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1
Gajda, Mark Andrzej. "Silicon sensors on membranes." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321077.
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Hout, S. R. in't. "High-temperature silicon sensors." Delft, the Netherlands : Delft University Press, 1996. http://books.google.com/books?id=dApTAAAAMAAJ.
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Thomas, Mikkel Andrey. "Integrated optical interferometric sensors on silicon and silicon cmos." Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26674.
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The main objective of this research is to fabricate and characterize an optically integrated interferometric sensor on standard silicon and silicon CMOS circuitry. An optical sensor system of this nature would provide the high sensitivity and immunity to electromagnetic interference found in interferometric based sensors in a lightweight, compact package capable of being deployed in a multitude of situations inappropriate for standard sensor configurations. There are several challenges involved in implementing this system. These include the development of a suitable optical emitter for the sensor system, the interface between the various optically embedded components, and the compatibility of the Si CMOS with heterogeneous integration techniques. The research reported outlines a process for integrating an integrated sensor on Si CMOS circuitry using CMOS compatible materials, integration techniques, and emitter components.
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Guardiola, Salmerón Consuelo. "Novel silicon sensors for neutron detection." Doctoral thesis, Universitat Autònoma de Barcelona, 2012. http://hdl.handle.net/10803/117536.
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La detección precisa y la dosimetría de neutrones en campos de radiación mixtos y pulsados es un tema instrumental demandado con gran interés por las comunidades médica e industrial. Estudios recientes de la contaminación de neutrones alrededor de los aceleradores lineales médicos han aumentado la preocupación sobre el riesgo de cáncer secundario en pacientes sometidos a tratamiento de radioterapia en las modalidades de fotones con energías superiores a 8 MeV. En respuesta a esa necesidad, en esta tesis se ha desarrollado una innovadora alternativa a los detectores estándares con un método activo para medir los neutrones alrededor de un acelerador lineal médico. Para tal fin, se han fabricado y optimizado nuevos detectores de silicio ultra delgados con electrodos 3D. El volumen activo de estos sensores tiene sólo 10 μm de espesor, lo que permite un alto rechazo a rayos gamma, lo cual es necesario para discriminar la señal de neutrones en el campo de la radiación periférica en radioterapia (con un alto fondo gamma). Estos detectores de neutrones son una solución prometedora para estimar el riesgo del paciente, puesto que pueden proporcionar al personal médico una respuesta rápida para una planificación óptima del tratamiento. También pueden ser utilizados en otras áreas con campos de radiación mixtos de neutrones/gamma tales como entornos nucleares y aeroespaciales, o microdosimetría. Además, las características intrínsecas de los dispositivos de silicio como robustez, pequeño tamaño, peso ligero y bajo consumo, los hacen ideales para ser empleados como sistemas de detección de neutrones portátiles.
La investigación presentada en este trabajo describe las simulaciones Monte Carlo llevadas a cabo para optimizar el diseño de los prototipos, los procesos de fabricación de los detectores y su caracterización con fuentes radiactivas. Finalmente, se muestra el buen funcionamiento de estos nuevos detectores 3D ultra–delgados de silicio para la detección de neutrones en salas de radioterapia.The accurate detection and dosimetry of neutrons in mixed and pulsed radiation fields is a demanding instrumental issue with great interest both for the industrial and medical communities. Recent studies of the neutron contamination around medical linear accelerators have increased the concern about the secondary cancer risk for radiotherapy patients undergoing treatment in photon modalities at energies greater than 8 MeV. In this thesis, an innovative alternative to standard detectors with an active method to measure neutrons around a medical linac has been developed in response to that need. Novel ultra–thin silicon detectors with 3D electrodes adapted for neutron detection have been fabricated and optimized for such purpose. The active volume of these sensors is only 10 μm thick, allowing a high gamma rejection, which is necessary to discriminate the neutron signal in the radiotherapy peripheral radiation field with a high gamma background. These neutron detectors are not only a promising solution to estimate patient risk since they may provide medical staff a fast feedback for optimal treatment planning, but expand the functional applications of current neutron detectors for other environments with mixed gamma–neutron radiation fields such as nuclear and aerospace environments or microdosimetry. Moreover, the intrinsic features of the silicon devices like robustness, small size, consumption and weight, make them ideal for portable systems. The research presented in this work describes first the Monte Carlo simulations to optimize the design of the prototypes, secondly the fabrication processes of the detectors, and third the electrical characterization and calibration with radioactive sources of these sensors. Finally, it is shown the good performance of the novel ultra–thin 3D silicon detectors for neutron detection inside a radiotherapy room.
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Weatherill, Daniel Philip. "Charge collection in silicon imaging sensors." Thesis, Open University, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.702424.
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The subject of this thesis is the analysis of instrumental effects caused by the interaction between collected signal charge and electric fields within precision CCD imaging sensors typically used for astronomy. These phenomena cause aberrations in the measured spatial distribution of subsequently collected signal, which may present a major error for upcoming astronomy projects which rely heavily on accurately determining shapes of compact sources. Examples are the Large Synoptic Survey Telescope and t he Euclid space telescope. The size of dynamic collection effects may be subtly affected by t he operating conditions and design parameters of the device. Dynamic charge collection effects differ in origin from many other errors introduced by imaging detect ors in that they are attributable t o changes in the confinement of charge carriers during the collection phase of operation, rather than the readout phase. The fact that t he exact aberration implied by dynamic charge collection effects depends exactly on the incident light field's spatial distribution also makes them comparatively difficult to correct for . A method of physically modelling charge collection within t he detector using analytical solutions to Poisson's equation is described, which is shown to qualitatively reproduce many features of measured dynamic charge collection effects. Since the model is derived from device physics, it differs in approach in a complementary way from previous efforts which are empirically based. Experimental charge collection measurements from two different CCDs both affect ed by dynamic collection effects are presented , and shown in large part to be consistent with the predictions from the theoretical model.
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DeBoer, John Raymond. "Evaluation Methods for Porous Silicon Gas Sensors." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4971.
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This study investigated the behavior of porous silicon gas sensors under exposure to CO, NO, and NH3 gas at the part per million level. Parameters of interest in this study included the electrical, environmental, and chemi-resistive performance associated with various porous silicon morphologies. Based upon the variability of preliminary results, a gas pulsing method was combined with signal processing in order to analyze small impedance changes in an environment of substantial noise. With this technique, sensors could be effectively screened and characterized. Finally this method was combined with various post-treatments in order to improve the sensitivity and selectivity of individual sensors.
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Singh, Tony. "Chromatically addressed micro-silicon Fabry-Perot sensors." Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399284.
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Su, Yi. "Micromachined piezoresistive single crystal silicon cantilever sensors." Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242637.
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Gupta, Shoubhik. "Ultra-thin silicon technology for tactile sensors." Thesis, University of Glasgow, 2019. http://theses.gla.ac.uk/41053/.
