Mikroèlektronika

The results of a study of the structural features and electrical properties of Si(Al) through thermomigration p-channels in a silicon wafer are presented. Structural studies were performed using X-ray methods of projection topography, diffraction reflection curves and scanning electron microscopy. It is shown that the channel-matrix interface is coherent without the formation of mismatch dislocations. The possibility of using an array of thermomigration p-channels of 15 elements to form a monolithic photovoltaic solar module in a Si(111) silicon wafer based on p-channels with a width of 100 microns with walls in the plane is shown. The monolithic solar module has a conversion efficiency of 13.1%, an idle voltage of 8.5 V and a short-circuit current density of 33 mA/cm².

Density functional theory (DFT) using the generalized gradient approximation (GGA) made it possible to optimize the crystal structure, calculate the lattice parameters and band structure of TlMS₂ (M = Ga, In) semiconductor compounds with a monoclinic structure (space group С2/с, No. 15). DFT calculations of the structure of compounds were expanded using two exchange-correlation functionals GGA-PBE and GGA + U (U is the Coulomb parameter) with a value of U – J = 2.1 eV (effective interaction parameter). Thermal diffusion coefficients (D_α) of atoms of individual types (α), i.e. atoms of thallium, gallium, indium and sulfur near the melting point of the compound were calculated by the molecular dynamics (MD) method. The values of atoms were obtained in the local neutrality approximation using the canonical MD ensemble. The values of the atoms were corrected to take into account the root-mean-square displacements of the atoms at a given time and temperature. The dependences D_α = f(1 / T) of atoms, described by the Arrhenius law, were constructed. The activation energy of atomic diffusion was calculated.

The model is proposed to explain the effects of low dose rate under the radiation influence in bipolar structures, taking into account the effects of subthreshold displacement in high-doped silicon layers. The base current degradation of bipolar transistor is determined of surface and displacement radiation effects in the near-surface base area. The conditions for the enhanced low dose rate sensitivity (ELDRS) in bipolar structures are shown. The presented results of the analysis allow us to explain most of the observed experimental results.

Mathematical models serve as the basis for unified methods for the calculation and designing of radio-electronic devices. The developed limiting continuous mathematical model of a DC/DC converter, built using SEPIC topology, allows to determine the range of changes in currents flowing through the inductor windings and voltages on the capacitor plates, as well as to determine their maximum and minimum values for various converter parameters, such as switching frequency of the power switch, fill factor, element ratings, etc. The research results have shown that the phase coordinates of the mathematical model tend to the real values of currents and voltages of the converter when the switching frequency of the power switch is more than 200 kHz. Correspondence is established between the calculated values of the pulsation ranges and the results obtained during modelling (with changes in the filling factor and switching frequency of the power switch).

The paper discusses the basic mechanisms of conductivity in silicon MIS structures. The object of the study is porous silicon doped with an erbium impurity of an aqueous solution of erbium nitrate Er(NO3)3 • 5H2O by temperature annealing in a diffusion furnace at a temperature of 800°C for 1 hour. Comparative characteristics of the current-voltage and capacitance-voltage dependences are presented, describing the regular changes in the mechanisms of current flow and charge capture in the samples under study. The results of the work qualitatively and quantitatively describe the temporary change in the electrical characteristics of porous silicon, which can be taken into account by technologists for better understanding the mechanisms of current transfer in luminescent structures of porous silicon with erbium ions, as well as in the study and manufacture of light-emitting diodes based on it.