Micro-machined gas sensor array based on metal film micro-heater

An integrated gas sensor array is promising to overcome the poor selectivity and drift encountered by individual gas sensor. Micro-machined gas sensor array was fabricated using the post-process micro-machining technology of silicon integrated circuit (IC). The size of a 2×4 array is 2 mm×4 mm, and the active area of each cell is 50 μm×50 μm. The electric properties, thermal characteristics, and the response to standard gases of the sensor array were investigated. The micro-heater can be driven to 400°C with about 9 mW applied power, and thermal response time constant of a micro-heater is about 10 ms. The techniques of oxygen radical assisted EB evaporation was utilized to prepare SnO2 sensitive films that show high sensitivity and good selectivity to C2H5OH.