A set of transfer and output current-voltage characteristics of a bipolar transistor with a short-period superlattice in the emitter region has been calculated. It is shown that the presence of a superlattice in the tr ansistor structure leads to the fo rmation of a negative differential conductivity region, which makes it possible to implement not only amplification, but also the generation and multiplication of high-frequency oscillations.

The article presents the results of studies of microrelief parameters and electrophysical characteristics of “silicon on insulator” structures after exposure to gamma and gamma neutron radiation. Experimental studies were carried out using the methods of atomic force microscopy and pseudo-MOS transistor. On the basis of the data obtained, an estimate was made of the average size and area of the space charge of clusters of radiation defects.

Computational and experimental studies of the characteristics of a high-power AlGaAs/InGaAs/GaAs DpHEMT were performed. A self-consistent numerical solution of the Schrodinger and Poisson equations was used to calculate the band diagram and the electron concentration in the channel of the transistor under study. The electron mobility in the transistor channel was estimated experimentally at 9300 cm2/V·s. The obtained transfer current--voltage characteristic of the transistor was used to calculate the parameters of a model differential amplifier (small-signal gain and third-order non-linear distortion factor). Keywords: AlGaAs/InGaAs/GaAs DpHEMT, nonlinear distortion, spacer layers.

The paper presents the results of studies of C–V characteristics of GaAs/In0.53Ga0.47As HEMT before and after neutron irradiation with a fluence of (6.3 ± 1.3) × 1014 cm–2. Based on the experimentally obtained characteristics, the effective electron distribution profiles of the structure were calculated before and after radiation impact. The effect of radiation defects on the δ-layers of the structure was analyzed.

Приведены результаты исследований параметров микрорельефа и электрофизических характеристик структур "кремний на изоляторе" после воздействия гамма- и гамма-нейтронного излучения. Экспериментальные исследования проведены методами атомно-силовой микроскопии и псевдо-МДП транзистора. На основе полученных данных проведена оценка эффективного радиуса ядер кластеров радиационных дефектов. Ключевые слова: Атомно-силовая микроскопия, кремний на изоляторе, "допороговое" дефектообразование, кластеры радиационных дефектов.

An experimental and theoretical study is performed of the change in the slope of current–voltage characteristics in the area of negative differential conductivity. Reasons are considered for the stepwise rise in current at high voltages inside superlattices with few (6–18) periods. Also examined is the effect of transitional layers of the superlattice that are used to enhance the injection of electrons into the active region at the junction of the metal contact and the n + layer–superlattice contact.

Проведены расчетно-экспериментальные исследования характеристик мощного AlGaAs/InGaAs/GaAs DpHEMT. При помощи самосогласованного численного решения уравнений Шредингера и Пуассона рассчитана зонная диаграмма исследуемого транзистора, получена концентрация электронов в канале. Экспериментально оценена подвижность электронов в канале транзистора, которая составила 9300 см2/В·с. На основе полученной проходной вольт-амперной характеристики транзистора рассчитаны параметры модельного дифференциального усилителя: малосигнальный коэффициент усиления и коэффициент нелинейных искажений 3-го порядка. Ключевые слова: AlGaAs/InGaAs/GaAs DpHEMT, нелинейные искажения, спейсерные слои.

Theoretical analysis of the degradation of the current–voltage characteristic and transient ionization processes occurring in a low-barrier uncooled GaAs Mott diode under the action of heavy ions from outer space and laser pulses simulating them is carried out. The response of the diode to the action of an arsenic ion with an energy of 200 MeV, which corresponds to a linear energy transfer of 26 MeV cm 2 /mg, is compared with the response to the action of femtosecond optical-radiation pulses with a duration of 10 fs at wavelengths of 870 and 670 nm.

The paper presents the results of modeling the electrophysical parameters of AlGaAs/InGaAs/GaAs pseudomorphic high electron mobility transistor (pHEMT) structures via self-consistent solution of the Schrödinger and Poisson equations. On the basis of numerical calculations, a method for analyzing nonlinear distortions of the transfer current–voltage characteristics of such transistors is proposed. The effect of the spacer layers and the doping level of the δ layer on the nonlinearity of the current–voltage characteristics is estimated.

