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作者： Thorsen, Todd California Institute of Technology

学位级别：Ph.D.

In this thesis, I present a strategy for the design and development of microfluidic devices for high-throughput screening applications, such as mutant enzyme libraries expressed in prokaryotic hosts, where a few point mutations at the DNA level translates to hundreds of thousands of enzyme variants. The work falls into three main sections. Section I addresses fundamental research in polymer chemistry, where I explore the suitability of several polymers for microfluidic applications, examining properties such as molding, fluorescence, solvent compatibility, and adhesion/sealing to glass substrates. Section ii describes my development of a two-phase microfluidic device, in which I report on crossflow-based dynamic formation of picoliter-sized water droplets in a continuously flowing oil-surfactant stream. A predictive model describing the fluid dynamics of droplet formation in this model is presented as well as its applications in screening bacterial populations. Section iiI reports the development of multilayer soft lithography technology using silicone rubber to build addressable high-density microfluidic arrays with thousands of integrated mechanical valves. This technology, which introduces the concept of fluidic large scale integration, is presented as a high-throughput parallel method to analyze bacterial enzyme expression at the single cell level. The detection of enzymatic activity in these high-density microarrays is described, comparing a self-constructed solid-state laser apparatus with a modified scanner (Axon Industries) used for looking at DNA arrays.

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A compact 3D imaging laser radar system using Geiger-mode APD arrays: system and measurements

A compact 3D imaging laser radar system using Geiger-mode AP...

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Conference on Laser Radar Technology and applications ViiI

作者： Marino, RM Stephens, T Hatch, RE McLaughlin, JL Mooney, JG O'Brien, ME Rowe, GS Adams, JS Skelly, L Knowlton, RC Forman, SE Davis, WR MIT Lincoln Lab Lexington MA 02420 USA

ISBN: (纸本)0819449458

MIT Lincoln Laboratory continues the development of novel high-resolution 3D imaging laser radar technology and sensor systems. The sensor system described in detail here uses a passively Q-switched solid-state frequency-doubled Nd:YAG laser to transmit short laser pulses (similar to 700 ps FWHM) at 532 rim wavelength and derive the range to target surface element by measuring the time-of-flight for each pixel. The single photoelectron detection efficiency has been measured to be > 20 % using these Silicon Geiger-mode APDs at room temperature. The pulse out of the detector is used to stop a > 500 MHz digital clock integrated within the focal-plane array. With appropriate optics, the 3202 array of digital time values represents a 3D spatial image frame of the scene. Successive image frames from the multi-kilohertz pulse repetition rate laser pulses are accumulated into range histograms to provide 3D volume and intensity information. In this paper, we report on a prototype sensor system, which has recently been developed using new 32x32 arrays of Geiger-mode APDs with 0.35 mum CMOS digital timing circuits at each pixel. Here we describe the sensor system development and present recent measurements of laboratory test data and field imagery.

关键词： laser radar ladar 3D imaging photon counting avalanche photodiode array

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Thin-film microsensors for high-temperature gas detection arrays

Thin-film microsensors for high-temperature gas detection ar...

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作者： Ward, Benjamin James Case Western Reserve University

学位级别：Ph.D.

Improvements in the control of engine and power generator exhausts, fire detection, and environmental monitoring can be achieved through the development of improved sensing methods. This study focused on the development of high temperature gas sensor arrays for use in these applications. sensors based on metal oxide resistors, specifically variations of tin oxide resistors and electrochemical cells were produced using microfabrication and micromachining techniques. The use of these techniques resulted in small, rugged sensors which can be produced in a repeatable manner. These sensors were designed to be usable in high temperature engine exhaust streams, but can be used in a wide range of environments due to the integration of a heater and temperature detector on chip for temperature control. Tin oxide thin films were deposited using a sol-gel technique. Three types of tin oxide sensing films were studied, including undoped tin oxide, platinum doped tin oxide, and a copper surface treated (by dip coating) tin oxide. These devices showed very different sensitivities to test gases in laboratory calibrations and were tested in several exhaust and fire-simulation systems. Two types of electrochemical cell devices were studied, including yttria stabilized zirconia (YSZ) for oxygen detection and a NASICON (sodium super ionic conductor)/sodium carbonate system for carbon dioxide detection. These sensors were operated in amperometric, diffusion limited mode. Both were produced on a generic “platform” for solid state, amperometric electrochemical microsensors. Laboratory testing showed sensitivity of these sensors to the gases of interest. Three separate designs of the YSZ sensor were investigated. Output currents on the order of 30 nA in nitrogen and 80 nA in air were noted. The diffusion barrier was not optimum for the desired linear change in output current compared to oxygen concentration. The NASICON based sensor included the novel processing step of electron beam evapo

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Laser based manufacturing of high-accuracy electrodes in brittle materials

Laser based manufacturing of high-accuracy electrodes in bri...

