A model of the interface charge and chemical noise due to surface reactions in Ion Sensitive FETs

We present a model of arbitrary chemical reactions at the interface between a solid and an electrolyte, aimed at computing the interface charge build-up and surface potential shift of ion-sensitive FETs in the presence of interfering ions. An expression for the rms value of the surface charge fluctuation and the resulting uncertainty in the ion concentration is derived as well. Application to nanoelectronic ISFET-based sensors for ions and proteins is demonstrated.