Sensor arrangement
AssigneeSiemens Aktiengesellschaft
InventorsEckhardt Hoenig, Volker Lehmann, Ulf Buerker
Life of this patent
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Abstract
A sensor arrangement having a substrate of doped silicon with channels in a principal face, a selective means for detecting a material, the selective means covering the principal face without filling the channels, and a measuring instrument for registering a physical quantity dependent on the influence of a material is provided. A catalytic layer is particularly used as selective means and a temperature sensor is particularly used as measuring instrument. Alternatively, the sensor arrangement is fashioned as a capacitor having a porous cooperating electrode. The channels are preferably produced by electrochemical etching.
Claims13
A method for manufacturing a sensor arrangement for sensing a material, comprising the steps of:
- providing a substrate of n-doped silicon having a principal face;
- forming channels in said principal face by electrochemically etching said principal face in a fluoride-containing, acidic electrolyte in contact with said principal face while applying a voltage between said electrolyte and said substrate with said substrate connected as an anode, to set a current density influencing erosion of said principal face by said etching, said channels respectively having channel surfaces;
- depositing a catalytic layer on said channel surfaces, without filling said channels, which reacts exothermally with the material to be sensed;
- and
- providing a temperature sensor in temperature-sensing relationship to said catalytic layer to sense a temperature produced by the exothermal reaction of said catalytic layer and said material.
A method for manufacturing a sensor arrangement for sensing a material, comprising the steps of:
- providing a substrate of n-doped silicon having a principal face;
- forming channels in said principal face by electrochemically etching said principal face in a fluoride-containing, acidic electrolyte in contact with said principal face while applying a voltage between said electrolyte and said substrate with said substrate connected as an anode, to set a current density influencing erosion of said principal face by said etching, said channels respectively having channel surfaces;
- depositing a dielectric layer on said channel surfaces by a process selected from a group consisting of thermal oxidation of TiS.sub.2, anodic oxidation of TiO.sub.2, vapor phase deposition of TiO.sub.2, and combined deposition of a sequence of respective layers of SiO.sub.2 and Si.sub.3 N.sub.4 and SiO.sub.2, and forming a conductive layer on said dielectric layer by vapor phase deposition, without filling said channels, said conductive layer, said dielectric layer and said substrate forming a capacitor having a capacitance which changes dependent on the material to be sensed;
- and
- providing a thin film coil on said substrate in series with said capacitor to form a resonant circuit having a resonant frequency which changes dependent on said changes in capacitance.
Dependencies are inferred from the claim text.