The quantum and chemical simulation (HF/MP2, cc-pVDZ basis) of diphenyl-2,2',4,4'-tetraamine (DPTA) molecule properties allows to determine the its thin film pyroelectric properties since hydrogen bonds between molecules in the film are weaker than intramolecular bonds. The study of a DPTA photosensitive pyroelectric film microstructure enables one to assume that the dipole moment of the needle-shaped crystallines densely stacked and extended along a film surface is aligned perpendicularly to the surface. The possibility of the reproduced control for DPTA properties may be used when producing the most effective pyroelectric film for photodetectors in infrared wavelength range.
Keywords: Diphenyl-2,2',4,4'-tetraamine, quantum chemical simulation, pyroelectric material, thin-film structure
A model is presented for the calculation of thermoelastic stress and displacement in semiconductor structures
due to laser processing. Developed software based on the model allows to determine the optimal parameters of laser processing with taking into account the physical and topological parameters of the structure. The model is divided into two tasks: the non-stationary heat conduction equation is solved, and the equilibrium equations and Hooke's law. For equations solution was used the finite difference method.
Keywords: Laser processing, thermal stress, finite difference method
In this work new circuit solutions of R-S-latch and D-trigger having nonvolatile electrically programmable memory and nonvolatile shift register are presented. It shows that nonvolatile R-S-latch can be effectively used as a memory cell and simultaneously as write and read circuits for it, thus it makes possible to increase reliability of read operation from EEPROM at the expense of differential read for every bit.
Keywords: CMOS, R-S-latch, D-tirgger, shift register, EEPROM, nonvolatile memory
The article describes the preparation of the sensitivity of the output voltage for a typical architecture of voltage reference to variations of the parameters of elements. Also considers the main advantages of this approach in the analysis and design of circuits. The article presents the corresponding graphs sensitivities. Based on the findings conclusions about the impact of deviations of circuit elements on the output parameters of the reference voltage was done.
Keywords: Sensitivity, CMOS voltage reference, bias voltage, group bias
Developed criteria for matching the oscillation frequencies of sensitive elements biaxial functionally integrated micromechanical gyroscopes-accelerometers LL-type. Review the results of modeling.
Keywords: microsystm technology, element base, model, modeling, gyroscope, accelerometer, sensor
Maximum power pointtracking algorithms are widely used in the solar converters in order to obtain maximum power from the solar array. The article provides a brief description of the work of these algorithms, description of the method of testing based on mathematical modeling using Matlab, Simulink and SimScape packages. The results of modeling and comparative analysis of the studied algorithms, its strengths and weaknesses revealed.
Keywords: maximum power point, maximum power point tracker, photovoltaic, buck converter, comparative study of algorithms, perturb and observe method, constant voltage method, constant current method, icremental conductance method
The analytical method for calculation of induction and inductive properties of conducting cylinder with azimuth density of rotational current has been proposed. The method permits: to calculate radial distributions of azimuth component for strength vector of rotational electric field, densities of whirling currents, specific heat rating, being emitted at the local area of conductor; to determine the dependence of average electro moving force (EMF) in the ring, inductive current and integral ohmic resistor from equivalent cavity’s radius of cylinder; on the base of energy considerations to calculate the inductance, being introduced by conducting cylinder. This calculation is executed for investigated electromagnetic fields, where the finite phase shift between the current and the flux exists.
Estimations, executed for real conductors and semiconductors, point out to that the great values of inductance can be achieved at the low frequencies for materials with a small specific resistance. The small values of inductance can be achieved at the very high frequency (VHF) and extremely high frequency (EHF) for materials with a large specific resistance.
Keywords: introduced inductance, induction, rotational electric field, alternating current, magnetic field flux
The temperature dependencies of the main parameters of p-channel MOSFET model in a temperature range 20 ... 300 K are measured. The universal formal four-parametric model, which allows approximating all experimental temperature dependencies with the relative error less than 1 % is proposed. The model is intended for the MOSFETs which are applying in low-noise amplifiers of the radio-receiving devices of an optical and infrared range on astronomical satellites, radio telescopes and space observatories. The presented results can be used to simulate the temperature modes of MOSFET amplifiers in SPICE-type electronic simulators. The solution of this problem will predict uptime device when the temperature changes in the cases of emergency or extraordinary situations and also will allow optimizing the choice of refrigerant and increasing the reliability of the amplifier in the conditions of cryogenic temperatures.
