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MIPRO, 2012 Proceedings of the 35th International Convention

Date 21-25 May 2012

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Displaying Results 1 - 25 of 349
  • [Front cover]

    Page(s): c1
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  • [Title page]

    Page(s): I
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  • [Copyright notice]

    Page(s): II
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  • Introduction

    Page(s): III - VIII
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  • Table of contents

    Page(s): IX - XXX
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  • Erbium doped silica microspheres for lasing applications

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (128 KB) |  | HTML iconHTML  

    Silica microspheres were made by melting the tip of a standard telecom fiber. They were coated using a dip coating apparatus with a 70% SiO2 - 30 HfO2 sol-gel derived glass activated by 0.3 % mol of Er3+. The whispering gallery modes of the coated resonator were studied using a full taper - microsphere coupling setup. Upon excitation at 1480 nm sharp peaks in the wavelength range from 1540-1565 nm were observed pertaining to the lasing modes of the microresonator. View full abstract»

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  • Synthesis flow for designing a high performance microprocessor

    Page(s): 5 - 12
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (267 KB) |  | HTML iconHTML  

    This paper describes the methodology for the automated synthesis flow used for a high-performance microprocessor project at Intel. The flow presents a standard method of automatically translating the RTL description of the microprocessor to placed and routed gates. The flow optimizes the design for timing and power, while ensuring that the final netlist is logically equivalent to the RTL and that all of the backend checks and rules are satisfied (for example noise, many electrical rules, routing rules, metal reliability, and so forth). The typical inputs to the flow are RTL, timing constraints and floorplan description, while the typical outputs are a netlist and layout. The netlist and layout are used as inputs to the other tools for logical and physical verification of the design. View full abstract»

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  • Porous silicon prepared by electrochemical etching of silicon eptaxial layer

    Page(s): 13 - 14
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (851 KB) |  | HTML iconHTML  

    Porous silicon (PSI) samples were prepared by electrochemical etching of n-type (111) epitaxialy grown silicon layer on n-type silicon (111) substrates, by varying the concentration of 48% HF in ethanol solution, and by varying the etching time. Electrical resistivity of epitaxial layer was ∼2 Ω cm and of silicon substrate was ∼ 0.015 Ω cm. Within the epitaxial layer, and on the substrate surface, the micro- and nano-pores of different sizes in dependence on HF concentration and etching time were obtained. With the etching time longer than 30 minutes, the epitaxially layer was detached from the substrate. The structural and optical properties of prepared samples were investigated by Raman and photoluminescence spectroscopy, field emission scanning electron microscopy (FE-SEM) and energy dispersive x-ray spectroscopy (EDS) spectroscopy. The FE-SEM images showed high density of micrometer sized pores on epitaxial layers. After detaching the epitaxial layer, the substrate showed fine nanometer sized cobweb-like silicon structures whose morphology and density depend on HF concentration and etching time. The Raman spectra of such structures show transversal optical (TO) phonon band that broadens and red-shifts depending on the size of silicon nanostructures. The size distributions of the silicon basic structural units where determined by applying the phonon confinement model and were compared with those determined by FE-SEM. The intensity of phtoluminescence peak of such fine porous substrate shows the sensitivity on a degree of optical phonon confinement. View full abstract»

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  • Formation and luminescence of p-type porous polycrystalline silicon

    Page(s): 15 - 16
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2114 KB) |  | HTML iconHTML  

    Luminescent porous silicon (PS) was obtained by galvanostatic electrochemical anodisation of p-type polycrystalline silicon (poly-Si) film in aqueous hydrofluoric acid (HF)/ethanol electrolyte. Poly-Si film was prepared and boron delta-doped on n-type silicon wafers by low pressure chemical vapor deposition (LPCVD) process. Porous poly-Si surface morphology varied as a function of anodisation time. Scanning electron microscope (SEM) images have shown macro-porous Si formation along grain boundaries. S-band photo-luminescence (PL) was measured in all samples, while Raman measurements indicated minimal or no confinement effects. View full abstract»

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  • Role of the substrate and the temperature of deposition on the properties of the TaxN thin films

