Dünnschicht-Halbleiter-Gassensor und Verfahren zum Nachweis von Gasen

摘要

The invention relates to a thin-film semiconductor gas sensor comprising a sensitive layer (1) whose electric conductivity can be modified by contact with or impingement by a gas. The electric conductivity of the sensitive layer (1) is measured by electrodes (2) so as to detect gases or determine gas concentrations. A heatable silicon membrane (3) which is porous or provided with through holes is positioned upstream of the sensitive layer (1) or arranged above said sensitive layer (1). In the silicon membrane (3) certain gas molecules undergo a chemical or catalytic reaction or are excited to higher vibrational states before the gas is brought into contact with the sensitive layer (1). This overcomes the problem of sensitivity shifts which occur in sensors with thin gas-sensitive layers. Molecules which react especially strongly or weakly with thin sensitive layers are converted into molecules which, respectively, react more weakly or strongly on the sensitive layer (1).