Nano-fractal gas sensr integrated on micro hteater fabricated with suspension coating

Semiconductor gas sensors are in widespread use for industrial applications. Some of them need heater for their operation. Downsizing of both of the sensor and heater is required with MEMS technology to make the power consumption lower. At the same time, the sensor should be produced as low cost and high productivity as possible. Thus, we apply suspension coating approach to the sensor element fabrication on Si micro heater. The element has different size of nano-pores, which was fabricated by mixing colloidal suspensions that contains different sizes of polystyrene micro-particles and SnO₂ nano-particles and then removing (oxidizing) polystyrene particles after the self-assembly. We here present a demonstration of such nano-fractal porous gas sensor fabrication and its evaluation.