Dielectric Tunability of Mn Doped Pb_0.3Sr_0.7TiO₃ Multilayered Thin Films Prepared by Sol-Gel Method

Abstract

Pb0.3Sr0.7TiO3 (PST) and 4.5 mol% Mn doped Pb0.3Sr0.7TiO3 (PSTMn) thin films as well as PST/PSTMn/PST/PSTMn/PST (ML-a) and PSTMn/PST/PSTMn/PST/PSTMn (ML-b) multilayered thin films have been fabricated on Pt/Ti/SiO2/Si substrate with sol–gel method. The structure and surface morphology of PST, PSTMn, ML-a and ML-b thin films were investigated by x-ray diffraction (XRD) and atom force microscopy (AFM). The dielectric measurements were conducted on metal-insulator-metal capacitors at the frequency from 100 Hz to 1M Hz and at room temperature. It was found that the surface microstructure of multilayered thin films is influenced by deposition sequence and the dielectric constant and tunability of two multilayered thin films lie between that of PST and PSTMn thin films. However, two multilayered thin films have higher the figure of merit (FOM) for lower dielectric loss. The FOM of PST and PSTMn single-component films as well as ML-a and Ml-b multilayered films are 14.2, 14.6, 16.3 and 20.2, respectively. Our results showed that multilayer structure can improve the comprehensive dielectric tunable performance of PST film.