Research Institute "Pulsar" (Russia)

Thermo-stress effects growth, developments and productivity of crops and plant cope with stress by adopting different mechanism including physiological, bio-chemical and genetic. Calmodulin is calcium binding protein in plant with multifunction to modulate thermo-stress by calcium based signaling process. Many diverse types of calcium sensors release owing to varying concentration of calcium (stimulus). In plants, CaM (calmodulin) is the most important calcium sensor. Achievements in designing of complete genomes of different crops have prompted to explicate and classify various CaM binding proteins. Genetic studies on CaM revealed that it contains multiple proteins, unique kinases and transcriptional factors which help the plants in adaptation against heat stress conditions. Crop improvement could be only possible by having satisfactory acquaintance on stress tolerance mechanism and a brief knowledge on CaM and its related proteins would be obliging in order to acquire its proper functions in plant growth and developmental pathways under extreme conditons. However, current review was conducted to check the role of CaM in heat stress modulation in plants and current research evaluation in this prespectives.

In the field-effect transistors based on the wide-band-gap nitride heterostructures, the dielectric layers are in widespread use as one of the main elements in the active regions of the devices and the passivation layers. Stringent requirements are imposed on the dielectrics in terms of the high dielectric capacitance, large band-gap energy, and the coating integrity. Furthermore, the films must withstand high electric fields and have a low surface state density in the dielectric/semiconductor interface. For these purposes, the low temperature films grown by plasma-enhanced chemical vapor deposition, atomic layer deposition (ALD), and plasma-enhanced deposition are usually used as effective coatings. The ALD films of Al2О3, SiNх (Si3N4), SiON, and ALD AlN are used most often, and offer the greatest promise for the AlGaN/GaN heterostructures. The influence of the passivation of the ALD Al2O3, SiNx, and SiON coatings of various thicknesses on the change of the charge and the density of the states of the AlGaN/GaN heterostructures is investigated. The physical parameters of the structures are estimated by the C–V characteristics measured on various frequencies and the I–V characteristics. It is demonstrated, according to the examined energy band diagrams of the structures at various control voltages, and estimation of the elemental composition of the films by the method of Auger electron spectroscopy, that the reason for the generation of a high positive charge at the deposition of the ALD Al2O3 and SiNx films is the occurrence of an additional piezoelectric charge in the buffer layer of AlGaN. It is demonstrated that use of the SiON films with the oxygen concentration in them higher than 3% does not result in the generation of an additional positive charge but can initiate current fluctuations during the measurement of the I–V characteristics. A possible mechanism of carrier transport in the space charge region resulting in such fluctuations is discussed.

In this paper results of design microwave highvoltage complementary bipolar transistor technology process with complementary junction field-effect transistors (CBiCJFET) are presented. Regimes formation of area of complementary junction field-effect transistors with drain-source breakdown voltage U DS > 36 V and cutoff voltage U GS (off) ~1.5 V are defined. Extension of basis of complementary bipolar technology process is provided with inclusion of 3 extra photolithography operations.

The article discusses the issues of design and methodology related to the current-voltage (I-V) characteristics of a GaN HEMT. Reliable I-V characteristics show the operability of a semiconductor device, provide initial data for functional application of the device, and provide insight into the quality and reproducibility of the technological process. The type and behavior of I–V characteristics are influenced by the design and technological features of a GaN HEMT. Measurements of I-V characteristics in continuous and pulsed operation modes provide more details about the electrical and thermal characteristics of the devices under study.

