Report on the Application of NEMO5 on Assessment of Band Tails and Tunneling Engineering with Respect to Nonlocal Charged Impurity Scattering in III-V MOSFETs and TFETs
The verification of self-energies of NEMO5’s nonequilibrium Green’s function framework describing the scattering of electrons on charged impurities in III-V materials and devices was continued. Good agreement of Urbach band tails with experiments is found when charged impurity and polar optical phonon scattering is both included. Close comparison with experimental data motivated updating the scattering models to use the screening length in semiconductor devices to the Lindhard formula (instead of the less general Debye one). To prepare the TFET calculations, the electrostatic model of NEMO5 was augmented to handle electron-only procures. Comparison with the electron/hole picture that is common in electronic and hole-based device calculations agree exactly when conduction and valence bands are well separated. Both models disagree, however, when a clear distinction between electrons and holes (such as in the ON-state of TFETs) is no longer possible. The electron-only picture (now fully implemented into NEMO5) gives a reliable device performance prediction then.