    Page(s): 17 - 18
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    We present an interim report on the investigations of the TaxN thin films deposited on the (100) Si wafers coated with a 140-nm thermal SiO2 layer. Our conclusions are based on the room temperature sheet resistance measurements, transport properties measurements from helium up to room temperature and on the Raman spectra analysis of the investigated series. In particular, we discuss a nonmonotonous concentration dependence of transport properties. This behaviour we attribute to a local minimum in the density of electronic states at the Fermi level calculated for the intermetallic Ta4N5 [1]. Such behaviour was not observed in other investigations on the transport properties of TaxN found in literature. Also our Raman spectra show some differences compared to other Raman investigations on TaxN. We ascribe these and other differences discussed to the substrate properties which were used in the preparation of these thin films. The overall properties of the TaxN deposited on the oxidized Si wafers are compared to the properties of the TaxN thin films deposited on sapphire. View full abstract»

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  • On the application of boron and phosphorus heavily doped LPCVD polycrystalline silicon thin films as thermoelectric materials

    Page(s): 19 - 20
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    Even in the metallic regime, heavily doped polycrystalline silicon has high thermopower, but since recently, due its high resistivity combined with high thermal conductivity, silicon was not considered as a possible thermoelectric material. However, various reasons have encouraged investigations on polycrystalline silicon in order to enhance its TE properties. We discuss these reasons and give a short overview of the most promising results and works done in the field. We also present our incipient work on the LPCVD obtained polysilicon thin films annealed in various ways. The main important result we obtained so far is the high thermopower of a Si:B sample: +200 μV/K at room temperature; much higher than predicted for the common metals and the same as of Bi2Te3, the only thermoelectric material commercially used nowadays. View full abstract»

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  • Room temperature visible luminescence in wide band gap chalcogenide glasses

    Page(s): 21 - 22
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    Visible photoluminescence (PL) was observed in binary g-As2S3, technologically modified g-GeS2(TiVj) and ternary glasses along (As2S3)x(GeS2)1-x line. PL maximum in g-As2S3 at 2.43 eV was assigned to band-to-band transitions and its position is in good agreement with value of optical band-gap edge absorption (Eo=2.4 eV). It is suggested that the peak at 2.2-2.3 eV in g-GeS2(TiVj) and GeS2-based ternary glasses may be attributed to presence of GeOx species. Complex PL peak at 2.6-2.7 eV in GeS2-based glasses was identified with germanium sulfur sites. View full abstract»

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  • Preparation and research in resistive-strain sensor based on transparent conducting graphene sheets

    Page(s): 23 - 24
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    The variation of the current as function of deformation in the multi-layered graphene films located on the flexible PET-substrate was researched. The current depends on deformation linearly. The gauge factor of the flexible films was calculated. Effect of temperature on conductivity of graphene samples was investigated. View full abstract»

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  • Study of electronic structures of MoX2 (X = S, Se, Te): Arguments for interactions of molybdenum atoms in layers

    Page(s): 25 - 26
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1235 KB) |  | HTML iconHTML  

    The electronic structures of bulk and single layers dichalcogenides MoX2 (X = S, Se, Te) were studied by quantum chemistry method of electron localization function (ELF). Three-center interaction between the molybdenum atoms in the layers was found. The nature of this interaction depends on the type of chalcogen X, similar interaction is weaker for MoTe2. The observed effect supposes that observed interaction determines the stability of MoTe2 and may explain the nature of the existence of two structural modifications of MoTe2. View full abstract»

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  • Investigation of memory effect by measurement of time delay of electrical breakdown in commercial gas-filled surge arresters

    Page(s): 27 - 30
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (124 KB) |  | HTML iconHTML  

    Experimental data of mean values of breakdown voltage ̅Ub of CITEL and SIEMENS gas-filled surge arresters (GFSA) obtained for voltage increase rates k=1-10 V/s with discretyzed dynamic method are presented in the paper. It has been shown that ̅Ub = f(k) data are fitted very well by a straight line. The values of static breakdown voltage, which have been found at the intersection of the fitted line with ̅Ub-axis ( k = 0 ), are in accordance with nominal values reported in datasheet and within tolerance of 20%. Based on the time delay of electrical breakdown data, it has been shown that the response time of GFSA made by SIEMENS is independent of relaxation time and is 60 μs . Response time of GFSA made by CITEL increases with relaxation time, which is a consequence of the decrease in concentration of positive ions and neutral active particles formed during breakdown. Response time decreases with the increase of applied voltage. This decrease is dependent on relaxation time in the case of GFSA made by CITEL, while this is not the case with SIEMENS made GFSA. View full abstract»

