Experimental studies and a double gate JFET model for analog integrated circuits

One of directions of improving parameters of analog integrated circuits is a development of new and modernization of existing designs of integrated elements without significantly changing of a technological route of integrated circuit manufacturing with a simultaneous creation of new integrated elements models. The article considers the results of experimental studies of the double gate junction field-effect transistor manufactured according to the 3CBiT technological route of JSC Integral. Based on the obtained results, the electrical model of double gate junction field-effect transistor is proposed, which describes the features of its application in analog integrated circuits. Comparison of I-V characteristics of measurements results and created model simulation are presented. A small capacity and a reverse current of a double gate junction field-effect transistor top gate, an ability to compensate for the DC (direct current) component of an input current provide a significant improvement in the characteristics of analog integrated circuits such as electrometric operational amplifiers and charge-sensitive amplifiers. The developed double gate junction field-effect transistor can be used in signal readout devices required in the analog interfaces of space instrument sensors and nuclear electronics.

Development of techniques for the formation of a planar electric vacuum diode based on an array of CNTs synthesized at the edge of the Co-Nb-N-(O) film

This work shows the possibility of forming a planar diode structure based on carbon nanotubes formed on a catalytic alloy film Co-Nb-N-(O). The paper presents a technological route for the formation of a planar diode structure Si/SiO2/Si3N4/Co-Nb-N-(O)/SiO2 and studies the emission characteristics. The current-voltage characteristic of the obtained diode structure in the Fowler-Nordheim coordinates is close to linear in the range from 15 to 22 V, which confirms the phenomenon of electron emission.

Influence of constructive and geometric parameters of the end cutters on the microprofile characteristics of casting surfaces

The object of research is the technological route of machining of an aluminum alloy casting. The research carried out is based on the basic principles of functionally oriented design of technological processes in the manufacture of products. The main hypothesis of the study is the need for a systematic approach to study the effect of cutting modes of a certain method of machining on the provision of quality parameters in the technological system (machine – device – tool – workpiece). In traditional automated systems for technological preparation of production, an object-oriented principle of designing technological processes is implemented, which provides for the step-by-step implementation of interrelated stages based on a prototyping algorithm without a functional analysis of the operational characteristics of the product. The processing of functional, mating surfaces, ensuring that the product performs its service purpose, must be implemented according to the principle of function-oriented design (FODT). A characteristic feature of FOT is the technological provision of effective operational characteristics of the product in compliance with the parameters of accuracy and quality of the surface layer of the product intended by the designer. The paper deals with the influence of the structural and geometric parameters of end mills manufactured by Sandvick (Sandviken, Sweden) on the formation of microrelief parameters of an aluminum alloy casting profile during machining on a numerically controlled vertical milling center (CNC) HAAS MINIMILL (USA). An atypical option for the FOT principle of the technological route of machining the surfaces of workpieces of machine-building products has been applied. Its feature is ignoring the requirements of the manufacturer of metal-cutting tools, which is an important element of the technological system (machine – tool – device – workpiece), regarding its use for a particular machine tool at a certain technological transition of machining. The performance criteria were the height and step characteristics of the microrelief of the profile of the surface layer of the workpiece being processed. The operating conditions of machine-building products have been determined, which make it possible to establish, in case of deviation from the manufacturer's recommendations at the stage of technological preparation of production, the rational elements of a certain technological system: a metal-cutting machine – a device – a metal-cutting tool – a workpiece and processing modes to ensure the necessary operational characteristics.

Research and Development of MEMS Accelerometer's Sensor

Currently, MEMS accelerometers are one of the most promising areas in the inertial sensor industry. The design and study of MEMS accelerometers structures is associated with solving problems of mathematical physics. Also, a very important task is to comply with the technological route, including carrying out such operations as deep etching of silicon. This article describes the modeling of the developed geometric model of the sensitive element MEMS accelerometer. The calculations were carried out, which showed that the developed structure is efficient. As a result of the study of the Bosch process using methods for planning multifactor experiments, the modes of deep etching of silicon were optimized. Prototypes of sensitive element MEMS accelerometers have been produced.

