Correlation of Gate Capacitance with Drive Current and Transconductance in Negative Capacitance Ge PFETs

Abstract

Correlation of gate capacitance ${C} _{G}$ with drive current ${I} _{\textsf {DS}}$ and transconductance ${G} _{m}$ in negative capacitance (NC) Ge pFETs is first investigated. Hysteresis-free NC Ge pFETs integrated with 4.5-nm HZO achieving the improved ${I} _{\textsf {DS}}$ and ${G} _{m}$ over the control devices are fabricated. A peak in the ${C} _{G}$ versus gate voltage curve is demonstrated in the NC Ge pFET, indicating the NC effect induced by HZO film. It is observed that ${I} _{\textsf {DS}}$ and ${G} _{m}$ of the NC transistors are enhanced as the ${C} _{G}$ peak gets increased. This is attributed to the fact that, as the device operates in the NC region, both ${C} _{G}$ and internal gate voltage amplification are proportional to ${C} _{\textsf {FE}}$ /( ${C} _{\textsf {FE}}+{C}_{\textsf {MOS}}$ ), where ${C} _{\textsf {FE}}$ and ${C} _{\textsf {MOS}}$ are the NC of HZO and the MOS capacitance of the device, respectively.