The micro hydrogen sensor chip with low power consumption

Abstract

An integrated micro H2 sensor chip with low power consumption is presented. A pair of interdigitated sensing electrodes, sensing layer and heating electrodes surrounding them were designed on the same layer. To realize low power consumption, the silicon substrate with high thermal conduction was released by wet etching and the 1.3#x03BC;m thick membrane with excellent thermal insulation which consists of Si3N4/SiO2/Si3N4/SiO2 four films, was reserved to support the above structure. Annealing was carried out to reduce the stresses of the films. The stacked TiO2/SnO2 composite materials were used to detect H2 and they had six layers consisting of deposited SnO2 and TiO2 through RF magnetron sputtering in turn. The preparation process of the composite materials was combined with the conventional MEMS process to realize mass production of the wafer-level sensor chips with good consistency. The H2 sensor can work steadily for H2 detection (100–900ppm) at 244 °C with low power consumption as 36mW.