Highly tetrahedral, diamond-like amorphous hydrogenated carbon prepared from a plasma beam source

Weiler, M.; Sattel, S.; Jung, K.; Ehrhardt, H.; Veerasamy, V.S.; Robertson, John

doi:10.1063/1.111428

Cited by 168 publications

(76 citation statements)

References 23 publications

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“…A peak in both the sp 3 fraction as well as the density is observed at an ion energy of 88 eV. Peaks in the density versus ion energy curve seem to be system dependent for different research groups and have been observed at; 40, 92, 140, and a threshold value of 50 eV in the results of McKenzie, 15 Weiler, 9 Fallon, 2 and Lifshitz, 16 respectively. The films deposited in the current work 17 use a similar apparatus to those used by McKenzie 15 and Fallon 2 .…”

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confidence: 64%

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Nanocrystallites in tetrahedral amorphous carbon films

Ravi

Silva

et al. 1996

Applied Physics Letters

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The microstructure of filtered cathodic vacuum arc deposited tetrahedral amorphous carbon films is studied as a function of ion energy. An optimum energy window in the density and C-C sp 3 content at an ion energy of ϳ90 eV observed in this study. It is shown that the density of the amorphous carbon films are closely related to the sp 3 content. The observation of nanocrystals embedded in the amorphous carbon matrix is reported. Most of the crystals observed by transmission electron microscopy can be indexed to graphite, but some of the crystals can be indexed to cubic diamond. The chemical composition of the crystals is analyzed using electron energy loss spectroscopy ͑EELS͒. The only discernible EELS edge is that of C at an energy of 285 eV. © 1996 American Institute of Physics. ͓S0003-6951͑96͒03230-5͔Filtered cathodic vacuum arc ͑FCVA͒ deposited carbon films have the unique property of producing high quality diamondlike amorphous carbon films with a high sp 3 content. 1,2 The film properties are critically dependent on the ion energy of the species. The carbon plasma initiated from a graphite target by the vacuum arc is sustained during the deposition and macroparticles associated with the arc process are filtered using a 90°bend toroidal solenoid in the deposition system. We have investigated the relationship between the bonding structure in the films and the ion energy of the C species. At a particular threshold ion energy the particles found in the tetrahedral amorphous carbon ͑ta-C͒ films have been studied using transmission electron microscopy ͑TEM͒ and electron energy loss spectroscopy ͑EELS͒. Although there are reports that diamond nanocrystallites have been observed in diamondlike carbon ͑DLC͒ films deposited under low temperature and low pressure conditions, 3-6 direct observation of diamond crystals in deposition techniques that do not operate at high temperatures and high pressures is not common. This is because graphite is the stable crystalline form of carbon under these conditions.Highly tetrahedrally bonded ta-C films have also been deposited using laser initiated vacuum arcs, and pulsed cathodic arcs, 7,8 and hydrogenated ta-C films deposited using a plasma beam source. 9 There is much interest in all of these films due to their unique mechanical properties. 7,10 Recently, Yin et al. 11 have found cauliflower-like growths ͑nanocrys-tals͒ which cannot be indexed to graphite in their FCVA deposited films, which are considered to be precursors for diamond growth. 12 However, there has been no published literature on the observation of diamond nanocrystallites in ta-C films deposited using the FCVA. In this letter, we report on the observation of nanocrystallites that index to diamond, deposited under low temperature/low pressure conditions using such a system.The FCVA films were deposited with a base pressure of 2ϫ10 Ϫ6 Torr which increased to 1ϫ10 Ϫ5 Torr during deposition. The substrate bias is varied from 0 to Ϫ120 V, while the arc current remained constant at ϳ60 A. A toroidal magnetic field ...

