A simple interpolation model for the carrier mobility in Trigate and gate-all-around silicon NWFETs

Abstract : We compute the electron and hole mobilities in Trigate and gate-all-around silicon nanowires (SiNWs) within the nonequilibrium Green’s Function framework. We then derive a simple model for the dependence of the mobility on the SiNW width and height. This model interpolates between the square SiNW and thin film limits. In order to provide a complete description of the mobility in SiNW devices, we calculate the phonon, surface roughness, and remote Coulomb-limited mobilities of square nanowires and of thin films with side or thickness t = 5, 7, and 10 nm. The mobility of arbitrary rectangular SiNWs with width W = t or height H = t can then be reconstructed from these partial mobilities using Matthiessen’s rule. We show that these models successfully reproduce the trends measured on n- and p-type devices with different widths and orientations.