Textured Barium Hexaferrite Films on Silicon Substrates with Aluminum Oxide and Titanium Oxide Barrier Layers

• Published in: Russian journal of inorganic chemistry 2021-12, Vol.66 (12), p.1802-1810
• Main Authors: Kostishin, V. G., Mironovich, A. Yu, Timofeev, A. V., Shakirzyanov, R. I., Isaev, I. M., Sorokin, A. V., Ril’, A. I.
• Format: Article
• Language: English
• Subjects: Alumina-Titanium; Aluminum oxide; Atomic force microscopy; Barium hexaferrite; Barrier layers; Chemistry; Chemistry and Materials Science; Crystal defects; Crystallization; Inorganic Chemistry; Oxidation; Phase transitions; Preferred orientation; Silicon substrates; Silicon wafers; Synthesis and Properties of Inorganic Compounds; Titanium; Titanium dioxide; Titanium oxides
• ISSN: 0036-0236; 1531-8613
• DOI: 10.1134/S0036023621120093

The possibility of synthesizing textured barium hexaferrite films on silicon wafers with Ti, Al 2 O 3 /Ti, or Al 2 O 3 /TiO 2 barrier layers was studied. X-ray diffraction (XRD) showed that, after crystallization annealing, the hexaferrite phase with the (00l) preferred orientation was formed only when there was contact between BaFe 12 O 19 and Al 2 O 3 . The hexaferrite microstructure in these samples, according to atomic force microscopy (AFM), is represented by rounded grains, which are typical of films where the hexagonal axis is perpendicular to the surface plane. Titanium in a BaFe 12 O 19 /Al 2 O 3 /Ti sample was partially oxidized during the synthesis. This process and the associated phase transformations in TiO 2 are assumed to induce mechanical stress in the structure and, as a consequence, the formation of macroscopic defects (bulges). Complete pre-oxidation of the titanium film produced a textured BaFe 12 O 19 structure without macroscopic defects.