L. Buchaillot

French National Centre for Scientific Research, Lutetia Parisorum, Île-de-France, France

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Publications (173)152.48 Total impact

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    ABSTRACT: In the above paper (ibid., vol. 23, no. 6, pp. 1252-1271, Dec. 2014), there were errors in Table V and Fig. 26. The corrected table and figure are presented here.
    Journal of Microelectromechanical Systems 02/2015; 24(1):249-249. DOI:10.1109/JMEMS.2014.2376351 · 1.92 Impact Factor
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    ABSTRACT: In the present work, AlGaN/GaN high electron mobility transistors (HEMTs) have been grown with very thin buffer layers on silicon substrates in view of developing nano electromechanical systems (NEMS) for sensors applications. To ensure transducer operation in the MHz range together with low mechanical stiffness, epitaxial structures with thickness below 1 μm have to be developed. We report on the evolution of the material and electrical properties of AlGaN/GaN HEMTs with thicknesses varying from 2 μm to 0.5 μm. The set of parameters obtained includes in-plane Young modulus of 250 GPa in association with carrier density of 6 × 1012 cm−2 and mobility above 1000 cm2 V−1 s−1. The resulting behavior of demonstration transistors validates these epilayers for electromechanical resonators operation.
    Semiconductor Science and Technology 11/2014; 29(11). DOI:10.1088/0268-1242/29/11/115018 · 2.21 Impact Factor
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    ABSTRACT: Most of commercial Atomic Force Microscope (AFM) oscillating probes use micrometric cantilevers that can make measurement with piconewton force resolution under vacuum. However, the flexure vibration cantilevers suffer from a degradation of both resonance frequency and quality factor when operating in liquids. Moreover, the additional laser set-up for amplitude detection also limits the integration and miniaturization of the resonator structure. In order to overcome these difficulties, we propose to replace cantilevers by bulk mode, in-plane vibrating MEMS resonators with integrated transduction methods.
    2014 IEEE International Frequency Control Symposium (FCS); 05/2014
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    ABSTRACT: Gallium nitride (GaN) is a wide bandgap semiconductor material and is the most popular material after silicon in the semiconductor industry. The prime movers behind this trend are LEDs, microwave, and more recently, power electronics. New areas of research also include spintronics and nanoribbon transistors, which leverage some of the unique properties of GaN. GaN has electron mobility comparable with silicon, but with a bandgap that is three times larger, making it an excellent candidate for high-power applications and high-temperature operation. The ability to form thin-AlGaN/GaN heterostructures, which exhibit the 2-D electron gas phenomenon leads to high-electron mobility transistors, which exhibit high Johnson's figure of merit. Another interesting direction for GaN research, which is largely unexplored, is GaN-based micromechanical devices or GaN microelectromechanical systems (MEMS). To fully unlock the potential of GaN and realize new advanced all-GaN integrated circuits, it is essential to cointegrate passive devices (such as resonators and filters), sensors (such as temperature and gas sensors), and other more than Moore functional devices with GaN active electronics. Therefore, there is a growing interest in the use of GaN as a mechanical material. This paper reviews the electromechanical, thermal, acoustic, and piezoelectric properties of GaN, and describes the working principle of some of the reported high-performance GaN-based microelectromechanical components. It also provides an outlook for possible research directions in GaN MEMS.
    Journal of Microelectromechanical Systems 01/2014; 23(6):1252-1271. DOI:10.1109/JMEMS.2014.2352617 · 1.92 Impact Factor
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    ABSTRACT: A new concept of atomic force microscope (AFM) oscillating probes using electrostatic excitation and piezoresistive detection is presented. The probe is characterized by electrical methods in vacuum and by mechanical methods in air. A frequency-mixing measurement technique is developed to reduce the parasitic signal floor. The probe resonance frequencies are in the 1 MHz range and the quality factor is measured about 53 000 in vacuum and 3000 in air. The ring probe is mounted onto a commercial AFM set-up and topographic images of patterned sample surfaces are obtained. The force resolution deduced from the measurements is about 10 pN Hz−0.5.
    Journal of Micromechanics and Microengineering 01/2013; 23(3):035016. DOI:10.1088/0960-1317/23/3/035016 · 1.73 Impact Factor
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    ABSTRACT: We report on a new concept of Atomic Force Microscope (AFM) oscillating probes using dog-bone resonator with thermal excitation and piezoresistive detection. The resonance frequency is 5.4 MHz and the quality factor is measured about 4,000 in air. AFM images are obtained over PMMA resist sample and the force resolution deduced from the measurement is about 320 pN/Hz0.5.
    Micro Electro Mechanical Systems (MEMS), 2013 IEEE 26th International Conference on; 01/2013
