Y. Scudeller

Institut des Materiaux Jean Rouxel, Naoned, Pays de la Loire, France

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Publications (40)50.8 Total impact

  • Microporous and Mesoporous Materials 05/2014; 190:109–116. · 3.37 Impact Factor
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    ABSTRACT: We report the thermal properties of carbon nanowall layers produced by expanding beam radio-frequency plasma. The thermal properties of carbon nanowalls, grown at 600 °C on aluminium nitride thin-film sputtered on fused silica, were measured with a pulsed photo-thermal technique. The apparent thermal conductivity of the carbon at room temperature was found to increase from 20 to 80 Wm−1 K−1 while the thickness varied from 700 to 4300 nm, respectively. The intrinsic thermal conductivity of the carbon nanowalls attained 300 Wm−1 K−1 while the boundary thermal resistance with the aluminium nitride was 3.6 × 10−8 Km2 W−1. These results identify carbon nanowalls as promising material for thermal management applications.
    Applied Physics Letters 01/2013; · 3.79 Impact Factor
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    ABSTRACT: This Letter reports the thermal conductivity of aluminium nitride (AlN) thin-films deposited by reactive DC magnetron sputtering on single-crystal silicon substrates (100) with varying plasma and magnetic conditions achieving different crystalline qualities. The thermal conductivity of the films was measured at room temperature with the transient hot-strip technique for film thicknesses ranging from 100 nm to 4000 nm. The thermal conductivity was found to increase with the thickness depending on the synthesis conditions and film microstructure. The conductivity in the bulk region of the films, so-called intrinsic conductivity, and the boundary resistance were in the range [120-210] W m{sup -1} K{sup -1} and [2-30 Multiplication-Sign 10{sup -9}] K m{sup 2} W{sup -1}, respectively, in good agreement with microstructures analysed by x-ray diffraction, high-resolution-scanning-electron-microscopy, and transmission-electron-microscopy.
    Applied Physics Letters 10/2012; 101(15):151908. · 3.79 Impact Factor
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    ABSTRACT: This paper reports the ultra-fast transient hot-strip (THS) technique for determining the thermal conductivity of thin films and coatings of materials on substrates. The film thicknesses can vary between 10 nm and more than 10 µm. Precise measurement of thermal conductivity was performed with an experimental device generating ultra-short electrical pulses, and subsequent temperature increases were electrically measured on nanosecond and microsecond time scales. The electrical pulses were applied within metallized micro-strips patterned on the sample films and the temperature increases were analysed within time periods selected in the window [100 ns–10 µs]. The thermal conductivity of the films was extracted from the time-dependent thermal impedance of the samples derived from a three-dimensional heat diffusion model. The technique is described and its performance demonstrated on different materials covering a large thermal conductivity range. Experiments were carried out on bulk Si and thin films of amorphous SiO2 and crystallized aluminum nitride (AlN). The present approach can assess film thermal resistances as low as 10−8 K m2 W−1 with a precision of about 10%. This has never been attained before with the THS technique.
    Journal of Physics D Applied Physics 07/2012; 45:295303. · 2.53 Impact Factor
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    ABSTRACT: This paper presents a model reduction approach for constructing lumped RC thermal networks of IGBT-modules of inverters for which heat and subsequent temperature increases vary with time on different scales ranging from nanosecond to second. It was observed that the time-dependent heat and temperature profiles of transistors and diodes of IGBT-modules of inverters oscillate at two frequencies, one in the range 0.1–50 Hz corresponding to the load current modulation, and the other in the range 1–20 kHz corresponding to the switching frequency. The reduction approach consisted of decomposing the module into different elements, each being described with a number of RC cells selected according to the time-constant of the element with regard to the module. The lumped RC thermal networks were found in good agreement with the continuous model by offering a considerably lower computational time on the different time scales. For simplicity, the reduction approach is presented for one-dimensional heat flow through the cross-plane direction of the module.
    Microelectronics Journal 06/2012; 43(6):345–352. · 0.91 Impact Factor
