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Monolithic integration of GaAs SAW chemical microsensor arrays and detection electronics

Description: The authors describe the integration of an array of surface acoustic wave delay line chemical sensors with the associated RF microelectronics such that the resulting device operates in a DC in/DC out mode. The microelectronics design for on-chip RF generation and detection is presented. Both hybrid and monolithic approaches are discussed. This approach improves system performance, simplifies packaging and assembly, and significantly reduces overall system size. The array design can be readily scaled to include a large number of sensors.
Date: April 17, 2000
Creator: CASALNUOVO,STEPHEN A.; HIETALA,VINCENT M.; HELLER,EDWIN J.; ASON,GREGORY CHARLES & BACA,ALBERT G.
Partner: UNT Libraries Government Documents Department

Monolithic GaAs surface acoustic wave chemical microsensor array

Description: A four-channel surface acoustic wave (SAW) chemical sensor array with associated RF electronics is monolithically integrated onto one GaAs IC. The sensor operates at 690 MHz from an on-chip SAW based oscillator and provides simple DC voltage outputs by using integrated phase detectors. This sensor array represents a significant advance in microsensor technology offering miniaturization, increased chemical selectivity, simplified system assembly, improved sensitivity, and inherent temperature compensation.
Date: March 9, 2000
Creator: HIETALA,VINCENT M.; CASALNUOVO,STEPHEN A.; HELLER,EDWIN J.; WENDT,JOEL R.; FRYE-MASON,GREGORY CHARLES & BACA,ALBERT G.
Partner: UNT Libraries Government Documents Department

Double Barrier Resonant Tunneling Transistor with a Fully Two Dimensional Emitter

Description: A novel planar resonant tunneling transistor is demonstrated. The growth structure is similar to that of a double-barrier resonant tunneling diode (RTD), except for a fully two-dimensional (2D) emitter formed by a quantum well. Current is fed laterally into the emitter, and the 2D--2D resonant tunneling current is controlled by a surface gate. This unique device structure achieves figures-of-merit, i.e. peak current densities and peak voltages, approaching that of state-of-the-art RTDs. Most importantly, sensitive control of the peak current and voltage is achieved by gating of the emitter quantum well subband energy. This quantum tunneling transistor shows exceptional promise for ultra-high speed and multifunctional operation at room temperature.
Date: July 13, 2000
Creator: MOON,J.S.; SIMMONS,JERRY A.; RENO,JOHN L.; BACA,WES E.; BLOUNT,MARK A.; HIETALA,VINCENT M. et al.
Partner: UNT Libraries Government Documents Department

The development of integrated chemical microsensors in GaAs

Description: Monolithic, integrated acoustic wave chemical microsensors are being developed on gallium arsenide (GaAs) substrates. With this approach, arrays of microsensors and the high frequency electronic components needed to operate them reside on a single substrate, increasing the range of detectable analytes, reducing overall system size, minimizing systematic errors, and simplifying assembly and packaging. GaAs is employed because it is both piezoelectric, a property required to produce the acoustic wave devices, and a semiconductor with a mature microelectronics fabrication technology. Many aspects of integrated GaAs chemical sensors have been investigated, including: surface acoustic wave (SAW) sensors; monolithic SAW delay line oscillators; GaAs application specific integrated circuits (ASIC) for sensor operation; a hybrid sensor array utilizing these ASICS; and the fully monolithic, integrated SAW array. Details of the design, fabrication, and performance of these devices are discussed. In addition, the ability to produce heteroepitaxial layers of GaAs and aluminum gallium arsenide (AlGaAs) makes possible micromachined membrane sensors with improved sensitivity compared to conventional SAW sensors. Micromachining techniques for fabricating flexural plate wave (FPW) and thickness shear mode (TSM) microsensors on thin GaAs membranes are presented and GaAs FPW delay line and TSM resonator performance is described.
Date: November 1, 1999
Creator: CASALNUOVO,STEPHEN A.; ASON,GREGORY CHARLES; HELLER,EDWIN J.; HIETALA,VINCENT M.; BACA,ALBERT G. & HIETALA,S.L.
Partner: UNT Libraries Government Documents Department

Microfabricated Gas Phase Chemical Analysis Systems

Description: A portable, autonomous, hand-held chemical laboratory ({micro}ChemLab{trademark}) is being developed for trace detection (ppb) of chemical warfare (CW) agents and explosives in real-world environments containing high concentrations of interfering compounds. Microfabrication is utilized to provide miniature, low-power components that are characterized by rapid, sensitive and selective response. Sensitivity and selectivity are enhanced using two parallel analysis channels, each containing the sequential connection of a front-end sample collector/concentrator, a gas chromatographic (GC) separator, and a surface acoustic wave (SAW) detector. Component design and fabrication and system performance are described.
Date: September 16, 1999
Creator: FRYE-MASON,GREGORY CHARLES; HELLER,EDWIN J.; HIETALA,VINCENT M.; KOTTENSTETTE,RICHARD; LEWIS,PATRICK R.; MANGINELL,RONALD P. et al.
Partner: UNT Libraries Government Documents Department