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In order to meet the requirements of high performance flexible electronics in fast growing portable consumer electronics, robotics and new fields such as Internet of Things (IoT), new techniques such as electronics based on nanostructures, molecular electronics and quantum electronics have emerged recently. The importance given to the silicon chips with thickness below 50 μm is particularly interesting as this will advance the 3D IC technology as well as open new directions for high-performance flexible electronics. This doctoral thesis focusses on the development of silicon-based ultra-thin chip (UTC) for the next generation flexible electronics. UTCs, on one hand can provide processing speed at par with state-of-the-art CMOS technology, and on the other provide the mechanical flexibility to allow smooth integration on flexible substrates. These development form the motivation behind the work presented in this thesis. As the thickness of any silicon piece decreases, the flexural rigidity decreases. The flexural rigidity is defined as the force couple required to bend a non-rigid structure to a unit curvature, and therefore the flexibility increases. The new approach presented in this thesis for achieving thin silicon exploits existing and well-established silicon infrastructure, process, and design modules. The thin chips of thicknesses ranging between 15 μm - 30 μm, were obtained from processed bulk wafer using anisotropic chemical etching. The thesis also presents thin wafer transfer using two-step transfer printing approach, packaging by lamination or encapsulation between two flexible layerand methods to get the electrical connections out of the chip. The devices realised on the wafer as part of front-end processing, consisted capacitors and transistors, have been tested to analyse the effect of bending on the electrical characteristics. The capacitance of metal-oxide-semiconductor (MOS) capacitors increases by ~5% during bending and similar shift is observed in flatband and threshold voltages. Similarly, the carrier mobility in the channel region of metal-oxide-semiconductor field effect transistor (MOSFET) increases by 9% in tensile bending and decreases by ~5% in compressive bending. The analytical model developed to capture the effect of banding on device performance showed close matching with the experimental results. In order to employ these devices as tactile sensors, two types of piezoelectric materials are investigated, and used in extended gate configuration with the MOSFET. Firstly, a nanocomposite of Poly(vinylidene fluoride-co-trifluoroethylene), P(VDF-TrFE) and barium titanate (BT) was developed. The composite, due to opposite piezo and pyroelectric coefficients of constituents, was able to suppress the sensitivity towards temperature when force and temperature varied together, The sensitivity to force in extended gate configuration was measured to be 630 mV/N, and sensitivity to temperature was 6.57 mV/oC, when it was varied during force application. The process optimisation for sputtering piezoelectric Aluminium Nitride (AlN) was also carried out with many parametric variation. AlN does not require poling to exhibit piezoelectricity and therefore offers an attractive alternative for the piezoelectric layer used in devices such as POSFET (where piezoelectric material is directly deposited over the gate area of MOSFET). The optimised process gave highly orientated columnar structure AlN with piezoelectric coefficient of 5.9 pC/N and when connected in extended gate configuration, a sensitivity (normalised change in drain current per unit force) of 2.65 N-1 was obtained.
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Cooper, Emily Barbara 1977. "Silicon field-effect sensors for biomolecular assays." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/87450.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.Includes bibliographical references.
System-level understanding of biological processes requires the development of novel biosensors capable of quantitative, real-time readout of molecular interactions. Label-free detection methods can minimize costs in time and resources by obviating preparatory steps necessary with label-based methods. They may further be valuable for monitoring biomolecular systems which are difficult or impossible to tag, or for which reporter molecules interfere with biological function. Field-effect sensing is a method of directly sensing intrinsic electrical charge associated with biomolecules without the need for reporter molecules. Microfabrication of field-effect biosensors enables their integration in compact microanalytical systems, as well as the potential to be scaled down in size and up in number. Applying field-effect sensing to the detection and real-time monitoring of specific molecular interactions has long been of interest for protein and nucleic acids analysis. However, these applications are inhibited by serious practical limitations imposed by charge screening in solution. The development of effective measurement techniques requires inquiry into aspects of device engineering, surface chemistry, and buffer conditions. This thesis describes a body of experimental work that investigates the feasibility of label-free analysis of biomolecular interactions by field-effect. This work begins with the microfabrication of field-effect sensors with extremely thin gate oxide, which enables improved surface potential resolution over previously reported sensors.
(cont.) The performance of these sensors has been characterized in terms of drift, noise, and leakage. To better understand the applicability of these sensors, we have characterized the sensors' response to pH, adsorption of polyelectrolyte multilayers, and high-affinity molecular recognition over a range of buffer conditions. Direct, label-free detection of DNA hybridization was accomplished by combining the high-resolution sensors, with enabling surface chemistry, and a differential readout technique. Finally, we explore the lateral scaling limits of potentiometry by applying a novel nanolithographic technique to the fabrication of a single electron transistor that demonstrates Coulomb oscillations at room temperature.
by Emily Barbara Cooper.
Ph.D.
11
Lai, Ching-Hung. "Simulation of 3D sensors." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/simulation-of-3d-sensors(81998ca6-7b0a-4253-89fc-f38a127a5457).html.
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The Large Hadron Collider (LHC) at CERN has the highest energy and luminosity in the world. Radiation hardness is then a critical requirement for the inner tracker design. The inner tracker is important for identifying heavy quarks using high spatial precision detectors. Silicon detectors are now the primary technology for this application. 3D silicon sensors use a novel technology with penetrating electrodes and have excellent radiation hardness by design. It overcomes the signal loss with a low operation voltage by reducing the collection length compared to the current planar technology used in the ATLAS pixel detector. The ATLAS insertable B-layer (IBL) is an upgrade to improve tracking resolution of the inner tracker and will be installed in 2013. It will be composed of 75% planar sensors and 25% 3D sensors in the large-η region. It is important to simulate the IBL tracking performance and to have a valid model for 3D sensors. This thesis investigated the experimental data for heavily irradiated planar strip sensors and 3D sensors to develop a device simulator, in which impact ionisation has to be included. The modelling has found that the radiation induced effective doping concentration has two linear regimes with a smaller growth rate at high fluences. This shows the possibility to operate silicon sensors with a higher irradiation level. The signal efficiency of each pixel is the basis to simulate the whole IBL response. A model and a code were developed to calculate the induced signal from electron-hole pairs generated by the traversing charge particles. This results in a 2D efficiency map used as an input of the 3D digitiser for the Geant4 simulation. This map was adopted by the IBL software team for the whole tracker simulation and has been validated by the test beam data.
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Padmanabhan, Aravind. "Silicon micromachined sensors and sensor arrays for shear-stress measurements in aerodynamic flows." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10257.
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Parameswaran, Lalitha. "Integrated silicon pressure sensors using wafer bonding technology." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10451.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (p. 151-156).
by Lalitha Parameswaran.
Ph.D.
14
Chen, Li. "SILICON CARBIDE PRESSURE SENSORS AND INFRA-RED EMITTERS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1195161915.
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Jin, Sheng. "Silicon carbide pressure sensors for high temperature applications." Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1296096110.
