Growth of hydrogenated amorphous carbon films in pulsed d.c. methane discharges

Andújar, J.L.; Vives, M.; Corbella, Carles; Bertrán, E.

doi:10.1016/s0925-9635(03)00009-8

Cited by 49 publications

(23 citation statements)

References 10 publications

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“…Therefore, pulsed-dc power not only provided large ion energies through high peak voltages, but it also gave rise to more active plasmas, thanks to stronger ionizations than those produced by the rf source. This could explain the significant increase in DLC deposition rates obtained using pulsed-dc compared to rf PECVD, as reported by Andújar et al 24 However, DLC deposition is associated with the on phase, where the plasma becomes more active. During the off phase, ionization was weaker as indicated by the lower values of T e and n e .…”

Section: Averaged Parametersmentioning

confidence: 57%

“…The deposition system included a load-lock chamber and a computer-controlled gas supply. 24 The reactor consisted of a cylindrical vessel of 30 cm diameter and 19.5 cm length, where the cathode ͑70 cm 2 ͒ and the anode ͑400 cm 2 ͒ were placed vertically and 4 cm apart in a capacitive configuration. Monocrystalline silicon wafers were used as substrates.…”

Section: A Reactor Description and Operating Conditionsmentioning

confidence: 99%

“…This leads to a reduction in compressive stress due to the accommodation of the deposited species at more stable sites. 24 …”

Section: Averaged Parametersmentioning

confidence: 99%

“…[20][21][22][23] Thanks to pulsed power supplies, the PECVD of DLC films has achieved higher growth rates and lower stress levels. 24 The waveform of the signal driven to the cathode and also the power input into the glow discharge W have a strong influence on the properties of the growing film. The energy of the ions impinging onto the DLC film has a decisive influence on its structure and hydrogen content.…”

Section: Introductionmentioning

confidence: 99%

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Plasma parameters of pulsed-dc discharges in methane used to deposit diamondlike carbon films

Corbella

Rubio‐Roy

Bertrán

et al. 2009

Journal of Applied Physics

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Here we approximate the plasma kinetics responsible for diamondlike carbon ͑DLC͒ depositions that result from pulsed-dc discharges. The DLC films were deposited at room temperature by plasma-enhanced chemical vapor deposition ͑PECVD͒ in a methane ͑CH 4 ͒ atmosphere at 10 Pa. We compared the plasma characteristics of asymmetric bipolar pulsed-dc discharges at 100 kHz to those produced by a radio frequency ͑rf͒ source. The electrical discharges were monitored by a computer-controlled Langmuir probe operating in time-resolved mode. The acquisition system provided the intensity-voltage ͑I-V͒ characteristics with a time resolution of 1 s. This facilitated the discussion of the variation in plasma parameters within a pulse cycle as a function of the pulse waveform and the peak voltage. The electron distribution was clearly divided into high-and low-energy Maxwellian populations of electrons ͑a bi-Maxwellian population͒ at the beginning of the negative voltage region of the pulse. We ascribe this to intense stochastic heating due to the rapid advancing of the sheath edge. The hot population had an electron temperature T e hot of over 10 eV and an initial low density n e hot which decreased to zero. Cold electrons of temperature T e cold ϳ 1 eV represented the majority of each discharge. The density of cold electrons n e cold showed a monotonic increase over time within the negative pulse, peaking at almost 7 ϫ 10 10 cm −3 , corresponding to the cooling of the hot electrons. The plasma potential V p of ϳ30 V underwent a smooth increase during the pulse and fell at the end of the negative region. Different rates of CH 4 conversion were calculated from the DLC deposition rate. These were explained in terms of the specific activation energy E a and the conversion factor x dep associated with the plasma processes. The work deepens our understanding of the advantages of using pulsed power supplies for the PECVD of hard metallic and protective coatings for industrial applications ͑optics, biomedicine, and electronics͒.

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Section: Averaged Parametersmentioning

confidence: 57%

Section: A Reactor Description and Operating Conditionsmentioning

confidence: 99%

“…This leads to a reduction in compressive stress due to the accommodation of the deposited species at more stable sites. 24 …”

Section: Averaged Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Plasma parameters of pulsed-dc discharges in methane used to deposit diamondlike carbon films

Corbella

Rubio‐Roy

Bertrán

et al. 2009

Journal of Applied Physics

Self Cite

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“…Spectra of the films deposited with 1.000 and 1.200 V are characteristic of hydrogenated amorphous carbons deposited from acetylene and argon plasma mixtures [7]. Bands ascribed to C-H vibrations are found around 2960 (ν in CH 2 ), 2870 (ν in CH 3 ), 1440 (δ in CH 3 ) and 1370 cm −1 (δ in CH 3 ) [8,9]. The incorporation of atmospheric oxygen in the structure is revealed by the absorptions related to O-H (ν 3400 cm −1 ) and C=O (ν 1700 cm −1 ) groups.…”

Section: Resultsmentioning

confidence: 99%

Hydrogenated amorphous carbon as protective coating for a forming tool

Martinatti

Santos

Cruz

et al. 2011

Eur. Phys. J. Appl. Phys.

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Abstract. This paper investigates the performance of hydrogenated amorphous carbon (a-C:H) films as protective coatings for a forming tool made from AISI M2 steel coated with a titanium nitride (TiN) PVD commercial layer. The samples were initially cleaned in ultrasonic baths and subsequently in a plasma ablation procedure. Films were then deposited by plasma immersion ion implantation using 91% of acetylene and 9% of argon at a total pressure of 5.5 Pa. Samples were biased with high voltage negative pulses, P (T = 3.33 ms, pulse on-time: 0.03 ms, pulse off-time: 3.30 ms and application rate: 299 Hz) with amplitudes varying from 1.000 to 4.000 V. The chemical structure and composition of the films were evaluated by infrared spectroscopy. The roughness was determined by profilometry while the surface topography and morphology were investigated by atomic force microscopy and scanning electron microscopy, respectively. The friction coefficient was determined by the ball on disk technique. A decrease in the proportion of C-H and O-H groups was observed while the concentration of dangling bonds enhanced with increasing P. Sharp structures were detected on the film surface affecting roughness in two different ways: it increased with enhancing pulse magnitude in the smoothest substrate (AISI M2) and decreased in the roughest one (AISI M2-TiN). The best tribological result was found for the sample deposited with 3.600 V of bias onto TiN-AISI M2 steel.

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