Modern Micro Research Articles

Patterning via self-organization and self-folding: Beyond conventional lithography

Abstract

Multilayer Graphene Nanoribbon and Carbon Nanotube Based Floating Gate Transistor for Nonvolatile Flash Memory

Floating gate transistor is the fundamental building block of nonvolatile flash memory, which is one of the most widely used memory gadgets in modern micro and nano electronic applications. Recently there has been a surge of interest to introduce a new generation of memory devices using graphene nanotechnology. In this article, we present a new floating gate transistor (FGT) design based on multilayer graphene nanoribbon (MLGNR) and carbon nanotube (CNT). In the proposed FGT, a MLGNR structure would be used as the channel of the field effect transistor (FET) and a layer of CNTs would be used as the floating gate. We have performed an analysis of the programming and erasing mechanism in the floating gate and its dependence on the applied control gate voltages. Based on our analysis we have observed that proposed graphene based floating gate transistor could be operated at a low voltage compared to conventional silicon based floating gate devices. We have presented detail analysis of the operation and the programming and erasing processes of the proposed FGT; the dependency of the programming and erasing current density on different parameters; and the impact of scaling the thicknesses of the control and tunneling oxides. To perform these analyses we have developed equivalent models for device capacitances.

Influence of the Method of Polymerization of Composite Material for Teeth Crown Fillings on its Strength Properties

Polymerization shrinkage of composite filling materials still becomes one of the most important features which decreases strength properties of reconstructed teeth crowns. From among various methods to reduce that disadvantageous phenomenon which are used in a dental practice sandwich filling processing of crown cavity seems to be the most effective one. The paper presents the results of the strength examination of the influence of the different ways of layered polymerization processing on the mechanical properties of modern hybrid micro composite material with regards to the following quantities: compressive strength, strain to fracture, modulus of elasticity and work to fracture.

Micro- and nanocoordinate measurements of micro-parts with 3-D tunnelling current probing

Abstract. Measurement tasks of modern micro- and nanometrology are posing a problem for current measurement instruments with decreasing structure sizes and rising aspect ratios. There is an open requirement for nanometre-resolving 3-D capable sensors and corresponding 3-D positioning systems to operate the sensors for 3-D measurements. A 3-D probing system based on electrical interaction is presented which is operated on a nanopositioning system type SIOS NMM-1. Furthermore, we demonstrate the progress and new possibilities for 3-D measurements with the nanopositioning and nanomeasurement machine NMM-1 and also with the application of a rotary kinematic chain. In addition new 3-D measurement routines for the NMM-1, also for micro-tactile probing systems as well as current plans, are shown.

Формирование нанопленок Cu, Ag, Au под воздействием атомов водорода

Due to their electrical properties, thin metallic films are widely used in modern micro- and nanoelectronics. These properties allow solving fundamental problems of surface and solid state physics. Up-to-date methods of producing thin films involve high vacuum or multi-stage processes, which calls for complicated equipment. The authors propose an alternative method of producing thin metallic films using atomic hydrogen. Exothermal reaction of atoms recombination in a molecule (about 4.5 eV / recombination act) initiated on the solid surface by atomic hydrogen may stimulate local heating, spraying and surface atoms transfer. We investigated the process of atomic hydrogen treatment of Cu, Ag and Au metal films, obtained by thermal vacuum evaporation. There are two methods of obtaining nanofilms using atomic hydrogen treatment: sputtering and vapor-phase epitaxy. In the first method, a film is formed by reducing the thickness of the starting film. This method allows obtaining a film as thick as the monolayer. In the second method, a nanofilm is formed by deposition of metal atoms from the vapor phase. This method allows obtaining a film thickness from monolayer to ~10 nm. These methods allow creating nanofilms with controlled parameters and metal thickness. Such films would be technologically pure and have good adhesion.

Energy Conversion at Micro and Nanoscale

Energy management is considered a task of strategic importance in contemporary society. It is a common fact that the most successful economies of the planet are the economies that can transform and use large quantities of energy. In this talk we will discuss the role of energy with specific attention to the processes that happens at micro and nanoscale. The description of energy conversion processes at these scales requires approaches that go way beyond the standard equilibrium termodynamics of macroscopic systems. In this talk we will address from a fundamental point of view the physics of the dissipation of energy and will focus our attention to the energy transformation processes that take place in the modern micro and nano information and communication devices.

