Comparing Crystallography and Ferroelectric Properties of a-Axis Oriented Bi_(3.25)La_(0.75) Ti_3O_(12) versus Non-c-Axis Oriented SrBi_2Ta_2O_9 Thin Films on Si(100)

摘要

Growth, structure and properties of a-axis oriented ferroelectric Bi_(3.25)La_(0.75)Ti_3O_(12) thin films on SrRuO3-electroded, buffered Si(l00) substrates are compared with those of (1 16)-oriented ferroelectric SrBi_2Ta_2O_9 thin films on the same substrate. It is shown how the ferroelectric properties of (116)-oriented SrBi_2Ta_2O_9 films suffer from certain inherent crystallographic properties of the films, whereas a-axis oriented Bi_(3.25)La_(0.75)Ti_3O_(12) thin films are free from such shortcomings. In result, the latter have a very large remanent polarization in amount of 32 mu C/cm~2- a new record for bismuth-layered perovskite thin films on substrates - pointing to the superiority of a-axis oriented Bi_(3.25)La_(0.75)Ti_3O_(12) thin films with respect to memory applications.