Effect of interfacial layers on dielectric properties in very thin SrBi2Ta2O9 capacitors

The effect of interfacial layers on the dielectric properties in very thin SrBi2Ta2O9 (SBT) capacitors has been investigated using static measurements. Total permittivity (εt) decreased as the film thickness was reduced in both Pt/SBT/Pt and Ir/SBT/Pt capacitors. The contribution of the interfacial capacitance (Cint) and bulk capacitance to the total capacitance indicates that Cint of the Ir/SBT/Pt structure was lower than that of the Pt/SBT/Pt structure, while the bulk permittivity (εb) was essentially the same. The dispersion of all capacitors followed the power law, while the Ir/SBT/Pt capacitor showed a larger dispersion of Cint. These results suggest that the Pt/SBT/Pt capacitor is preferred for obtaining the high performance with less effect of the interfacial layers on the dielectric properties.