Mobility in UTB-SOI PFETS: local coordinate-based modeling with the density gradient method

Here, for the first time, a local coordinate-based method is used to model surface acoustic phonon and thickness variation scattering in Si/SiO/sub 2/ PMOS structures using the density-gradient method. A reduction in mobility below that predicted by the electric-field based "universal mobility" curves for ultra-thin-body SOI devices is predicted in excellent agreement with recently published experimental data. An extension to multiple dimensions, demonstrated with some simple examples, is then applied to cylindrical devices, showing the mobility reduction of two-dimensional confinement.