Importance of tailoring the thickness of SiO2 interlayer in the observation of ferroelectric characteristics in yttrium doped HfO2 films on silicon

• Published in: Vacuum Vol. 183; p. 109835
• Main Authors: Sun, Nana, Zhou, Dayu, Liu, Wenwen, Zhang, Yu, Li, Shuaidong, Wang, Jingjing, Ali, Faizan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-01-2021
• Subjects: Ferroelectric property; SiO2 interlayer; Sputtering; Thin film; Yttrium doped hafnium oxide; Ferroelectric property; SiO2 interlayer; Yttrium doped hafnium oxide; Sputtering; Thin film
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2020.109835

When being integrated in the fabrication processes of conventional silicon devices, hafnium oxide (HfO2) based films are routinely grown directly on the bare Si, thus causing an unavoidable SiO2 layer at the HfO2/Si interface. In this work, yttrium doped hafnium oxide (Y:HfO2) films were prepared on Si via reactive magnetron co-sputtering. The high-resolution transmission electron microscopy investigation presents a SiO2 layer formed at Y:HfO2/Si interface. The effects of SiO2 interlayer on the properties of Y:HfO2 metal insulator semiconductor (MIS) capacitors are studied in detail in terms of electric field, leakage current and polarization behaviors. After being prepared at the optimized thickness of SiO2, the ferroelectric property of Y:HfO2 capacitor is obtained successfully.
•Y:HfO2 thin films were deposited on bare silicon using reactive magnetron co-sputtering.•The TEM study shows that a ~3 nm-thick SiO2 layer is formed at the Y:HfO2/Si interface.•The effect of SiO2 interlayer on the electric properties of Y:HfO2 capacitors was investigated systematically.•After being prepared at optimized thickness of SiO2, the ferroelectric property of HfO2 was obtained successfully.