Vol 45, No 7 (2016)

The influence of the doping concentration in the active layer and in the bulk substrate on the drain current of a silicon-on-insulator (SOI) field-effect Hall sensor (FEHS) using Sentaurus TCAD is studied. At the initial stage, the numerical model is corrected by comparing the transfer current-voltage characteristics of the calculation and the experimentally measured SOI FEHS sample. It is shown that, under low concentrations in the active layer, the drain current depends on the capacity of the front gate, while the doping concentration in the bulk substrate affects the drain current only when the device is operating in depletion mode.

The results devoted to the development of a method for creating an RF transistor, in which a T-shaped gate is formed by nanoimprint lithography, are presented. The characteristics of GaAs p-HEMT transistors have been studied. The developed transistor has a gate “foot” length of the order of 250 nm and a maximum transconductance of more than 350 mS/mm. The maximum frequency of current amplification f_t is 40 GHz at the drain-source voltage V_DS = 1.4 V and the maximum frequency of the power gain f_max is 50 GHz at V_DS = 3 V.

A theoretical investigation of the IMPATT diode supply current on the operation mode of a generator is out. As additional parameters affecting the operation mode, the coefficients of signal reflection from the inhomogeneity in the output transmission line and the delay time of this signal have been analyzed. It is shown that the following modes of synchronization may appear at various relations between these parameters: with an instability of the amplitude, multifrequency mode, dynamic chaos mode, single-frequency mode, and oscillation suppression mode. Based on the solution to the autogenerator equation, the possible operation modes of a generator based on the IMPATT diode were analyzed. The results make it possible to assess the range of parameters where a negative effect upon the operation mode of the oscillator will be absent and the ranges of the oscillator’s parameters when the mode of dynamic chaos can be obtained.

The results of research and development of a 320 × 240 platinum silicide focal plane array (FPA) for the spectral range of 3–5 μm are presented. The development is based entirely on CMOS technology. It is shown that the FPA makes it possible to adjust the photosignal accumulation time at a fixed frame rate and subtract the background constant component in the output device.

A new type of a double-electrode MIS varicap with a carrier transfer has been proposed. It is shown that in a device of this type, there are no negative effects associated with the processes of thermal generation and accumulation of minority carriers. This makes it possible to increase the limiting frequency and improve the temperature stability of varicap operation. Two designs of the device are considered. The characteristics of the varicaps that were measured experimentally agree with the results of the calculations.

Using the methods of finite element and conformal mapping, analytical models with low and ultralow resistance of the film resistors of the main types of comb-like (interdigital) structures with an arbitrary ratio between the surface resistivities of resistive and conductive films have been worked out. In the resultant resistance, the resistances of comb-like and connecting electrodes are taken into account, as well as the additional resistance caused by the passage of the current from the conductive to the resistive film and vice versa. The conditions under which an interface between the films can be treated as an equipotential surface are revealed. An equivalent circuit of low-impedance comb resistors, which are used as the sensors of the current in the circuits of stabilization and control, as well as thermal and current protection.

The models of the analog and digital parts of a GLONASS receiver obtained using a Matlab Simulink simulation environment are presented. The possibilities of estimating the characteristics of the analog part of the GLONASS receiver in the ADS CAD software are investigated. The design flow is proposed based on the construction of a cross-cutting radio channel model using a different CAD software. The considered models expand the opportunities for thoroughly investigating radio channels in the field of satellite navigation and improving the existing devices for receiving and processing GLONASS signals.

Discrete electrostatic microwave microelectromechanical switches on gallium arsenide wafers are designed and fabricated. The possibility of integrating the switches in one circuit with monolithic integrated circuits of transreceiving devices fabricated in one production cycle is estimated.

The results of the development of technologies of magnetic semiconductor chips based on thinfilm magnetoresistive multilayer structures are presented. A brief overview of the main achievements in the field of magnetometric devices based on anisotropic and giant magnetoresistive effects is made.