On the influence of residual stresses and density fluctuations on the crystallization of amorphous carbon films

Pompe, W.; Scheibe, H.‐J.; Richter, Asta; Bauer, H.‐D.; Bewilogua, K.; Weißmantel, C.

doi:10.1016/0040-6090(86)90071-4

Cited by 32 publications

(9 citation statements)

References 26 publications

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“…Depending on the laser energy and beam diameter focused on the target, laser intensities in the 10 8 -10 11 W/cm 2 range are most commonly achieved. Past experiments have indicated that the fraction of sp 3 bonds increased as a function of increasing laser intensity. The plasma formed under these conditions was found to consist of ionized carbon particles with moderately high kinetic energies, increasing from several eV up to several hundreds of eV as a function of laser intensity.…”

Section: Introductionmentioning

confidence: 98%

“…1 DLC can be considered as a metastable form of carbon material covering the spectrum between diamond and graphite. But unlike crystalline graphite or diamond, which consists of 100% sp 2 and 100% sp 3 , respectively, hybridized carbon atoms, DLC films have a mixture of sp 3 and sp 2 bonding and are generally amorphous, due to the lack of a long range. DLC possesses properties similar to those of diamond rather than graphite, including high mechanical hardness, high electrical resistivity, excellent chemical inertness, and optical transparency.…”

Section: Introductionmentioning

confidence: 99%

“…Most successful PLD depositions of DLC films conducted so far have employed either excimer ͑KrF, ArF, XeCl͒ or Q-switched solid state lasers such as various frequency modified Nd:YAG beams. [2][3][4][5] These lasers all have pulse duration in the nanosecond range. Depending on the laser energy and beam diameter focused on the target, laser intensities in the 10 8 -10 11 W/cm 2 range are most commonly achieved.…”

Section: Introductionmentioning

confidence: 99%

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High intensity femtosecond laser deposition of diamond-like carbon thin films

Qian

Crăciun

Singh

et al. 1999

Journal of Applied Physics

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Hydrogen-free diamond-like carbon ͑DLC͒ films have been deposited with a 100 fs ͑FWHM͒ Ti:sapphire laser beam at intensities I in the 10 14-10 15 W/cm 2 range. The films were studied with scanning probe microscopy, variable angle spectroscopic ellipsometry, Raman spectroscopy, and electron energy loss spectroscopy. DLC films with good scratch resistance, excellent chemical inertness, and high optical transparency in the visible and near infrared range were deposited at room temperature. As the laser intensity was increased from 3ϫ10 14 to 6ϫ10 15 W/cm 2 , the films showed an increased surface particle density, a decreased optical transparency (85%˜60%), and Tauc band gap (1.4˜0.8 eV), as well as a lower sp 3 content (60%˜50%). The time-of-flight spectra recorded from the laser plume exhibited a double-peak distribution, with a high energy suprathermal ion peak preceding a slower thermal component. The most probable ion kinetic energy showed an I 0.55 dependence, increasing from 300 to 2000 eV, when the laser intensity was varied from 3ϫ10 14 to 6ϫ10 15 W/cm 2 , while the kinetic energy of suprathermal ions increased from 3 to over 20 keV and showed an I 0.33 dependence. These high energy ions are believed to have originated from an electrostatic acceleration field established by suprathermal electrons which were formed by resonant absorption of the intense laser beams.

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High intensity femtosecond laser deposition of diamond-like carbon thin films

Qian

Crăciun

Singh

et al. 1999

Journal of Applied Physics

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“…If this disorder energy is high enough, as indicated by the stress exceeding a threshold, a change in bond configuration could gain energy and therefore become possible. Pompe et al 24 and McKenzie et al 8 developed the idea of such a phase transition for the formation of large amounts of sp 3 bonds when stress values above a threshold are present: McKenzie et al 8 gives a threshold of 1.46 GPa while Schwan et al 23 found a transition above 14 GPa Beside sp 3 C-C and sp 2 C-C bonds, there are C-H bonds in hydrogenated films too. Assuming that the stress would invoke a transition at local sites in the films, stress values above a threshold at 10-12 GPa, according to the observed data, could force neighboring C-H bonds to be eliminated by forming C-C and H-H bonds.…”

Section: Figmentioning

confidence: 99%

Nitrogen doping of amorphous carbon thin films

Schwan

Batori

Ulrich

et al. 1998

Journal of Applied Physics

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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“…% of hydrogen. 19,20 Stress investigation has been used to study the properties of the hydrogenated amorphous carbon film. 11 Hydrogen is incorporated in the film because amorphous carbon is deposited as a result of the condensation of the hydrocarbon species from the gas phase in the plasma CVD techniques.…”

Section: Introductionmentioning

confidence: 99%

X-ray photoelectron spectroscopy study of the atomic structure change of amorphous carbon films annealed in vacuum

Fang

Yang

et al. 1991

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Articles you may be interested inLight-induced changes in an alkali metal atomic vapor cell coating studied by X-ray photoelectron spectroscopy Amorphous carbon films deposited at near room temperature on Si substrates by a direct current plasma chemical vapor deposition technique using CH 4 gas have been annealed in vacuum. X-ray photoelectron spectroscopy measurements show that, as the annealing temperature increases from room temperature to 300 °C, a significant shift (0.5 eV) of the C Is electron binding energy is observed. The observed shift may be the indication of an atomic structure change of the amorphous films upon the thermal annealing. On the other hand, a large shift in the Sp2 bond peaks of the Raman spectra only occurs at annealing temperatures higher than 300 °C, which may be the indication of a structural change of the amorphous carbon films by the annealing. A two stage stress release mechanism is suggested: One for the atomic structure change and one for the film structure change.

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On the influence of residual stresses and density fluctuations on the crystallization of amorphous carbon films

Cited by 32 publications

References 26 publications

High intensity femtosecond laser deposition of diamond-like carbon thin films

High intensity femtosecond laser deposition of diamond-like carbon thin films

Nitrogen doping of amorphous carbon thin films

X-ray photoelectron spectroscopy study of the atomic structure change of amorphous carbon films annealed in vacuum

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