Investigation of phase growth and the effect of thickness on bismuth titanate thin films for microelectronic device applications

Bismuth titanate (Bi₄Ti₃O₁₂, BTO) thin films were deposited on a platinized silicon (Pt/Ti/SiO₂/Si) substrate using a spin-coating method with varying thicknesses (138-528 nm). XRD results revealed that the growth temperature and film thickness were major factors that influenced the quality and morphology of the film surface. The thickness-dependent structural, morphological, and optical properties of BTO thin films were analyzed. The Bi/Ti ratio was quantitatively assessed through EDS analysis to obtain compositional data. The decreasing of the substrate clamping effect and the interfacial-layer effect caused the dielectric constant to increase the thickness. A series capacitor model was used to illustrate the relationship between dielectric behavior and thickness. The optimum value of the dielectric constant (4228 at 100 Hz) and dielectric loss (0.074) was observed for the PT/BTO/Pt interfacial layer with a film thickness of 528 nm.