Modelling and performance evaluation of Si-NW ISFETmicrosensor

Compared to the conventional ISFET device, the silicon nanowire ion-sensitive field-effect transistors sensors (Si-nw-ISFET) has attracted a lot of attention and is considered as one of the most promising candidates because of their biocompatibility, very high surface-to-volume ratio due to the very small sizes of the nanowires, fast response, and good reliability of the signal. This paper deals with the modeling and performance evaluation of Si-nw-ISFET (Silicon-nanowire chemical field effect transistor) microsensor. The modeling approach used in this work takes into account the nanowire size effects to evaluate the response of Si-nw-ISFET transistor and introduces two parameters: the total resistance of nanowire R
T
and the rectangular capacity C
ox
of the gate insulator all-around the Si-nw. This model investigates the main influential parameters of nanowire on the sensor response as: (i) different wire lengths Lnw, (ii) channel gate lengths of Si-nw-ISFET (i.e. short and large gate length) and (iii) different numbers of parallel wires. The model developed is tested on large pH range, evidencing a good fit between simulation and experimental results. The model studied can predict the Si-nw-ISFET response behavior and creates new opportunities for new innovative applications.