Characterization of surface and buried channel ion sensitive field effect transistors (ISFET´s)

Surface and buried channel Ion Sensitive Field Effect Transistors (ISFET´s) are characterized for application in an integrated ISFET sensor/amplifier. These sensors have been characterized with a Site Bonding Theory applied to the insulator-electrolyte interface. A CMOS-sensor amplifier is employed to realize a low-power circuit The sensor dielectric is a Al2O3-SiO2gate insulator which displays an almost ideal Nernstian response of 58mV/pH unit at room temperature. The sensor-amplifier circuit is characterized with a computer-controlled data acquisition system for steady-state and transient response to pH and temperature variations.