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Gao, Ting. "Vapor sensors using porous silicon-based optical interferometers /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2002. http://wwwlib.umi.com/cr/ucsd/fullcit?p3061646.
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Hendrickson, Benjamin William. "Dark Current RTS-Noise in Silicon Image Sensors." PDXScholar, 2018. https://pdxscholar.library.pdx.edu/open_access_etds/4475.
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Random Telegraph Signal (RTS) noise is a random noise source defined by discrete and metastable changes in the magnitude of a signal. Though observed in a variety of physical processes, RTS is of particular interest to image sensor fabrication where progress in the suppression of other noise sources has elevated its noise contribution to the point of approaching the limiting noise source in scientific applications.
There have been two basic physical sources of RTS noise reported in image sensors. The first involves a charge trap in the oxide layer of the source follower in a CMOS image sensor. The capture and emission of a charge changes the conductivity across the source follower, altering the signal level. The second RTS source in image sensors has been reported in CCD and CMOS architectures and involves some metastability in the structure of the device within the light collection area.
A methodology is presented for the analysis of RTS noise. Utilizing wavelets, a time-based signal has white noise removed, while RTS transitions are preserved. This allows for the simple extraction of RTS parameters, which provide valuable insight into defects in semiconductor devices. The scheme is used to extract RTS transition amplitudes and time constants from radiation damaged CMOS image sensor pixels.
Finally, the generation of ionizing radiation induced RTS centers is investigated and discussed. Surprisingly, the number of RTS centers does not scale linearly with absorbed dose, but instead follows a quadratic dependence. The implications and possible mechanisms behind the generation of these RTS centers are discussed.
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Seo, Jae Hyeong. "Silicon-Based Resonant Microsensor Platform for Chemical and Biological Applications." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19835.
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The main topic of this thesis is the performance improvement of microresonators as mass-sensitive biochemical sensors in a liquid environment. Resonant microstructures fabricated on silicon substrates with CMOS-compatible micromachining techniques are mainly investigated. Two particular approaches have been chosen to improve the resolution of resonant chemical/biochemical sensors. The first approach is based on designing a microresonator with high Q-factor in air and in liquid, thus, improving its frequency resolution. The second approach is based on minimizing the frequency drift of microresonators by compensating for temperature-induced frequency variations.
A disk-shape resonant microstructure vibrating in a rotational in-plane mode has been designed, fabricated and extensively characterized both in air and in water. The designed resonators have typical resonance frequencies between 300 and 1,000kHz and feature on-chip electrothermal excitation elements and a piezoresistive Wheatstone-bridge for vibration detection. By shearing the surrounding fluid instead of compressing it, damping is reduced and quality factors up to 5800 in air and 94 in water have been achieved. Short-term frequency stabilities obtained from Allan-variance measurements with 1-sec gate time are as low as 1.1 10-8 in air and 2.3 10-6 in water. The performance of the designed resonator as a biological sensor in liquid environment has been demonstrated experimentally using the specific binding of anti-beta-galactosidase antibody to beta-galactosidase enzyme covalently immobilized on the resonator surface.
An analytical model of the disk resonator, represented by a simple harmonic oscillator, has been derived and compared with experimental results. The resonance frequency and the Q-factor of the disk resonator are determined from analytical expressions for the rotational spring constant, rotational moment of inertia, and energy loss by viscous damping. The developed analytical models show a good agreement with FEM simulation and experimental results and facilitate the geometrical optimization of the disk-type resonators.
Finally, a new strategy to compensate for temperature-induced frequency drifts of resonant microstructures has been developed based on a controlled stiffness modulation by an electronic feedback loop. The developed method is experimentally verified by compensating for temperature-induced frequency fluctuations of a microresonator. In principle, the proposed method is applicable to all resonant microstructures featuring excitation and detection elements.
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Wu, Zhaohui. "Modeling and characterization of high-temperature silicon-based thermal sensors." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B31057652.
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Page, Ryan. "Silicon carbide foam as a support structure for silicon sensors in a vertex detector." Thesis, University of Bristol, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.573389.
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In this thesis a complete study of silicon carbide (SiC) foam is presented. The aim of which is to show that this material is sufficiently understood that it could be used as a support material in the vertex detector at the International Linear Collider (ILC). Through this research a deep understanding of SiC foams has been acquired. This knowledge has come from a combination of machining and material tests, along with detailed analyses of SiC foams at the level of its microstructure. The later was carried out by modelling a foam as a set of tetrakaidecahedra unit cells. These were in turn analysed using Finite Element Analyses. The elastic moduli from these studies were within 16% of the manufacturer's values for SiC foams with relative densities 8%, 12% and 16%. The ability to machine the material was vital if it were to be used to make a support structure. Studies presented here showed that this was indeed possible and intricate components were machined, which led the way for the first all SiC foam vertex detector prototype. This structure was temperature cycled to check its stability. The best obtained flatness relative to room temperature was 8 ± 6 um: in the x - y plane of the ladder, over the temperature range -20°C < T < -lOoC. To ensure that an all SiC foam detector was competitive with the current baselines, a series of performance tests were carried out. One of the benchmark tests was the vertex finding capability at the Z-pole energy. This test showed that all the concepts were within 5% of each other. Also carried out were tests on the impact parameter resolutions and the purity and efficiency of heavy jet favour tagging. The research presented here shows that SiC foam is a credible choice and should be seriously considered in 'any future R&D into vertex detector support structures.
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Müller, Thomas. "An industrial CMOS process family for integrated silicon sensors /." [S.l.] : [s.n.], 1999. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13463.
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Schott, Christian. "Accurate magnetic field transducers based on silicon hall sensors /." Lausanne, 1999. http://library.epfl.ch/theses/?nr=1985.
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Thèse, Sciences techniques, EPF Lausanne, no 1985, 1999, Département de microtechnique. Rapporteur: R. S. Popovic ; co-rapporteur: M. Ilegems ; co-rapporteur: J. Korvink ; co-rapporteur: S. Middelhoek.
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Weng, Ming-Hung. "Novel high-κ gas sensors for silicon carbide technology." Thesis, University of Newcastle Upon Tyne, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443105.
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Borri, Marcello. "Characterization of 3D silicon assemblies for ATLAS pixel upgrade." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/characterization-of-3d-silicon-assemblies-for-atlas-pixel-upgrade(ade5b052-e8f5-45bc-bef8-7bd259d09444).html.
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The ATLAS pixel detector will be upgraded with a new Insertable B-layer (IBL). The IBL will be inserted between the existing pixel detector and the reduced diameter vacuum pipe of the Large Hadron Collider. The extreme operating conditions at this location have required the development of new radiation hard pixel sensor technologies and a new front end chip.3D-silicon sensors will populate 25% of the IBL sensing area. They are a newgeneration of micro-machined sensors with electrodes etched inside the silicon bulk rather than on the wafer surface. 3D-silicon sensors were studied by performing simulations, laboratory measurements and beam tests on irradiated and not irradiated samples.This thesis describes the development of a fast algorithm of the signal response in 3D-silicon sensors using Geant4 simulations. The simulation of the signal response is compared to actual data from test-beam and radioactive source measurements. The setup for each of these measurements is also simulated in Geant4 using experience gained after working with the real setup.
