Sub-60 mV/Decade Dynamic Subthreshold Swing in Bulk Negative Capacitance Junctionless MOSFET

Abstract

Through well-calibrated simulations, this work provides physical insights into the occurrence of dynamic sub-60 mV/decade switching in a negative capacitance (NC) junctionless (JL) transistor designed on a bulk substrate. Recognizing that the location of the conduction channel is a key factor governing the matching between ferroelectric and gate capacitances, we showcase the outperformance of bulk NCJL transistors compared to NCJL devices designed on a silicon-on-insulator (SOI) substrate. Results highlight that NCJL transistors designed with relatively higher bulk doping can achieve better dynamic ${S}_{\text {swing}}$ along with a higheron-to-off current ratio. We also investigate the short-channel performance comparison of bulk and SOI NCJL transistors. The results demonstrate the superiority of bulk NCJL transistors due to the enhanced NC effect resulting from the better ferroelectric and gate capacitances matching. The work provides a new viewpoint for designing of NCJL transistor on bulk substrate to facilitate steep ${S}_{\text {swing}}$ at scaled gate lengths.