Theoretical Study of Some Physical Aspects of Electronic Transport in nMOSFETs at the 10-nm Gate-Length

We discuss selected aspects of the physics of electronic transport in nMOSFETs at the 10-nm scale: Long-range Coulomb interactions, which may degrade performance and even prevent ballistic transport from occurring; scattering with high-k insulator interfacial modes, which depresses the electron mobility but is found to affect minimally the saturated transconductance of 15-nm devices; and the use of high-mobility small effective-mass substrates, which poses serious concerns related to performance limitations due to the density-of-states (DOS) bottleneck and to the band-to-band (Zener) leakage current. On the basis of our results, we argue that ballistic transport may not only be unachievable (because of unavoidable electron-electron collisions) but may also be undesirable, as it may enhance the DOS bottleneck. We also argue that the knowledge of low-field mobility is of little use in predicting quantitatively the performance of devices in the saturated region.