Correlations Between Composition, Texture, and Polarization in Sr x Bi y Ta 2 O 5+x+3y/2 Thin Films Deposited by MOCVD

Sr x Bi y Ta 2 O 5+x+3y/2 (SBT) is a promising material for ferroelectric random access memories (FeRAM’s) because of its inherently high resistance to fatigue and imprint. Metalorganic chemical vapor deposition (MOCVD) offers the ability to produce high quality, conformal SBT films for both high and low density memory applications. An MOCVD process based on liquid delivery and flash vaporization has been developed which allows precise control of film stoichiometry and thickness. In this study, wavelength dispersive x-ray fluorescence and x-ray diffractometry have been used to survey composition and preferred crystallographic orientation (texture) relationships. It is shown that as-deposited film composition can be used to influence the texture of the Aurivillius phase in the annealed film. The polarization of the films increases with increasing (115) and (200)/(020) peak intensity due to the relationship of the electric field direction with the polarization direction in the film. The highest values of polarization are found with Sr content, x<0.8 and Bi content, 2.1 更多