Research on Positioning System Based on ZigBee Wireless Sensor Network

Modern micro sensor has low cost, low power characteristic, it can realize the wireless communication and computing performance, a large number of the sensors organizations constitute the wireless sensor network. This paper realized the design of wireless sensor network positioning system based on CC2430 using Zigbee technology and RSSI ranging technology. Through the experiment test, the technology improved fixed position accuracy and resistance to environment base on RSSI calculate method.

Economic safety problem in modern macro and micro concepts

Purpose. Security is an important component of economic security and the guaranteeing of appropriate national interests in the state. All these things are closely related to the economic efficiency of operations of economic entities, with economic independence, stability and security of a society. In addition, economic security is a part of national security, its foundation and material basis. The problem of economic security in modern conditions at the micro and macro levels requires determining the main directions of its formation. Methodology. To achieve this goal, basic directions of a security mechanism of the economic system, in particular on the macro level were grounded. Findings. Economic security is such state of the state economy operation in which the order of equilibrium occurred in certain organizational and legal norms on the basis of social life. These regulations are created be the state, principles of coexistence, which are transmitted from generation to generation. The current state of economic security guaranteeing at the macro and micro levels was analyzed. The system of indicators that can be used in the assessment of the security system was determined. Originality. Propositions concerning necessary changes in the policy of economic security in a state were formulated. The system of indicators which can be used in the assessment of the security system was offered. Practical value. Using of the proposed system of economic security indicators will expand the list of important factors affecting on its status and allow us determining the main directions of its formation.

Low Power Digital Signal Processor Architecture For Wireless Sensor Nodes By Using Parallel Prefix Technique

Radio communication has highest energy consumption. To reduce the energy and power parallel prefix technique is used. This paper describes the design and implementation of newly proposed folded tree architecture. Folded tree architecture has two phases. They are trunk and twig phase. Normally the power is reduced to 60-70% compared to existing methods. Measurements of the silicon implementation show an improvement of 10-20 × in terms of energy as compared to traditional modern micro controllers found in sensor nodes. Commonly this technique is used to wireless communication.

Dopant-induced stress in microfabricated silicon devices

The modification of material characteristics by introducing dopant atoms into a crystal lattice is a fundamental basis for modern micro- and nanosystems technology. In this work, the uneven distribution of dopants is shown to have a remarkable effect on the residual stress and the consequent deformation of released, mechanical silicon structures. In particular, the focus is on segregation of initial dopants inside the bulk silicon which takes place in such fabrication processes as thermal oxidation. A theoretical model based on perceiving the dopant-induced change in Si crystal lattice parameter is developed. We experimentally investigate a series of silicon-on-insulator wafers, including samples with dopant types B, P, and Sb, and concentrations in the range from 1015 to 5 × 1019 atoms cm−3. Released cantilevers are fabricated as test structures and the residual stress is determined by measuring their final curvature. Experimental results are compared with the modelled values obtained utilizing the dopant profiles determined by secondary ion mass spectrometry and concentration distribution simulations. The use of lightly doped substrates or the selection of processes not modifying the underlying Si surface (e.g., plasma enhanced chemical vapour deposition PECVD or metal deposition) is shown to be an effective solution for minimizing the dopant redistribution-induced stress. Besides the scientific impact, knowledge of the stress generated by dopants is of great significance for industrial manufacturing of a wide range of micro- and nanomechanical systems.

Problems in measurements of parameters of elements and structures in modern micro- and nanoelectronics considering TiN/Ti diffusion barrier structures as an example

Results of a comprehensive analysis of process variables of TiN/Ti diffuse barrier structures used in modern microelectronics are presented. To provide reliable spectral ellipsometry results, which is a common technique for postprocess control of these structures during the testing stage of the manufacturing process, a comprehensive approach is suggested that consists in consistent processing of transmission electron microscopy and X-ray reflectometry data. The resulting data were used to calculate the variances of optical coefficients of spectral ellipsometry, which depend on features of the manufacturing process and are required for analysis of the parameters of manufactured diffuse barrier structures.

Modern Micro and Nanoparticle-Based Imaging Techniques

The requirements for early diagnostics as well as effective treatment of insidious diseases such as cancer constantly increase the pressure on development of efficient and reliable methods for targeted drug/gene delivery as well as imaging of the treatment success/failure. One of the most recent approaches covering both the drug delivery as well as the imaging aspects is benefitting from the unique properties of nanomaterials. Therefore a new field called nanomedicine is attracting continuously growing attention. Nanoparticles, including fluorescent semiconductor nanocrystals (quantum dots) and magnetic nanoparticles, have proven their excellent properties for in vivo imaging techniques in a number of modalities such as magnetic resonance and fluorescence imaging, respectively. In this article, we review the main properties and applications of nanoparticles in various in vitro imaging techniques, including microscopy and/or laser breakdown spectroscopy and in vivo methods such as magnetic resonance imaging and/or fluorescence-based imaging. Moreover the advantages of the drug delivery performed by nanocarriers such as iron oxides, gold, biodegradable polymers, dendrimers, lipid based carriers such as liposomes or micelles are also highlighted.

