Effect of Mobile Ions on Subthreshold Swing of HfO2-based Ferroelectric Field-Effect Transistors

This paper proposes a physics-based model of ferroelectric field-effect transistors (FeFETs) considering the migration of mobile ions in ferroelectric $HfO_{2}$-based dielectrics. The model is based on the ion drift-diffusion (IDD) equations, the time-dependent Ginzburg-Landau (TDGL) equation, coupling with Poisson’s equation, and semiconductor charge/transport equations. The effects of mobile ions on ferroelectric characteristics are investigated in detail by the developed model which is verified and calibrated by measurement results of $Hf_{0.5}Zr_{0.5}O_{2}$ (HZO). It is proved that the mobile ions in HZO films are beneficial to reduce the subthreshold swing (SS) of FeFETs.