@article{Kim2024, 
author = {Se Hyun Kim and Younghwan Lee and Dong Hyun Lee and Geun Hyeong Park and Hyun Woo Jeong and Kun Yang and Yong Hyeon Cho and Young Yong Kim and Min Hyuk Park},
title = {Depolarization mitigated in ferroelectric Hf0.5Zr0.5O2 ultrathin films (< 5 nm) on Si substrate by interface engineering},
year = {2024},
journal = {Journal of Advanced Ceramics},
volume = {13},
number = {3},
pages = {282-292},
keywords = {ferroelectric, charge trapping, hafnia, depolarization},
url = {https://www.sciopen.com/article/10.26599/JAC.2024.9220852},
doi = {10.26599/JAC.2024.9220852},
abstract = {(Hf,Zr)O2 offers considerable potential for next-generation semiconductor devices owing to its nonvolatile spontaneous polarization at the nanoscale. However, scaling this material to sub-5 nm thickness poses several challenges, including the formation of an interfacial layer and high trap concentration. In particular, a low-k SiO2 interfacial layer is naturally formed when (Hf,Zr)O2 films are directly grown on a Si substrate, leading to high depolarization fields and rapid reduction of the remanent polarization. To address these issues, we conducted a study to significantly improve ferroelectricity and switching endurance of (Hf,Zr)O2 films with sub-5 nm thicknesses by inserting a TiO2 interfacial layer. The deposition of a Ti film prior to Hf0.5Zr0.5O2 film deposition resulted in a high-k TiO2 interfacial layer and prevented the direct contact of Hf0.5Zr0.5O2 with Si. Our findings show that the high-k TiO2 interfacial layer can reduce the SiO2/Si interface trap density and the depolarization field, resulting in a switchable polarization of 60.2 μC/cm2 for a 5 nm thick Hf0.5Zr0.5O2 film. Therefore, we propose that inserting a high-k TiO2 interfacial layer between the Hf0.5Zr0.5O2 film and the Si substrate may offer a promising solution to enhancing the ferroelectricity and reliability of (Hf,Zr)O2 grown on the Si substrate and can pave the way for next-generation semiconductor devices with improved performance.}
}