Numerical Analysis of Metal-Ferroelectric- Semiconductor Field-Effect-Transistors (MFS-FETs) Considering Inhomogeneous Ferroelectric Polarization

摘要

An improved numerical computation model is presented to calculate the metal-ferroelectric-semiconductor field effect transistor (MFSFET) characteristics with a sufficiently large gate area which can be applied for large drain voltages. In the presented model, the polarization of the ferroelectric gate insulator is inhomogeneous and treated as a variable along the channel. We have calculated electrical properties of SrBi_2Ta_2O_9/ Si MFSFETs and demonstrate that the conventional model, in which the polarization of the ferroelectric gate insulator (P_d) is treated as a constant, overestimate the drain current when the drain voltage is large. In addition, effects of the ratio of remanent polarization to spontaneous polarization (P_r/P_s ratio) of the ferroelectric film on the transistor characteristics are discussed.