A Low Power Cantilever-Based Metal Oxide Semiconductor Gas Sensor

This letter, for the first time, reports a novel metal oxide semiconductor (MOS) gas sensor based on a single cantilever. The extremely brief Platinum micro-heater without any coil, is on a 10 mu m wide cantilever, which shows very low static power consumption and fast heating response. Sensors were fabricated on a four inch Si wafer using typical micro-electro-mechanical system (MEMS) process, and SnO2 was chosen as the sensing material. Test results indicate that the static power consumption is only 2.96 mW. With this applied power, the sensor can reach 400 degrees C and the heating-up time is just 260 mu s. Both of them are enormously improved, comparing with the MEMS MOS gas sensors with suspended membrane supported by slender beams. The sensor shows a good linear characteristic to 0-10 ppm ethanol. Moreover, due to the single cantilever structure, ten sensors can be fabricated inside a die of 1 mm(2), improving the integration by an order of magnitude.