Gaseous sensors with area- and energy-efficient microhotplates through silica aerogel for heat insulation

Abstract

Arrays of microsensors may be employed for accurate detection of multiple gases possibly existing simultaneously in an environment. They can be made reconfigurable for improving efficiency and reliability. Constituent microsensors in such a reconfigurable array are highly desirable to operate in an ultra low power regime, have a short response time, and take as small chip area as possible. Metal oxide (MOX) materials used for detecting gaseous species usually operate at high temperatures, say, 350° C or beyond. In this work, we introduce and evaluate the use of silica aerogel as the insulating material of choice over the air gap (commonly produced by costly micromachining). Superior properties of aerogel lead to considerable reduction in power consumption and in array chip area while lowering the fabrication cost, based on our extensive simulation evaluation using IntelliSuite software. Silica aerogel is compatible with the CMOS process, ensuring a low overall production cost.