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

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 µm
²
vs. 573 × 573 µm
²
) 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.