Studies of ferroelectric film growth and capacitor interface processes viain situ analytical techniques and correlation with electrical properties

Precise control of composition and microstructure of multicomponent oxide t hin films is critical for the production of ferroelectric and high dielectr ic constant thin film devices. In addition, the integration of film-based c apacitors with semiconductor substrates, for device fabrication, requires g ood control of the composition and structure of the dielectric/substrate an d top electrode / dielectric interfaces to control the capacitor properties . In order to understand the processes described above, we are using a vari ety of integrated complementary in situ analytical techniques including tim e-of-flight ion scattering and recoil spectroscopy, X-ray photoelectron spe ctroscopy, spectroscopic ellipsometry, and ex situ methods such as transmis sion electron microscopy, scanning force microscopy, and scanning electron microscopy. Examples of studies recently performed by our group that are re viewed here include: (a) effects of microstructure on the oxidation of Ti-A l layers that can be used in a dual functionality as a diffusion barrier an d bottom electrode for integration of ferroelectric capacitors with semicon ductors; (b) studies of the surface and dielectric layer/bottom electrode i nterface during growth of BaxSr1-xTiO3 films on Ir/TiN/SiO2/Si for fabricat ion of BST capacitors for DRAMs; and (c) studies of the effect of interface contamination and structure on the electrical properties of BST capacitors for high frequency devices.