The electrophysical parameters and surface morphology of n / n – GaAs structures with Schottky contacts before and after exposure to neutrons with an average energy of ~1 MeV are studied. Changes in the electron concentration and mobility profiles in the structures are determined by capacitance–voltage measurements. Using atomic force microscopy, radiation-induced defect clusters are revealed; a comprehensive approach to determining their parameters is proposed.

The results of experimental studies of the electrical parameters and surface morphology of GaAs structures of ring and circular Schottky diodes before and after irradiation with ~ 1 MeV neutrons are presented. Bulk radiation defects were revealed by atomic force microscopy (AFM). Based on the results of capacitance-voltage measurements, the concentration of electrons was determined and their mobility was estimated before and after irradiation. On the basis of the results obtained using a combination of these methods, a technique is proposed for determining the average sizes of the space charge regions of clusters of radiation defects.

Transient ionization processes occurring in a low-barrier GaAs Mott diode under the influence of heavy charged particles from outer space and laser pulses that imitate such particles are analyzed theoretically. The response of a diode to the influence of an As + ion with an energy of 200 MeV, which corresponds to a linear energy transfer of 26 MeV cm 2 /mg, is compared with the response to the influence of optical radiation pulses of various durations (10–1000 fs) with a photon energy exceeding the band gap of GaAs.

A theoretical analysis of transient ionization processes occurring in a low-barrier GaAs Mott diode under the influence of space radiation high energy charged particles and simulating pulsed laser radiation is carried out. The diode response to the As+ ion action with an energy of 200 MeV, corresponding to a linear energy transfer of 26 MeV cm2/mg, is compared with the response to the femtosecond pulses optical radiation action of various durations (10-1000 fs) and photon energies exceeding the GaAs band gap.

The electrophysical parameters and surface morphology of GaAs n/n- structures with Schottky contacts before and after neuron impact with an average energy of about 1 MeV were studied. Changes in the profiles of the concentration and mobility of electrons in the structures were determined by the C-V method measurements. The method of atomic force microscopy helped to find radiation defect clusters which appearing during impact. A complex approach to the determination of their parameters is proposed.

A theoretical analysis of the degradation of the current-voltage characteristic and transient ionization processes occurring in a low-barrier uncooled GaAs Mott diode under the action of heavy ions of outer space and laser pulses simulating them is carried out. The response of the diode to the action of an arsenic ion with an energy of 200 MeV, corresponding to a linear energy transfer of 26 MeV∙cm2/mg, is compared with the response to the action of femtosecond pulses of optical radiation with a duration of 10 fs with a wavelength of 870 nm and 670 nm.

The electrical parameters and surface morphology of the GaAs structures of ring and circular Schottky diodes before and after irradiation by neutrons with an energy of ~1 MeV have been experimentally studied. Using atomic force microscopy, volumetric radiation defects have been revealed. The density of electrons has been determined and their mobility before and after irradiation has been estimated from the results of the C – V measurements. Based on the results obtained by these two techniques, a method for determining the average size of the space charge regions of the radiation defect clusters has been proposed.

The work is devoted to the results of modeling of the parameters of pHEMT structures based on the AlGaAs / InGaAs / GaAs compound using a self-consistent solution of the Schrödinger and Poisson equation. Based on numerical calculations, a method for analyzing nonlinear distortions of transfer I-V characteristics is proposed. The influence of the spacer layers and the degree of doping of the δ-layer on the nonlinearity of the I – V characteristic is estimated.

The nonlinearity of the gate–drain current–voltage characteristics in classical Schottky transistors and two-dimensional electron gas field-effect transistors based on AlGaAs/InGaAs/GaAs and InGaAs/GaAs compounds is analyzed. The carrier velocity-overshoot effect in the transistor channel is analyzed for various doping profiles of the structures under study.

Abstract The nonlinearity of the gate–drain current–voltage characteristics in classical Schottky transistors and two-dimensional electron gas field-effect transistors based on AlGaAs/InGaAs/GaAs and InGaAs/GaAs compounds is analyzed. The carrier velocity-overshoot effect in the transistor channel is analyzed for various doping profiles of the structures under study.

The influence of nonequilibrium processes in semiconductor structures under the effect of radiation on the characteristics of structures and microwave transistors based on them is analyzed. Special attention is paid to the comparison of pilot (experimental) and series-produced structures and transistors based on them before and after γ-neutron irradiation.