Thermal and gas-sensing properties of planar-type micro gas sensor

A new planar-type micro gas sensor in which a gas-sensing layer was surrounded by a platinum heater horizontally on the same plane of a diaphragm was proposed to fit well to forming the gas-sensing layer by wet processes like spin-coating. The planar-type sensor simply fabricated by using only three masks for the photolithography processes shows very uniform temperature distribution over sensing layer and the device attached with a spin-coated thin layer of metal oxide of SnO2, In2O3 or WO3 showed a reasonable sensing performance to gases at 300°C.