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Conference on Photon Processing in Microelectronics and Photonics ii

作者： Kulik, C Ostendorf, A Meyer, F Laser Zentrum hannover EV D-30419 Hannover Germany

ISBN: (纸本)0819447773

Dielectric sensors with smallest electrode structures are used to monitor several technical applications. Thus, durable substrate materials are essential for the exploitation of the sensors in hostile process environment. Here, ceramics and different glasses show ideal material properties, but are difficult-to-machine in the micrometer range. UV-laser beam sources are well suited for an economic manufacturing of micro-structures in these brittle materials. Especially, advanced laser tools like excimer- and frequency converted solid-state lasers show excellent machining results. This paper presents the development of new laser based production techniques and innovative process chains for the fabrication of distinctive electrode structures in high stable materials. Two different machining concepts are shown. A conductive Indium Tin-Oxide (ITO) layer with a thickness of about 600nm has been structured with a KrF excimer laser (lambda = 248 nm, H = 5 J/cm(2)), without damaging the underlying borosilicate glass substrate. The dimension of the electrodes and insulation channels of the sensor are as small as 50mum. For the second approach of manufacturing a dielectric sensor, aluminum oxide as a bulk substrate materials has been machined with the same laser type. No thermal damage was observed by an operating fluence H = 20 J/cm(2). The obtained extreme durable embedded-electrode-type sensor can be completed by. filling the cavity with conductive material by standard electroplating techniques. For the manufacturing process, a high flexible NC-controlled machining concept is presented, which allows a time and pulse minimized fabrication as well, as an optimization of the surface,quality of. the micro-sensor, including a process. optimization via simulation.

关键词： laser based micro-machining brittle materials sensor manufacturing UV-laser electrodes

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A low-cost 64x64 uncooled infrared detector array in standard CMOS 12

A low-cost 64x64 uncooled infrared detector array in standar...

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12th International Conference on solid-state sensors, Actuators and Microsystems (TRANSDUCERS 03)

作者： Eminoglu, S Tanrikulu, MY Akin, T Middle E Tech Univ Dept Elect & Elect Engn TR-06531 Ankara Turkey

ISBN: (纸本)0780377311

This paper reports the development of a low-cost, 64 x 64 uncooled infrared focal plane array (FPA) based on suspended and thermally isolated p(+)-active/n-well diodes in a standard 0.35 mum CMOS process. The array is implemented using a simple post-CMOS process that do not require any critical lithography or complicated deposition steps. The pixel is 40 mum x 40 mum in size with a fill factor of 44%, and it has a measured DC responsivity of 4970 V/W with a thermal time constant of 36 msec at 80 mToff vacuum. The detector noise is measured as 0.52 muV for a 4 kHz electrical bandwidth with a 1/f corner frequency of 4.4 Hz, resulting in a measured detectivity of 9.7 x 10(8) cmHz(1/2)/W and an estimated NETD value of 470 mK for an f = 1 optics. The FPA is scanned at 30 fps using a 16-channel parallel readout circuit with low noise preamplifiers. The preampliers have a measured noise of 0.48 muV, resulting in an overall estimated NETD of 800 mK, which can be decreased by increasing the number of parallel readout channels. The uncompensated pixel voltage non-uniformity is measured as 0.82%, which easily decreases down to 0.05% by compensating the fixed pattern noise. Considering its simple fabrication method and its moderate performance, this approach is suitable for low-cost commercial infrared imaging applications.

关键词： Circuit noise Diodes Electric variables measurement Frequency estimation Frequency measurement Infrared detectors Noise measurement Optical noise Preamplifiers sensor arrays

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A low-cost 64/spl times/64 uncooled infrared detector array in standard CMOS

A low-cost 64/spl times/64 uncooled infrared detector array ...

