Microhotplates for low power, and ultra dense gaseous sensor arrays using recessed silica aerogel for heat insulation

Abstract

In the operation of air pitted gaseous sensor the microhotplate (μHP) consumes almost all the power used by the sensor. The required area to micromachine the air pit for the μHP of a single sensor is several times more than the actual area required by the sensor itself. The feasibility of implementing low power and ultra dense gaseous sensor array is investigated by developing a new μHP structure using recessed silica aerogel. In comparison with the conventional μHP structure, the recessed aerogel not only has decreased the utilized area of the chip almost ten folds (181 × 181 μm2 vs. 573 × 573 μm2) to maintain a temperature of 360 °C but also has decreased the power consumed by each μHP more than two folds (1 mW vs. 2:1 mW). As the number of sensors increases in a sensor array, the saved area of the chip increases quadratic by using the new structure. Moreover, the power consumed by the new designed structure reduces drastically.