Chromium-carbon films were deposited by utilizing reactive high-power impulse magnetron sputtering at different mixture ratios of ethyne and argon atmosphere, and different substrate bias voltages and deposition temperature, with the same pulse frequency, duty cycle, and average power. The microstructure and mechanical properties of the obtained films were compared. The films consist of amorphous or nanocrystalline chromium carbide, hydrogenated amorphous carbon, and minor α-chromium phase. Decreasing the fraction of ethyne increases the content of the α-chromium phase but decreases hydrogenated amorphous carbon phase. The film’s hardness increases by enhancing the negative substrate bias and raising the deposition temperature, which could be attributed to the increase of film density and the Hall–Petch strengthening effect induced by the nanoscale crystallization of the amorphous carbide phase.
AbstractThe kinetics of the deposition of ruthenium thin films from the hydrogen assisted reduction of bis(2,2,6,6-tetramethyl-3,5-heptanedionato)(1,5-cyclooctadiene)ruthenium(II), [Ru(tmhd)2cod], in supercritical carbon dioxide was studied in order to develop a rate expression for the growth rate as well as to determine a mechanism for the process. The deposition temperature was varied from 240°C to 280°C and the apparent activation energy was 45.3 kJ/mol. Deposition rates up to 30 nm/min were attained. The deposition rate dependence on precursor concentrations between 0 and 0.2 wt. % was studied at 260°C with excess hydrogen and revealed first order deposition kinetics with respect to precursor at concentrations lower then 0.06 wt. % and zero order dependence at concentrations above 0.06 wt. %. The effect of reaction pressure on the growth rate was studied at a constant reaction temperature of 260°C and pressures between 159 bar to 200 bar and found to have no measurable effect on the growth rate.
AbstractAmorphous alumina films were deposited by metal-organic chemical vapour deposition (MOCVD) on stainless steel, type AISI 304. The MOCVD experiments were performed in nitrogen at low pressure (0.17 kPa (1.25 torr)).The effect of deposition temperature (200 − 380 °C), growth rate, film thickness, and post-deposition thermal treatment on the mechanical properties was studied. The experiments were performed with a scanning-scratch tester. The experiments are based on the estimation of the film adhesion to the substrate by determining a critical load, Lc: the load where the film starts to spall or to delaminate.The best mechanical properties were obtained with unannealed samples. After thermal annealing the critical load decreases. Regarding the unannealed samples, the critical load increased with increasing film thickness. The deposition temperature and the growth rate had no effect on the critical load.
The time separation between related extremes in the values of surface temperature and growth rate of a floating ice cover are shown to depend on the mean ice temperature and thickness. A quantity termed the lag coefficient is introduced for which observations from Churchill, Hudson Bay, and Davis, Antarctica, suggest a dependence on temperature but not on geography.
ABSTRACTWe have used a 30 kHz ac glow discharge formed from methane gas to grow carbon films on InP substrates. Both the growth rate, and the relative Ar ion sputtering rate at 3 keV varied monotonically with deposition power. The Ar ion etchigg rate of the films decreased with deposition power. Results from the 15N nuclear reaction profile experiments indicated a slight drop in the hyorogen concentration as more energy was dissipated in the ac discharge. Values for the inoex of refraction and extinction coefficient ranged from 1.721 to 1.910 and 0 to -0.188, respectively. Optical bandgaps as high as 2.34 eV were determined.
Reactive High-Power Impulse Magnetron Sputtering of Chromium-Carbon Films