Modeling and simulation of Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) isrnvery essential in order to understand the device physics, electrostatics and other importantrnphenomena occurring in this device. Therefore, in this thesis the modeling and simulation ofrnSilicon Nano Wire field Effect Transistors (SiNW FETs) is done. The modeling is done assumingrnboth ballistic transport and transport in the presence of scattering. The modeling of SiNW FETsrnassuming ballistic transport is an extension of the Natoriâ€™s theory of ballistic MOSFETs. Thernsecond part of the modeling, which is developed on the assumption of scattering transport, isrnbased on McKelveyâ€™s flux method. When the scattering effects are assumed to be absent, thernscattering model reduces to the ballistic model. Therefore, the main novelty introduced in thisrnthesis is the extension of the previous models and the incorporation of these two models together.rnAfter the derivation of the model, its benchmarking is also done. This is accomplished byrncomparing the simulation results of the developed model, which is implemented using MATLABrnprogramming, with that of the experimental and numerical simulation results. Various importantrnparameters are extracted and used for comparison, the main ones being the On-state current (Ion),rnthe Off-state current (Ioff), the Subthreshold Slope (SS) and drain induced barrier loweringrn(DIBL). The comparison shows that there is a good agreement between the simulation results ofrnthe developed model and the experimental and numerical simulation results, which indicates thernvalidity of the model. Finally, the effect of scaling of the physical parameters on the devicernperformance is investigated. The main parameters chosen for this investigation are the diameterrnof the Nano Wire (NW) and the gate oxide thickness. When a simulation is done by varying thesernparameters, Ion and Ioff currents are found to be affected greatly.