Development of micro-hotplate with TaN heater based Cu-doped SnO2 gas sensor for low concentration of H2S gas

In this study, the MEMS-based SnO₂ gas sensor with a TaN heater, MSGST, was designed and fabricated using micromachining technology. The heating performance of the TaN heater was measured using an IR thermometer. The response of the MSGST sensor to H₂S gas was analyzed by obtaining the relationship between the resistance of the sensor and the gas concentration to determine the best design parameters. Experimental results indicate that a MEMS-based SnO₂ gas sensor, integrating TaN with a micro-hotplate, was successfully implemented using micromachining technology. The TaN heater can operate at over 300 ^oC and produce a uniform thermal distribution on the micro-hotplate. The sensitivity of the MSGST sensor to the H₂S gas is significantly improved using a Cu catalyst and the optimal design parameters (Sensing film = 100 μm², Cu catalyst = 7.5 mM) are obtained by measuring the gas concentration characterization for each the designed sensor.