Coupled drift-diffusion (DD) and multi-subband Boltzmann transport equation (MSBTE) solver for 3D multi-gate transistors

This paper presents a self-consistent coupled DD/MSBTE solver for the device simulation of realistic 3D multi-gate transistors. The MSBTE for quasi-1D k-space is solved in the channel region while the DD equation is solved in the source/drain regions with an appropriate boundary condition at the DD/MSBTE region interfaces. In the MSBTE region, 2D Schrödinger equation with the two (electrons) or six (holes) band k · p Hamiltonian is solved to obtain the subband structure for arbitrary crystal orientations and stress conditions. Phonon and surface roughness scattering processes are taken into account in the MSBTE where the surface roughness scattering model has been extended to consider arbitrary cross-sections. Silicon nanowire transistors are considered as an application.