Wafer‐level fabrication of low power consumption integrated alcohol microsensor

Abstract

An integrated alcohol microgas sensor was designed and fabricated based on TiO 2 /SnO 2 nanocomposites acting as a sensing layer and microheater providing working temperature. The stacked TiO 2 /SnO 2 nanocomposites were prepared by magnetron sputtering. A unique suspended membrane consisting of Si 3 N 4 /SiO 2 /Si 3 N 4 /SiO 2 four layers was prepared by different methods, respectively, and applied in microheater to support the electrodes and sensing layer for reducing power consumption. The fabrication process tackled the difficulty that the sensing layer preparation is incompatible with microelectromechanical systems micromachining technology and realised the mass production of the wafer-level sensor chips with good consistency. The microalcohol sensors showed excellent response characteristics for alcohol (50-600 ppm) detection at low power consumption (39 mW).