Electric field-induced crystallization of ferroelectric hafnium zirconium oxide

• Published in: Scientific reports Vol. 11; no. 1; p. 22266
• Main Authors: Lederer, Maximilian, Abdulazhanov, Sukhrob, Olivo, Ricardo, Lehninger, David, Kämpfe, Thomas, Seidel, Konrad, Eng, Lukas M.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 15.11.2021; Nature Publishing Group UK; Nature Portfolio
• Subjects: Casting; Crystallization; Electric fields; Hafnium; Thin films; Zirconium; Zirconium oxides
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-021-01724-2

Abstract Ferroelectricity in crystalline hafnium oxide thin films is strongly investigated for the application in non-volatile memories, sensors and other applications. Especially for back-end-of-line (BEoL) integration the decrease of crystallization temperature is of major importance. However, an alternative method for inducing ferroelectricity in amorphous or semi-crystalline hafnium zirconium oxide films is presented here, using the newly discovered effect of electric field-induced crystallization in hafnium oxide films. When applying this method, an outstanding remanent polarization value of 2P $$_{\mathrm{R}}$$ R  = 47  $$\upmu$$ μ C/cm $$^{2}$$ 2 is achieved for a 5 nm thin film. Besides the influence of Zr content on the film crystallinity, the reliability of films crystallized with this effect is explored, highlighting the controlled crystallization, excellent endurance and long-term retention.