Keywords: MOSFET, MOSFET parameters, cryogenic temperature, parameters measurement, temperature dependencies
The proposed method of designing hardware components optical switching systems simplifies prototyping and development of systems of optical switching and multi-core VLSI. This method allows to automatically set parameters of the optical system at the design stage, depending on the requirements. This method may be cost-effective at the stage of technical specifications of the project, as will reduce the time required for its coordination between the customer and the design engineer.
At the heart of developing a method of designing systems, optical switching elements is a comprehensive analysis of the equations and functions describing the electrical and optical properties of laser heterostructures, as well as electro-optic modulators and Fabry-Perrot resonators. Fundamental static and dynamic characteristics of semiconductor diode lasers can be calculated by using a set of kinetic equations describing the interaction of electrons, holes and photons in the active layer of the laser structure. At various stages of this method is processing, evaluation and calculation of the main characteristics of the elements of integrated optical switching systems.
Keywords: optical switching, integrated injection laser, quantum-scale heterostructure, amplitude modulation, terahertz range
The mathematical model and the simulation of metal-semiconductor contacts with Schottky barrier volt-ampere characteristics taking into account electrically active impurities inhomogeneous distribution in semiconductor are proposed in this work. The developed mathematical model takes into account quantum mechanical effects during the charge carriers transfer in metal-semiconductor junctions with Schottky barrier and allows forecasting their volt-ampere characteristics. The simulation results meet the experimental data from famous literary sources. The developed mathematical model can be used in computer aided design of integrated circuits elements.
Keywords: Schottky diode, potential, Poisson equation, volt-ampere characteristic
Computer-aided diagnostic system of semiconductor structures for the tested structures volt-ampere and voltage-capacitance characteristics measuring at different temperatures in wide ranging bias voltage was made in this work. Computer-aided diagnostic system of semiconductor structures allows to define parameters of deep-lying levels, profiles of alloying impurities distribution, charge carriers life span, surface states energy spectrum density with high reliability and efficiency and can be used for processing and optimization of technological modes for solid-state electronics structures generation.
Keywords: diagnostics, dynamic spectroscopy of deep-lying levels , spectrum, deep-lying levels, surface states, profile of impurity distribution
Recently, BiFeO3 multiferroics have drawn a great deal of attention due to their superior ferroelectric properties in epitaxial thin film form in comparison to counterpart bulk single crystals or ceramics. In this work we present the results on magnetic properties of multiferroic ultrathin films (30-300 nm) of BiFeO3, (BiLa)FeO3 and (BiNd)FeO3 obtained by sputtering in transverse high frequency discharge, vacuum laser oblation and metalorganic chemical vapour deposition on monocrystalline substrates of (001) SrTiO3, (100) MgO and (100) Al2O3. The concentration of Bi, La и Nd in dodecahedral sublattices was varied. A novel effect of treatment of multiferroic films in a negative corona discharge has been investigated. It is demonstrated that the magnetisation may be increased by up to 35% whilst the change in is not noticeable. This effect does not depend on neither film composition no technological method.
Keywords: multiferroics, magneto-electric materials, methods of preparation, the films of bismuth ferrite, pseudomorphic structure, magnetic properties, corona discharge
Measurement results of basic characteristics of electronic module based on two specialized analog integrated circuits depending on different square area silicon detectors using source of 239Pu alpha particles is given. Processing of current pulses typically consists to convert them into a voltage by charge sensitive amplifiers and reduce noise by bandpass filters. Earlier for work with avalanche photodiode we have developed, constructed and tested two electronic modules "CRP-MDL-1" and "CRP-MDL-2". During the measurements was investigated spectrometric channel response on exposure to ionizing radiation from a source of alpha particles 239Pu and test input signals, thus we determined basic technical characteristics including energy resolution and noise characteristics. As a result, research found, that the output signal has the following timings: rise time - 1 us (levels of 0.1-0.9), peak time - 1.4 us, fall time - 1.8 us pulse width - 3.5 us. The conversion factor of module working with silicon detector (area of 1000 mm2 and a capacity 500 pF) consists about 10.6 mV / fC, or 0.47 V / MeV. Integral nonlinearity of spectrometer path is not worse 0.4% in the range from about 0.1 to 3.2 V. The energy resolution was 89.1 keV line of 5157 keV. The experimental studies revealed that using an external low-noise transistors developed module can be used in the construction of standard radiometric paths. It is appropriate to use the developed design-circuit solutions for implementing 4-channel chip for multi-channel radiometric and spectrometric systems.
