Персона: Лещев, Сергей Валерьевич
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Thermal stability of tantalum nitride based thin film resistors
© 2019 Published under licence by IOP Publishing Ltd. Tantalum nitride thin films were deposited on Al2O3 substrates by the dc-magnetron sputtering technique. The nitrogen content in the argon/nitrogen flow varied from 5 to 50%. Structural properties were studied using X-ray diffraction. The ratio of Ar:N2 was 4:1; the ratio of Ta:N became 1:1. Sheet resistance depends on thickness and is in the range of 20 - 80 Ω/□ due to thickness 100 - 50 nm. The TaN films deposited at a nitrogen/argon ratio of 20% show the thermal stability of the resistance in the 25-400°C temperature range. Sheet resistance degradation was ∼ 5%. The TCR value was determined in the range of 25 - 300 C and was equal to - 21 ppm/K.
Poster: Influence of the Direction of Movement of Earth-Moving and Construction Machines on the Stability of Remote Control Data Transmission via Mobile Communication Channels
© 2019, Springer International Publishing AG, part of Springer Nature. In the article authors give research results of the influence of the movement direction of earth-moving machines on the stability of the remote control data transmission through mobile communication channels. The authors carried out an extensive analysis of the state of research in this and related fields. If movement direction of earth-moving and construction machines changes with respect to the nearest radio transmitting tower of the mobile communication base station, theoretically an instability in data transmission of data over mobile communication channels will appear. To establish the admissibility of such instability, experiments were performed in real conditions, the results of which are presented in the article.
Temperature influence on process of Ti/Al/Ni/Au contact formation to heterostructure AlGaN/GaN
© 2019 Published under licence by IOP Publishing Ltd. This paper is dedicated to the experimental investigation of Ohmic contacts to the n+-doped region of the AlGaN/GaN transistor heterostructure based on Ti/Al/Ni/Au metallization. The Al-Ti-N system has been assessed on the basis of available thermodynamic descriptions for binary subsystems. The effect of annealing temperature on the specific resistance of Ohmic contact was studied.
Formation of nanoscale structures in thin films deposited by reactive magnetron sputtering of binary metal targets in Ar+O2+N2 gas mixture
© Published under licence by IOP Publishing Ltd.Bi-metal targets of ZnSn and SiAl were sputtered in A+O2+N2 gas mixtures at various N2/O2 ratios, and the deposited films were investigated by AFM and XPS. No nitrogen was detected in the films even at the highest nitrogen partial pressure in the gas, and the films were oxides. The concentration of the doping metal component in the deposited film increases with the increase of nitrogen partial pressure in the working gas. These experimental observations were supported by numerical calculations of the sputter-deposition process using a SRIM/SIMTRA+RSD software. It was shown that added nitrogen promotes sputtering of doping metal components of the targets, and the concentration of oxygen remains high enough to substitute the less active nitrogen in the growing film. The films consisted of nanograins with the average diameter, which decreased from 18 nm to 3 nm with increase of nitrogen content in the working gas. This effect was explained by the mechanism of abnormal grain growth: the film consisted of grains of oxides of two metals with different concentrations. The doping metal forms very fine nanograins of oxides, which suppress the growth of oxides of the main metal. With increase of nitrogen in the working gas mixture, the sputtering rate of doping metals from the cathodes and their respective concentration in the growing films increases, so the average diameter of oxide grains forming the coating decreases.