5. Results

In this chapter results of the low and high field electron mobility models are presented. The modeling results have been compared against Monte Carlo simulations. The models have been implemented in the general purpose device simulator, MINIMOS-NT which has then been used to perform drift-diffusion based device simulations. A novel device structure, the so called dotFET, has been simulated.

In Section 5.1 the results obtained from the bulk-low field model are presented. It is demonstrated that the analytical model reproduces the anisotropy of the electron mobilities as obtained from Monte Carlo simulations, for different orientations of SiGe substrates and doping concentrations. The effect of shear stress on the mobility is also quantified in terms of the change in the effective masses and valley splittings. The electron high-field transport is discussed in Section 5.2. Peculiarities in the velocity-field curves arising due to strain are investigated using full-band Monte Carlo simulations. A comparison of the semi-empirical high-field mobility model presented in Section 4.6 and the Monte Carlo simulations is performed for different field directions. The models have been used to perform device simulations which is discussed in Section 5.3. Device simulation results of the effective-mobility in strained Si are shown. Lastly, a novel device structure, the so called dotFET has been simulated.