Keywords: silicon detector, charge sensitive amplifier, spectrometer, radiometric system, ionizing radiation
Сollector mm-wave load circuit of differential stages, as well as the optimization of Q-factor are considered. Optimization of the form of microstrip line in order to increase quality factor is shown. Differential line shorted at one end, at the resonant frequency in the operating mode of the standing wave. At the shorted end of the line voltage is at minimum level, while the current at the maximum, so losses are mainly due to the series resistance of the microstrip line. On the other side of the line, the current is minimized, and the voltage - maximum, so the parasitic losses associated with shunt conductance between the differential lines. This effect use for reducing line losses and increasing the Q-factor. To this end, at the shorted end of the line is necessary to increase the line width and the gap between them, and at the other end to reduce the width and gap.
Keywords: resonant circuit, SiGe, mm-wave, BiCMOS, monolithic integrated circuit
In the introduction the relevance of the study of diffusion along grain boundaries in metals. The aim of the work was to develop a method for determining the diffusion coefficient of impurity atoms at the grain boundaries in metals based on the numerical solution of the model by Fisher. The methodology laid plotting the ratio of the depth of bulk diffusion and grain boundary diffusion on the ratio of the diffusion coefficients of impurity atoms in them. In the construction of numerical solutions available to simplify the modeling of the physical nature of the process of diffusion along grain boundaries. The technique may be used in experiments with widely varying parameters diffusion annealing. Examples of the application procedure. The estimation of the coefficient of grain-boundary diffusion of copper in polycrystalline nickel. Also calculated the ratio of maximal depth of diffusion of silver in the grain and the grain boundary in the SMC copper.
Keywords: diversification of management, production diversification, financial and economic purposes of a diversification, technological purposes of ensuring flexibility of production
The synthesis of nanocomposite FeNi3/C based on the PAN, FeCl3 · 6H2O and NiCl2 · 6H2O, whereby the first time by the IR heating at 400 ÷ 700 ° C obtained nanocomposite FeNi3/C FeNi3 particle size of 10 to 80 nm are uniformly distributed UM. Using thermodynamic calculations based on the minimization of the Gibbs energy, confirmed the synthesis of nanocomposite FeNi3/C at T=400 ° C reduction of Fe and Ni with H2, produced during the process of carbonization of polyacrylonitrile with infrared heating. Designed as a nano material of the films can be effectively used as a carrier material for a magnetic information recording superdense. Recording density is achieved in such a carrier (85-100) Gb/dyuym2.
Keywords: nanocomposite, polyacrylonitrile, infrared heating, recording information, the magnetic properties, the carbon matrix
This paper describes a hardware-based and software system parametric estimation of signals. It`s experimental accuracy was achieved measuring the phase difference between the two quasi-harmonic signals at 10 μrad.
Keywords: parametric analysis, technical diagnostics, the phase difference
Tendencies of technological improvement of electronic chips led to reduction of their sizes, weight, development of functionality and decrease in power consumption. It allows us to discuss questions of developing renewable micro power sources which can provide power supply of autonomous microelectronic and micro circuitry systems for charge indication, paying attention to snow transfer, etc.
The purpose of the paper is researching a profile of electrostatic field potential in the mountain district which was estimated as a possible use as a renewable micro power source.
It is found out that on windward sides of snow relieves the potential of electrostatic field exceeds three times to a similar indicator for lee sides and is 80 V. The potential is 3,5kV on polymeric surfaces (Nylon, teflon).
Keywords: snow storming electricity, electrization, potential of electrostatic field, charge, the salting, the loaded particles of snow, innovation electronics, micro circuitry, renewable micro power sources.
The simulation of the process of the electrically active impurities relocation in the electric field of Schottky diode space charge region has been made. The analysis of the simulation results shows the possibility of controlled alloying impurities relocation on the depth about tens of nanometers caused by electrically active atoms diffusion in the electric field of Schottky diode space charge region.
