Single-chip CMOS capacitive sensor for ubiquitous dust detection and granulometry with sub-micrometric resolution

A monolithic CMOS chip able to count single airborne particles down to a diameter of 1 µm is presented. This mm-sized ASIC addresses the growing need for portable and miniaturized solid-state sensors monitoring air quality to be disseminated in the environment within pervasive wireless sensors networks. Particle counting and sizing are based on high-resolution capacitive detection. State-of-the-art performances (65 zF resolution with 40 Hz bandwidth) are enabled by the combination on the same chip of interdigitated microelectrodes (separated by 1 µm distance, matched with the particle size), and ultra-low-noise electronics connected to them achieving the lowest possible parasitic input capacitance. Chip design and characterization are illustrated.