The Fountain of Love Credit Union: A Vibrant Microfinance Institution in a Hostile Inter-Ethnic Society

The Fountain of Love Credit Union (FLCU) is a rare example of a vibrant microfinance institution in Indonesia. Located at the heart of a hostile inter-ethnic society in the province of West Kalimantan, the FLCU invents unique types of social capital and financial organization that bolster its unparallel financial performance. In recognition of this achievement, the Indonesian government presented the FLCU with the 2005 Award for Small-Medium Corporate Excellence. Decades of inter-ethnic hostility inspired school teachers to establish the FLCU in 1987. They dreamt of creating a big microfinance institution and promoting the economic well-being of the Dayak ethnic group. The Dayak, one of Kalimantan's two largest ethnic groups, defines itself as disadvantaged. A sense of grievance evolving around these issues culminated in a series of ethnic conflicts. Today, after more than two decades of operations, the FLCU has not only won the trust of most Dayak people but also inspires other ethnic groups to establish microfinance institutions. This environment has allowed unique types of social capital and financial organization to flourish. The Fountain of Love Foundation (FLF), the parent organization of the FLCU, has set up a variety of social and economic organizations. They work in partnership with the FLCU in all aspects of its business, from recruiting, disciplining, and empowering clients to weaving organizational networks with other microfinance institutions. The latter plays a vital role in curbing the penetration of modern micro banking in the province. The FLF, therefore, has become an ethnic-based conglomerate in which the FLCU functions as one of its driving forces. However, the FLCU faces a number of hurdles. Almost all FLCU clients, in rural and urban areas, are of the Dayak ethnic group. From organizational and policy points of view, the legal status of the FLCU is vulnerable as its assets grow beyond the mandatory requirement of the current banking law.

Printing solder droplets for micro devices packages using pneumatic drop-on-demand (DOD) technique

A pneumatic drop-on-demand (DOD) system has been applied to solder complex and dense interconnects of modern micro electronic devices. Initial parameters of uniform droplets were first measured. Then influences of experiment parameters, such as the crucible temperature, the substrate temperature and the droplet velocity on spread of solder droplets, were investigated experimentally and theoretically. The results showed that effects of impact velocity on the spreading could be negligible and the solder spreading process was driven by capillary forces because of the low Weber (We) number of depositing droplet. The influence of initial droplet temperature on the droplet spreading was not regular. The contact diameter of solder droplets on copper substrate increased when the substrate temperature increased from 443K to 493K. At last, copper cables were successfully soldered to pins of a flexible circuit using the direct solder deposition and re-melting process. The soldering results showed the feasibility of the data-driven soldering technique using the pneumatic DOD deposition technology.

Are Micro and Macro Labor Supply Elasticities Consistent? A Review of Evidence on the Intensive and Extensive Margins

We evaluate whether state-of-the-art macro models featuring indivisible labor are consistent with modern quasi-experimental micro evidence by synthesizing evidence on both the intensive and extensive margins. We find that micro estimates are consistent with macro estimates of the steady-state (Hicksian) elasticities relevant for cross-country comparisons on both the extensive and intensive margins. However, micro estimates of intertemporal substitution (Frisch) elasticities are an order of magnitude smaller than the values needed to explain business cycle fluctuations in aggregate hours by preferences. The key puzzle to be resolved is why micro and macro estimates of the Frisch extensive margin elasticity are so different.

Thermo mechanical properties and plastic deformation of gold nanolines and gold thin films

The material behavior of nano-shaped and -scaled materials is a key issue for their system integration in modern micro electro-mechanical systems (MEMS). In this article, the thermo mechanical properties of (i) homogeneous gold thin films with a thickness of 20 nm on polyimide substrate and (ii) gold nanoline ensembles with 40 nm width, 20 nm height and 1 mm length on polyimide substrate were measured using the synchrotron based sin 2( φ)-tensile testing technique. Both, passivated and unpassivated samples were tested in a temperature range of 173–393 K. As main findings: (i) homogeneous thin films are remarkably stronger than the nanolines, (ii) the yield strength shows a strong temperature dependence, and (iii) the yield strength of passivated samples is significantly increased compared to their unpassivated counterparts. The activation energy also shows a pronounced temperature dependency and indicates plastic deformation controlled by (i) dislocation motion for temperatures below 223 K, (ii) diffusion along (1 1 1) surfaces in the temperature range of 223–343 K and (iii) diffusion along the remaining surfaces (others than (1 1 1)) in the temperature range of 334–393 K.

