Quantum treatment of phonon scattering for modeling of three-dimensional atomistic transport
Résumé
Based on the nonequilibrium Green's function formalism, we show a numerically efficient method to treat inelastic scattering in multidimensional atomistic codes. Using a simple rescaling approach, we detail the calculations of the lowest-order approximation (LOA) [Y. Lee et al., Phys. Rev. B 93, 205411 (2016)] series to the usual, computationally intensive, self-consistent Born approximation (SCBA). This, combined with the analytic continuation technique of Pade approximants, is applied to an atomistic code based on a tight-binding sp(3)d(5)s* model for electrons and holes, and a modified valence-force-field method for phonons. Currents in Si and Ge gate-all-around nanowire transistors are then computed considering the main crystallographic transport directions (< 100 >, < 110 >, < 111 >) for both n-type and p-type devices. Our results show that in most configurations, third-order LOA currents are enough to achieve a high agreement with SCBA results, while reducing the calculation time by about one order. In addition, we propose a criterion to determine the validity of such expansion techniques.
Origine | Fichiers produits par l'(les) auteur(s) |
---|