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We are grateful to the scientific grant agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic for financial support of project VEGA No. 1/0947/16. In this experimental work we examined the temperature and mechanical stress in the thin films of microelectronic structures based on GaN and AlN by Raman spectroscopy. The rise in temperature in the Raman spectrum is shown by shifting the Raman bands toward lower wavenumbers. Similarly like with changes of temperature, the changes of the positions of Raman bands may indicate the changes of mechanical stress in the structure. It was confirmed experimentally that in the case of tensile stress the Raman bands are shifted towards lower wavenumbers, and under compressive stress to higher wavenumbers.

The study deals with the vacuum evaporation technique of thin layers, considering different process parameters and their influence on electrical properties. Parameters, such as temperature, different substrate types, substrate vibrations, etc., are considered. The effects of the process parameters on the coating structure are observed. The temperature affects the coating quality and stability [1] [2]. Regarding electrical properties, the surface resistivity is measured by four-point method, whereas the influence of process parameters on the surface resistivity is determined as well.

Aluminum nitrides layers prepared on sapphire substrates are examined. The substrate surface was treated by dry plasma etching. The morphology of aluminum nitride thin films was studied by atomic force microscopy. Lateral force atomic force microscopy was used to study the morphology heterogeneity. The dependence of films morphology on the formation conditions has been defined. The objective of the study contributes to the improvement of technological process of dry etching and film deposition.

This study describes morphology and structure of SiC thin films which are grown up by sublimation epitaxy in vacuum on the 6H-SiC substrates with thickness from tens of nanometers up to units of micrometers. Fashioned films are quite uniform in surface and volume. The crystal properties of the wafers and epitaxial layers are studied by electron diffraction investigation, X-ray techniques, and scanning probe microscopy. X-ray rocking curves show that structural perfection of SiC films is comparable with the structural perfection of monocrystalline 6H-SiC substrates. Calculated lattice parameters of epilayer by X-ray diffractometry also match with known values for 6H-SiC. Electron-diffraction measurement gives the confirmation of the crystallinity of the obtained layers and it is also proved by scanning probe microscopy. This technology allows making of defect treatment of the wafer in dependence on epitaxial conditions. Fundamental analysis in this field allows optimize conditions of thin films formation with prescribed properties and hence the using of them in the technology for elements of electronic engineering and by this reason the surface of monocrystalline SiC was analyzed.

In this paper, the current stability analysis was performed on the cold-emission cathode covered by a thin epoxy film. Non-destructive spectroscopic method, which is based on measuring current fluctuations, has been used to determine cathodes’ quality, which directly influents the stability of the emission current. Our investigations have been performed on tungsten cathodes with extra-sharp nanotip, operating under the HV (high-vacuum)conditions, usually in vacuums of 10-5 Pa order. All the cathodes used for this experiment have been prepared in our lab by improved electrochemical etching method, which is based on the presence of increased surface tension allowing reaching the geometrically precise shape of the cathodes’ tip. After the two phase etching method, the tip was cleared and covered by thin epoxy film, which prevents the tip to be destroyed by ion bombardment that is caused by ions attracted back on to the cathode surface. A comprehensive investigation was carried out to determine particular noise sources and to compare clean cathodes with the resin-coated one, in order to describe the influence of the oxide and dielectric epoxy layer on to the emission current stability. Spectra obtained, for various emission currents at different voltages, are described and explained. The results suggest that the resin-layer changes cathode performance and extends its durability.

Dependence of leakage current on applied voltage was studied for samples of Nb2O5 thin films in the wide temperature range from 10 K to 400 K. Simultaneously low frequency noise characteristics and CV characteristics were measured and evaluated. The studied samples were niobium NbO capacitors with Nb2O5 insulating layer of thickness about 156 nm. IV characteristics measured for different temperature were evaluated and dominant charge carrier transport mechanisms were determined. The ohmic conduction is dominant for the low electric field. It was found that tunneling current is dominant for low temperatures and electric field higher than 125 MV / m while Poole-Frenkel and Shottky mechanisms are more pronounced for electric field below 125 MV / m and temperature above 350 K. The low frequency noise of 1/f type is observed for the tunneling current while G-R noise is observed in case that P-F and Shottky current is dominant.

This paper deals with the process of electropolymerization. The electropolymerization is the method used mainly for creating thin film sensor layers. In this paper the creating of sensor layers by electropolymerization on interdigital structure is discussed. Three methods of electropolymerization are demonstrated. The results of experiments with creating sensor layers are in the next part. The problems with electropolymerization are described in the last part of this paper.