Papers by Christophe Serre
2009 Spanish Conference on Electron Devices, 2009
... 2009. Santiago de Compostela, Spain. Design and fabrication of Si technology miicrogenerators... more ... 2009. Santiago de Compostela, Spain. Design and fabrication of Si technology miicrogenerators for vibrational energy scavenging N. Fondevilla, C. Serre, A. Perez-Rodriguez, JR Morante, J. Montserrat* and J. Esteve*. EME ...
Conference on Electron Devices, 2005 Spanish, 2005
This work describes the design and characterization of Si technology microinductive devices to be... more This work describes the design and characterization of Si technology microinductive devices to be integrated within resonant differential filters for high sensitivity detection of biological molecules. The simulation of these simple circuits shows sensitivity values of the differential output voltage up to 339 mV/nH. This has allowed to detect down to about 2700 magnetic particles per mm 2, which corresponds
Conference on Electron Devices, 2005 Spanish, 2005
Microcoils integrated with standard CMOS technology show an increasing interest in biosensor appl... more Microcoils integrated with standard CMOS technology show an increasing interest in biosensor applications, as they allow very high sensitivity and selectivity. Simulations of the electromagnetic behaviour of the microcoils suggest the way for optimizing their properties. The sensitivity can be improved essentially by decreasing the external radius of the device, and the inductance variation increases with the number of rings, so the optimum configuration corresponds to a small coil with the highest number of rings. Focused ion beam (FIB) shows optimal capabilities to achieve these design rules, as it is a very versatile and precise direct-write technique. In this work, the fabrication process of reduced-size coils using FIB is described, as well as their preliminary characterization, showing the ability of this technique for achieving optimized sensing devices.
2011 International Conference on Power Engineering, Energy and Electrical Drives, 2011
This work describes the design and optimization of an electromagnetic energy harvester to generat... more This work describes the design and optimization of an electromagnetic energy harvester to generate electrical power from slow oscillating movements present in the ambient (produced by the sea waves, the wind,…). A spherical magnet with a spindle moves inside a cylindrical coil along large distances owing to the little inclination produced by the oscillations. Such inertial generator has many advantages for powering remote systems and autonomous applications. It is clean, robust, and can be manufactured as hermetic systems without maintenance costs. Simulations of the generated average power densities are compared to experimental results from a first set of prototypes.
Sensors and Actuators a-Physical, 1998
ELSEVIER Sensors and Actuators A 67 ( 1998) 215-219 A PHYSICAL Measurement of micromechanical pro... more ELSEVIER Sensors and Actuators A 67 ( 1998) 215-219 A PHYSICAL Measurement of micromechanical properties of polysilicon microstructures with an atomic force microscope C. Serre ay*2 P. Gorostiza b3c , A. P6rez-Rodriguez a, F. Sanz b, JR Morante aa EME, Dept. Electr&ica, Universitnt ...
IEEE 2002 28th Annual Conference of the Industrial Electronics Society. IECON 02, 2002
MRS Proceedings, 2000
ABSTRACTThe electrochemical deposition of Cu metal layers for Si based microactuator devices is i... more ABSTRACTThe electrochemical deposition of Cu metal layers for Si based microactuator devices is investigated as a function of the substrate structure. For the direct deposition of Cu onto Si, a two step process involving pre-deposition of an intermediate layer under alkaline conditions has been developed. This has allowed the optimization of the process in terms of film adherence and thickness. On the other hand, for processes involving the use of dielectric sacrificial layers, the electrochemical growth of the Cu film requires a metallic seed layer. In this case, the growth of Cu onto Au coated surfaces has been investigated, and the process has been applied to the development of test microactuator structures based on the integration of Cu coils onto Si micromachined devices. The fabrication of these devices demonstrates the full compatibility of Electrochemical processes with Si standard micromachining technologies.
Perspectives, Science and Technologies for Novel Silicon on Insulator Devices, 2000
Sensors and Actuators A: Physical, 2010
Mechanically resonant ferromagnetic MEMS sensors intended for magnetic field gradient measurement... more Mechanically resonant ferromagnetic MEMS sensors intended for magnetic field gradient measurements are presented. Suspended quad-beams with proof mass have been designed to improve their sensitivity and to simplify the detection. Fabricated devices exhibit the compact size of current MEMS technologies and are built within a simple deep-reactive-ion etching-based process. Nanometer-resolution detection based on optical interferometry and signal processing techniques have
Sensors and Actuators A: Physical, 2005
This work reports the microstructural and stress analysis of Cu layers and Ni/Cu multilayer struc... more This work reports the microstructural and stress analysis of Cu layers and Ni/Cu multilayer structures grown onto Au (1 1 1) seed surfaces by EC processes that are developed for the fabrication of magnetic microactuator devices in Si technology. X-ray diffraction (XRD) measurements performed onto the electrochemically grown Cu layers has revealed the existence of a Cu/Au interface region with (1 1 1) texture and with a high tensile stress. Increasing the Cu layer thickness leads to a change of the preferential orientation of the Cu grains towards (2 2 0) texture, likely related to a stress relaxation. The Ni layers also show the coexistence of both (1 1 1) and (2 2 0) preferential orientations. In this case, the existence of an underlying Cu layer with dominant (2 2 0) texture leads to an enhancement in the (2 2 0) preferential orientation of the Ni grains. These layers are also characterised by the existence of high tensile stress levels, which, together with the high stress at the Cu/Au interficial region, lead to stress gradients, which might compromise the viability of the grown multilayer structures for microsystem applications.