MULTICHOICE APPROACH TO SOLUTION OF OPTIMIZATION PROBLEMS OF ALGORITHMIC DESCRIPTION FORMATION OF PROCESSING ROUTES

The paper is aimed at the solution of the problem in the formation of multi-level structural optimization of promising technological processes. Here there is manifested the necessity in thorough development of algorithmic problems on the formation of the best technological route for components and units processing taking into account requirements to quality and choice of the smallest cost characteristics of an industrial process. At the solution of optimization problems in engineering process designing there are used simulators reflecting basic principles of production work functioning. The search of an optimum solution was carried out by a mechanism of threshold structural optimization realization on network graphs. In the course of the investigation fulfillment on the problems of automated production introduction there were formed simulators taking into account single-phase and multi-phase systems of mass maintenance. At that to the first place there were moved cost parameters for the assessment of engineering process versions. In such a way was confirmed a hypothesis on the purposefulness of the definition of engineering process functional parameters with the further choice of an optimum solution. Conclusions: time decrease, high quality, and also a financial profit can be complex for the majority of real applications, therefore the majority of optimization methods try to find an ideal method for the solution of limited resources problem in the framework of different limitations.

Optimization of guard rings construction and epitaxial film resistivity of power n-channel DMOS-transistor

Powerful n-channel DMOS-transistor with drain-source breakdown voltage Uds br value over 800 V and thresh-old voltage from 2 to 5 V was considered in this paper. One or more guard rings are formed on perimeter of such transistor for the breakdown voltage raising. The optimal guard rings construction was described and resistivity value of epitaxial film ρv was determined for obtaining required transistor Uds br value. The regression model was built, with the help of which the most optimal construction variants of guard rings of investigated transistor and resistivity value of epitaxial film, were selected. It was established that the five-dimensional polynomial of second order using as regression model allowed choosing the optimal topological spaces values in the guard rings area and ρv value which made it possible to obtain required Uds br values of the transistor. Experimental values of transistor drain-source breakdown voltage were 876 and 875 V, but calculated values (at identical parameters of definitional regression model) were 874 and 880 V, accordingly, that were errors of 0.23 % and 0.57 %, i. e. made model fits well with experimental data. It was established that ρv makes contribution to breakdown voltages values of the transistor that is more substantial than parameters of guard rings construction. This NDMOS-transistor was manufactured under production conditions of OJSC INTEGRAL” – “INTEGRAL” Holding Managing Company according to the technological route developed by the author. Such device is used in various electronic devices for energetics, in mobile phones, as part of high-voltage integrated circuits of AC/DC- and DC/DC-converters and high-voltage, high-stable LED-drivers.

AUTOELECTRONIC CATHODES BASED ON ARRAYS OF NIOBIUM-OXIDE COLUMNAR NANOSTRUCTURES FOR FIELD EMISSION DISPLAYS

The article discusses the prospects of creating controlled field-effect cathodes based on arrays of columnar oxide niobium nanostructures for field emission displays. Geometrical models of field-emission cathodes and vacuum elements have been developed and investigated. The distribution of the electric field in the vacuum device at various distances between the cathode and the anode, the applied voltages between them, the shape and microgeometry of the cathodes were obtained. The optimal geometric parameters of nanostructured autoelectronic cathodes and matrices of these were calculated based on the simulation. The technological route has been developed for the production of autoelectronic cathode matrices based on arrays of niobium-oxide columnar nanostructures formed by electrochemical anodization of Al/Nb thin-film system. The samples of controlled arrays of autoelectronic cathodes were fabricated and the current-voltage characteristics with interelectrode gap of 2, 5 and 10 μm in various electric modes with change in the electric field strength from 3 to 85 V/μm were studied. At 2 μm gap between the anode and cathode, the emission occurs at minimum threshold voltages, but it is characterized by limited current values. The increasing in the interelectrode gap allows rising the emission currents, however, the threshold voltages increase. In the pulsed mode, the large emission currents are achieved. The threshold voltage of autoelectronic cathode matrices with interelectrode gap of 5 μm was 9.16 V, the maximum currents reached 350 μA at voltage of 22.5 V. In the pulsed mode, the emission arose at 11.06 V, the maximum current reached 1500 μA at 40 V.