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    ABSTRACT: A new photothermal method for measuring the thermal contact resistance in the interfacial area is presented. Copper thin films were prepared on alumina substrates by physical vapour deposition. On the basis of a mathematical model developed here, thermal contact resistance was determined in samples of various thicknesses and processed under various argon pressures. The effects of these parameters on the films and interface properties are discussed. A correlation between the thermal contact resistance and the adhesion, as determined by the scratch test, is found. In order to understand the origin of the mean critical load and the thermal contact resistance evolution, observations were made by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results obtained have shown that the change in stress level in the copper film and the formation of a new compound in the interfacial area seem to be the main reasons for the enhancement of heat transfer.
    Journal of Adhesion Science and Technology 04/2012; 15(12):1403-1416. · 0.90 Impact Factor
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    ABSTRACT: The relationship between thermal conductivity and microstructures of aluminium nitride films is reported. Films were deposited on silicon substrates by magnetron sputtering of a pure Al target in nitrogen argon plasma at low temperatures (
    Journal of Physics D Applied Physics 01/2012; 45(1). · 2.53 Impact Factor
  • A. Alnukari, Y. Mahe, S. Toutain, Y. Scudeller
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    ABSTRACT: This paper reports the design and performance of Sapphire-based active heatsink antenna for Integrated RF transmitter. The antenna consists of a high-thermal-conductivity Sapphire layer serving as electromagnetic emitter and heatsink. We present the topology of such antenna as its electromagnetic and thermal performance. The antenna has been investigated by simulations and measurements. It is evidenced that the Sapphire layer has no substantial influences on the gain, radiation pattern and return loss of the antenna. Heat removed by the Sapphire layer was found as high as 1 Watt per centimeter square while the thermal resistance of the transmitter was of 5.5 ° C/W. The transmitter could operate over a wide temperature range.
    Antennas and Propagation (EUCAP), 2012 6th European Conference on; 01/2012
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    ABSTRACT: This paper presents a technique for measuring local electromagnetic energy loss through a transmission line by infra- red thermal imaging. The technique offers an attractive route to investigate solid-state radio-frequency (RF) structures with differ- ent sizes and an arbitrary layout of lines by achieving an electro- magnetic energy mapping over a wide frequency range between 300 MHz and 6 GHz. The measurement setup and the microstrip RF transmission line test device are described. An analytical model expressing the dissipated power profile as a function of signal frequency, transmission line features, and impedance mismatch is presented. Electromagnetic loss and temperature increase induced by dissipation are numerically studied. Experimental results are presented and discussed.
    IEEE Transactions on Instrumentation and Measurement 01/2011; 60:496-506. · 1.71 Impact Factor
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    ABSTRACT: This paper presents an approach for constructing a multi-frequency compact electro-thermal model of IGBT-devices as inverters. Frequencies and time-scales of heat oscillations of transistors and diodes of IGBT devices were revealed as a function of operating parameters of inverters. It was shown that heat could oscillate according to different frequency domains, one referring to the load amplitude modulation in the range 0.1 Hz -50 Hz and the other associated with the switching frequency of the IGBT in the range 1 kHz - 20 kHz. A methodology was established for designing lumped RC thermal networks achieving good precision and low computational time for temperature calculation with respect to different components of heat oscillations. It was found that temperature varies according to different time-windows ranging from nanosecond to second. The model reduction strategy has been implemented on a unidirectional heat flow through a layered structure corresponding to the cross-plane of the IGBT device. The approach is based on analysis of heat diffusion rates and thermal penetration depths with regards to device topologies, materials, and frequencies. Results are presented and discussed.
    01/2011;
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    ABSTRACT: A calorimetric technique was developed for determining time-dependant heat profiles of electrochemical capacitors. The profiles were extracted from the temperature change of the capacitor during charge–discharge current cycles. The technique is described and its good performance is demonstrated. Experiments were carried out on symmetric and asymmetric aqueous capacitors prepared with activated carbon and manganese oxide as active materials. Heat in double-layer and hybrid capacitors, C–C and C–MnO2, varied with time, according to special profiles depending on storage processes. In carbon double-layer capacitors, the heat component was decomposed into a reversible and an irreversible term. Results suggested that irreversible heat was caused by the Joule loss through the porous structure and the reversible heat by the ion adsorption on the carbon surface. Moreover, endothermic and exothermic processes were observed on the MnO2 electrode of the asymmetric capacitor, over the charge and the discharge respectively, proportional to the charge rate. These results suggested that heat in the MnO2 electrode originated from the redox reactions and ion adsorption on the active material.
