Thermoelektrische Gas- und Stroemungssensoren

DE 10212167 A UPAB: 20031125 NOVELTY - A gas and/or flow sensor comprises thermocouples (6, 7) with n-conducting and p-conducting doped sections (8, 9, 12, 13) arranged on a substrate (1), and contacts (2) for the voltage. The doped sections are made from at least one thermoelectric oxide. At least one section is gas-sensitive and the thermocouples have a temperature gradient produced via a heating element and have a thermo-voltage. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for the quantitative determination of gases using the above sensor. Preferred Features: At least one section is gas-sensitive in several defined regions separated from each other. At least one thermocouple is made from a gas-sensitive material with a layer of gas-insensitive material or is made from a gas-insensitive material with a layer of gas-sensitive material. The thermoelectric oxide is made from SnC2, Co3O4, NiO, WO3, V2O5, Ga2O3, Cr2-xTixO3, NaCo2O4, CaCoO3, Skutterudite, semiconducting silicide and semiconductor alloys. USE - Used for determining gases e.g. in gas mixtures, for measuring the flow of gases and fluids, and in production and process measurement technology, e.g. in the automobile industry, in security technology and in environmental technology (claimed). ADVANTAGE - The sensor has reduced cross-sensitivity

Mikrostrukturierter Gassensor mit Steuerung der gassensitiven Eigenschaften durch Anlegen eines elektrischen Feldes

WO2003076921 A UPAB: 20040318 NOVELTY - Integrated gas sensor comprises a gas-sensitive resistance layer (4) contacted by electrodes (5) arranged on a semiconductor body (1), and a field electrode (2) separated by an insulating layer (3) arranged underneath the gas-sensitive resistance layer. DETAILED DESCRIPTION - Integrated gas sensor comprises a gas-sensitive resistance layer (4) contacted by electrodes (5) arranged on a semiconductor body (1), and a field electrode (2) separated by an insulating layer (3) arranged underneath the gas-sensitive resistance layer. The insulating layer has a thickness which is approximately less than or equal to 10 times the Debye length LD, in which LD = ( epsilon epsilon 0kT/q2N)1/2 (where T = temperature; epsilon = dielectric constant depending on the material; epsilon 0 = dielectric constant; k = Boltzmann constant; N = charge carrier concentration; and q = elementary charge). USE - Used for measuring air pollutant concentrations in the ppm and ppb regions e.g. in production and process measuring technology, in the car industry and in environmental technology. ADVANTAGE - The sensor is economical

CMOS-compatible nanoscale gas-sensor based on field effect

The integration of a solid state gas sensor of the metal oxide sensor type into CMOS technology still is a challenge because of the high temperatures during metal oxide annealing and sensor operation that do not comply with silicon device stability. In the presence of an external electric field sensor sensitivity can be controlled through a change of the Fermi energy level and consequently it is possible to reduce the operation temperature. Based in this effect, a novel field effect gas sensor was developed resembling a reversed insulated gate field effect transistor (IGFET) with the thickness of gas sensing layer in the range of the Debye length (L-D). Under these conditions the controlling electrical field reaches the sensitive surface and a modulation of the Fermi energy level occurs, producing an effective control of gas sensitivity and sensor response. In this paper several aspects are treated, like technological fabrication process, complete sensor characterization by means of an electrical model and sensor response measurements. Other effects as base-line drift effects and layer thickness implications also are studied

Intelligente Gassensoren (IGS). Integrierte Intelligente Metalloxid-Gassensorsysteme Abschlussbericht

Gas sensor arrays with SnO_2 as an active material were developed on Si and sapphire substrates. The sensitivity and selectivity were varied applying design and technology parameters. Solid-state physics interpretations of sensor effects are suggested. The chemico-analytical properties are analyzed applying a newly set-up gas measuring technique. Multivariate analytical methods and pattern recognition methods are successfully applied to high-purity gas mixtures and to olfactometric problems. (orig.)SIGLEAvailable from TIB Hannover: RO 7155(1996,13)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman