Significant k-point selection scheme for computationally efficient band structure based UTB device simulations

The accurate calculation of channel electrostatics parameters in ultra-thin body devices requires self-consistent solution of the Poisson's equation and the full-band structure of the thin channel. For silicon channel, the full-band structure is obtained using the semi-empirical sp3d5s* tight-binding model. To make this approach computationally tractable for a wide range of channel thicknesses, in terms of time and resource, only significant k-points in the irreducible Brillouin zone need to be considered. In this work, we present a scheme for precisely identifying the significant k-points based on Fermi-Dirac probability and show that the band-structure approach using those significant k-points can be applied over a wide range of channel thicknesses, oxide thicknesses, device temperatures and different channel orientations. The benchmarking of the obtained channel electrostatics parameters is performed with the results from accurate full-band structure simulations showing excellent agreement (maximum error within 0.5%) along with significant reduction in computational time.