GAS SENSOR AND METHOD OF MANUFACTURING THE SAME

摘要

27341-9 Disclosed is a gas sensor, particularly, an inflammable gas sensor for detecting an inflammable gas, such as leaked natural gas. The sensor comprises an n-type metal oxide semiconductor film, such as SnO2 film, whose resistivity varies responsive to the detection of the inflammable gas. The semiconductor film is covered on its surface by an oxide film insulator made of an oxide such as SiO2, MnO, MnO2 and V2O5. While the inflammable gas which may contain ethanol passes through the oxide film insulator, the concentration of the more reactive ethanol decreases and as a result, the sensitivity to methane and hydrogen is improved. Also disclosed is a preferred production method of the sensor. The process involves (1) the formation of the n-type metal semiconductor film, (2) the formation of electrodes and (3) the formation of the oxide film insulator on the n-type metal semiconductor film by sputtering through an opening of a mask placed over the electrodes. The opening of the mask has a specific size with respect to the thickness of the mask.