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    ABSTRACT: We investigate the response of a GaN microelectromechanical resonator where the strain detection is performed by a resonant high-electron mobility transistor (R-HEMT). The R-HEMT gate located above the 2-DEG (two-dimensional electron gas) appears to enable a strong control of the electromechanical response with a gate voltage dependence close to a transconductance pattern. A quantitative approach based on the mobility of the carriers induced in the device by the piezoelectric response of the GaN buffer is proposed. These results show for the first time the electromechanical transconductance dependence versus external biasing and confirm that active piezoelectric transduction is governed by the AlGaN/GaN 2-DEG transport properties.$\hfill$ [2010-0210]
    Journal of Microelectromechanical Systems 04/2012; 21(2):370-378. DOI:10.1109/JMEMS.2011.2179010 · 1.92 Impact Factor
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    ABSTRACT: A concept of atomic force microscopy (AFM) oscillating sensors using electromechanical silicon microresonators is presented, and imaging capabilities are demonstrated. The microresonators are designed to feature MHz resonance frequencies, and they are batch fabricated using standard silicon microtechnologies. Integrated capacitive transducers allow to drive the resonator and to sense its vibration amplitude. A nanotip is located at a maximum of displacement for sensing near-field forces when interacting with a surface. The device has been mounted on a commercial AFM setup through a dedicated probe holder and a preprocessing electronic circuit. Experiments show that intermittent contact AFM is possible with a tip vibration amplitude of a few nanometers. AFM images have been acquired on silicon micro and nanopatterns. A force resolution of 0.2 $\hbox{nN}/ \surd\hbox{Hz}$ is deduced from the measurements.$\hfill$ [2011-0210]
    Journal of Microelectromechanical Systems 04/2012; 21(2):385-397. DOI:10.1109/JMEMS.2011.2179012 · 1.92 Impact Factor
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    ABSTRACT: We investigate the size distribution of electrically charged nanodroplets using atomic force microscopy (AFM). The droplets were generated using nano- and micro-scale silicon tips. A brief voltage pulse results in a “snapshot” of charged nanodroplets on a Cr surface. AFM of the traces left by the nanodroplets revealed that certain droplet diameters are favored suggesting droplet fission due to Rayleigh instability at nanometer length scales. The most occurring droplet diameters are 85.9(4.1) nm and 167.1 nm (9.7 nm) for nano- and micro-scale tips, respectively.
    Applied Physics Letters 02/2012; 100(7). DOI:10.1063/1.3684979 · 3.52 Impact Factor
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    ABSTRACT: For the first time, 100nm side DNA origami squares have been imaged using 10.9MHz laserless AFM MEMS probe. This sensor takes advantage of the high resonance frequency of a silicon bulk mode resonator integrating a nano-tip fabricated in batch process. After integration in a commercially available AFM set-up with a modified probe holder, the AFM MEMS probe has demonstrated its capability of soft matter imaging.
    Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS) 01/2012; DOI:10.1109/MEMSYS.2012.6170236
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    ABSTRACT: A new concept of Atomic Force Microscope (AFM) oscillating probes using electrostatic excitation and piezoresistive detection is presented. The probe is characterized by electrical methods in vacuum chamber and by mechanical methods in air. The frequency-mixing measurement technique is developed to reduce the parasitic signal level. These probes resonance frequencies are in the 1MHz range and the quality factor is measured about 53,000 in vacuum and 3,000 in air. The force resolution deduced from the measurements is about 8 pN/Hz0.5.
    Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS) 01/2012; DOI:10.1109/MEMSYS.2012.6170180
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    ABSTRACT: A new concept of Atomic Force Microscope (AFM) oscillating probes using electrostatic excitation and piezo-resistive detection is presented. The probe is characterized by electrical methods in a vacuum chamber and by mechanical methods in air. The frequency-mixing measurement technique is developed to reduce the parasitic signal level. These probes resonant in the 1MHz range and the quality factor is measured about 53,000 in vacuum and 3,000 in air. The ring probe is mounted onto a commercial AFM set-up and the surface topography of PMMA sample (2 μm square) is obtained. The force resolution deduced from the measurements is about 10 pN/Hz0.5.
    Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO), 2012 International Conference on; 01/2012
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    ABSTRACT: This paper presents strain measurements using digital image correlation of common microelectronic metal nanofilms deposited onto a polymer substrate (SU-8), which has applications in flexible electronics and nano/microsystems reliability analysis. The novel experimental method is based on digital image correlation coupled with microtensile test apparatus for the in situ investigation of the deformation behaviour of the deposited thin films under uniaxial tensile loading. One of the key features of the method is the real-time two-dimensional strain field measurements on a bare thin film surface, during the deformation process, without any initial speckle or grid deposition. The outstanding performances of the method, having a spatial resolution of 0.7 µm, allow one to envisage further studies related to the understanding of the mechanical behaviour of such thin films and, in particular, the damage localization process.
