Simulation and Performance Study of Silicon Nanowire (Si-NW) Field-Effect Transistor (FET) pH Microsensor

In modern industry which is characterized by very small scales and sizes, the Silicon nanowire Ion-Sensitive Field-Effect Transistors Sensors (Si-nw-ISFET) are considered as a pioneer in this field. These sensors are known by 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. In this paper, a simplified BSIM level 1 model is presented to explain the characteristics of Si-nw-ISFET microsensor in linear, saturation and sub-threshold regions with eight parameters at the maximum. This model is suitable for our simulation because it includes a short channel and narrow-width effects, as well as the nanowire parameters, such as the resistance of nanowire R_nw and the number of wires in parallel. In addition, the effect of voltage Vds on the response of Si-nw-ISFET sensor is studied in this work and it can be related to the transconductance parameter. The BSIM1 model presented for Si-nw-ISFET microsensor was compared with the experimental data, and the simulation results show that this model can fit the experimental results with good accuracy for different pH values compared to the Spice level 3 model.