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