BiFeO3/Al2O3 gate stack for metal-ferroelectric-insulator-silicon memory FET for IoT applications

Abstract

The Effect of plasma enhanced atomic layer deposited (PEALD) Al 2 O 3 buffer layer on the electrical and ferroelectric characteristics of the metal/ferroelectric/insulator/silicon (MFIS) gate stack has been investigated for ferroelectric field effect transistor (FeFET) structure for its potential application in internet of things. Radio frequency sputtering has been used for the deposition of ferroelectric (BiFeO 3 ) film at room temperature. Structural and optical characteristics of the ferroelectric and dielectric films deposited on TiN and the silicon substrate has been obtained using X-ray diffractometer and laser ellipsometer. Polycrystalline rhombohedrally distorted perovskite structure of BiFeO 3 film with dominant crystal peak {(104)/(110)} and refractive index 2.4 has been obtained at the annealing temperature of 500\xa0°C. Different capacitor structures have been fabricated to obtain electrical and ferroelectric characteristics. Metal/ferroelectric/silicon structure shows the memory window of 4.75\xa0V that has been further improved to 8.53\xa0V with the introduction of 10\xa0nm Al 2 O 3 between ferroelectric and silicon as in MFIS structure. MFI (10\xa0nm) S structure shows excellent data retention, fatigue resistant, and breakdown characteristics that make it a potential candidate for the gate stack of FeFET. To the best of author’s knowledge, this is the first report to integrate pure BiFeO 3 film on PEALD-Al 2 O 3 /silicon substrate for non-volatile memory applications.