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Wu, Zhaohui, and 吳朝暉. "Modeling and characterization of high-temperature silicon-based thermal sensors." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B31057652.
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Esteban, Martí Sergi. "Development of advanced silicon sensors for neutron detection and microdosimetry." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/399780.
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Aquesta tesi presenta el desenvolupament de sensors avançats de silici fabricats al IMB-CNM per aplicacions en detecció de neutrons i per mesures microdosimètriques en feixos de teràpia amb hadrons.
La precisa detecció de neutrons es de gran interès en la comunitat mèdica, en seguretat nacional i en molts altres camps com la ciència de materials o l’exploració de l’espai. Donat el seu efecte biològic, la detecció de neutrons es essencial per controlar, per exemple, el flux de neutrons produïts durant els tractament de radioteràpia o hadronteràpia i minimitzar així el risc de contraure tumors secundaris induïts per la radiació. A més a més, per seguretat nacional, la detecció de neutrons es imprescindible per reduir amenaces radio-biològiques ja que, els materials que poden ser utilitzats per construir armes nuclears o bombes brutes, son fonts d’emissió de neutrons. Aquestes aplicacions es basen actualment en detectors gasosos d’heli-3 però, degut a la escassetat d’aquest gas, en un futur pròxim una tecnologia substitutòria per a la detecció de neutrons es necessària.
Els sensors presentat en aquesta tesi per a la detecció de neutrons són: l’ultra prim 3D (U3DTHIN) i el micro-estructurat (MS), cobert i omplert respectivament amb un material convesor. Els sensors U3DTHIN són nomes de 10 or 20 µm de gruix, permetent un alt rebuig als rajos gamma, propietat necessària per discriminar la senyal deguda als neutrons en un medi mixt amb rajos gamma. Els sensors MS consisteixen en una formació de micro-canals gravats dins el silici i omplerts amb un material conversor. Aquests detectors proporcionen un augment en la eficiència de detecció degut a la major àrea de contacte entre el volum sensible de silici i el material convesor.
La teràpia amb hadrons es un tipus en expansió de radiació externa per tractar el càncer utilitzant feixos protons o ions pesats. La posada en marxa d’aquests tipus de feixos, per obtenir un tractament més precís, requereix una caracterització completa de la qualitat de la radiació, és a dir, tipus de partícula i espectre d’energia, que resulta de mesures microdosimètriques. Per a la realització d’aquestes mesures, els sensors presentats en aquesta tesis són els U3DTHIN i els microdosimetres 3D cilíndrics. Els U3DTHIN, ja introduïts per a la detecció de neutrons també s’utilitzen per tals mesures a causa del seu petit gruix, mentre que els microdosimetres cilíndrics van ser específicament fabricats per mesures microdosimètriques. Aquesta nova generació de dispositius consisteix en una matriu de micro-sensors amb elèctrodes cilíndrics que permeten un ben definit volum micromètric sensible a la radiació.
La investigació presentada en aquest treball inclou els processos de fabricació dels sensors, la seva caracterització elèctrica, les simulacions GEANT4 per optimitzar els dissenys i per validar resultats i els tests experimentals realitzats en diferents instal·lacions d’irradiació.This thesis presents the development of advanced silicon sensors fabricated at IMB-CNM for neutron detection applications and for microdosimetry measurements of hadron therapy ion beams. The accurate detection of neutrons has great interest for the medical community, for homeland security and for many other different fields such as material science or space exploration. Given their biological effect, neutron detection is essential to control, for example, the neutron flux produced during a radiotherapy or hadrontherapy treatment to minimize the patient's risk of secondary radiation-induced tumours. Moreover, for national security purposes, neutron detection is crucial to elude radiological threats since the nuclear materials, that could be used to assemble nuclear weapons or dirty bombs, are a significant source of fission neutrons. These applications mostly rely on 3He gas proportional counters but due to the shortage of this gas, a replacement technology for neutron detection is required in the near future. The presented sensors in this thesis for neutron detection are the ultra-thin 3D (U3DTHIN) and the microstructured (MS) sensors, which are covered and filled respectively, with a thermal neutron converter material. The U3DTHIN sensors are only 10 or 20 µm thick, allowing for a high gamma rejection, which is necessary to discriminate the signal coming from the neutrons in a mixed neutron-gamma ray environment. The MS sensors consist of an array of microchannels etched inside the silicon bulk and filled with a converter material. They lead to an improvement of the neutron detection efficiency due to the increased contact area between the silicon sensitive volume and the converter material. Hadron therapy is an expanding branch of external radiation therapy for treating cancer using protons or heavy ion beams. The commissioning of such beams, to lead to a more accurate treatment plan, requires a complete characterization of the radiation quality (i.e. particle types and their energy spectra) that results from microdosimetric measurements. To perform these measurements, the presented sensors in this thesis are the U3DTHIN and the 3D cylindrical microdosimeter. The U3DTHIN, already introduced for neutron detection, is also used for such measurements due to its thin thickness, while the 3D cylindrical microdosimeter was manufactured specifically for microdosimetry measurements. This new generation device consists of an array of micro-sensors that have 3D-cylindrical electrodes resulting in a well-defined micrometric radiation sensitive volume. The research presented in this work includes the fabrication processes of the sensors, their electrical characterization, the GEANT4 simulations to optimize the designs and to validate the experimental results and the experimental tests performed at different irradiation facilities.
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Guillén-Torres, Miguel Ángel. "Feasibility of optical gyroscopic sensors in silicon-on-insulator technology." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54606.
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In the last decade, silicon photonics has become a strategic technology for the development of telecommunications and sensors. Due to its compatibility with well-developed complementary metal oxide semiconductor (CMOS) fabrication processes, silicon on insulator (SOI) wafers can be processed to create thousands of devices per die in a fast and inexpensive way. Being solid state devices with no movable parts, optical gyroscopes have longer life expectancies and shock resistance compared to micro-electro-mechanical gyroscopes. Thus, the implementation of SOI-based gyroscopes is desirable for large-scale, low-cost production. This thesis presents a study of the feasibility of implementing optical gyroscopes in SOI technology. A comprehensive theoretical study has been carried out to develop a device-level optimization and robustness analysis, showing that the most crucial resonator parameter is the propagation loss, followed by length and coupling. For a given propagation loss, there is an optimal resonator size, beyond which the angular speed resolution is severely degraded. On the system level, the impact of signal-to-noise ratio and insertion loss on the resolution are described.
