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The modular hardware platform architecture for the development of industrial IoT devices is presented as an example of information harvesting and its analysis. Variants of modules implementing typical functions of such devices are given: data acquisition from a distributed array of sensors; preprocessing, aggregation and data transmission; data mining; storage of primary data and analysis results.

The article presents a hardware and software system used for functional testing of NAND-memory chips based on FPGA. The system's module structure allows simultaneous testing of up to 144 memory chips. The system performs testing according to the predetermined algorithms and allows controlling time characteristics of NAND-memory integrated circuits. The developed software is used to tune and control the process of testing according to the user's needs, and to analyze the obtained data. Validation is performed using a NAND testing commercial system. The results of testing trial batches of multi-chip NAND-memory modules are presented.

The paper presents the results of a study of electron-beam modification (EBM) of VO2-switch I-V curve threshold parameters and the self-oscillation frequency of a circuit containing such a switching device. EBM in vacuum is reversible and the parameters are restored when exposed to air at pressure of 150 Pa. At EBM with a dose of 3 C/cm2, the voltages of switching-on (Vth) and off (Vh), as well as the OFF-state resistance Roff, decrease down to 50% of the initial values, and the oscillation frequency increases by 30% at a dose of 0.7 C/cm2. Features of physics of EBM of an oscillator are outlined considering the contribution of the metal and semiconductor phases of the switching channel. Con-trolled modification allows EBM forming of switches with preset parameters. Also, it might be used in artifi-cial oscillatory neural networks for pattern recognition based on frequency shift keying.

We present the results on excimer laser modification and patterning of amorphous vanadium pentoxide films. Wet positive resist-type and Ar ion-beam negative resist-type etching techniques were employed to develop UV-modified films. V2O5 films were found to possess sufficient resistivity compared to standard electronic materials thus to be promising masks for sub-micron lithog-raphy, 4 pages, 2 figures

Electrical and optical properties of amorphous vanadium oxide thin films obtained by electrochemical anodic oxidation are studied. It is shown that under cathodic polarization the hydrogen insertion into vanadium oxide from an electrolyte occurs. Metal-insulator transition in amorphous HxVO2 is found to be preserved up to high concentration (x ~ 1.5) of hydrogen. Memory switching with the N-type negative differential resistance, associated with the H+ ionic transfer, is observed in "V/hydrated amorphous vanadium oxide/Au" sandwich structures., 3 pages, 2 figures

We explore a prototype of an oscillatory neural network (ONN) based on vanadium dioxide switching devices. The model system under study represents two oscillators based on thermally coupled VO2 switches. Numerical simulation shows that the effective action radius RTC of coupling depends both on the total energy released during switching and on the average power. It is experimentally and numerically proved that the temperature change dT commences almost synchronously with the released power peak and T-coupling reveals itself up to a frequency of about 10 kHz. For the studied switching structure configuration, the RTC value varies over a wide range from 4 to 45 mkm, depending on the external circuit capacitance C and resistance Ri, but the variation of Ri is more promising from the practical viewpoint. In the case of a "weak" coupling, synchronization is accompanied by attraction effect and decrease of the main spectra harmonics width. In the case of a "strong" coupling, the number of effects increases, synchronization can occur on subharmonics resulting in multilevel stable synchronization of two oscillators. An advanced algorithm for synchronization efficiency and subharmonic ratio calculation is proposed. It is shown that of the two oscillators the leading one is that with a higher main frequency, and, in addition, the frequency stabilization effect is observed. Also, in the case of a strong thermal coupling, the limit of the supply current parameters, for which the oscillations exist, expands by ~ 10 %. The obtained results have a universal character and open up a new kind of coupling in ONNs, namely, T-coupling, which allows for easy transition from 2D to 3D integration. The effect of subharmonic synchronization hold promise for application in classification and pattern recognition., 24 pages, 10 figures

We have studied electrical switching with S-shaped I-V characteristics in two-terminal MOM devices based on vanadium dioxide thin films. The switching effect is associated with the metal-insulator phase transition. Relaxation oscillations are observed in circuits with VO2-based switches. Dependences of the oscillator critical frequency Fmax, threshold power and voltage, as well as the time of current rise, on the switching structure size are obtained by numerical simulation. The empirical dependence of the threshold voltage on the switching region dimensions and film thickness is found. It is shown that, for the VO2 channel sizes of 10*10 nm, Fmax can reach the value of 300 MHz at a film thickness of ~20 nm. Next, it is shown that oscillatory neural networks can be implemented on the basis of coupled VO2 oscillators. For the weak capacitive coupling, we revealed the dependence of the phase difference upon synchronization on the coupling capacitance value. When the switches are scaled down, the limiting time of synchronization is reduced to Ts ~13 {\mu}s, and the number of oscillation periods for the entering to the synchronization mode remains constant, Ns ~ 17. In the case of weak thermal coupling in the synchronization mode, we observe in-phase behavior of oscillators, and there is a certain range of parameters of the supply current, in which the synchronization effect becomes possible. With a decrease in dimensions, a decrease in the thermal coupling action radius is observed, which can vary in the range from 0.5 to 50 {\mu}m for structures with characteristic dimensions of 0.1 to 5 {\mu}m, respectively. Thermal coupling may have a promising effect for realization of a 3D integrated oscillatory neural network., Comment: 28 pages, 13 figures

