ISFET-based measuring device and method for fabricating the ISFET used therein.

摘要

@ The measuring device (10) comprises an ISFET (12) used as a chemically selective ion sensor, a reference electrode (20) positioned adjacent the ISFET (12), an amplifier (22) coupled to the ISFET and controlicorrection circuitry (30) coupled to the ISFET (12), to the reference electrode (20) and to the amplifier (22). The control/correction circuitry (30) is operable to maintain the drain-source current IDs of the ISFET (12) at a constant value and to correct drift effects of the ISFET (12) on the basis of the logarithmic equation:where:
ΔVP = potential driftA = scale factor for drift and amplitudeto = time constant defining the dependence on timet = time during which the sensor is operative in the event of continuous operation.