Given that the propagation loss is the most important parameter, strategies were proposed to reduce it as much as possible while still using CMOS-compatible processes. The quality factor, Q was chosen as the figure of merit to be maximized during the design iterations. As a result, the largest Q factors reported to date on SOI, using standard CMOS-compatible processes, were achieved. These Q factors are comparable to, or exceed, those of optical resonators intended for gyroscopic applications that are fabricated in materials such as indium phosphide (InP). Innovative approaches to compensate for fabrication variations are proposed, such as thermally-tuneable coupling and reference rings for differential measurements. Complex mechano-opto-electrical measurement setups were designed and implemented to characterize SOI gyroscopes, both at rest and under rotation. As a result, the Microsystem Integration Platform for Silicon-Photonics (Si-P MIP) was created. This characterization platform is now being commercialized by CMC Microsystems for academic and industrial applications. The main practical and theoretical challenges regarding the implementation of optical ring gyroscopes on SOI have been identified. Schemes to address them and suggestions for future work are proposed.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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Gong, Jianwei. "NON-SILICON MICROFABRICATED NANOSTRUCTURED CHEMICAL SENSORS FOR ELECTRIC NOSE APPLICATION." Doctoral diss., University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4082.
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A systematic investigation has been performed for "Electric Nose", a system that can identify gas samples and detect their concentrations by combining sensor array and data processing technologies. Non-silicon based microfabricatition has been developed for micro-electro-mechanical-system (MEMS) based gas sensors. Novel sensors have been designed, fabricated and tested. Nanocrystalline semiconductor metal oxide (SMO) materials include SnO2, WO3 and In2O3 have been studied for gas sensing applications. Different doping material such as copper, silver, platinum and indium are studied in order to achieve better selectivity for different targeting toxic gases including hydrogen, carbon monoxide, hydrogen sulfide etc. Fundamental issues like sensitivity, selectivity, stability, temperature influence, humidity influence, thermal characterization, drifting problem etc. of SMO gas sensors have been intensively investigated. A novel approach to improve temperature stability of SMO (including tin oxide) gas sensors by applying a temperature feedback control circuit has been developed. The feedback temperature controller that is compatible with MEMS sensor fabrication has been invented and applied to gas sensor array system. Significant improvement of stability has been achieved compared to SMO gas sensors without temperature compensation under the same ambient conditions. Single walled carbon nanotube (SWNT) has been studied to improve SnO2 gas sensing property in terms of sensitivity, response time and recovery time. Three times of better sensitivity has been achieved experimentally. The feasibility of using TSK Fuzzy neural network algorithm for Electric Nose has been exploited during the research. A training process of using TSK Fuzzy neural network with input/output pairs from individual gas sensor cell has been developed. This will make electric nose smart enough to measure gas concentrations in a gas mixture. The model has been proven valid by gas experimental results conducted.Ph.D.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Mechanical Engineering
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Pike, Andrew Charles. "Design of chemoresistive silicon sensors for application in gas monitoring." Thesis, University of Warwick, 1996. http://wrap.warwick.ac.uk/36261/.
Full textAbstract:
The growing concerns over our exposure to hazardous substances have been addressed by stringent legislation to ensure air quality. A wide variety of applications have therefore arisen which require the reliable detection of hazardous gases. Hence, the motivation behind the research presented in this thesis was the aim of developing a portable gas monitor to detect nitrogen dioxide, carbon monoxide and volatile organic compounds (e.g. benzene, toluene). The need to improve gas sensor technology for suitability to this demanding application has been identified. Thus, the objectives were to develop a number of ultra-low power devices consisting of an array of chemoresistive gas sensors for incorporation into an intelligent sensor system. The operation of these sensors relies on the measurement of a change in resistance of a gas-sensitive material when exposed to specific gases. Silicon technology has been employed in order to obtain reproducible, miniaturised sensors with a low unit cost. Furthermore, chemoresistors employing metal oxide semiconductor (MOS), metal-substituted phthalocyanine (XPc) and conducting polymer (CP) materials have been used because of their sensitivity to the gases of interest. Common problems associated with these materials are poor specificity to a target gas and poor stability. However, the approach to minimising these problems was to design arrays of cross-sensitive chemoresistors for use in a microprocessor-based intelligent sensor system. The microprocessor applies a pattern recognition algorithm to the sensor outputs to extract the required information. This thesis describes the design, fabrication and characterisation of these sensor arrays. MOS and XPc materials have shown an optimum performance at elevated temperatures. Micromachining techniques have therefore been employed to integrate resistance heaters in a micro-hotplate structure, which can allow temperatures of 600°C to be attained in —15 ms with a typical power consumption of —150 mW/sensor. A pulsed mode of operation should provide average power consumptions of less than 1 mW. A low power consumption is critical for a portable batterypowered instrument. The design, modelling and characterisation of the micro-hotplate structures have also been described. The design and development of a novel automated gas sensor test system was also fundamental to this research, in order to accurately characterise sensor responses and to validate theoretical models. The research objectives have been fulfilled in that a number of sensor array devices have been produced, which are suitable for a portable intelligent instrument. The different designs and materials are compatible for integration into a hybrid sensor. The advancements achieved in sensor technology provide a foundation for future research into the production of a portable intelligent sensor system.
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French, P. J. "Piezoresistance in polycrystalline silicon and its application to pressure sensors." Thesis, University of Southampton, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373564.
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Russo, Peter R. (Peter Raphael) 1980. "Integrated silicon field-effect sensors and microfluidics for biomolecular detection." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/17977.
Full textAbstract:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 52-53).
Microfabricated silicon field-effect sensors with integrated poly(dimethylsiloxane) microfluidic channels have been demonstrated. These devices are designed for the label-free detection and recognition of specific biomolecules such as DNA. Label-free methods eliminate the time-consuming and costly step of tagging molecules with radioactive or fluorescent markers prior to detection. The devices presented here are sensitive to the intrinsic charge of the target molecules, which modulates the width of the carrier-depleted region of a lightly-doped silicon sensor. The variable depletion capacitance is precisely measured, indicating changes in sensor surface potential of less than 30[micro]V. The integrated microfluidic channels enable the delivery of small (nanoliter-scale) amounts of fluid directly to the sensors. Capacitance-voltage curves were recorded using phosphate buffered saline (PBS) as the test electrolyte; a maximum slope of 44pF/V was measured in depletion. pH sensitivity was also demonstrated using modified PBS solutions. A device with dual 80x80Om sensors yielded a response of 40mV/decade, referenced to the fluid electrode. A device with dual 50x50[micro]m sensors yielded a response of 12mV/decade, referenced to the sensors.
by Peter R. Russo.
M.Eng.
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Afrasiabi, Roodabeh. "Silicon Nanoribbon FET Sensors : Fabrication, Surface Modification and Microfluidic Integration." Doctoral thesis, KTH, Material- och nanofysik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-191178.
