Analysis of switching characteristics for negative capacitance ultra-thin-body germanium-on-insulator MOSFETs

Abstract

The impact of device parameters on the switching characteristics of negative capacitance ultra-thin-body (UTB) germanium-on-insulator (NC-GeOI) MOSFETs is analyzed. NC-GeOI MOSFETs with smaller gate length (Lg), EOT, and buried oxide thickness (Tbox) and thicker ferroelectric layer thickness (TFE) exhibit larger subthreshold swing improvements over GeOI MOSFETs due to better capacitance matching. Compared with GeOI MOSFETs, NC-GeOI MOSFETs exhibit better switching time due to improvements in effective drive current (Ieff) and subthreshold swing. NC-GeOI MOSFET exhibits larger ST improvements at Vdd = 0.3 V (−82.9%) than at Vdd = 0.86 V (−9.7%), because NC-GeOI MOSFET shows 18.2 times higher Ieff than the GeOI MOSFET at Vdd = 0.3 V, while 2.5 times higher Ieff at Vdd = 0.86 V. This work provides the device design guideline of NC-GeOI MOSFETs for ultra-low power applications.