Nanosale Effects in Junctionless FETs

We investigate the performance of multi-gate junctionless FETs in the nanoscale regime of operation, and show how thin-channel, gate type, quantum size-quantization, random dopant fluctuations, and self-heating, affect the recently-proposed junctionless FET characteristics and compare to a junctioned FET counterpart. A 3-D fully \textit{atomistic} quantum-corrected Monte Carlo device simulator has been used in this work. The essential bandstructure parameters (such as bandgap, effective mass, and the density-of-states) have been computed using a 20-band nearest-neighbour \textit{sp}$^{3}d^{5}s^{\ast }$ tight-binding scheme. Quantum size-quantization effects have been accounted for via a \textit{parameter-free} effective potential scheme (and benchmarked against the NEGF approach as implemented in the \textit{nanoFET }toolkit, in the ballistic limit). To treat electron-ion and electron-electron interactions, the simulator implements a real-space corrected Coulomb electron dynamics (ED) scheme. Results on $I_{ON}$/$I_{OFF}$, S, DIBL, $r_{0}$, $g_{m}$, $f_{T}$, $V_{TH}$ variation, RTS, and current degradation due to self-heating will be presented.