    Thermochimica Acta - THERMOCHIM ACTA. 01/2011; 526(1):1-8.
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    ABSTRACT: We present In this paper two topologies based on microstrip heatsink antenna with higher thermal performance. No major influences on the electromagnetic performances of the antenna (gain, radiation pattern and return loss) are consequently observed by the presence of different heatsinks.
    Antennas and Propagation (EuCAP), 2010 Proceedings of the Fourth European Conference on; 05/2010
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    ABSTRACT: This paper deals with the design of an active heat-sink antenna for radio-frequency transmitter. The antenna achieves electromagnetic and thermal functions by offering a suitable radiating pattern for transmission as high efficiency to remove the dissipated power within the transmitter by heat exchange to the surrounding medium. A test transmitter has been performed by combining a 2 GHz MESFET power amplifier in a conductor-backed coplanar wave-guide with a wire-fed patch heat-sink antenna connected to the ground plane. The active heat-sink antenna has been investigated by measurement and simulation. As expected, it was found that the antenna exhibits desirable electromagnetic performance as achieving an efficient thermal control by offering suitable operating temperature. A heat spreader connecting the transistor to the antenna, was especially developed to cause any significant influence on transmitter performance. The amplifier can deliver an output power as high as 5 W under natural convection with air at room temperature and atmospheric pressure. According to the temperature and direction of the antenna, thermal resistance of the transmitter was found between 6 and 8 K.W <sup>-1</sup>. The transmitter can thus operate over a wide temperature range without any additional cooling device.
    IEEE Transactions on Advanced Packaging 03/2010; · 1.12 Impact Factor
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    ABSTRACT: A calorimetric technique was developed for measuring heat generated within a Double-Layer Capacitor cell under cycling by analyzing its transient temperature change. Measurements were performed for a short time period of the current cycle to get small temperature changes and thus not substantially affect the properties of the cell during charge and discharge. The calorimetric technique is described and its performance demonstrated on a symmetrical activated carbon cell with 1M N(C2H5)4BF4 in propylene carbonate as electrolyte over a wide current range. Capacitance of the cell at room temperature was around to 0.25Fcm−2. Power density was found between 2×10−3 to 70×10−3Wcm−2 according to the current density that varied between 0.01 and 0.15Acm−2 for a cell load pressure equal to 25kgcm−2. Equivalent resistance, measured on the calorimeter, was found to vary between 4 and 8Ωcm2, according to the charge rate. Calorimetric measurements were found in good agreement with the energy balance of the cell deduced from the potential profiles and currents.
    Thermochimica Acta - THERMOCHIM ACTA. 01/2010; 510(1):53-60.
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    ABSTRACT: Different aqueous-based electrolytes have been tested in order to improve the electrochemical performance of hybrid (asymmetric) carbon/MnO2 electrochemical capacitor (EC). Chloride and bromide aqueous solutions lead to the formation of Cl2 and Br2 respectively upon oxidation of the corresponding salt, thus limiting the useful electrochemical window of the MnO2 electrode and producing gas evolution (in the case of chloride salts) detrimental to the cycling ability of an hybrid device. For sulfate and nitrate salts, MnO2 electrode exhibits a 20% increase in capacitance when lithium is used as the cation compared to sodium or potassium salts, probably due to partial lithium intercalation in the tunnels of α-MnO2 structure. The higher ionic conductivity and solubility of LiNO3 has led to the investigation of this electrolyte in carbon/MnO2 supercapacitor compared to standard hybrid cell using K2SO4. A lower resistance increase was evidenced when the temperature was decreased down to −10°C. Long term cycling ability of carbon/MnO2 supercapacitor was also evidenced with 5M LiNO3 electrolyte.
    Electrochimica Acta - ELECTROCHIM ACTA. 01/2010; 55(25):7479-7483.
