CMOS-based programmable gate ISFET

A CMOS-based PG-ISFET (programmable gate-ion sensitive field effect transistor) is presented, which compensates for large threshold voltage and device mismatch observed with ISFETs fabricated in an unmodified CMOS process. The proposed device uses a capacitively coupled floating gate to allow tunability of its operating point to counteract the presence of trapped charge, thus allowing the device to operate within a tolerable gate voltage range. Fabricated in a 0.35 m CMOS process, the device shows good weak-inversion operation for low-power chemical sensing.