Apparatus and method for increasing the selectivity of FET-based gas sensors

US7992426B2 · kind B2 · utility

Assignee

• Micronas GmbH · DE

Inventors

• Maximilian Fleischer · Ehrenkirchen, DE
• Uwe Lampe · Buxtehude, DE
• Hans Meixner · Haar, DE
• Roland Pohle · Füssen, DE
• Ralf Schneider · Birkenfeld, DE
• Elfriede Simon · Munich, DE

Key dates

• Filing date: Apr 21, 2005
• Grant date: Aug 9, 2011
• Expiry date: Dec 27, 2026

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N27/4143
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A FET gas sensor having a relatively low operating temperature, for example, room temperature, is free from cross sensitivities from interfering gases by a preceding in-line filter. The sensor's service life is substantially stabilizable by using fabric-like activated charcoal filters which can be regenerated by a moderate temperature increase, and by limiting the diffusion of the analyte gas, which is made possible by the relatively small amount of gas detectable on the sensitive layer of the sensor. This substantially increases the service life of the filters. The gas sensor eliminates cross sensitivities to thereby increase the detection reliability thereof. Also, the gas sensor has relative long term stability and is economical to build. The gas sensor can read relatively weak signals generated by gas-sensitive layers, for example, without other stronger gas signals interfering with the weak signals.