Temperature and size dependences of electrostatics and mobility in gate-all-around MOSFET devices

Abstract

The temperature and diameter dependences of capacitance and electron mobility in gated silicon nanowires are analyzed and discussed. The self-consistent solution of the 2D Schrödinger and Poisson equations is used to extract the inversion charge and capacitance curves as a function of the gate bias. Electron–phonon and surface-roughness scattering mechanisms are accounted for using the Fermi golden rule and the low-field electron mobility is computed using the Kubo–Greenwood approach. An understanding of the role of each scattering mechanism for a given nanowire width and temperature range is proposed highlighting oscillations of both capacitance and mobility at low temperature. These properties associated with one-dimensional structures result from electronic instabilities at the crossing of the Fermi energy with a Van Hove singularity in the density of states.