Tri-gate heterojunction SOI Ge-FinFETs

Abstract

This paper proposes structures of tri-gate heterojunction (HJ) FinFETs with different configuration of gate dielectric and gate material stacks: Single Gate Material Single Dielectric (SGMSD), Single Gate Material Dual Dielectric (SGMDD) and Dual Gate Material Dual Dielectric (DGMDD), and compares their characteristics with conventional FinFET. The heterojunction formed between the Germanium (fin) and Silicon layer (at source/channel or drain/channel junction) is found to produce low leakage current than conventional FinFET, the best being obtained for DGMDDHJ FinFET. Since the highest on-off current ratio is obtained for DGMDDHJ FinFET, so, further analysis is done for DGMDDHJ FinFET for various parameters like length of the Silicon layer, doping concentration of the Silicon layer and fin widths, considering two cases of position of the Silicon layer, one at source end and the other at drain end. The Subthreshold Swing reduces as fin width is increased. Interestingly, when the Silicon layer is at the drain end, the transfer characteristics are almost similar for variation in length and doping concentration of the Silicon layer. The DGMDDHJ FinFET is found to exhibit low DIBL, thus proving its superiority over MOSFETs.