Mohammed, MazharuddinVerhulst, Anne S.Verreck, DevinVan de Put, Maarten L.Magnus, WimSoree, BartGroeseneken, Guido2020-08-172020-08-172019-01-020021-8979http://dx.doi.org/10.1063/1.5044256https://hdl.handle.net/10735.1/8808In tunnel field-effect transistors, trap-assisted tunneling (TAT) is one of the probable causes for degraded subthreshold swing. The accurate quantum-mechanical (QM) assessment of TAT currents also requires a QM treatment of phonon-assisted tunneling (PAT) currents. Therefore, we present a multi-band PAT current formalism within the framework of the quantum transmitting boundary method. An envelope function approximation is used to construct the electron-phonon coupling terms corresponding to local Frohlich-based phonon-assisted inter-band tunneling in direct-bandgap III-V semiconductors. The PAT current density is studied in up to 100 nm long and 20 nm wide p-n diodes with the 2- and 15-band material description of our formalism. We observe an inefficient electron-phonon coupling across the tunneling junction. We further demonstrate the dependence of PAT currents on the device length, for our non-self-consistent formalism which neglects changes in the electron distribution function caused by the electron-phonon coupling. Finally, we discuss the differences in doping dependence between direct band-to-band tunneling and PAT current. Published under license by AIP Publishing.en©2018 The AuthorsField-effect transistorsTunneling (Physics)SemiconductorsElectron-phonon interactionsarticleMohammed, Mazharuddin, Anne S. Verhulst, Devin Verreck, Maarten L. Van de Put, et al. 2019. "Phonon-assisted tunneling in direct-bandgap semiconductors." Journal Of Applied Physics 125(1): art. 015701, doi: 10.1063/1.50442561251