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Over the past decade, the field of medical diagnostics has seen an incredible amount of research towards the integration of one-dimensional nanostructures such as carbon nanotubes, metallic and semiconducting nanowires and nanoribbons for a variety of bio-applications. Among the mentioned one-dimensional structures, silicon nanoribbon (SiNR) field-effect transistors (FET) as electro-chemical nanosensors hold particular promise for label-free, real-time and sensitive detection of biomolecules using affinity-based detection. In SiNR FET sensors, electrical transport is primarily along the nanoribbon axis in a thin sheet (< 30 nm) serving as the channel. High sensitivity is achieved because of the large surface-to-volume ratio which allows analytes to bind anywhere along the NR affecting the entire conductivity by their surface charge. Unfortunately, sensitivity without selectivity is still an ongoing issue and this thesis aims at addressing the detection challenges and further proposing effective developments, such as parallel and multiple detection through using individually functionalized SiNRs.We present here a comprehensive study on design, fabrication, operation and device performance parameters for the next generation of SiNR FET sensors towards multiplexed, label-free detection of biomolecules using an on-chip microfluidic layer which is based on a highly cross-linked epoxy. We first study the sensitivity of different NR dimensions followed by analysis of the drift and hysteresis effects. We have also addressed two types of gate oxides (namely SiO2 and Al2O3) which are commonly used in standard CMOS fabrication of ISFETs (Ion sensitive FET). Not only have we studied and compared the hysteresis and response-time effects in the mentioned two types of oxides but we have also suggested a new integrated on-chip reference nanoribbon/microfluidics combination to monitor the long-term drift in the SiNR FET nanosensors. Our results show that compared to Al2O3, silicon-oxide gated SiNR FET sensors show high hysteresis and slow-response which limit their performance only to background electrolytes with low ionic strength. Al2O3 on the other hand proves more promising as the gate-oxide of choice for use in nanosensors. We have also illustrated that the new integrated sensor NR/Reference NR can be utilized for real-time monitoring of the above studied sources of error during pH-sensing. Furthermore, we have introduced a new surface silanization (using 3-aminopropyltriethoxysilane) method utilizing microwave-assisted heating which compared to conventional heating, yields an amino-terminated monolayer with high surface coverage on the oxide surface of the nanoribbons. A highly uniform and dense monolayer not only reduces the pH sensitivity of the bare-silicon oxide surface in a physiological media but also allows for more receptors to be immobilized on the surface. Protocols for surface functionalization and biomolecule immobilization were evaluated using model systems. Selective spotting of receptor molecules can be used to achieve localized functionalization of individual SiNRs, opening up opportunities for multiplexed detection of analytes.Additionally, we present here a novel approach by integrating droplet-based microfluidics with the SiNR FET sensors. Using the new system we are able to successfully detect trains of droplets with various pH values. The integrated system enables a wide range of label-free biochemical and macromolecule sensing applications based on detection of biological events such as enzyme-substrate interactions within the droplets.QC 20160825
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Tudor, Michael John. "Optical detection and excitation of vibrations in silicon resonator sensors." Thesis, University of Surrey, 1988. http://epubs.surrey.ac.uk/848140/.
Full textAbstract:
The principle aim of this work was to investigate optical techniques for the excitation and detection of vibrations, at resonance, in Silicon resonator sensors. Two all-fibre detection techniques have been developed: one is based on phase modulation and the other on intensity modulation of the optical wave train. Both detection techniques may be implemented in either single mode or multimode fibre. The choice of measurement technique is determined by the desired system performance and cost. The development of these detection systems naturally led to a study of the properties of the sensors, and the characteristics of a pressure transducer and an accelerometer were investigated; the latter is reported in more detail here. The main characteristics studied were modes of resonance, quality factors, resonant frequency shift with temperature, resonant frequency shift with the measurand and the non-linearity of the resonator. Optical excitation of vibrations at resonance was achieved by using a pulsed laser source directly incident on the resonator. The addition of a thin Chrome layer to the resonator improved the largest optically excited amplitude of vibration by a factor of 9 compared with the uncoated resonator.
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Zayouna, Sarah. "Characterization of Silicon Waveguides For Non-Dispersive Infrared Gas Sensors." Thesis, Luleå tekniska universitet, Rymdteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-80451.
Full textAbstract:
Carbon dioxide is an important gas for life on Earth. But as human activities have been expanding throughout modern history, the CO2 concentration in the atmosphere is increasing. High concentrations of carbon dioxide can lead to various consequences, such as climate change and poor air quality both indoors and outdoors. It is therefore of importance to detect this gas, in order to understand our environment, and to avoid health impacts that it may cause. Non-dispersive infrared sensors are widely used in CO2 sensing and are based on optical absorption technology. This thesis investigates the optical performance of suspended waveguides for non-dispersive infrared sensors, with regard to different material qualities, i.e. monocrystalline and polycrystalline silicon, and geometries of these waveguides. The waveguides that are studied in this thesis consist of splitters, and at the end of each splitter a grating coupler that projects the IR radiation perpendicularly from the plane of the chip. Measurements are conducted to evaluate the IR radiation propagation loss of the waveguides and their feasibility for sensing carbon dioxide. It has been found that longer waveguides suffer from high propagation losses. When comparing the polycrystalline silicon with monocrystalline silicon waveguides, it has been observed in the measurements that the IR radiation propagates better in monocrystalline silicon waveguides than in polycrystalline silicon because of their crystal structures. The measured propagation loss in polycrystalline silicon waveguides is less than the loss obtained for the monocrystalline silicon waveguides, although some intensities from the grating couplers are excluded in the calculations, due to low signal strength. It is also concluded that the studied waveguides are feasible for detecting carbon dioxide with a concentration of 1%. Further investigation regarding the feasibility of gas sensing using lower concentrations of CO2 would be interesting for future work.
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Patil, Amita C. "Silicon Carbide JFET Integrated Circuit Technology for High-Temperature Sensors." Cleveland, Ohio : Case Western Reserve University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1238786695.
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Weller, Harald. "CMOS monolithic pyroelectric infrared focal plane arrays using PVDF thin films." Thesis, Edinburgh Napier University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323080.
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Haneef, Ibraheem. "SOI CMOS MEMS flow sensors." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611843.
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Beeby, Stephen Paul. "Mechanical isolation of miniature resonant sensors and stress relieving packages." Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242715.
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Li, Bin, and 李斌. "A study of integrated semiconductor thin-film sensors on sio2/si substrate." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B30446752.
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Li, Bin. "A study of integrated semiconductor thin-film sensors on sio2/si substrate." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23000995.
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Wonsak, Sven. "Characterisation of irradiated planar silicon strip sensors for HL-LHC applications." Thesis, University of Liverpool, 2016. http://livrepository.liverpool.ac.uk/3006162/.
