Thermally stable micro hot wire sensor with Borofloat glass membrane

We report on the fabrication and characteristics of micro hot wire sensor with Borofloat glass membrane on diaphragm by using anodic bonding. Borofloat membrane was thermally stable and strong for mechanical stress. The four types of sensing materials SnO₂, In₂O₃ and mixed oxide of adequate ratio with these two type metal oxide semiconductor were prepared by thermal evaporation method and then oxidized at 600 °C, 3 hrs. Various sensing materials for NO_x, CO, etc. were prepared. And then the response characteristics were investigated. For mixed oxide semiconductor with Sn and In oxide, these showed the high sensitivity for NO_x and CO gas. And by using the Borofloat glass substrate, the power consumption was much reduced about 60 mW in condition of the best sensitivity.