Sensors and Actuators A: Physical, 2006
This work presents the design and fabrication of inductive devices integrated in Si technology ai... more This work presents the design and fabrication of inductive devices integrated in Si technology aimed at high sensitivity biodetection applications. The sensing principle is based on the changes of the coil inductance due to the presence of magnetic particles in the active region of the device. These particles act as markers of the biological molecule to be detected. For the
Sensors and Actuators A: Physical, 1999
Micromechanical measurements have been performed with a beam bending based technique using an ato... more Micromechanical measurements have been performed with a beam bending based technique using an atomic force microscope (AFM). This technique combines a very high load resolution with a nanometric precision in the measurement of the cantilever deflection. It has been ...
Journal of Micromechanics and Microengineering, 2000
SiC on insulator for microelectromechanical systems has been directly synthesized by high-dose ca... more SiC on insulator for microelectromechanical systems has been directly synthesized by high-dose carbon ion implantation of amorphous or polycrystalline Si on SiO 2. For this, a four-step implant process has been defined by TRIM simulation. X-ray diffraction and in-depth ...
Journal of Micromechanics and Microengineering, 1999
Journal of Applied Physics, 1995
High-dose carbon-ion-implanted Si samples have been analyzed by infrared spectroscopy, Raman scat... more High-dose carbon-ion-implanted Si samples have been analyzed by infrared spectroscopy, Raman scattering, and x-ray photoelectron spectroscopy (XPS) correlated with transmission electron microscopy. Samples were implanted at room temperature and 500 "C~with doses between lOI7 and 10's C+/cm'. Some of the samples were implanted at room temperature with the surface covered by a capping oxide layer. Implanting at room temperature leads to the formation of a surface carbon-rich amorphous layer, in addition to the buried implanted layer. The dependence of this layer on the capping oxide suggests this layer to be determined by carbon migration toward the surface, rather than surface contamination. Implanting at 500 "C, no carbon-rich surface layer is observed and the Sic buried layer is formed by crystalline /!-Sic precipitates aligned with the Si matrix. The concentration of SIC in this region as measured by XPS is higher than for the room-temperature implantation. 0 1995 American Institute sf Physics.
Microsystem Technologies, 2009
In this work, the design, fabrication and characterization of an electromagnetic inertial microge... more In this work, the design, fabrication and characterization of an electromagnetic inertial microgenerator compatible with Si micro-systems technology is presented. The device includes a fixed micromachined coil and a movable magnet mounted on a resonant polymeric structure. The characterization of the fabricated prototypes has allowed to observe the presence of non linear effects that lead to the appearance of hysteretic vibrational phenomenon. These effects are likely related to the mechanical characteristics of the polymeric membrane, and determine an additional dependence of vibration frequency on the excitation amplitude. Under such non linear conditions, power densities up to 40 µW/cm 3 are obtained for devices working with low level excitation conditions similar to those present in domestic and office environment. I.
Journal of Applied Physics, 1996
The analysis of SiC films obtained by carbon ion implantation into amorphous Si ͑preamorphized by... more The analysis of SiC films obtained by carbon ion implantation into amorphous Si ͑preamorphized by Ge ion implantation͒ has been performed by infrared and Raman scattering spectroscopies, transmission electron microscopy, Rutherford backscattering, and x-ray photoelectron spectroscopy ͑XPS͒. The data obtained show the formation of an amorphous Si 1Ϫx C x layer on top of the amorphous Si one by successive Ge and C implantations. The fitting of the XPS spectra indicates the presence of about 70% of Si-C bonds in addition to the Si-Si and C-C ones in the implanted region, with a composition in the range 0.35 Ͻ x Ͻ 0.6. This points out the existence of a partial chemical order in the layer, in between the cases of perfect mixing and complete chemical order. Recrystallization of the layers has been achieved by ion-beam induced epitaxial crystallization ͑IBIEC͒, which gives rise to a nanocrystalline SiC layer. However, recrystallization is not complete, observing still the presence of Si-Si and C-C bonds in an amorphous phase. Moreover, the distribution of the different bonds in the IBIEC processed samples is similar to that from the as-implanted ones. This suggests that during IBIEC homopolar bonds are not broken, and only regions with dominant Si-C heteropolar bonds recrystallize.
Boletin de la Sociedad Espanola de Ceramica y Vidrio
En este trabajo se presenta un estudio químico y estructural de las capas metálicas de Pt y TaSi ... more En este trabajo se presenta un estudio químico y estructural de las capas metálicas de Pt y TaSi x utilizadas como puerta catalítica en sensores de gas de alta temperatura basados en dispositivos MOS de SiC. Para ello se han depositado capas de diferentes espesores sobre substratos de Si. Los resultados muestran que con la reducción del espesor de Pt y con un recocido se consigue aumentar la rugosidad de las capas de puerta, lo que debería aumentar la sensibilidad y la velocidad de respuesta de los dispositivos que las incorporasen. Otro efecto del recocido es la transformación química del material de la puerta que, para capas delgadas de Pt con TaSi x , produce la transformación total Pt en Pt 2 Ta, lo que podría afectar a las características catalíticas de la puerta. Los primeros resultados eléctricos indican que, a pesar de que las capas de Pt empleadas son gruesas y compactas, los diodos MOS túnel de SiC son sensibles a los gases CO y NO 2 , aunque presentan una velocidad de respuesta bastante lenta.
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Papers by Christophe Serre