Deformation of NAND memory multichip packages (MCPs) with various thicknesses of substrate and silicon dies have been numerically simulated. The results of calculations are consistent with experimental data and show equivalence of the deformation in single- and multichip packages with the same total thickness of silicon. Analytical relationship between the values of MCP deformation, substrate core thickness, and total thickness of silicon dies is proposed, which agrees quite well with the data of modeling and can be used for preliminary estimation of MCP deformations.

The paper presents the results of the development of a package-on-package multichip microcircuit with three-dimensional integration of processor and memory dies. The stages of fabrication the upper part of the microcircuit with several memory dies, which are mounted by the wire bonding method, and the lower part of the microcircuit, on which the processor die is attached by the flip-chip method, are described. After the fabrication of the microcircuit by combining the upper and lower substrates, a multi-stage functional testing of the processor and memory dies is performed using a test board and software loaded into the microcircuit memory.

Hard aluminum–magnesium boride (BAM) films were fabricated onto Corning® Gorilla® Glass by radio-frequency magnetron sputtering of a single stoichiometric AlMgB14 target. BAM films exhibit a Vickers hardness from 10 to 30 GPa and a Young’s modulus from 80 to 160 GPa depending on applied loading forces. Deposited hard coating increases the critical load at which glass substrate cracks. The adhesion energy of BAM films on Gorilla® Glass is 6.4 J/m2.

New operation regimes of single and coupled oscillators in circuits based on planar VO2 switches have been studied. The phenomenon of bistability is discovered, which consists in controlled switching of self-sustained oscillations by external pulses, which is a promising basis for the creation of oscillatory memory cells and implementation of pulse coupling regimes in artificial neural networks (ANNs). The duration of switch-on and switch-off pulses is no less that ~20 μs and 30 ms, respectively. It is established that the region of threshold voltages for bistable switching in coupled oscillators is much wider than in a single oscillator and the hysteresis width in the former case can reach 2 V. A regime of initiation of switching packets has been observed that models the ANN packet activity.

The paper presents the concept of a modular hardware platform for the development of IoT devices using the example of a system for collecting and analyzing information. Design variants of modules that implement the basic functions of IoT devices are presented: obtaining primary data and their preliminary processing, data aggregation and transmission, data analysis and storage of results. The technologies of multi-chip packaging and three-dimensional integration are presented, which can significantly reduce the size of the developed modules.

The paper provides a technical solution and methodology for conducting automated electrical and functional testing of small series samples of multi-chip assemblies. The results of multi-chip assembly samples testing combining Wire Bond and Flip-Chip technologies are presented. Based on the test results, defects that occur during the packaging process are localized and the assembly stages at which these defects occur are determined.

On the basis of finite-element computer modeling, the temperature distribution of a multi-chip integrated circuit was calculated in System on Package configuration, combining Wire-Bond and Flip-Chip technologies. Technical recommendations are suggested for choosing a compound, taking into account the continuous layer of the compound separating the active elements and the heat sink.

In the circuit of two thermally coupled VO2 oscillators, we studied a higher order synchronization effect, which can be used in object classification techniques to increase the number of possible synchronous states of the oscillator system. We developed the phase-locking estimation method to determine the values of subharmonic ratio and synchronization effectiveness. In our experiment, the number of possible synchronous states of the oscillator system was twelve, and subharmonic ratio distributions were shaped as Arnold's tongues. In the model, the number of states may reach the maximum value of 150 at certain levels of coupling strength and noise. The long-range synchronization effect in a one-dimensional chain of oscillators occurs even at low values of synchronization effectiveness for intermediate links. We demonstrate a technique for storing and recognizing vector images, which can used for reservoir computing. In addition, we present the implementation of analog operation of multiplication, the synchronization based logic for binary computations, and the possibility to develop the interface between spike neural network and a computer. Based on the universal physical effects, the high order synchronization can be applied to any spiking oscillators with any coupling type, enhancing the practical value of the presented results to expand spike neural network capabilities., 25 pages, 13 figures

