Ferroelectric behavior of bismuth titanate thin films grown via magnetron sputtering

Abstract Bismuth titanate (Bi x Ti y O z ) thin films were grown using the r.f. magnetron sputtering technique on (100) silicon substrates. In the process, annealing was performed in both oxygen and dry air atmospheres at 600 °C for 30 and 120 min. The structure of the thin films was characterized through X-ray diffraction (XRD), and the ferroelectric response was determined with measurements of piezoelectric force microscopy (PFM). Bi 4 Ti 3 O 12 with a predominant orthorhombic phase was obtained in the annealed thin films. All the annealed films exhibited the characteristic hysteresis and butterfly loops of ferroelectric materials. Thermal annealing of Bi x Ti y O z films in an atmosphere of air for 30 min resulted in the highest d 33 value of 78±14 pm/V, which decreased to 64±26 pm/V for 120 min. On the other hand, annealing in an oxygen atmosphere produced Bi x Ti y O z films with more uniform d 33 values, 54±3 pm/V and 42±6 pm/V for 30 and 120 min, respectively. Ferroelectric coefficient values decreased with the increase of annealing time in an oxidant atmosphere, which can be explained by the vacancies present. These results are consistent with the experimental measurements carried out in other investigations.