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  • RADFET as a sensor and dosimeter of gamma-ray irradiation

    Page(s): 31 - 35
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    Gamma-ray irradiation and post irradiation response at room and elevated temperature have been studied for RADFETs with gate oxide thickness of 100 nm with gate polarization during irradiation of 5 V as well as for RADFETs with gate oxide thickness of 400 nm with gate polarization of 0, 2.5 and 5 V. The response was observed on the basis of threshold voltage shift, ΔVT. Approximately linear dependence between ΔVT and absorbed dose was established. During the annealing at room temperature the RADFETs with the gate thickness of 400 nm and the gate polarization during irradiation of 2.5 V and 5 V shows the tendency in ΔVT decrease, while for 400 nm RADFETs with the zero gate polarization during irradiation and 100 nm RADFETs ΔVT remains approximately unchanged. Continued annealing at 120°C leads to the decrease of ΔVT. For 100 nm RADFETs, ΔVT decreases to zero while for 400 nm RADFETs such decrease is considerably smaller. View full abstract»

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  • Modelling of electrical characteristics of ultrashallow pure amorphous boron p+n junctions

    Page(s): 36 - 41
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (161 KB) |  | HTML iconHTML  

    Diodes fabricated by a pure amorphous boron (PureB) deposition technology show outstanding performance. Depositing a PureB-layer on Si at temperatures from 500 - 700°C creates an effective p+-layer at the interface and ultrashallow p+n-junctions less than 10 nm deep can be made. The PureB layer can also be used as an emitter region in pnp bipolar transistors having a high effective emitter Gummel number (GE) that appears to be related to the properties of the amorphous boron layer. In this paper, we suggest a wide-bandgap model of the amorphous boron layer to explain how its properties can lead to a suppression of the electron injection from the base into the emitter region thus giving the high GE. The presence of trap states in the bandgap of amorphous boron layer is also considered. They could reduce the majority carrier concentration and change the mobility in the layer contributing to a decrease of GE. It is concluded that the wider bandgap together with the trap states in the bandgap of amorphous boron layer could account for the high emitter Gummel number. View full abstract»

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  • Model optimization of nanocrystalline Si:H thin film solar cells

    Page(s): 42 - 47
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB) |  | HTML iconHTML  

    Photovoltaic properties of nanocrystalline (nc-Si:H) heterojunction thin film solar cells with the single junction structure of TCO/p- nc-Si:H/i1- nc-Si:H/i2- a-Si:H/n- nc-Si:H/AZO was studied by a computer modeling software AMPS-1D in this paper. Due to spectral response of solar cells with the examined nc-Si thin films as active elements showed a narrower spectral distribution and a blue shift comparing to pure amorphous solar cells. The results were higher efficiency than amorphous cells due to higher optical gap (higher output voltage) and better fill factor (higher mobility). View full abstract»

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  • Measurement of thermal boundary resistance in AlGaN/GaN HEMTs using Liquid Crystal Thermography

    Page(s): 48 - 53
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (282 KB) |  | HTML iconHTML  

    Liquid Crystal Thermography (LCT) is commonly used for hotspot identification and peak-temperature measurement in electronic devices. We use LCT to characterize GaN/Si and GaN/SiC high-electron mobility transistors and extract the thermal boundary resistance between the GaN epilayers and the substrate on these transistors. View full abstract»

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  • Design of a planar inductor for DC-DC converter on flexible foil applications

    Page(s): 54 - 59
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1477 KB) |  | HTML iconHTML  

    This paper presents the design of a planar inductor for a DC-DC converter for flexible foil applications. The design challenges related to the flexible foil structure and the DC-DC converter requirements are analysed. The main design challenges are due to the constraints on the inductor physical size, the proximity of a conductive plane to the inductor and very high operating frequency of the DC-DC converter. The methodology of the inductor design is based primarily on EM simulations of the inductor structure and on the evaluation of the simulation results in the context of the resulting lumped-element electrical model. The simulations are verified by measurements of the inductors processed on the FR4 substrate which presently emulates the flexible foil substrate. View full abstract»

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  • Development of an analog simulator for the transient analysis of electric circuits, with the aim of teaching circuit phenomena by simulating equations