Subjective Data in a Test of the Life Cycle Model

The life cycle model is a cornerstone model in modern micro– and macro economics. The life cycle model offers a rationale for savings behavior, as individuals or households are assumed to value future utility in current period decisionmaking. A frequently employed test on the validity of the life cycle model is based on the orthogonality conditions implied by the first order condition of the problem: the Euler equation of consumption (Hall 1978). Such tests are convenient as they do not rely on a specification of income processes for example. Conventional approaches subsequently define preferences (i.e., the marginal rate of substitution between future and current consumption) and test the empirical validity of this –one specific– parameterization of the model. In this paper I propose “self-reported changes in food consumption adequacy” as a direct proxy for the marginal rate of substitution of food consumption in two consecutive periods. Indonesian households were asked to rate the change in the adequacy of food consumption from a year ago until now on a five-point scale. The methodology has two clear advantages over conventional approaches. First, the test does not rely on ex ante specified preferences, such that it scrutinizes the validity of a life cycle model of unknown form (e.g., habit formation, within period nonseparabilities, etc. are implicitly allowed for). 1 Secondly, conventional tests may suffer from low power as it can be difficult to statistically distinguish an “extended life cycle model” from alternative theories of behavior. In this paper, I strongly reject the life cycle model with constant discount rates. The model with house

Engineering supported membranes for cell biology

Cell membranes exhibit multiple layers of complexity, ranging from their specific molecular content to their emergent mechanical properties and dynamic spatial organization. Both compositional and geometrical organizations of membrane components are known to play important roles in life processes, including signal transduction. Supported membranes, comprised of a bilayer assembly of phospholipids on the solid substrate, have been productively served as model systems to study wide range problems in cell biology. Because lateral mobility of membrane components is readily preserved, supported lipid membranes with signaling molecules can be utilized to effectively trigger various intercellular reactions. The spatial organization and mechanical deformation of supported membranes can also be manipulated by patterning underlying substrates with modern micro- and nano-fabrication techniques. This article focuses on various applications and methods to spatially patterned biomembranes by means of curvature modulations and spatial reorganizations, and utilizing them to interface with live cells. The integration of biological components into synthetic devices provides a unique approach to investigate molecular mechanisms in cell biology.

III-V Compounds-on-Si: Heterostructure Fabrication, Application and Prospects

While silicon and gallium arsenide are dominant materials in modern micro- and nanoelectronics, devices fab- ricated from them still use Si and GaAs substrates only separately. Integrating these materials on the large and cheep Si substrate has been the subject of enormous research efforts for the past three decades. This review attempts to systematize and generalize the current understanding of the fundamental physical mechanisms governing the epitaxial growth of GaAs and related III-V compounds on Si substrates. Different kinds of bonding as a very promising non-epitaxial method for III-V thin film integration on Si substrate are reviewed. Basic techniques available for improving the quality of such het- erostructures are described, and recent advances in fabricating of device-quality III-V-on-Si heterostructures and corre- sponding devices are also presented.

Influence of interface structure on mass transport in phase boundaries between different ionic materials: Experimental studies and formal considerations.

Internal and external interfaces in solids exhibit completely different transport properties compared to the bulk. Transport parallel to grain or phase boundaries is usually strongly enhanced. Transport perpendicular to an interface is usually blocked, i.e., transport across an interface is often much slower. Due to the high density of interfaces in modern micro- and nanoscaled devices, a severe influence on the total transport properties can be expected. In contrast to diffusion in metal grain boundaries, transport phenomena in boundaries of ionic materials are still less understood. The specific transport properties along metal grain boundaries are explained by structural factors like packing densities or dislocation densities in the interface region. In most studies dealing with ionic materials, the interfacial transport properties are merely explained by the influence of space charge regions. In this study the influence of the interface structure on the interfacial transport properties of ionic materials is discussed in analogy to metallic materials. A qualitative model based on the density of misfit dislocations and on interfacial strain is introduced for (untilted and untwisted) phase boundaries. For experimental verification, the interfacial ionic conductivity of different multilayer systems consisting of stabilised ZrO2 and an insulating oxide is investigated as a funtion of structural mismatch. As predicted by the model, the interfacial conductivity increases when the lattice mismatch is increased.Graphical abstract