We have developed technology and construction solutions system to increase differential pairs (DP) of JFet with p- and n-channels identity, which are included into silicon complementary bipolar process of SPE “Pulsar” (Moscow). The possibility of creating several types of JFet DPs within the process is shown. The paper presents the results of experimental studies of two types of DP JFet designs with p- and n-channels for the spread of gate-source voltage ΔVGS depending on the drain current and drain-source voltage. The main features of the first design of p-channel JFets were the following: formation of drain/source area due to passive base of npn-transistor and deep collector areas for pnp-transistor; channel formation based on p-layer collector of pnp-transistor; formation of bottom gate using p+ buried layer; top gate formation due to active base and polysilicon emitter of npn-transistor. A feature of the second JFet design was top gate formation due to passive base. The designs of the first and second types of n-channel Jfet were formed similarly, taking into account the replacement of the applied areas of bipolar transistors with opposite ones in the type of conductivity. It was found that with increasing drain current ΔVGS decreases, and with increasing drain-source voltage ΔVGS at high currents increases for DP based on p-channel JFet with the first type of design. The maximum difference ΔVGS was in the range of 5–80 mV for a given differential pair JFet with a p-channel. On plots for DP p-channel JFet with the second type design a significantly lower voltage spread ΔVGS was shown: for example, for the drain current ID = 50 μA the voltage spread ΔVGS did not exceed 10 mV. In this case the voltage spread ΔVGS practially did not depend on drain-source voltage in contrast to differenctial pair of the first type. The second type JFet n-channel differential pairs like for the DP p-channel JFet provided lower spread values in comparison with the first type design: ΔVGS reached values of 5-20 mV. Moreover, for the design of the second type, a significantly weaker effect of the drain-source voltage on ΔVGS was observed at high current densities. The developed designs of differential pairs based on p- and n-channel JFet are recommended for use in organizing the production of CBiCJFet analog circuits, including operations at low temperatures.

The possibility of using symmetric and asymmetric X-ray schemes on an XMD-300 single-crystal diffractometer to estimate the crystal structure of AlGaN/GaN heterostructure buffer layers is investigated. The developed algorithm for calculating the angles of incidence of a primary X-ray beam, angles of emergence of the diffracted beam to the AlN/GaN/Al2O3 heterostructure surface, and diffraction angles for certain crystallographic planes of these materials allows us to obtain reflections from the $$(10\bar {1}4),$$ $$(10\bar {1}3),$$ and $$(11\bar {2}2)$$ planes, which lie at angles to the surface. A study of the $$11\bar {2}2$$ reflection shows that the crystal lattice of the transition layer between the Al2O3 substrate and bulk GaN buffer layer is turned to the basal plane normal by an azimuthal angle of 30°. The embedding of С and Fe to the GaN buffer layer during a certain chosen growth process leads to a change in the GaN crystal structure, specifically, to the filling of vacant tetrapores through which the $$(10\bar {1}3)$$ plane passes.

A method for increasing the slew-rate (SRHS) in the invert connection of an operational amplifier (OA) with a dual-input-stage is proposed. The principle of the method includes introduction of two nonlinear differentiating correction circuits (DCc) of the transient into the classical OA circuit which form additional overcharge currents of the integrating capacitance of the OA correction in the high-signal operation. At the same time, the DCcs practically don't affect the small-signal response of the OA. The OA circuits of the proposed subclass can have a low consumption current in the steady-state behavior and be performed on the basis of typical technological processes (CMOS, BiJFet, BJT, SiGe, etc.). The results of computer modeling of BJT OA on integrated transistors of JSC “SPE Pulsar” (Moscow) show that the SRHS of the inverting OA, with ideal current mirrors and the buffer amplifier, increases more than 15 times (to 20,000 V/µs).

A design for a high-sensitivity photodetector with a single layer of MoS2 transition-metal dichalcogenide used as the basic functional element is proposed and the process of its fabrication is presented step by step. Quality evaluation and the selection of functional MoS2 flakes is based on the results of combined optical characterization. The main operating characteristics of the fabricated device are investigated and a photosensitivity of 1.4 mA/W is demonstrated. A difference of this device in comparison with existing analogues is its high photosensitivity at low operating voltages (in the range of ±3 V).

A unified SPICE macromodel of the SiGe HBTs taking into account radiation effects is presented. It consists of two parts: 1) the standard core model (GP, VBIC, HICUM, MEXTRAM) selected by the designer; 2) an additional subcircuit taking into account the radiation-induced current and voltage shifts. The macromodel was included on SPICE-like simulators. The advantages of SPICE-RAD version of HBT model are: 1) high accuracy of description for device characteristics; 2) convenience to use for IC designers; 3) simplicity of parameter determination. The I-V characteristics of SiGe HBTs irradiated by gamma-rays, protons, neutrons, electrons are measured and simulated. The error for static characteristics is 10–15% and for dynamic characteristics is 15–20% in wide range of doses and/or fluencies.