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International Conference on solid state sensors and Actuators (TRANSDUCERS)

作者： S. Eminoglu M.Y. Tanrikulu T. Akin Department of Electrical and Electronics Engineering Middle East Technical University Ankara Turkey

This paper reports the development of a low-cost, 64/spl times/64 uncooled infrared focal plane array (FPA) based on suspended and thermally isolated p/sup +/-active/n-well diodes in a standard 0.35 /spl mu/m CMOS process. The array is implemented using a simple post-CMOS process that do not require any critical lithography or complicated deposition steps. The pixel is 40 /spl mu/m/spl times/40 /spl mu/m in size with a fill factor of 44%, and it has a measured DC responsivity of 4970 V/W with a thermal time constant of 36 msec at 80 mTorr vacuum. The detector noise is measured as 0.52 /spl mu/V for a 4 kHz electrical bandwidth with a 1/f corner frequency of 4.4 Hz, resulting in a measured detectivity of 9.7/spl times/10/sup 8/cm Hz/sup 1/2/W and an estimated NETD value of 470 mK for an f=1 optics. The FPA is scanned at 30 fps using a 16-channel parallel readout circuit with low noise preamplifiers. The preamplifiers have a measured noise of 0.48 /spl mu/V, resulting in an overall estimated NETD of 800 mK, which can be decreased by increasing the number of parallel readout channels. The uncompensated pixel voltage non-uniformity is measured as 0.82%, which easily decreases down to 0.05% by compensating the fixed pattern noise. Considering its simple fabrication method and its moderate performance, this approach is suitable for low-cost commercial infrared imaging applications.

关键词： Infrared detectors sensor arrays Noise measurement Optical noise Frequency measurement Electric variables measurement Frequency estimation Circuit noise Preamplifiers Diodes

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Recent advances in biologically sensitive field-effect transistors (BioFETs)

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ANALYST 2002年第9期127卷 1137-1151页

作者： Schöning, MJ Poghossian, A Univ Appl Sci Aachen D-52428 Julich Germany Forschungszentrum Julich Inst Thin Films & Interfaces D-52425 Julich Germany

Thirty years have elapsed since the invention of the ISFET by Bergveld. Since that time, various types of BioFETs have been developed using different biological recognition elements starting with enzymes and immunological species through DNA molecules to living cells and even living organisms. The study of the current state of BioFETs reveals that some BioFETs, like EnFETs are at a well-developed stage, whereas other BioFETs such as GenFETs and beetle/chip FETs are in the initial stages of development. There are still a number of fundamental and technological problems that must be overcome, before the first reliable BioFET-based bioanalytical microsystem will appear on the market. Therefore, intensive interdisciplinary research and cooperation of specialists from different disciplines is still required, not only in the field of biotechnology and bioengineer- ing but also in related disciplines, like informatics, solid-state physics, microtechnology, genetics as well as specific tech- niques such as sensor integration and packaging, interfacing circuits, etc. Hence, future prospects for BioFET developments can be expected in the following directions: (i) BioFETs utilising intact biological receptors (ion channel receptors, binding proteins, etc.) that bind specific drugs and reagents in such a way that they produce a conformational change in the protein structure. This conformational change, in turns, triggers a cellular response, (e.g., the opening of an ion channel of the membrane (so-called ion-channel switch biosensor); (ii) ISFET-based DNA chips can be considered as a new tool for the simultaneous analysis of thousands of nucleic acids with a broad area of potential applications in biomedical research and clinical diagnostics, genomics, drug screening, environmental monitor- ing and food industry. They combine both the possibility of direct DNA hybridisation detection without the use of labelled probes and the large integration ability of these active microelect

关键词： Glucose Oxidase chemical analysis micro total analysis systems Field effect transistors Biosensors signal acquisition biological organs hybrid systems Electronic Nose Oxygen electrodes sensor arrays Si technology

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Progress in iiI-nitride based white light sources

Progress in III-nitride based white light sources

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2nd Conference on solid state Lighting

作者： Gaska, R Zukauskas, A Shur, MS Khan, MA Sensor Elect Technol Inc Latham NY 12110 USA

ISBN: (纸本)0819445436

We review two complementary approaches to the development of white light solid-state sources. The first approach, which involves polychromatic LED modules, is targeted at advanced optimization of spectral power distribution in order to establish an optimal trade-off between luminous efficacy and color rendering. We apply a stochastic method of optimization of a white-light source that relies on additive color mixing of the emissions from colored primary LEDs. We present the results on optimized spectra for all-semiconductor lamps composed of four primary LEDs with the line widths typical of present AlGaInP and AlInGaN technologies. We point out the problem of the lack of efficient yellow-green (570 nm) emitters required for polychromatic lamps with four and more primary LEDs. The second approach is based on the development of AlInGaN-based UV emitters that can be tailored to directly excite different phosphors without sensitizers. AlInGaN materials system demonstrated potential for making UV LEDs with a high power and short wavelengths required for such applications. This has been achieved by using Strain Energy Band Engineering (SEBE) and Pulsed Atomic Epitaxy (PALE) techniques. SEBE relies on quaternary AlGaInN compounds for controlling strain and band offset and for producing UV emitters with improved device performance. PALE allows us to incorporate the required significant amount of indium (few percent) in AlGaN, since it can be performed at lower growth temperatures required for In incorporation. Further improvements in materials quality of AlInGaN layers with a high molar fraction of Al will be achieved by using bulk AIN substrates.

