(001)-Oriented Sr:HfO2 Ferroelectric Films Deposited by a Flexible Chemical Solution Method

• Published in: ACS applied electronic materials 2024-03, Vol.6 (3), p.1809-1820
• Main Authors: Badillo, Miguel, Taleb, Sepide, Carreno Jimenez, Brenda, Mokabber, Taraneh, Castanedo Pérez, Rebeca, Torres-Delgado, Gerardo, Noheda, Beatriz, Acuautla, Mónica
• Format: Article
• Language: English
• ISSN: 2637-6113; 2637-6113
• DOI: 10.1021/acsaelm.3c01725

Remnant polarization values of ferroelectric HfO2-based films depend on proper control of the polar orthorhombic phase crystallization and the orientation of the polar domains. Most of the best quality films reported so far are (111)-oriented. While the largest polarization is expected in (001)-oriented films, with the polar axis out of the plane, such orientation is far less common. This paper demonstrates that highly (001)/(010)-oriented heterostructures of Sr:HfO2 on Pt(111)-buffered Si can be attained in layered films deposited by a recently reported chemical solution deposition route. The oriented films display the short c-axis out of plane, giving place to a longer a lattice in plane. By tailoring the duration of rapid thermal processing, such oriented films produce highly ferroelectric, leakage-free capacitors. After wake-up cycling, a remnant polarization of 17 μC/cm2, which is the highest reported for this dopant and technique, was achieved. Even though optimization is still needed to improve the electrical cyclability, our facile approach produces high-k, highly oriented Sr:HfO2 films, through chemical deposition and annealing, and shows that the crystal orientations and phase purity of HfO2-based films can be further optimized by cost-effective chemical methods.