samples were deposited with negative bias voltage V b range from +20 V to -95 V. The relative fraction of sp 3-bonded carbon in these films was qualitatively and quantitatively estimated by a fitting of the Raman and XPS spectra, respectively. Raman results show that the sp 3 fraction of the films deposited in the range from -10 V to -50 V was estimated to be more than 80%. The C 1s spectra were consistently decomposed into the two gaussian components, one is at 284.4±0.1 eV corresponding to sp 2-hybridized bonds, and another is at 285.2±0.1 eV corresponding to sp 3-hybridized bond. The sp 3 content can be quantitatively calculated from the integrated area of the respective gaussian peak divided by the total area of the spectra. The comparison of XPS with Raman analysis, the trend of qualitative variation of sp 3 content with V b is in agreement. We concluded that XPS analysis is a useful method for quantitatively calculating sp 3 content in hydrogen-free tetrahedral amorphous carbon films.

Plasma deposition of amorphous carbon films from CH4 atmospheres highly diluted in Ar

2002 ◽  
Vol 419 (1-2) ◽  
pp. 46-53 ◽  
Author(s):  
L.G. Jacobsohn ◽  
G. Capote ◽  
N.C. Cruz ◽  
A.R. Zanatta ◽  
F.L. Freire Jr
Keyword(s):  
Amorphous Carbon ◽  
Plasma Deposition ◽  
Carbon Films ◽  
Amorphous Carbon Films

Characterization of Plasma-Deposited Amorphous Carbon Films

1987 ◽  
Vol 98 ◽  
Author(s):  
Wen. L. Hsu ◽  
G. W. Foltz ◽  
F. A. Greulich ◽  
K. F. Mccarty ◽  
G. J. Thomas ◽  
...  
Keyword(s):  
Power Density ◽  
Deposition Rate ◽  
Amorphous Carbon ◽  
Carbon Films ◽  
Average Density ◽  
Rf Discharge ◽  
Amorphous Carbon Films ◽  
Hydrogen Molecules ◽  
Thin Carbon

ABSTRACTThin carbon films of ˜ 600 Å have been deposited on Si <111> wafers by striking an RF discharge in gas mixtures of hydrogen and methane. The deposition rate increased with increasing methane fraction. The peak rate was ˜ 1 Å/sec at an applied power density of 0.4 W cm−2. The films, with an average density of 2.54 gm cm−3, are amorphous in nature but exhibit broad diffraction maxima corresponding to interatcidc spacings of 2.05Å and 1. 15Å. Measurements of hydrogen concentration in the films showed that the hydrogen at. % [H/(H+C)] increased from 30 to 40% as the hydrogen fraction in the feed gas increased. By using a D2-CH4, we were also able to deduce that hydrogen molecules can be a large source of hydrogen trapped in the films.

Plasma deposition of amorphous carbon films from methane atmospheres highly diluted in argon

2001 ◽  
Vol 697 ◽  
Author(s):  
L. G. Jacobsohn ◽  
F. L. Freire
Keyword(s):  
Mechanical Properties ◽  
Raman Spectroscopy ◽  
Amorphous Carbon ◽  
Plasma Deposition ◽  
Carbon Films ◽  
X Ray Diffraction ◽  
Amorphous Carbon Films ◽  
X Ray ◽  
Partial Pressures ◽  
Amorphous Character

AbstractWe investigated the deposition, structure and mechanical properties of a-C:H films grown in Ar-CH4 mixtures with the Ar partial pressure ranging from 0 to 99 %. The deposition rate strongly decreased with progressive Ar dilution of the CH4 atmosphere. Films deposited in pure CH4 atmospheres have a hydrogen content of 20 at.% that showed a trend to decrease for lower CH4 partial pressures, while the density remained nearly constant at around 1.4x1023 at./cm3. Raman spectroscopy and x-ray diffraction revealed the amorphous character of the films. The compressive internal stress remained constant around 2.5 GPa and the hardness decreases for Ar rich precursor atmospheres.

Solid-State NMR Studies of the Bonding Structure of Diamondlike Amorphous Carbon Films

1994 ◽  
Vol 339 ◽  
Author(s):  
Susan M. Holl ◽  
Robert D. Johnson ◽  
Vlad. J. Novotny ◽  
Jeffrey L. Williams ◽  
Catherine E. Caley ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
Protective Coatings ◽  
Variable Temperature ◽  
Chemical Vapor ◽  
Carbon Films ◽  
Nmr Studies ◽  
Amorphous Carbon Films ◽  
Bonding Structure ◽  
Amorphous Hydrogenated Silicon ◽  
Deposition Power

ABSTRACTAmorphous carbon films are (a-C:H) of interest because of their useful physical properties. They are extremely hard and chemically inert, resisting degradation by both acids and alkalis. They are insoluble and can be conformably coated onto virtually any substrate. These properties make the films ideal protective coatings on magnetic disks and tools. We have studied several thin (one to two micron) films prepared by plasma enhanced chemical vapor deposition with varying radiofrequency fields strengths to determine structural differences at the atomic level. Several properties of the films, such as hardness and wear rate, are dependent on deposition power. We have found that the sp2/sp3 ratio increases with increasing deposition power. Thus, films that are harder are more “graphitic” and less “diamondlike”. The films studied here contain 11–16 atomic percent hydrogen, most of which is associated with sp3 carbon sites. At least two distinct phases of hydrogens exist. Variable temperature studies reveal that, in contrast to amorphous hydrogenated silicon, proton linewidths in carbon films are temperature dependent, suggesting some molecular motion is present at room temperature.

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