Structural and Electrical Properties of BiFeO₃ Nanocrystalline Thin Films Crystallized by Rapid Thermal Annealing Process

This study investigates the effect of annealing temperature on the crystalline phase microstructure and dielectric properties of Bismuth ferrite (BiFeO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>) thin films deposited on Pt(111)/Ti/SiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>/Si(100) substrate. The samples are prepared using sol-gel process and anneaed at four different annealing temperatures of 400 °C, 450 °C, 500 °C, and 550 °C. The thin film annealed at 450 °C showed a higher dielectric constant by 25.84%, 16.25%, 30.98% than the thin films annealed at 400 °C, 500 °C, and 550 °C, respectively. These results indicate that the thin films annealed at 450 °C demonstrates superior properties compared due to the formation of highest tetragonal (P4mm) phase. In contrast, no crystalline phase is observed in BiFeO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> thin films annealed at 400 °C, while a secondary phase of Bi<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>Fe<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">9</inf> is observed in samples annealed at 500 °C and 550 °C. Thus, BiFeO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> thin films annealed at 450 °C showed characteristics than other samples annealed at 400 °C, 500 °C, and 550 °C.