Ultra-high remnant polarization in wake-up-free ferroelectric thin films realized by atomic layer annealing
Journal
Acta Materialia
Journal Volume
288
Start Page
120855
ISSN
1359-6454
Date Issued
2025-04-15
Author(s)
Abstract
In recent years, Hf0.5Zr0.5O2 (HZO) thin films have gained substantial interest due to their exceptional ferroelectric properties and high compatibility with advanced semiconductor technology for non-volatile memory (NVM). However, the ferroelectricity of nanoscale HZO thin films below 10 nm is limited due to the difficulty of increasing the orthorhombic (o-) phase content at the annealing temperatures that can be used in the back-end process, which should not exceed 400 °C. In this study, by introducing the atomic layer annealing (ALA) technology during the deposition of the HZO thin film, significant ferroelectricity is realized with an exceptionally high remnant polarization (2Pr) of ∼68.6 μC/cm2 at a low annealing temperature of 400 °C, which sets a new record 2Pr value for HZO thin films compatible with the back-end process in advanced semiconductor technology nodes. This achievement can be attributed to the facilitated adatom migration enabled by the ALA treatment, which not only enhances the o-phase crystallinity but also allows for the preferred orientation along the polar (002) axis in the out-of-plane direction. Furthermore, the ALA process also eliminates the need for a wake-up process, leading to the realization of wake-up-free ferroelectricity in HZO. The distinguished ferroelectric properties of nanoscale HZO thin films achieved through ALA open up new perspectives in NVM applications.
Subjects
Atomic layer annealing
Ferroelectricity
Preferred orientation
Remnant polarization
Wake-up-free
Publisher
Elsevier BV
Type
journal article