Vol 45, No 1 (2016)

Characteristics of ferroelectric thin films of niobium-doped strontium–bismuth tantalate (SBTN), which were deposited by magnetron sputtering on Pt/TiO₂/SiO₂/Si substrates, are investigated. To form the ferroelectric structure, deposited films were subjected to subsequent annealing at 700–800°C in an O₂ atmosphere. The results of X-ray diffraction showed that the films immediately after the deposition have an amorphous structure. Annealing at 700–800°C results in the formation of the Aurivillius structure. The dependences of permittivity, residual polarization, and the coercitivity of SBTN films on the modes of subsequent annealing are established. Films with residual polarization 2P_r = 9.2 µC/cm², coercitivity 2E_c = 157 kV/cm, and leakage current 10^–6 A/cm² are obtained at the annealing temperature of 800°C. The dielectric constant and loss tangent at frequency of 1.0 MHz were ε = 152 and tan δ = 0.06. The ferroelectric characteristics allow us to use the SBTN films in the capacitor cell of high density ferroelectric random-access non-volatile memory (FeRAM).

We present the results of the numerical simulation of the dependence of the absorption spectrum of a single-electron semiconductor double quantum dot placed in a microcavity on structural parameters and the time dependence of populations of quantum dot states. The investigated physical system can be used for quantum information coding and processing. Initialization and one-qubit operations correspond to the redistribution of populations of localized states of a quantum dot under the action of laser and cavity optical fields.

Memristors based on films of Cu and Cr, as well as their chlorides, which provide better characteristics of electronic components compared to the commonly used ones, are investigated.

A problem, which concerns the effect of the diamond heat-spreading layer on the temperature and voltage-current characteristics of gallium nitride (GaN) high-electron-mobility transistors (HEMTs) is solved for the first time in a hydrodynamic model (which includes the continuity equation, Poisson equation, and equations for electron and lattice temperatures). The mechanism of the occurrence of peak electron and lattice temperatures (hot spots) is analyzed. It is shown that introducing a heat spreader considerably reduces the maximum temperature (by 263 K for a sapphire substrate and by 163 K for a silicon carbide substrate) and improves the voltage-current characteristics. The effectiveness of the heat spreader is evaluated depending on its thickness, gate size, and substrate material to find the optimum design.

The results of designing a set of basic circuit and functional blocks (amplifying, oscillating, mixing, etc.) to construct the radiation-hard transceiver CMOS Silicon-on-Insulator (SOI) large-scale integration circuits (LSICs) are presented. It was established experimentally that the test chips of the circuit and functional blocks (CFBs) produced by domestic CMOS SOI technologies at a feature size of 0.35 µm are functionally operable in the frequency range of 1 MHz to 1.8 GHz, and the values of the main parameters are close to the calculated ones. The results of the experimental research on the hardness of the developed CFBs to pulse and dose impact of ionizing radiation are presented and the hardness levels were evaluated.