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    ABSTRACT: This paper investigates different topologies of active heat-sink antenna combining electromagnetic and cooling functions within RF devices. Each topology of antenna is presented and its performance analysed. In addition, a thermal imaging technique has been developed, with respect to electro-thermal design of RF devices, for determining the power loss distribution through transmission lines as a function of the input-output impedance of power amplifiers, line features, and operating frequency. The technique is described and illustrated by different results.
    01/2010;
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    ABSTRACT: This paper presents methods for determining power loss profiles of Si-IGBT-based inverters and the induced junction temperature. Power losses were decomposed into different waveforms in order to investigate their influence on the junction temperature of the IGBT. Junction temperature has been determined by a dynamic thermal model using the transmission matrix technique.
    Thermal, Mechanical & Multi-Physics Simulation, and Experiments in Microelectronics and Microsystems (EuroSimE), 2010 11th International Conference on; 01/2010
  • V. Feuillet, Y. Scudeller, Y. Jarny
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    ABSTRACT: This paper presents a method developed for determining temperature distribution in a semi-analytical way within tri-dimensional solid-state circuits and packaged devices in steady state conditions. The method is an efficient route to investigate large ranging sized structures with an arbitrary complex layout composed of multiple material layers and localized heat sources.The method, called the Discrete Boundary Resistance (DBR), consists in decomposing the structure into layers of different sizes to develop the temperature solution as a Double Fourier Series after subdividing the contact boundaries into discrete elements. The solution is expressed as a function of thermal resistance attached to the contact boundaries connected to a temperature reference. The performance of the method has been studied in regards with a three-dimensional device involving a non-uniform distribution of voids between layers. Computational time was found to be shorter than ones achieved with the Finite Element method.
    International Journal of Thermal Sciences. 01/2009;
  • P. Guillemet, C. Pascot, Y. Scudeller
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    ABSTRACT: Self-heating of electric double-layer-capacitors during charge and discharge current cycles has a strong influence on performance, reliability and safety. This paper presents a compact thermal modelling of electric double-layer-capacitors suitable for determining static and dynamic temperature under cycling, at any point of the active components, as a function of topology, materials properties, and operating conditions. Thermal circuits have been created by combining different branches of multi-ports matrix elements referring to each direction of heat transport. Circuits were developed by considering a uniform volume heat generation and, for each branch, a one-directional thermal transport. Performance of the modelling has been investigated in terms of accuracy and computational cost. Compact models were found in good agreement with simulations by the finite-elements method. Deviation did not exceed 8 %.
    01/2008;
  • P. Guillemet, C. Pascot, Y. Scudeller
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    ABSTRACT: Electric double layer capacitors (EDLCs) operate between rechargeable batteries and electrolytic capacitors with respect to energy and power performance. Prediction of internal heating due to discharge and charge current cycles is one of key elements for producing reliable and safe devices with long cycle-life. A calorimetric technique was developed for measuring the heat generation rates of EDLCs under cycling. The as developed technique is described. The heat generation rates were measured on carbon cells as a function of current cycles. Thermal measurements were found in quite good agreement with a porous electrode model of double layer capacitance describing the charging mechanisms. Calculations were performed after estimating the electrical properties of the cell by fitting the dynamic cell voltage. Investigations have conducted to a better understanding of the electro-thermal behavior of EDLCs.
    Thermal Inveatigation of ICs and Systems, 2008. THERMINIC 2008. 14th International Workshop on; 01/2008

Publication Stats

98 Citations
50.80 Total Impact Points

Institutions

  • 2012–2014
    • Institut des Materiaux Jean Rouxel
      Naoned, Pays de la Loire, France
  • 2013
    • French National Centre for Scientific Research
      • Institut des Matériaux Jean Rouxel
      Lutetia Parisorum, Île-de-France, France
  • 2007–2012
    • University of Nantes
      • • Jean Rouxel Institute of Materials
      • • Nantes Atlantique Electrical Engineering Research Institute (IREENA)
      Naoned, Pays de la Loire, France