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confidence: 64%

“…9 There is much interest in all of these films due to their unique mechanical properties. 7,10 Recently, Yin et al 11 have found cauliflower-like growths ͑nanocrys-tals͒ which cannot be indexed to graphite in their FCVA deposited films, which are considered to be precursors for diamond growth.…”

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confidence: 99%

Nanocrystallites in tetrahedral amorphous carbon films

Ravi

Silva

et al. 1996

Applied Physics Letters

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“…The PBS apparatus is similar to that used by Weiler et al 13 in which the structure of the a-C:H film is controlled solely by ions. A radio frequency ͑rf͒ power of 30 W at 13.56 MHz is applied via a capacitor and matching network between the ground electrode and the powered electrode.…”

Section: Methodsmentioning

confidence: 99%

“…Weiler et al 13 reported that it is possible to deposit amorphous hydrogenated carbon films with high sp 3 ͑75%͒ and H contents ͑27%͒, and stated 14 that it is possible to dope the ta-C:H films deposited using the plasma beam source ͑PBS͒. However, it should be noted that ta-C films 15 as well as a-C films deposited by PBS 14 possess defect densities as high as 1ϫ10 20 defects/cm 3 .…”

Section: Introductionmentioning

confidence: 99%

“…The operation with pure acetylene revealed results similar to previous studies in terms of energy distribution and ion current on a PBS. 13 Surprisingly, the PBS produces ions with roughly the same energy regardless of whether argon or acetylene, or a mixture of both gases, are used. Argon content was measured by Rutherford backscattering.…”

Section: A Deposition Of A-c:h In An Ar/c 2 H 2 Atmospherementioning

confidence: 99%

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Nitrogen doping of amorphous carbon thin films

Schwan

Batori

Ulrich

et al. 1998

Journal of Applied Physics

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103

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Nitrogenated and hydrogenated amorphous carbon (a-C:H:N) films have been deposited by a plasma beam source using a gas mixture of C2H2, Ar and N2. The Ar/C2H2 ratio is kept constant at a ratio of 3, with the nitrogen flow allowed to vary. Nonnitrogenated films, with Ar/C2H2 ratios of 3 and 6 were also deposited and analyzed before attempting to identify the modifications to the microstructural properties due to nitrogen doping. The nitrogenated and hydrogenated a-C (a-C:H:N) films deposited in this study reveal interesting properties with regard to their optical gap, electrical conductivity, and mobility of the charge carriers. The optical E04 gap passes through a maximum of 2.7 eV as a function of incorporated nitrogen. The electrical conductivity, too, reaches a peak value of 10−3(Ω cm)−1 with increasing optical gap and remains constant for higher N2 flows. The electrical conductivity process is thermally activated with activation energies in the range 0.1–0.3 eV. This is discussed in terms of the mobility of the charge carriers (determined by Hall measurements) and electronic doping. The defect density (measured by electron spin resonance) is found to decrease with increasing nitrogen incorporation. The films have also been characterized by infrared spectroscopy, photo thermal deflection, and Raman spectroscopy. The microstructure of the deposited a-C:H:N films is discussed in terms of the electronic density of states.

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The Preparation, Characterization and Tribological Properties of TA-C:H Deposited Using an Electron Cyclotron Wave Resonance Plasma Beam Source

Morrison¹,

Mühl

Rodil

et al. 1999

phys. stat. sol. (a)

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A compact electron cyclotron wave resonance (ECWR) source has been developed for the high rate deposition of hydrogenated tetrahedral amorphous carbon (ta‐C:H). The ECWR provides growth rates of up to 900 Å/min over a 4″ diameter and an independent control of the deposition rate and ion energy. The ta‐C:H was deposited using acetylene as the source gas and was characterized in terms of its sp3 content, mass density, intrinsic stress, hydrogen content, C–H bonding, Raman spectra, optical gap, surface roughness and friction coefficient. The results obtained indicated that the film properties were maximized at an ion energy of approximately 167 eV, corresponding to an energy per daughter carbon ion of 76 eV. The relationship between the incident ion energy and film densification was also explained in terms of the subsurface implantation of carbon ions into the growing film.

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Highly tetrahedral, diamond-like amorphous hydrogenated carbon prepared from a plasma beam source

Cited by 168 publications

References 23 publications

Nanocrystallites in tetrahedral amorphous carbon films

Nanocrystallites in tetrahedral amorphous carbon films

Nitrogen doping of amorphous carbon thin films

The Preparation, Characterization and Tribological Properties of TA-C:H Deposited Using an Electron Cyclotron Wave Resonance Plasma Beam Source

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