Keywords: diffusion, space charge region, Schottky diode
The coloration centres (CC) in crystals of rear earth gallium garnets (REGG): Gd3Ga5O12 (GGG), Gd3Sc1,6Ga3,4O12 (GSGG) и Nd3Ga5O12 (NGG) obtained by Chohraljskiy method, were investigated by methods of optical spectroscopy and spectral analysis in the wavelength range of 0,2-0,87 microns. In the case of keeping the samples under dark conditions, unstable CC were formed in the crystals of GGG and GSGG. The absorption maxima are at λmax1 = 0,243 m and λmax2 = 0,275 m at concentration of N ~ 1018 cm-3. It is suggested that the observed enlightenment is caused by the recharging of growth defects and occurring the energy levels in the band gap of garnets. It appears that these CC correspond to centres of O- holes, originated from gallium vacancies V3-Ga 3+ in tetrahedral and octahedral nots which form near clusters of [V3-Ga 3+ - V2+O2- ]
Keywords: color centers, rare earth gallium garnets, kristylly, Czochralski method, the crystal lattice
To date, the main method of mass production of advanced functional materials for various purposes is the ceramic technology. In the manufacture of multi-component oxide compounds using of ceramic technology is difficult to achieve high uniformity of chemical composition. For activation of the raw ingredients and make it more uniform use of chemical-tions (co-precipitation of salts or hydroxides, spray drying, Cryochemistry) and physical-tions (mechano-chemical, microwave, ultrasonic) methods. The paper presents the results of work on obtaining Ni-Zn-ferrite 2000NN radiation-thermal sintering. The influence of base composition and alloying additions on the electromagnetic properties of the ferrites. Confirmed the effectiveness of the use of surface-active additives To increase the density of the raw pieces and level parameters. We propose a model that explain schaya efficiency of dopants in the radiation-thermal sintering.
Keywords: Nickel-zinc ferrite, radiation thermal sintering, base composition, alloying additives, permeability
Promising absorbing materials along with a Ni-Zn-ferrites are Mg-Zn-ferrites, as they are also intensively absorbs electromagnetic waves in the frequency range from 50 MHz to 1000 MHz. The main advantage of the Mg-Zn-ferrite is used as an inexpensive raw material magnesium oxide. The paper presents the results of research to improve the efficiency of broadband radio-magnesium-zinc ferrite by increasing the contribution of the dielectric loss. The influence of alloying elements of the atmosphere gas and cooling after the sintering thermal radiation by absorption of electromagnetic waves. Confirmed cooling efficiency of products after sintering in an atmosphere with reduced oxygen partial pressure to increase the dielectric constant. A model is proposed to explain the increase in the dielectric loss ferrite during cooling in a reducing atmosphere.
Keywords: radioabsorbing ferrites, microstructure grain boundaries radio measurement radiation thermal sintering
The model of micromechanical mirrors mobile elements balance is developed. The received results of modelling of a micromechanical mirror are considered.
Keywords: microsystm technology, element base, model, modeling, mirror
"This article is devoted to the development of the method for modeling elements of microsystems technology(MST) of membrane type. In this paper perforated membranes are considered and the impact of perforation on the mechanical properties of the membranes is examined. In numerical simulations of the elements it is proposed to use the equivalent mechanical parameters of perforated membranes obtained at the initial stage of the simulation. This will allow to obtain find the optimal parameters of perforation, reduce the time and resource modeling of MST elements. To test the technique numerical experiments were conducted for the two square membranes with sides 1.5 and 3 mm fixed on the contour of the same thickness. We studied the influence of the size of the perforation on the equivalent Young's modulus of the perforated membrane. "
Keywords: microsystems technology, numerical modeling, perforated membrane
Finding of small concentrations of various gases as an important task for the environment and for the industry. In this paper, investigated gas-sensitive properties of the films of graphene on silicon carbide to NO2 and vapour C2H5OH. The principle of operation of graphene sensor based on the change of electrical conductivity by reason of adsorption of gas molecules. Temperature dependence of the gas desorption from the surface of graphene is obtained. Mode of getting graphene films with the best gas sensing characteristics is defined. The obtained results suggest that graphene is a promising material for gas-sensitive sensors
Keywords: graphene, graphene films on silicon carbide, gas sensor, gas-sensitive of graphene