Results are presented for experimental studies of the plasma glow in a high-current pulsed magnetron discharge by using a high-speed optical frame camera. It is found that the discharge plasma is inhomogeneous in the azimuthal direction. The plasma bunches rotate with a linear velocity of ∼1 cm/μs in the direction of electron Hall drift, and their number is proportional to the discharge current. Plasma inhomogeneities in the form of plasma jets propagate in the form of plasma jets from the cathode region toward the anode. It is shown analytically that the formation of inhomogeneities is caused by the necessity to transfer high-density electron current across the magnetic field.
The mechanical properties of thin Ag films of equal thickness containing grains of various sizes were studied. The film hardness was measured using the Oliver-Pharr techniques based on indentation work calculations or on direct measurements of the area of pyramid imprints in AFM images. In order to avoid the influence of a substrate on the measured hardness, a technique was developed to determine the true values of the film hardness. It was established that the hardness of Ag films decreases with an increase in mean grain size, whereas the elastic modulus remains almost unchanged. It was shown that the dependence of the yield stress of Ag films on grain size does not obey the classical Hall-Petch law.
1 November 1997 in Surface and Coatings Technology
The hardness and the elastic modulus of Cu thin films on Si, Ti, Cu, and Al substrates are investigated. It is demonstrated that the use of the Oliver-Pharr method in combination with the technique for evaluating the true hardness makes it possible to determine uniquely the hardness of Cu thin films at different ratios between the hardnesses of the film and the substrate. The elastic modulus of thin films can be correctly measured by the Oliver-Pharr method only in the case where the film and the substrate exhibit identical elastic properties. In order to determine the elastic moduli of films with the use of the parameter P/S2, the film and the substrate should have close values of both the hardness and the elastic modulus.