    Journal of Micromechanics and Microengineering 11/2011; 21(12):125005. DOI:10.1088/0960-1317/21/12/125005 · 1.73 Impact Factor
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    ABSTRACT: This paper reports on the description of a new high force-resolution microgripper with large jaw displacement, electrostatically actuated by a comb-drive and instrumented with an integrated differential capacitive displacement sensor. This microgripper has been non-intuitively designed using a multi-objective optimization method, to reach the best compromise between chosen performance criteria. It has been modeled and fabricated using silicon micro-technology. The theoretical gripping force resolution obtained is 78 pN along the direction of the mobile tip displacement. This performance is many times of magnitude better than the monolithically fabricated MEMS based grippers mentioned in the literature. First experimental characterization tests have been conducted and show good agreement with the expected theoretical performances.
    2011 IEEE/RSJ International Conference on Intelligent Robots and Systems, IROS 2011, San Francisco, CA, USA, September 25-30, 2011; 09/2011
  • E. Herth, E. Algré, B. Legrand, L. Buchaillot
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    ABSTRACT: This paper presents the optimization of polysilicon doping and metallization to form ohmic contact with etching resistance. Indeed, polysilicon doped by ion implantation and ohmic contacts are an important and interesting part of integrated circuit technology or MEMS and NEMS. LPCVD-polysilicon doping parameters, such as ion energy, dose, and annealing were investigated. In particular a superficial implantation realized after a deep implantation enables one to slightly decrease the polysilicon resistivity while the contact resistance is reduced. And ohmic contacts with wet etching resistance were realized by depositing the different metallization stacks. We demonstrate that ohmic contact pad Cr/Pt/Au has provided a good adhesion on LPCVD-polysilicon after wet etching.
    Microelectronic Engineering 05/2011; DOI:10.1016/j.mee.2010.06.032 · 1.34 Impact Factor
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    G. Guisbiers, E. Herth, L. Buchaillot
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    ABSTRACT: The mechanical properties (Young’s modulus, hardness, wear resistance) of aluminium nanofilms on silicon substrate are studied. Size effect on these mechanical properties are exhibited. Young’s modulus, hardness and wear resistance increases when the thickness is reduced. Experimental investigations have been led by atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nanoindentation. Compared to the bulk values, hardness and wear resistance of one aluminium nanofilm (thickness = 100 nm) have increased by a factor ∼7 whereas the Young’s modulus only increased by a term ∼15%. By comparing mechanical properties between high and low melting point materials, we conclude that high melting point materials have a decreasing behaviour of the Young’s modulus with size whereas low melting point materials have an increasing one.
    Microelectronic Engineering 05/2011; DOI:10.1016/j.mee.2010.06.028 · 1.34 Impact Factor
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    ABSTRACT: The properties of a new class of electromechanical resonators based on GaN are presented. By using the two-dimensional electron gas (2-DEG) present at the AlGaN/GaN interface and the piezoelectric properties of this heterostructure, we use the R-HEMT (Resonant High Electron Mobility Transistor) as an active piezoelectric transducer up to 5MHz. In addition to the amplification effect of piezoelectric detection, we show that the active piezoelectric transduction has a strong dependence with the channel mobility that is controlled by a top gate. This allows to envision highly tunable sensors with co-integrated HEMT electronics.
    Micro Electro Mechanical Systems (MEMS), 2011 IEEE 24th International Conference on; 02/2011
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    ABSTRACT: We report here on high resonance frequency AFM probes based on MEMS bulk mode resonators. They consist on silicon ring resonators with capacitive transducers vibrating in the in-plane elliptic mode. Nano-tips placed at the maximum of vibration are fabricated in batch process. After electrical and optical characterizations, chips supporting the resonator and the prominent tip are extracted from the wafer. Next, the AFM nanoprobes are integrated in a commercially available AFM set-up with a modified probe holder. Experimental results of high resonance frequency AFM images are presented.
    Micro Electro Mechanical Systems (MEMS), 2011 IEEE 24th International Conference on; 02/2011
  • B. Legrand, J.P. Aime, L. Buchaillot

Publication Stats

894 Citations
152.48 Total Impact Points

Institutions

  • 2001–2014
    • French National Centre for Scientific Research
      Lutetia Parisorum, Île-de-France, France
    • Institut Supérieur de l'Electronique et du Numérique
      Brest, Brittany, France
  • 1997–2009
    • The University of Tokyo
      • • Center for International Research on Micronano Mechatronics (CIRMM)
      • • Institute of Industrial Science
      Tokyo, Tokyo-to, Japan
  • 2000
    • University of Lille Nord de France
      Lille, Nord-Pas-de-Calais, France