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Search Publications by: Steve Semancik (Fed)

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Displaying 76 - 100 of 116

A Monolithic CMOS Microhotplate-based Gas Sensor System

December 1, 2002
Author(s)
Muhammad Afridi, John S. Suehle, Mona E. Zaghloul, David W. Berning, Allen R. Hefner Jr., Richard E. Cavicchi, Stephen Semancik, C B. Montgomery, C J. Taylor
A monolithic CMOS microhotplate-based conductance type gas sensor system is described. A bulk micromachining technique is used to create suspended microhotplate structures. The thermal properties of the microhotplates include a one-millisecond thermal time

A Monolithic Implementation of Interface Circuitry for CMOS Compatible Gas-Sensor System

July 1, 2002
Author(s)
Muhammad Afridi, John S. Suehle, Mona E. Zaghloul, David W. Berning, Allen R. Hefner Jr., Stephen Semancik, Richard E. Cavicchi
A monolithic CMOS micro-gas-sensor system, designed and fabricated in a standard CMOS process, is described. The gas-sensor system incorporates an array of four microhotplate-based gas-sensing structures. The system utilizes a thin film of tin-oxide (SnO 2

MEMS Device Platforms as Research Tools for Developing Improved Sensing Films

February 1, 2002
Author(s)
C J. Taylor, Richard E. Cavicchi, Stephen Semancik
Gas sensing characteristics of metal oxide films are dependent on the preparation method used in their fabrication. To optimize sensing film performance, one must understand how processing parameters influence composition andmicrostructure, and then

Sol-Gel Materials for Gas Phase Sensing Using Microhotplate Arrays

February 1, 2002
Author(s)
N O. Savage, Richard E. Cavicchi, Michael J. Tarlov, Stephen Semancik, J Greg Gillen
Sol-gel chemistry is used to create suspensions (sols) of small particles of materials such as metal oxides. These suspensions can be dried to a gel or powder or used in the sol form for coatings and thin films. One promising application of sol-gel derived

Micromachined Arrays as Sensor Platforms and Materials Research Tools

November 27, 2001
Author(s)
Stephen Semancik, Richard E. Cavicchi
We describe temperature-controlled elements called microhotplates which are formed by micromachining Si, as well as thin film deposition methods and interfacial phenomena, utilized to create low power, application-tunable microdevices for analyzing gases

Chemical Crosstalk Between Heated Gas Microsensor Elements Operating in Close Proximity

June 1, 2001
Author(s)
M C. Wheeler, J E. Tiffany, R M. Walton, Richard E. Cavicchi, Stephen Semancik
Gas microsensor arrays often have closely-spaced elements typically separated by hundreds of microns. For such devices, crosstalk between elements operated within a gaseous environment is a concern because sensing materials held at elevated temperatures

Microhotplate Platforms for Chemical Sensor Research

June 1, 2001
Author(s)
Stephen Semancik, Richard E. Cavicchi, M C. Wheeler, J E. Tiffany, G Poirier, R M. Walton, John S. Suehle, B. Panchapakesan, D. E. DeVoe
This paper describes the development and use of microdevices and microarrays in chemical sensor research. The surface-micromachined microhotplate structure common within the various platforms included here was originally designed for fabricating

Using Chemical Kinetic Effects for Understanding and Developing Chemical Sensors

February 1, 2000
Author(s)
M C. Wheeler, Richard E. Cavicchi, G Poirier, Stephen Semancik
While conductometric gas sensing has been widely studied, the mechanisms are not well understood (particularly for modified oxides). For example, what magnitude of conductance change occurs for a given coverage of adsorbed analyte? We are using specially

Microhotplate Gas Sensor Arrays

November 18, 1999
Author(s)
Richard E. Cavicchi, Stephen Semancik, R M. Walton, B Panchapakesan, Don L. DeVoe, M I. Aquino-Class, J D. Allen, John S. Suehle
In this work, micromachining and planar processing has been used to achieve solid state sensing devices with lower power consumption at lower cost. The small size brings new advantages for chemical selectivity as well: multi-element whose time-varying

Property-Performance Studies of SnO 2 Sensing Films Using Micromachined Arrays

February 22, 1999
Author(s)
R M. Walton, Richard E. Cavicchi, Stephen Semancik
The microstructure and composition of sensing materials profoundly affect the performance of solid state gas sensors. We report property/performance relationships of conductometric gas sensing films deposited on micromachined devices called microhotplates

Solid State Gas Microsensors for Environmental and Industrial Monitoring

January 1, 1999
Author(s)
R M. Walton, Richard E. Cavicchi, Stephen Semancik, B Panchapakesan, Don L. DeVoe, M I. Aquino-Class, J D. Allen, John S. Suehle
We describe solid state gas microsensor array technology for real-time, low-cost environmental and industrial monitoring. The four-element, surface-micromachined arrays are designed in CMOS technology and consist of multiple platforms called microhotplates
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