Sensor having tin oxide thin film for detecting methane gas and propane gas, and process for manufacturing thereof

摘要

The present invention relates to a sensor for detecting hydrocarbon type gas such as methane gas and propane gas, and process for manufacturing thereof. SiO.sub.2 was deposited in 1 &mgr;m by ion beam sputtering with a mixed gas (3:2) of argon and oxygen on a silicon wafer in the process. In case of a propane sensor, platinum electrode is deposited in 600 Å by ion beam sputtering on a tin oxide thin film synthesized by ionized beam of which the oxygen ion energy is 0 to 500 eV by using poly alumina. In case of a methane sensor, heat treatment at 500. degree. C. was performed for 1 hour in the air in order for the thin film to be stable at high operation temperature, while heat treatment was not performed in case of propane sensor. The sensor was manufactured by adding platinum or palladium thereto by argon ion beam sputtering. The thin film type tin oxide sensor according to the present invention exhibited an excellent selectivity of 47.4% even at low temperature of 150° C. at a gas concentration of 3,000 ppm in case of the methane sensor, while a sensor having high electric sensitivity and selectivity as 93.4% was obtained in case of the propane sensor.