Analytical Calculation of Influence of Ferroelectric Properties on Electrical Characteristics Negative Capacitance Germanium FETs

Abstract

Negative capacitance (NC) germanium (Ge) p-channel field effect transistors with different ferroelectric parameters are investigated by the analytical model. The channel surface potential amplification induced by the NC effect, which determines the subthreshold swing (SS) and the drain current ${I} _{\mathrm{ DS}}$ of the device, can be tuned by varying the thickness ${t} _{\mathrm{ fe}}$ , the coercive field ${E} _{c}$ , and the remnant polarization ${P} _{r}$ of the ferroelectric film. For the logic device, hysteresis phenomenon must be avoided, which is enabled by reducing $t_{\mathrm{ fe}} $ or $E_{c} $ of the ferroelectric film. Under the condition of $t_{\mathrm{ fe}} =30$ nm, $E_{c} =30$ KV/cm, and $P_{r} =30\,\,\mu \text{C}$ /cm2, NC Ge transistors display the superior SS and $I_{\mathrm{ DS}} $ compared to the baseline FETs.