Size effects and performance assessment in nanoscale multigate MOSFET structures

This work aims at using full-band Monte Carlo simulation coupled with full phonon dispersion to investigate the electro-thermal behavior of Silicon-on-insulator (SOI) multigate devices at the limit of cross section scalability. We particularly explore the dependence of short channel effects and Joule heating on the lateral scaling of the cross section. In the transistor level, heating is manifested through electron phonon interaction. We devise an efficient algorithm for the inclusion of full phonon dispersion in order to account for anisotropy and details of heat generation with great accuracy. The basic tradeoff between n-channel double gate, trigate, and gate-all-around transistors with square cross section lengths varying from 30 nm down to 5 nm are presented. Results indicate that multigate drive current decline well below their ideal limit as we reduce the cross section. In addition, at the limit of cross section scalability, series resistance increases as we add more gates. Furthermore, phonon observables demonstrate proliferation of energy dissipation rate as we add more gates and/or shrink the lateral cross section.