Transistor-type nonvolatile memory using hafnium-based ferroelectric thin films

Abstract

In this article, nonvolatile memory transistors using Hf-based ferroelectric thin films are described. Ferroelectric-gate transistors, metal–oxide–Si field-effect transistors, are explained using ferroelectric HfO₂ and HfN thin films, which can be formed directly on the Si substrate as a gate insulator. Furthermore, FeNOS-type nonvolatile memory transistors that is the metal–oxide–nitride–oxide–Si-type flash memory with ferroelectric HfO₂ thin films, which achieves precise threshold voltage control using polarization and charge trap characteristics, are explained.