IR spectroscopy of diamondlike silicon-carbon films

IR spectra of metal-containing diamondlike silicon-carbon films are taken for the first time. It is shown that the optical response from the subsystem of free charge carriers in chromium-containing films can be described in terms of a simple model that deals with carriers localized inside clusters several nanometers in size. The data obtained indicate that the electric and dielectric properties of the films can be controlled by technological means during their synthesis and by varying the size, concentration, and conductivity of metallic nanoclusters.     

Enhancing the intensity of x-ray reflection from surfaces by depositing diamondlike carbon films on them

The possibility of fabricating reflecting surfaces with a roughness low enough for x-ray optics is demonstrated experimentally. Zh. Tekh. Fiz. 68, 136–138 (July 1998)     

In situ Raman spectroscopy of annealed diamondlike carbon-metal composite films

Diamondlike carbon films and diamondlike carbon-metal composite films may provide increased component reliability, decreased fuel consumption, decreased noise/vibration/harshness (NVH), and decreased lubricant use in next generation automotive components. Raman spectra were obtained for diamondlike carbon, diamondlike carbon-platinum composite films, and diamondlike carbon-gold composite films, which were annealed to a temperature of 523 °C. The Raman spectra for these films were fitted using a two-Gaussian function. The variation of the G-peak position, the D-peak position, and the I_D/I_G ratio was examined as a function of temperature. The unalloyed diamondlike carbon film demonstrated greater thermal stability than the diamondlike carbon-noble metal composite films. These results suggest that the operating temperatures of the diamondlike carbon-coated automotive components must be kept under careful consideration.     

Determination of an optimal pressure under field emission from diamondlike films

A model accounting for anomalously high field emission of electrons from diamondlike films in a rough vacuum is suggested. This effect is shown to be associated with a positive ion charge forming on the film. The ions arise because of residual gas ionization in the electrode gap. The pressure maximizing the emission current is determined.     

Method for pulsed magnetron deposition of diamondlike films on large-area substrates

The circuit of the pulse power supply of a magnetron sputtering system and the circuit of a high voltage generator used to realize the process of pulsed magnetron deposition of diamondlike films on large-area substrates are described. Measurements of the parameters of the plasma produced on pulsed magnetron sputtering of graphite in the argon medium have been performed. The plasma density (10¹⁷–10¹⁸ cm⁻³) has been shown to be one or two orders of magnitude higher than that in the case of dc magnetron sputtering and approach the plasma density achievable on vacuum arc cathode sputtering and pulsed laser sputtering. Samples of diamondlike films on crystalline silicon, titanium, and stainless steel have been prepared and examined. It has been demonstrated that high voltage bias pulses applied to the substrate promote production of high-quality diamondlike films showing high adherence to the substrate. Institute of High Current Electronics, Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 53–60, December, 1999.     

New method to calibrate binding energy using Au nanocolloids in X-ray photoelectron analysis of diamondlike carbon films with different electrical resistivities

A new method to calibrate the binding energy (E_B) using Au nanocolloids as a calibrant in XPS analysis of diamondlike carbon (DLC) is proposed by considering the DLC films with different electrical resistivities. A few microliters of a dilute aqueous solution containing Au nanocolloids were dropped onto a small local surface area of the DLC film, which became a stain before XPS measurements by gradually drying in vacuo. The observed peak E_B of the C 1s spectrum at another native surface (an area without Au nanocolloids) of the DLC film was calibrated by setting that of the Au 4f_7/2 spectrum of the Au nanocolloids to 84.0 (83.98 ± 0.02) eV. The adequacy of this method was investigated by considering the correlation among the full width at half maximums (FWHMs) of the Au 4f_7/2 spectra of the Au nanocolloids on the DLC surfaces and that of a Au plate as a reference. Consequently, the FWHM of the Au 4f_7/2 spectrum of the Au nanocolloids on the DLC surface is a candidate to investigate the differential charging effect of the DLC surface, and the calibration method is reliable if the FWHM agrees with that of the Au plate.     

Properties of diamondlike films obtained in a barrier discharge at atmospheric pressure

Diamondlike films are synthesized from gaseous hydrocarbons in a barrier discharge at atmospheric pressure. The films were investigated using transmission electron microscopy, electron diffraction, and infrared spectroscopy. A technique for determining the quantitative characteristics of the films (hydrogen content, ratio of different types of carbon-carbon bonds and hydrocarbon groups) using standard samples is described. The highest-quality films were obtained from methane (ratio of hydrogen to carbon atoms H/C=1.04, fraction of diamondlike to graphitelike bonds sp ³: sp ²=100%: 0%) and from a mixture of acetylene and hydrogen in the ratio 1:19 (H/C=0.73, sp ³: sp ²=68%: 32%). Zh. Tekh. Fiz. 67, 100–104 (August 1997)     

Cylindrical spike model for the formation of diamondlike thin films by ion deposition

T /n_S of n_T rearrangements and n_S atoms in the spike volume as the crucial parameter characterizing the ability of a given ion–target combination to achieve complete rearrangement of the spike volume. n_T/n_S>1 is the optimum condition for diamondlike film growth. For aC films the ion energy dependence of n_T/n_S agrees well with the measured sp³ bond fraction. For Ar⁺-ion-assisted deposition of aC we find n_T/n_S>1 above 50 eV with no pronounced ion energy dependence. Furthermore, our model predicts optimum conditions for the formation of cubic boron nitride between 50 eV and 3 keV. Accepted: 14 October 1997