Ferroelectric characteristics of SrBi_4Ti_4O_(15) thin films grown on Pt/Ti/SiO_2/Si substrates by the soft chemical method

摘要

Ferroelectric SrBi_4Ti_4O_(15) thin films were successfully prepared on a Pt (1 ll)/Ti/SiO_2/Si(100) substrate for the first time by spin coating, using the polymeric precursor method. X-ray diffraction patterns of the films indicate that they are polycrystalline in nature. Atomic force microscopy (AFM) analyses showed that the surface of these films is smooth, dense and crack-free with low surface roughness (6.4 nm). At room temperature and at a frequency of 1 MHz, the dielectric constant and the dissipation factor were, respectively, 150 and 0.022. The C-V characteristics of perovskite thin film prepared at low temperature show normal ferrolectric behaviour. The remanent polarization and coercive field for the films deposited were 5.4 mu C/cm~2 and 85 kV/cm, respectively. All the capacitors showed good polarization fatigue characteristics at least up to 1 X 10~(10) bipolar pulse cycles indicating that SrBi_4Ti_4O_(15) thin films can be a promising material for use in nonvolatile memories.