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 microheater without any coil, is on a 10 μm 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 °C and the heating-up time is just 260 μs. 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 cantileverstructure, ten sensors can be fabricated inside a die of 1 mm², improving the integration by an order of magnitude.