Electric and ferroelectric properties of a multilayer film of Nd<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub> and Bi<sub>3.25</sub>La<sub>0.75</sub>Ti<sub>3</sub>O<sub>12</sub> for use as a ferroelectric field effect transistor

Abstract

Ferroelectric materials are of interest due to their applications, such as in ferroelectric field effect transistor memory (FeFET). For this application, reducing retention time according to the leakage current is an important matter. Ferroelectric materials are able to be improved through multilayer fabrication of ferroelectric films. This study investigated multilayer ferroelectric thin films using strong candidate ferroelectric materials such as Bi 3.25 La 0.75 Ti 3 O 12 (BLT) and Nd 2 Ti 2 O 7 (NT). The ferroelectric materials were prepared with a stable interface using broad stoichiometry, without occurrence of a secondary phase or a disruption in stoichiometry. For the characterization of BLT, NT, and BLT/NT multilayer ferroelectric films, various analyses and measurements were carried out, including X-ray diffraction, X-ray photoelectron spectroscopy, current-voltage and polarization-voltage. The multilayer ferroelectric films showed improved ferroelectric properties using multilayer fabrication with a highly insulating ferroelectric film.