Molecular-dynamics simulations of steady-state growth of ion-deposited tetrahedral amorphous carbon films

Jäger, H.U.; Albe, Karsten

doi:10.1063/1.373787

Cited by 141 publications

(93 citation statements)

References 38 publications

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“…Consequently, it leads to overestimation of stresses and strains in atomic structures simulated with the Tersoff-Brenner [20][21][22] and the REBO [23] potentials. In order to avoid this, many authors have used the small cutoff distance given by R ij = S ij , e.g., see [22][23][24][25]. It should be noted that when the small cutoff distance is extended to the large one, the cutoff function allows, before failure, bond strains of about 46% and 44% for C-C interactions with the Tersoff [18] and the REBO potentials [26], respectively.…”

Section: Cutoff Functionmentioning

confidence: 99%

Mode-I stress intensity factor in single layer graphene sheets

Batra

2016

Computational Materials Science

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a b s t r a c tWe use the freely available software, LAMMPS, and the Tersoff potential to find the mode-I stress intensity factor during crack propagation in an edge-cracked single layer graphene sheet deformed at a constant axial strain rate. The axial stress and the stress intensity factor (SIF) at atoms' locations are computed by using, respectively, the Virial theorem and either the stress at the atom located at the crack-tip or the average axial stress in the sheet. It is found that the two values of the SIF differ from each other by about 8%, and agree with those reported in the literature derived either analytically or from test data. The method proposed and used herein can be applied to find the SIF in any nanostructure.

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Section: Cutoff Functionmentioning

confidence: 99%

Mode-I stress intensity factor in single layer graphene sheets

Batra

2016

Computational Materials Science

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“…Another example is the densification that occurs when low energy carbon atoms are deposited onto a carbon substrate. 19,20 This can be predicted using MD alone at unrealistically high deposition rates. On the other hand, Sprague 22 showed how the growth patterns could differ when comparing TAD simulations with MD at enhanced rates.…”

Section: The Need For Pathway Determination In Thin Film Growthmentioning

confidence: 99%

“…19,20 In the former case, the reaction pathways and transition rates are usually prescribed in advance so many important mechanisms can be missed and in the latter case, transitions with energy barriers greater than a few tenths of an eV are ignored. Sometimes the simulations were run at higher temperatures but without the corrections implicit in TAD.…”

Section: The Need For Pathway Determination In Thin Film Growthmentioning

confidence: 99%

Reaction pathways in atomistic models of thin film growth

Lloyd

Zhou

et al. 2017

The Journal of Chemical Physics

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The atomistic processes that form the basis of thin film growth often involve complex multi-atom movements of atoms or groups of atoms on or close to the surface of a substrate. These transitions and their pathways are often difficult to predict in advance. By using an adaptive kinetic Monte Carlo (AKMC) approach, many complex mechanisms can be identified so that the growth processes can be understood and ultimately controlled. Here the AKMC technique is briefly described along with some special adaptions that can speed up the simulations when, for example, the transition barriers are small. Examples are given of such complex processes that occur in different material systems especially for the growth of metals and metallic oxides.

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“…Widely used are hydrogenated diamond-like carbon (DLC or a-C:H) [11], nitrogen-doped amorphous carbon (a-C:N) [12] or amorphous carbon nitride (CN x ) [13][14][15], hydrogenated carbon nitride (CH x N y ), hydrogen-free amorphous carbon (a-C) [16], silicon-doped amorphous carbon (a-C:Si) or silicon carbide (SiC) [17], and metal-doped amorphous carbon (a-C:Me) [18]. Amorphous carbon films (a-C) that have more than 80% tetrahedral (sp 3 ) bonding are referred to as tetrahedral amorphous carbon (ta-C) [7,9,19], or sometimes even as "amorphous diamond." [20,21] There are large variations even within each class of materials, depending on the method and parameters of deposition.…”

Section: Introductionmentioning

confidence: 99%

“…For carbon, it is well known that films that are rich in sp 3 (diamond) bonds should be grown in a kinetic mode at low temperature (less than 200°C, preferably room temperature), with film-forming carbon atoms or ions having an energy of about 100 eV. This energy is optimized for subplantation film growth of diamond-like carbon [4][5][6][7][8][9][10]. If the energy is too low, say less than 20 eV, ions do not have the kinetic energy to penetrate the surface; if the energy is too high, thermal spikes and a general enhancement of the temperature will allow the carbon atoms of the film to move to configurations of smaller energy.…”

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confidence: 99%

Ultrathin diamond-like carbon films deposited by filtered carbon vacuum arcs

Anders

Fong

Kulkarni

et al. 2001

IEEE Trans. Plasma Sci.

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Ultrathin (< 5 nm) hard carbon films are of great interest to the magnetic storage industry as the areal density approaches 100 Gbit/in 2 . These films are used as overcoats to protect the magnetic layers on disk media and the active elements of the read-write slider. Tetrahedral amorphous carbon films can be produced by filtered cathodic arc deposition, but the films will only be accepted by the storage industry only if the "macroparticle" issue has been solved. Better plasma filters have been developed over recent years. Emphasis is put on the promising twist filter system -a compact, open structure that operates with pulsed arcs and high magnetic field. Based on corrosion tests it is shown that the macroparticle reduction by the twist filter is satisfactory for this demanding application, while plasma throughput is very high. Ultrathin hard carbon films have been synthesized using Sfilter and twist filter systems. Film properties such as hardness, elastic modulus, wear, and corrosion resistance have been tested. Index Terms: diamond-like carbon, cathodic vacuum arc, macroparticle filtering, magnetic storage, carbon overcoats 3 I. INTRODUCTIONUltrathin (< 5 nm) hard carbon films are used as protective overcoats on hard disks and readwrite heads. The tribological properties of the head-disk interface are not only of mechanical but also of chemical nature: the overcoat should protect the magnetic layers against wear and corrosion [1, 2]. The areal density of information stored in disk drive products increased at an amazing rate of over 65% for many years rate, and continues to accelerate to even greater rates [3]. To accomplish this, the "magnetic spacing" between the magnetic layers of the disk and read/write sensor of the head must continue to decrease. The magnetic spacing includes the overcoats, lubrication, and the fly height. Thinner overcoats allow the read-write head to be closer to the magnetic layer of the disk, and hence, the size of individual bits on the disk to be smaller. As we work toward an areal density of 100 Gbit/in 2 , the magnetic spacing approaches the sub-10-nm regime (pseudo-contact recording) and overcoat thickness must shrink to 1-2 nm. Overcoats currently used are sputtered or ion-beam deposited diamond-like carbon films, typically doped with hydrogen or nitrogen. They cease to provide acceptable levels of corrosion protection when the film thickness is less than 5 nm.Overcoats need to be tough (hard and elastic), chemically inert, pinhole-free, and compatible with the lubricant. The challenge of ultrathin film synthesis is to make the films as thin as possible and still continuous, as opposed to an assembly of islands.Nucleation and growth of ultrathin films is a field of intense research. For carbon, it is well known that films that are rich in sp 3 (diamond) bonds should be grown in a kinetic mode at low temperature (less than 200°C, preferably room temperature), with film-forming carbon atoms or ions having an energy of about 100 eV. This energy is optimized for subplantat...

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Molecular-dynamics simulations of steady-state growth of ion-deposited tetrahedral amorphous carbon films

Cited by 141 publications

References 38 publications

Mode-I stress intensity factor in single layer graphene sheets

Mode-I stress intensity factor in single layer graphene sheets

Reaction pathways in atomistic models of thin film growth

Ultrathin diamond-like carbon films deposited by filtered carbon vacuum arcs

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