Quantum-mechanical modeling of phonon-limited electron mobility in bulk MOSFETs, ultrathin-body SOI MOSFETs and double-gate MOSFETs for different orientations

A comprehensive study of low-field phonon-limited mobility behavior with downscaling of silicon body thickness in ultrathin-body SOI MOSFETs and double-gate MOSFETs is presented. Phonon-limited mobility is obtained by self-consistent Schrödinger-Poisson simulations and momentum relaxation rate calculations. Single- and double-gate devices with (100), (110) and (111) active surfaces and body thickness down to 2 nm are investigated. Physical mechanisms which govern mobility behavior are studied by calculating form factors and ladder/subband occupancy.