Full textAbstract:
The upgrade of the Large Hadron Collider (LHC) to the High Luminosity LHC (HL-LHC) will increase the requirements on radiation hardness of silicon sensors of the two multi-purpose experiments, ATLAS and CMS, at CERN. For this purpose the CERN RD50 collaboration is investigating radiation hard semiconductor detectors for high luminosity applications. The work for this thesis was done within this framework. Charge multiplication can be beneficial in this context because the collected charge of irradiated devices decreases with increasing irradiation fluence. Thus the effect of different read-out strip pitch values and strip widths, as well as double implant energy or double diffusion time and intermediate strips, have been investigated for irradiated sensors. Intermediate strips have not shown any benefits, but sensors with a low width-over-pitch (W/P) ratio collect more charge then sensors with higher W/P values. This can be improved by doubling the implant energy. Annealing the sensors irradiated to 5 x 10¹⁵ neq/cm2 has shown that at bias voltages higher then 1000V the collected charge can increase with increasing annealing time. Measuring the collected charge of highly irradiated 50 μm thick sensors has been challenging because random noise peaks could be misidentified as signal due to the low signal value at fluences larger then 1 x 10¹⁶ neq/cm2. New analysis methods were tested and the use of a different fit function shows promising results. The measurement of the current of irradiated sensors with thicknesses from 50 μm to 298 μm has shown that the effective energy value has an upper limit, given by the literature value. For the current related damage rate of highly irradiated sensors the literature value describes an upper limit as well. The knowledge of these limits allows the design of large detector systems. A novel approach was tested to generate a multiplication layer close to the strip surface by irradiating sensors with low energy protons at the Birmingham irradiation facility. The target thickness of this multiplication layer is approximately 10 to 20 μm, but in the irradiations shown in this thesis this target has not been reached. However, the results have improved the knowledge of the irradiation facility and the simulation so that it should be possible to reach the expected thickness in a future irradiation.
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Weld, Andrew Mark. "Optical diffraction-based silicon sensors for the detection of DNA sequences." Thesis, University of Southampton, 2007. https://eprints.soton.ac.uk/47762/.
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This thesis describes the design, fabrication and characterisation of diffraction-based sensors on silicon (100) substrates for the detection of complementary DNA sequences using colloidal gold labels. In-depth analysis of variations of DNA sequence within the human genome and association with diseases is expected to lead to personalised medical treatment. There is a great need for DNA analysis technologies and for techniques to determine whether sequence variations occur on the same chromosomal strand with applications in disease screening and diagnosis. Novel two-dimensional diffraction structures are designed and fabricated. It is shown that two-dimensional diffraction approaches may potentially offer multiplexing of DNA detection assays.
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Kopsalis, Ioannis [Verfasser], and Erika [Akademischer Betreuer] Garutti. "Surface Effects in Segmented Silicon Sensors / Ioannis Kopsalis ; Betreuer: Erika Garutti." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2017. http://d-nb.info/1134866011/34.
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Koshkinbayeva, Ainur. "New photonic architectures for mid-infrared gaz sensors integrated on silicon." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI019.
Full textAbstract:
Les travaux portent sur les multiplexeurs optiques fonctionnant à mi-IR pour la source à large bande dans l'application de détection de gaz. Deux configurations ont été étudiées: réseau de guides d'onde (AWG) et réseau concave planaire (PCG). Premièrement, le principe du fonctionnement a été compris afin de développer une solution analytique pour le champ de sortie en utilisant une approximation gaussienne du champ et de l'optique de Fourier. Ensuite, un outil de simulation semi-analytique de la réponse spectrale pour les deux configurations de multiplexeur a été développé dans MATLAB. La distribution normale des erreurs de phase a été introduite dans le modèle semi-analytique AWG, ce qui nous a permis d'étudier la corrélation entre l'écart-type des erreurs de phase et le niveau de diaphonie de la réponse spectrale AWG. AWG à 5,65 μm a été fabriqué à partir de la technologie SiGe / Si à l'aide de l'outil MATLAB pour le calcul des paramètres de conception et de l'outil P.Labeye pour le calcul de la géométrie AWG. Les dispositifs avec des paramètres légèrement variables ont été caractérisés: AWG1 avec guides d'ondes de 4,6 μm et MMI de 9 μm; AWG2 avec guides d'ondes de 4,6 μm et MMI de 11 μm; AWG3 avec guides d'ondes de 4,8 μm et MMI de 9 μm. Des mesures des dispositifs sur la puce 36 (centre de la plaquette) et sur la puce 32 (côté de la plaquette) ont été effectuées et analysées. Les mesures de température de AWG2 et AWG3 (puce 32 et puce 36) aux points cinq points de température ont montré une dépendance linéaire du déplacement spectral avec la température qui a une bonne corrélation avec les prédictions de simulationThe work focuses on optical multiplexers operating in mid-IR for broadband source in gas sensing application. Two configurations were studies – arrayed waveguide grating (AWG) and planar concave grating (PCG). First, principle of operation was understood in order to develop analytical solution for output field using Gaussian approximation of the field and Fourier Optics. Then, semi-analytical simulation tool of the spectral response for both multiplexer configurations was developed in MATLAB. Normal distribution of phase errors was introduced to semi-analytical AWG model, which allowed us to study the correlation between standard deviation of phase errors and the level of crosstalk of AWG spectral response. AWG at 5.65 µm was fabricated based on SiGe/Si technology using the MATLAB tool for design parameters calculation and P.Labeye’s tool for AWG geometry calculation. Devices with slightly varying parameters were characterized: AWG1 with 4.6 µm waveguides and 9µm MMI; AWG2 with 4.6 µm waveguides and 11µm MMI; AWG3 with 4.8 µm waveguides and 9µm MMI. Measurements of devices on chip 36 (center of the wafer) and chip 32 (side of the wafer) were performed and analyzed. Temperature measurements of AWG2 and AWG3 (chip 32 and chip 36) at points five temperature points showed linear dependence of spectral shift with the temperature which has a good correlation with simulation predictions
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Serrano, Diego Emilio. "Integrated inertial measurement units using silicon bulk-acoustic wave gyroscopes." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54283.
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This dissertation discusses the design, simulation and characterization of process-compatible accelerometers and gyroscopes for the implementation of multi-degree-of-freedom (multi-DOF) systems. All components presented herein were designed to operate under the same vacuum-sealed environment to facilitate batch fabrication and wafer-level packaging (WLP), enabling the development of small form-factor single-die inertial measurement units (IMUs). The high-aspect-ratio poly and single-crystal silicon (HARPSS) process flow was used to co-fabricate the devices that compose the system, enabling the implementation ultra-narrow capacitive gaps (< 300 nm) in thick device-layer substrates (40 um).
