Design points of ferroelectric field-effect transistors for memory and logic applications as investigated by metal-ferroelectric-metal–insulator–semiconductor gate stack structures using Hf0.5Zr0.5O2 films

Abstract

The potential of ferroelectric field-effect transistors (FeFETs) was investigated in regard to memory and logic applications. Integrating ferroelectric Hf0.5Zr0.5O2 thin films into FETs, we fabricated FeFETs with a metal-ferroelectric-metal–insulator–semiconductor gate stack structure. It was experimentally confirmed that the memory properties and the subthreshold swing behaviors of FeFETs change in accordance with the area ratios of MIS and MFM capacitors. On the basis of these results, design points of FeFETs were studied using the load-line analysis method. In summary, the absolute value of spontaneous polarization of the ferroelectric material is responsible for the memory applications, while the differential of the spontaneous polarization is crucial for the logic applications, respectively.