Gas phase chemical detection with an integrated chemical analysis system

Description: Microfabrication technology has been applied to the development of a miniature, multi-channel gas phase chemical laboratory that provides fast response, small size, and enhanced versatility and chemical discrimination. Each analysis channel includes a sample preconcentrator followed by a gas chromatographic separator and a chemically selective surface acoustic wave detector array to achieve high sensitivity and selectivity. The performance of the components, individually and collectively, is described.
Date: April 12, 2000
Creator: CASALNUOVO,STEPHEN A.; FRYE-MASON,GREGORY CHARLES; KOTTENSTETTE,RICHARD; HELLER,EDWIN J.; MATZKE,CAROLYN M.; LEWIS,PATRICK R. et al.
Partner: UNT Libraries Government Documents Department

Acoustic Wave Chemical Microsensors in GaAs

Description: High sensitivity acoustic wave chemical microsensors are being developed on GaAs substrates. These devices take advantage of the piezoelectric properties of GaAs as well as its mature microelectronics fabrication technology and nascent micromachining technology. The design, fabrication, and response of GaAs SAW chemical microsensors are reported. Functional integrated GaAs SAW oscillators, suitable for chemical sensing, have been produced. The integrated oscillator requires 20 mA at 3 VK, operates at frequencies up to 500 MHz, and occupies approximately 2 mmz. Discrete GaAs sensor components, including IC amplifiers, SAW delay lines, and IC phase comparators have been fabricated and tested. A temperature compensation scheme has been developed that overcomes the large temperature dependence of GaAs acoustic wave devices. Packaging issues related to bonding miniature flow channels directly to the GaAs substrates have been resolved. Micromachining techniques for fabricating FPW and TSM microsensors on thin GaAs membranes are presented and GaAs FPW delay line performance is described. These devices have potentially higher sensitivity than existing GaAs and quartz SAW sensors.
Date: September 20, 1998
Creator: Baca, Albert G.; Heller, Edwin J.; Frye-Mason, Gregory C.; Reno, John L.; Kottenstette, Richard; Casalnuovo, Stephen A. et al.
Partner: UNT Libraries Government Documents Department

Photonic Band Gap Structures as a Gateway to Nano-Photonics

Description: This LDRD project explored the fundamental physics of a new class of photonic materials, photonic bandgap structures (PBG), and examine its unique properties for the design and implementation of photonic devices on a nano-meter length scale for the control and confinement of light. The low loss, highly reflective and quantum interference nature of a PBG material makes it one of the most promising candidates for realizing an extremely high-Q resonant cavity, >10,000, for optoelectronic applications and for the exploration of novel photonic physics, such as photonic localization, tunneling and modification of spontaneous emission rate. Moreover, the photonic bandgap concept affords us with a new opportunity to design and tailor photonic properties in very much the same way we manipulate, or bandgap engineer, electronic properties through modern epitaxy.
Date: August 1, 1999
Creator: FRITZ, IAN J.; GOURLEY, PAUL L.; HAMMONS, G.; HIETALA, VINCENT M.; JONES, ERIC D.; KLEM, JOHN F. et al.
Partner: UNT Libraries Government Documents Department

Microfabricated Gas Phase Chemical Analysis Systems

Description: A portable, autonomous, hand-held chemical laboratory ({mu}ChemLab{trademark}) is being developed for trace detection (ppb) of chemical warfare (CW) agents and explosives in real-world environments containing high concentrations of interfering compounds. Microfabrication is utilized to provide miniature, low-power components that are characterized by rapid, sensitive and selective response. Sensitivity and selectivity are enhanced using two parallel analysis channels, each containing the sequential connection of a front-end sample collector/concentrator, a gas chromatographic (GC) separator, and a surface acoustic wave (SAW) detector. Component design and fabrication and system performance are described.
Date: August 2, 1999
Creator: Casalnuovo, Stephen A.; Frye-Mason, Gregory C; Heller, Edwin J.; Hietala, Vincent M.; Kottenstette, Richard J.; Lewis, Patrick R. et al.
Partner: UNT Libraries Government Documents Department

An Integrated Surface Acoustic Wave-Based Chemical Microsensor Array for Gas-Phase Chemical Analysis Microsystems

Description: This paper describes preliminary results in the development of an acoustic wave (SAW) microsensor array. The array is based on a novel configuration that allows for three sensors and a phase reference. Two configurations of the integrated array are discussed: a hybrid multichip-module based on a quartz SAW sensor with GaAs microelectronics and a fully monolithic GaAs-based SAW. Preliminary data are also presented for the use of the integrated SAW array in a gas-phase chemical micro system that incorporates microfabricated sample collectors and concentrators along with gas chromatography (GC) columns.
Date: July 20, 1999
Creator: Casalnuovo, stephen A.; Frye-Mason, Gregory C.; Heller, Edwin J.; Hietala, Vincent M.; Kottenstette, Richard J.; Lewis, Patrick R. et al.
Partner: UNT Libraries Government Documents Department

Gas Phase Chemical Detection with an Integrated Chemical Analysis System

Description: Microfabrication technology has been applied to the development of a miniature, multi-channel gas phase chemical laboratory that provides fast response, small size, and enhanced versatility and chemical discrimination. Each analysis channel includes a sample concentrator followed by a gas chromatographic separator and a chemically selective surface acoustic wave detector array to achieve high sensitivity and selectivity. The performance of the components, individually and collectively, is described. The design and performance of novel micromachined acoustic wave devices, with the potential for improved chemical sensitivity, are also described.
Date: July 8, 1999
Creator: Baca, Albert G.; Casalnuovo, Stephen A.; Frye-Mason, Gregory C.; Heller, Edwin J.; Hietala, Susan L.; Hietala, Vincent M. et al.
Partner: UNT Libraries Government Documents Department