    Page(s): 60 - 65
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1684 KB) |  | HTML iconHTML  

    Teaching electric circuit theory involves the use of Ohm's and Kirchhoff's laws; branch, mesh and node analysis, as well as AC analysis and transient analysis. The latter gives the most comprehensive insight into circuit behavior. When analytical transient circuit analysis is used, one needs to solve the differential equations that describe the circuit behavior. Electrical engineering students often find this difficult. Alternatives to the mathematical analysis are: a) the simulation of the given problem with a commercial circuit simulator, and b) building a physical circuit, the behavior of which can then be observed and analyzed. These approaches are most productive when optimizing the behavior of a circuit, but they can easily add their own noise to the circuit study. The presented approach for the effective transient analysis is by simulating equations. The circuit in question is analyzed using Kirchhoff's laws with reference to specific time slices. The equations describing circuit components that store energy (capacitors, inductors) are then used to connect the consecutive time slices. The coding of equations for a given circuit allows students to gain a thorough understanding of the circuit's workings. Test cases show that results match perfectly between the simulation of equations and the analytical results from different RLC example circuits. Keywords: electronics education, electrical circuit simulation, simulation of equations, time variant circuit, transient response View full abstract»

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  • A fast and accurate simulation method of impulse sensitivity function in oscillators

    Page(s): 66 - 71
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (264 KB) |  | HTML iconHTML  

    This paper presents a novel and simple simulation method to evaluate the impulse phase response of an oscillator. The technique, based on the linear-time variant (LTV) analysis of oscillators, computes the phase response in the frequency domain. It can be performed by means of periodic steady-state (PSS) and periodic transfer function (PXF) simulations available in commercial simulators (Spectre, Eldo, etc.). This method overwhelms the classical simulation method based on transient analysis and injection of charge pulses along the oscillator period in terms of both speed and precision. The good accuracy of the frequency domain method has been verified in two practical case studies, evaluating the 1/f3 phase noise in a classical Van der Pol oscillator and estimating the injection locking range in a ring oscillator-based frequency divider. View full abstract»

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  • A brief overview of the black-box behavioural modelling of electronic circuits for transient simulations

    Page(s): 72 - 77
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (994 KB) |  | HTML iconHTML  

    Transient simulations of electronic circuits in the time domain can be one of the most complex tasks that engineers encounter in the field of electronics and microelectronics due to two main problems: slow speed of SPICE transistor level circuit simulations and limited accuracy of classic techniques for improving speed of circuit simulations. The black-box approach to behavioural modelling of electronic circuits, although very challenging, is particularly interesting due to possibility of fast and accurate simulations and that is the reason why black-box modelling techniques are gaining more and more attention in industry and academic community. The goal of this professional paper is to give a brief overview of the topic, identify current state-of-the-art and give suggestions for the future research in the area of black-box behavioural modelling of electronic circuits in the time-domain. View full abstract»

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  • A 2.5-GHz GaN power amplifier design and modeling by circuit-electromagnetic co-simulation

    Page(s): 78 - 82
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    In this paper a 2.5-GHz GaN power amplifier is presented. The amplifier is designed to achieve unconditional stability in the frequency range from DC to 6 GHz. The circuit-EM co-simulation model of the complete amplifier, including transistor model, passive components, connector model and the EM model of the critical parts of the design is created. The impact of each component is addressed. The amplifier is processed and measured, the measurements are compared to simulations and a good agreement is achieved. The amplifier parameters power added efficiency (PAE), drain efficiency (DE) and IP3 are measured and compared to results published in open literature. View full abstract»

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  • Pseudo-exponential computational circuit with improved accuracy and frequency response

    Page(s): 83 - 86
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    A new higher-order CMOS current-mode pseudo-exponential circuit will be presented. The advantage of the circuit with respect to the previous reported similar ones is the smaller value of the limited expansion error obtained by using a higher order approximation of the exponential function. The circuit presents the important advantage of the independence of the output current on technological parameters. Due to the strong inversion operation of all MOS transistors and to the current-mode operation of the circuit, the circuit frequency response can be strongly improved. The second-order effects will be taken into account for evaluating the total error of the circuit core, resulting an additional error summed to the error caused by the neglecting of the superior-order terms from the exponential function Taylor series expansion. The circuit area is relatively small due to the exclusively utilization of MOS transistors. View full abstract»

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