Gas-sensing device implemented on a micromachined membrane: A combination of thick-film and very large scale integrated technologies

We report developing a SnO2 thick-film gas sensor deposited by screen print ing onto a micromachined dielectric stacked membrane equipped with an embed ded polysilicon microheater and two resistors for temperature measurement. The microheaters were designed to enable an operating temperature of 400 de greesC at about 30 mW power consumption. A newly developed scheme for tempe rature measurement was adopted for on-line adjustment of the film temperatu re through a conventional low-power feedback circuit. The electrical respon se of the prototypes to CO and CH4 is discussed, and their performance is c ompared to traditional devices fabricated via thick-film methods. (C) 2000 American Vacuum Society. [S0734-211X(00)01805-9].