Characterization of chemical bonding and physical characteristics of diamond-like amorphous carbon and diamond films

Abstract

Diamond-like (amorphous) carbon (DLC) films were prepared by dc magnetron sputtering and plasma enhanced chemical vapor deposition (PECVD) and diamond films were prepared by microwave plasma enhanced chemical vapor deposition (MPECVD). For the first time, chemical and mechanical characterization of the films from each category are carried out systematically and a comparison of the chemical and physical properties is provided. We find that DLC coatings produced by PECVD are superior in microhardness and modulus of elasticity to those produced by sputtering. PECVD films contain a larger fraction of sp3-bonding than the sputtered hydrogenated carbon films. Chemical and physical properties of the diamond films appear to be close to those of bulk diamond.

An EELS and XAS Study of Cubic Boron Nitride Synthesized under High Pressure - High Temperature Conditions

“…We see in the C-K edge a hump that may correspond to a 7r* resonance characteristic of sp2 hybridized carbon atoms. It also shows marked EXELFS oscillations up to the N-K edge that are quite different from those observed in amorphous carbon [11]. These well-defined EXELFS oscillations correspond to the existence of long-range order around the carbon atoms since they result in an interference process between the outgoing electron wave and the wavelets back-scattered by each of them.…”

“…They show plasmon energies of 30.4 and 25.3 eV respectively, values that are 1.4 eV higher than those quoted in reference 3. One should observe the existence of a 7r* plasmon characteristic of the hexagonal structure [11] at about 8 eV for the h-BN sample. The plasmon energy provides a useful measure of the density of BN samples (3.450 g/cm3 for c-BN, 2.271 g/cm3 for h-BN) assuming the number of nearly free electrons is on average four per atom, whatever the bonding arrangement is.…”

Application of Cathodic Arc Deposited Amorphous Hard Carbon Films to the Head/Disk Tribology

“…These films show the highest sp3 fraction for hydrogenated films of 75%, a hardness of 60 GPa, and a mass density of 2.9 g/cm3. Hydrogen and nitrogen containing films deposited by other methods such as variations of the sputter technique and plasma enhanced CVD have a lower sp3 fraction around 20-40%, a hardness of 15-35 GPa, an elastic modulus of 100-200 GPa, a mass density of 1.7-2.3 g/cm3, and a stress of 1-3 GPa [16,18,[19][20][21]25,26].…”

Dynamic relaxation of the elastic properties of hard carbon films

“…6 The Young's modulus measurements were based on the determination of the frequency-dependent propagation velocity of ultrasonic surface acoustic waves ͑US-SAW͒. 7,8 This allows the nondestructive determination of Young's modulus in thin films to an accuracy of several per cent. In order to carry out measurements a train of elastic surface waves is excited by using the thermoelastic effect of a short laser pulse ͑0.5 ns pulse length͒ with a broad frequency range.…”

“…Use of a suitable curve-fitting procedure allows some of the unknown film parameters ͑as well as the elastic modulus of the substrate͒ to be determined. 7,8 Figure 1 shows the experimentally determined Young's moduli for ta-C films deposited at different substrate temperatures. At low temperatures a high value of Young's modulus of about 700 GPa is obtained.…”