关键词： solid-state lighting white solid-state lamp color mixing optimization UV light emitting diodes phosphor conversion

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Real time /spl beta/-imaging with silicon hybrid pixel detectors: kinetic measurements with C-14 amino acids and P-32 nucleotides

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IEEE Transactions on Nuclear Science 2002年第5期49卷 2213-2217页

作者： E. Bertolucci M. Conti A. Di Cosmo M. Maiorino G. Mettivier M.C. Montesi G. Paolella T. Pecorella P. Russo R. Scognamiglio Dipartimento di Scienze Fisiche INFN Universitá di Napoli Federico II Napoli Italy CTI PET System Inc. Knoxville TN USA Dipartimento di Zoologia Universitá di Napoli Federico II Napoli Italy CEINGE c/o Dipartimento di Biochimica e Biotecnologie Mediche INFN Universitá di Napoli Federico II Napoli Italy

We present some additional results obtained with the BETAview system, a digital system for real time /spl beta/-imaging based on semiconductor pixel detectors and on a single photon counting read-out chip. We describe the system assembled with a Si detector, 300-/spl mu/m thick, segmented into 64 /spl times/64 square pixels with 170-/spl mu/m pitch. The solid-state pixel array detector is bump-bonded pixel by pixel to a low threshold, single particle counting electronics, the photon counting chip (PCC) developed by the Medipix1 Collaboration for biomedical applications. Each cell (corresponding to a detector pixel) of the front-end chip has a maximum count rate of 2 MHz, a minimum nominal threshold of 1400 e/sup -/ (corresponding about 5 keV in Si), and contains a 15-bit counter. The detector sensitive area is about 1 cm/sup 2/, but several detectors could be assembled in arrays. The measured background counts were about 3.5/spl times/10/sup -2/ cps/cm/sup 2/, which implies a very high sensitivity of the device. The detection threshold used in this experiment was /spl sim/15 keV. We show the results obtained in the real-time monitoring of two biological dynamic processes: an amino acid uptake by living cells and the thermal denaturation process of oligonucleotides. Specifically, we have followed over time the accumulation of a marked amino acid ([/sup 14/C]L-Leucine) into Octopus vulgaris eggs cells. The results, described in Section iiI-B, show that after about 20 min from the beginning of the uptake process, the radioactively marked eggs become clearly visible over the background culture radioactive medium. In Sections iiI-C and iiI-D, we also describe the successful performance of the /spl beta/-imaging system in genetic studies involving the real time reconstruction of denaturation and kinetics curves for two different /sup 32/P-radiolabeled nucleotides.

关键词： Silicon Detectors Kinetic theory Nuclear measurements Amino acids Biomedical measurements Real time systems sensor arrays Semiconductor device measurement Digital systems

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New piezoceramic PZT-PNN material for medical diagnostics applications

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JOURNAL OF THE EUROPEAN CERAMIC SOCIETY 2001年第10-11期21卷 1469-1472页

作者： Bove, T Wolny, W Ringgaard, E Pedersen, A Ferroperm Piezoceram AS DK-3490 Kvistgaard Denmark

The development of a new piezoceramic material, Ferroperm. Pz21, optimised for use in medical diagnostics applications is described. The requirements to such a material are very high permittivity, sensitivity and coupling factors, and at the same time a relatively high Curie temperature. The structure must furthermore be very dense and fine-grained, since dicing of small sub-elements for medical arrays must be performed without damaging the material. The developed material is a solid solution between a PZT phase and the relaxor phase Pb(Ni1/3Nb2/3)O-3. A comparison between different production processes is given, and a new solid state route for production of very dense and fine-grained materials is presented. Very positive characteristics are generally observed, and a stable behaviour even at elevated temperatures indicate that the material can find applications not only in the medical market, but also as a more general sensor/actuator. (C) 2001 Elsevier Science Ltd. All rights reserved.

关键词： functional applications perovskites piezoelectric properties powders : solid state reaction PZT

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