The presented gyroscopes were implemented as high-frequency BAW disk resonators operating in a mode-matched condition. A new technique to reduced dependencies on environmental stimuli such as temperature, vibration and shock was introduced. Novel decoupling springs were utilized to effectively isolate the gyros from their substrate, minimizing the effect that external sources of error have on offset and scale-factor. The substrate-decoupled (SD) BAW gyros were interfaced with a customized IC to achieve supreme random-vibration immunity (0.012 (deg/s)/g) and excellent rejection to shock (0.075 (deg/s)/g). With a scale factor of 800 uV/(deg/s), the complete SD-BAW gyro system attains a large full-scale range (2500 deg/s) with excellent linearity. The measured angle-random walk (ARW) of 0.36 deg/rthr and bias-instability of 10.5 deg/hr are dominated by the thermal and flicker noise of the IC, respectively. Additional measurements using external electronics show bias-instability values as low as 3.5 deg/hr.
To implement the final monolithic multi-DOF IMU, accelerometers were carefully designed to operate in the same vacuum environment required for the gyroscopes. Narrow capacitive gaps were used to adjust the accelerometer squeeze-film damping (SFD) levels, preventing an under-damped response. Robust simulation techniques were developed using finite-element analysis (FEA) tools to extract accurate values of SFD, which were then match with measured results. Ultra-small single proof-mass tri-axial accelerometers with Brownian-noise as low as 30 ug/rtHz were interfaced with front-end electronics exhibiting scale-factor values in the order of 5 to 10 mV/g and cross-axis sensitivities of less than 3% before any electronic compensation.
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Vargas, German R. "Silicon Photonic Device for Wavelength Sensing and Monitoring." FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/734.
Full textAbstract:
Over the last decade advances and innovations from Silicon Photonics technology were observed in the telecommunications and computing industries. This technology which employs Silicon as an optical medium, relies on current CMOS micro-electronics fabrication processes to enable medium scale integration of many nano-photonic devices to produce photonic integrated circuitry.
However, other fields of research such as optical sensor processing can benefit from silicon photonics technology, specially in sensors where the physical measurement is wavelength encoded.
In this research work, we present a design and application of a thermally tuned silicon photonic device as an optical sensor interrogator.
The main device is a micro-ring resonator filter of 10 $\mu m$ of diameter. A photonic design toolkit was developed based on open source software from the research community. With those tools it was possible to estimate the resonance and spectral characteristics of the filter. From the obtained design parameters, a 7.8 x 3.8 mm optical chip was fabricated using standard micro-photonics techniques. In order to tune a ring resonance, Nichrome micro-heaters were fabricated on top of the device. Some fabricated devices were systematically characterized and their tuning response were determined. From measurements, a ring resonator with a free-spectral-range of 18.4 nm and with a bandwidth of 0.14 nm was obtained. Using just 5 mA it was possible to tune the device resonance up to 3 nm.
In order to apply our device as a sensor interrogator in this research, a model of wavelength estimation using time interval between peaks measurement technique was developed and simulations were carried out to assess its performance. To test the technique, an experiment using a Fiber Bragg grating optical sensor was set, and estimations of the wavelength shift of this sensor due to axial strains yield an error within 22 pm compared to measurements from spectrum analyzer. Results from this study implies that signals from FBG sensors can be processed with good accuracy using a micro-ring device with the advantage of ts compact size, scalability and versatility. Additionally, the system also has additional applications such as processing optical wavelength shifts from integrated photonic sensors and to be able to track resonances from laser sources.
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Laminack, William I. "Characterization of functionalized and unfuctionalized metal oxide nanoparticle interactions with gas mixtures on porous silicon." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53877.
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In order to create more sensitive and accurate gas sensors, we have
studied the interactions of gas mixtures on metal oxide nanoparticle
decorated porous silicon interfaces. The nanoparticles control the
magnitude and direction of electron transduction from the interaction of
analyte gases to an extrinsic porous silicon semiconductor. These
interactions can be predicted by the Inverse Hard Soft Acid Base (IHSAB)
principle. Moreover, the metal oxide nanoparticles can be functionalized
with nitrogen and sulfur, modifying the oxide’s band structure. These
modifications are demonstrated to change analyte interactions in line
with the IHSAB concept and allow for light enhanced sensors. Further we
looked at how the analyte gases interact with other analyte gases on the
surface of these sensors. Studying these systems does two things, first
the research will lead to cheaper, more accurate gas sensors, and second
it helps explore the role of nanoparticles in modifying the interactions
between bulk materials (porous silicon) and molecules (analyte gases).
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Ozdemir, Serdar. "Formation, characterization and flow dynamics of nanostructure modified sensitive and selective gas sensors based on porous silicon." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39541.
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Nanopore covered microporous silicon interfaces have been formed via an electrochemical etch for gas sensor applications. Rapid reversible and sensitive gas sensors have been fabricated. Both top-down and bottom-up approaches are utilized in the process. A nano-pore coated micro-porous silicon surface is modified selectively for sub-ppm detection of NH3, PH3, NO, H2S, SO2. The selective depositions include electrolessly generated SnO2, CuxO, AuxO, NiO, and nanoparticles such as TiO2, MgO doped TiO2, Al2O3, and ZrO2. Flow dynamics are analyzed via numerical simulations and response data. A general coating selection method for chemical sensors is established via an extrapolation on the inverse of the Hard-Soft Acid-Base concept.
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Yang, Wenjian. "Microwave Photonics and Sensing based on Silicon Photonics." Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/23482.
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Chip scale photonic integrated circuits can provide important new functions in communications, signal processing and sensing. Recent research on microwave photonics (MWPs) and integrated optical sensors using the silicon photonic devices has opened up new opportunities for signal processing and sensing applications. MWPs brings together the world of microwave engineering and optoelectronics, which provides solutions for processing high frequency microwave signals. It has attracted significant interest in many different areas including communications, sensors, radar systems and defence applications. The use of photonic integrated circuit enhances functionalities and flexibilities as well as enabling a reduction of size and weight for MWP applications. The high integratablity of the photonic circuit not only boosts the filtering, time delay and phase shifting functionalities, but also enables the sensing applications in the nano-scale range. Integrated sensors are under high demand in many environmental chemical and biomedical applications. The mass fabricated integrated sensor provides opportunities for multi-functional sensor array with minimized volume. The research work presented in this thesis aims to investigate silicon photonics applications in MWP signal processing and different sensing circumstances. Firstly, the MWP filter based on the SOI microring resonator with phase compensation method is demonstrated. In addition, instantaneous frequency measurement based on frequency to time mapping is presented. Then, a novel integrated optical sensor system based on SOI add drop microring resonator structure is presented. The MWP techniques for high performance sensing application is explored. Lastly, to address the multi-functionality of silicon photonics based sensor, an application of integrated ultrasound optical sensor is demonstrated. It is expected the work provided in this thesis can assist in the emergence of real-world silicon photonic applications. (1992 out of 2000 characters)
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Manic, Dragan. "Drift in silicon integrated sensors and circuits due to thermo-mechanical stresses /." Konstanz : Hartung-Gorre, 2000. http://www.gbv.de/dms/ilmenau/toc/318293013.PDF.
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