Katarzyna Nowakowska-Langier, Rafal Chodun and Krzysztof Zdunek
Pulsed plasma in the impulse plasma deposition (IPD) synthesis is generated in a coaxial accelerator by strong periodic electrical pulses, and it is distributed in a form of energetic plasma packets. A nearly complete ionization of gas, in these conditions of plasma generation, favors the nucleation of new phase of ions and synthesis of metastable materials in a form of coatings which are characterized by amorphous and/or nanocrystalline structure. In this work, the Fe–Cu alloy, which is immiscible in the state of equilibrium, was selected as a model system to study the possibility of formation of a non-equilibrium phase during the IPD synthesis. Structural characterization of the layers was done by means of X-ray diffraction and conversion-electron Mössbauer spectroscopy. It was found that supersaturated solid solutions were created as a result of mixing and/or alloying effects between the layer components delivered to the substrate independently and separately in time. Therefore, the solubility in the Fe–Cu system was largely extended in relation to the equilibrium conditions, as described by the equilibrium phase diagram in the solid state.
K. Nowakowska-Langier, R. Chodun, K. Zdunek, R. Minikayev and R. Nietubyc
AlN films on a Si substrate were synthesized by magnetron sputtering method. A dual magnetron system operating in AC mode was used in the experiment. Processes of synthesis were carried out in the atmosphere of a mixture of Ar/N2. Morphology and phase structure of the AlN films were investigated at different pressures. Structural characterizations were performed by means of SEM and X-ray diffraction methods. Our results show that the use of magnetron sputtering method in a dual magnetron sputtering system is an effective way to produce AlN layers which are characterized by a good adhesion to the silicon substrate. The morphology of the films is strongly dependent on the Ar/N2 gas mixture pressure. An increase of the mixture pressure is accompanied by a columnar growth of the layers. The films obtained at the pressure below 1 Pa are characterized by finer and compacter structure. The AlN films are characterized by a polycrystalline hexagonal (wurtzite) structure in which the crystallographic orientation depends on the gas mixture pressure.
G.W. Strzelecki, K. Nowakowska-Langier, R. Chodun, S. Okrasa, B. Wicher and K. Zdunek
The research on the influence of modulation frequency on the properties of films synthesized using a unique pulsed power supply combined with a standard unbalanced circular magnetron was conducted in the process of pulsed magnetron sputtering (PMS). It was shown that by using different levels of modulation, the composition of plasma (measured by optical emission spectroscopy, OES) as well as film growth rate and morphology (observed with scanning electron microscope, SEM), can be changed. The impact of modulation is related to the used materials and gases and can vary significantly. It was concluded that modulation frequency can greatly influence the synthesis of materials and can be used as an additional parameter in PMS. Specific relations between modulation frequency and synthesized material require further investigation.