We calculate the rarefaction of Ar background gas in front of a magnetron caused by sputtered target material atoms (so called 'sputtering wind effect') during pulsed sputtering. For a detailed analysis, we use a three-dimensional particle simulation using the direct simulation Monte Carlo (DSMC) method. We compare the results with those of two volume-averaged (V-A) models describing the same problem but with significantly lower computational demands. The comparison is made for three values of flux of sputtered atoms (expressed as 'sputtering current' in the units of amperes) and for three target materials (Zr, Al and C) sputtered from a circular target of 5 cm diameter placed in a chamber with realistic geometry. Ar rarefaction is more pronounced for target atoms with higher mass, but the difference between the three target materials is surprisingly small. The region where Ar is significantly rarefied extends much further from the target than a typical extent of the high-density plasma confined by the magnetic field. The V-A models provide good approximation of the time evolution of the target material density in front of the target compared to the DSMC simulation. However, the presented V-A models underestimate (in all but one case) the magnitude of Ar rarefaction during the pulse-on time and also predict faster return to equilibrium during the pulse-off time comared to the DSMC simulation.

Articles you may be interested inModified high power impulse magnetron sputtering process for increased deposition rate of titanium J. Vac. Sci. Technol. A 31, 060604 (2013); 10.1116/1.4819296Ion mass spectrometry investigations of the discharge during reactive high power pulsed and direct current magnetron sputtering of carbon in Ar and Ar/N2 Spatial and temporal evolution of ion energies in high power impulse magnetron sputtering plasma discharge High power impulse magnetron sputtering of zirconium was investigated at the average target power density of up to 2.22 kW cm −2 in a pulse. The depositions were performed using a strongly unbalanced magnetron with a planar zirconium target of 100 mm diameter at the argon pressure of 1 Pa. The repetition frequency was 500 Hz at duty cycles ranging from 4% to 10%. Time-averaged mass spectroscopy was carried out at the substrate positions of 100 and 200 mm from the target. The increase in the average target power density from 0.97 kW cm −2 to 2.22 kW cm −2 in shortened voltage pulses ͑from 200 to 80 s͒ at an average target power density of 100 W cm −2 in a period led to high fractions ͑21%-32%͒ of doubly charged zirconium ions in total ion fluxes onto the substrate located 100 mm from the target. However, the respective fractions of singly charged zirconium ions decreased from 23% to 3%. It was observed that ion energy distributions were extended to high energies ͑up to 100 eV relative to the ground potential͒ under these conditions. The increased target power densities during the shortened voltage pulses resulted in a reduced deposition rate of films from 590 to 440 nm/min and in a weakly decreasing ionized fraction ͑from 55% to 49%͒ of the sputtered zirconium atoms in the flux onto the substrate. The doubly charged zirconium ions became strongly predominant ͑up to 63%͒ in the total ion flux onto the substrate at the distance of 200 mm from the target. Model calculations were carried out to explain the complicated deposition processes.

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L’objectif de cette communication est de comparer un échantillon d’emprunts néologiques du domaine de la mode en français et en tchèque. L’idée de la conception comparative évoquée dans le titre de l’article puise dans le projet international intitulé « EmpNéo » (Emprunts Néologiques), projet visant à confronter et à examiner la diffusion des emprunts néologiques dans diverses langues. Dans cette étude, nous analyserons les termes récents de la mode vestimentaire apparus respectivement dans les deux langues. Le corpus est fondé sur nos propres connaissances et expériences quotidiennes du thème et sur un lexique repéré dans la presse écrite. Cette restriction méthodologique – ne travailler que sur un corpus issu des périodiques – correspond à l’esprit du projet en question. L’objectif principal est de décrire la présence des lexèmes choisis dans les deux langues et de comparer leur existence dans les différents types de documents, leur diffusion, ainsi que leur nature et leur place dans les deux langues étudiées.

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