Enlargement of Memory Window of Si Channel FeFET by Inserting Al2O3 Interlayer on Ferroelectric Hf0.5Zr0.5O2

TL;DR

This study enhances Si channel FeFET memory window by inserting an Al2O3 interlayer, revealing charge trapping at the interface as the key mechanism, achieving a 3.2 V window with high endurance and retention.

Contribution

It introduces a novel dielectric interlayer engineering approach to enlarge the memory window of FeFETs with detailed physical analysis.

Findings

Memory window of 3.2 V achieved

Endurance of approximately 10^5 cycles

Retention over 10 years

Abstract

In this work, we demonstrate the enlargement of the memory window of Si channel FeFET with ferroelectric Hf0.5Zr0.5O2 by gate-side dielectric interlayer engineering. By inserting an Al2O3 dielectric interlayer between TiN gate metal and ferroelectric Hf0.5Zr0.5O2, we achieve a memory window of 3.2 V with endurance of ~105 cycles and retention over 10 years. The physical origin of memory window enlargement is clarified to be charge trapping at the Al2O3/Hf0.5Zr0.5O2 interface, which has an opposite charge polarity to the trapped charges at the Hf0.5Zr0.5O2/SiOx interface.