Computer Engineering

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Browsing Computer Engineering by Author "Adeyabeba, Abera (PhD)"

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    Modeling of Silicon Nanowire Field Effect Transistors
    (Addis Ababa University, 2011-07) Moges, Kidist; Adeyabeba, Abera (PhD)
    Modeling and simulation of Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) is very essential in order to understand the device physics, electrostatics and other important phenomena occurring in this device. Therefore, in this thesis the modeling and simulation of Silicon Nano Wire field Effect Transistors (SiNW FETs) is done. The modeling is done assuming both ballistic transport and transport in the presence of scattering. The modeling of SiNW FETs assuming ballistic transport is an extension of the Natori’s theory of ballistic MOSFETs. The second part of the modeling, which is developed on the assumption of scattering transport, is based on McKelvey’s flux method. When the scattering effects are assumed to be absent, the scattering model reduces to the ballistic model. Therefore, the main novelty introduced in this thesis is the extension of the previous models and the incorporation of these two models together. After the derivation of the model, its benchmarking is also done. This is accomplished by comparing the simulation results of the developed model, which is implemented using MATLAB programming, with that of the experimental and numerical simulation results. Various important parameters are extracted and used for comparison, the main ones being the On-state current (Ion), the Off-state current (Ioff), the Subthreshold Slope (SS) and drain induced barrier lowering (DIBL). The comparison shows that there is a good agreement between the simulation results of the developed model and the experimental and numerical simulation results, which indicates the validity of the model. Finally, the effect of scaling of the physical parameters on the device performance is investigated. The main parameters chosen for this investigation are the diameter of the Nano Wire (NW) and the gate oxide thickness. When a simulation is done by varying these parameters, Ion and Ioff currents are found to be affected greatly.