The CMOS MEMS nose-fact or fiction?

This is an attempt to explore the prospect of chemical microsensors based on CMOS integrated micro electro mechanical systems (MEMS), notably for analytical or olfactory electronic systems. The concept of the CMOS MEMS nose is discussed and narrowed down to micro-structured layers of sensitive polymers combined with post-CMOS micromachined beams or membranes. CMOS cantilever beams coated with sensitive layers can operate in resonant (adsorbed mass), swelling (volume modulation) or calorimetric (heat generation) modes. A post-CMOS beam equipped with resistive heater and piezoresistive and optical readout structures is presented as an example. The case of the modulation of CMOS capacitors with post-CMOS polymer layers sensitive to hydrocarbons and on-chip digital read-out is updated. The CMOS MEMS approach is found to offer unique features for future chemical sensor arrays and olfactory systems.