الفهرس 
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Abstract
The increasing complexity of semiconductor devices and thereby the raised manufacturing cost and time, increase the demand for sophisticated simulation tools. The continuous down scaling of the feature size makes it necessary to extend existing physical models in order to investigate and understand the impact of additional second order effects. Moreover, many effects can be investigated in more detail and more efficiently by simulation than would be possible by experiments.This thesis present efficient electrostatic two-dimensional (2-D) and three-dimensional (3-D) models for complex short channel MOSFET structures. The models are based on the numerical solution of Poisson equation using the five-point and seven-point finite difference approximation methods. The models take into account all device details and are capable of simulating a wide range of device structures. The applicability and usefulness of the proposed models are demonstrated through two studies:In the first study, the 2-D version of the model is used to study the hot-carrier degradation phenomena in short channel lightly doped drain (LDD)-MOSFETs. The model takes into consideration all devices details and the spatial and energy distribution of hot carrier included interface traps. Potential and charge distributions throughout the device in weak and strong inversion are extensively studied. The degradation of the drain current and transconductance in the linear region are investigated. The model is efficiently applied to a real device whose experimental results have been published.In the second study, the 3-D version of the model is employed to study the dynamic behavior of short channel MOSFETs. The statistical nature of physical parameters such as the substrate doping, gate oxide thickness and interface trap density are included in the model. The effect of surface potential fluctuations on the MOSFET dynamic behavior, comprising the capacitance and conductance characteristics as a function of operating frequency in different operating regimes, is thoroughly investigated. To permit such a study of dynamic behavior, a nonuniform small-signal transmission-line model is also presented.