CMOS Integrated Gas Sensors
This chapter provides a comprehensive discussion on the necessity and importance of developing gas sensors on a low-cost complementary metal oxide semiconductor (CMOS) platform technology. The main focus is on the challenges of integrating microhotplate-based gas sensors into a standard CMOS process: microhotplate-based sensors typically operate at much higher temperatures of 200 °C–500 °C. This is beyond the normal limit of CMOS operation at +125 °C. The chapter focuses on both different on-chip circuit schemes to interface these microhotplate-based sensors and also the challenges associated with depositing/growing nanosensing materials (particularly carbon nanotubes [CNTs] and graphene) on a CMOS platform. Finally, there is a brief discussion on the existing gas sensor market and its future outlook.