Electrical switching and rectifying properties of the metal-VO2-Si structures, on both p-type and n-type silicon, with vanadium dioxide films obtained by an acetylacetonate sol-gel method, are studied. The switching effect is shown to be due to the semiconductor-to-metal phase transition (SMPT) in vanadium dioxide. The shift of the switching threshold voltage, accompanied by the memory effect, in forward bias of the p-Si-VO2 anisotype heterojunction is observed. To explain this effect, a model is proposed which suggests the existence of an additional series resistance associated with a channel at the VO2/Si interface, where a SiOx layer forms during the VO2 deposition process. This resistance is responsible for both threshold switching characteristics, and the memory effect, and the oxygen ion electromigration process is shown to underlie this effect. Potential applications of the observed phenomena, combining the effects of ReRAM and SMPT, in oxide electronics are discussed., 12 pages, 5 figures

The paper presents the results of electrical and functional testing of 160 experimental samples of solid-state drives with capacities ranging from 256 to 1024 GB, assembled using 4 types of NAND-memory chips. As a result of testing, read and write speeds of SSD were measured in sequential and random modes. The maximum read and write speeds in the sequential mode were 540 and 410 MB/s, and in the random mode, 72000 and 68000 IOPS. When measuring disks of the same type, a relative speed variation was observed, which was significantly greater with write operations (3.7%) than with read operations (0.45%). It was also found that the write and read speeds were limited by the performance of the disk controller.

In this work we present the results of selective chemical etching of amorphous vanadium pentoxide films after their modification by ultraviolet (UV) radiation. V2O5 resist can be either positive or negative, depending on the developer composition. It was shown that UV-exposed V2O5 films after development and vacuum annealing can be transformed into VO2 structures which exhibit an electrically induced resistance switching effect. The proposed method demonstrates the feasibility of using V2O5 as an effective inorganic resist material for ambient condition UV photomicrolithography. Also, this material has a great potential for fabrication of vanadium oxide-based devices.

The investigation of the photovoltaic properties of a Si-NiO structure was carried out. NiO films were prepared by thermal oxidation of metallic nickel at different temperatures. The load and luminous characteristics were obtained, and on the basis of these measurements the efficiency, fill factor, short circuit current and open-circuit voltage were determined. Finally, possible mechanisms of the observed phenomena, as well as the possibility of their use for optoelectronic devices, are briefly discussed (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Recently, hard AlMgB14 (BAM) coatings were deposited for the first time by RF magnetron sputtering using a single stoichiometric ceramic target. High target sputtering power and sufficiently short ...

In the present paper, we report on the switching dynamics of both single and coupled VO2-based oscillators, with resistive and capacitive coupling, and explore the capability of their application in oscillatory neural networks. Based on these results, we further select an adequate SPICE model to describe the modes of operation of coupled oscillator circuits. Physical mechanisms influencing the time of forward and reverse electrical switching, that determine the applicability limits of the proposed model, are identified. For the resistive coupling, it is shown that synchronization takes place at a certain value of the coupling resistance, though it is unstable and a synchronization failure occurs periodically. For the capacitive coupling, two synchronization modes, with weak and strong coupling, are found. The transition between these modes is accompanied by chaotic oscillations. A decrease in the width of the spectrum harmonics in the weak-coupling mode, and its increase in the strong-coupling one, is detected. The dependences of frequencies and phase differences of the coupled oscillatory circuits on the coupling capacitance are found. Examples of operation of coupled VO2 oscillators as a central pattern generator are demonstrated., 33 pages, 23 figures

First time AlMgB14 films were prepared in Ames Lab by pulsed laser deposition technique. In this work, RF magnetron sputtering from a single stoichiometric target was employed to fabricate hard AlMgB14 coatings on Si wafer and industrial items. Measurements of nanohardness and elastic Young's modulus were performed to determine reliable strength characteristics of samples. Smooth 3 μm thick AlMgB14 films with the RMS surface roughness to be less than 1 nm exhibit hardness of 34 GPa and modulus of elasticity of 230 GPa at 20 mN peak load.

In this paper we describe a prototype of a field effect transistor (FET) based on the Mott metal–insulator transition (MIT) in vanadium dioxide. It has been shown that increasing the modulation of the channel resistance, the gain of the field effect, and an increase of the amplification factor can be achieved by lowering the temperature of the channel. An increase of the transistor amplification factor by more than twice is shown while reducing the temperature from RT down to −21 °C. It is also shown that the modulation of the channel resistance is not associated with the occurrence of dynamic current through the gate insulator and the VO2-channel. Possible solutions to increase the efficiency of the VO2-based FET are analyzed and described.

Influence of ultra-violet radiation of the KrF laser (wave length 248 nm, pulse duration 20 ns) on atomic structure of amorphous vanadium pentoxide thin films, prepared by the pulsed laser deposition method, is studied. Calculations of the short-range order characteristics (radii and diffusiveness of coordination spheres, coordination numbers) were performed by the Finbak -Warren method. It is established that minimal structure unit of amorphous V2O5 film before and after irradiation is a strongly deformed oxygen octahedron. Distortions of tetragonal pyramids in the initial and modified film are different. Also, oxygen deficiency in a tetragonal pyramid is observed.