Dielectric properties of (Pb,Sr)TiO3 heterolayered thin films for tunable application

Dielectric PST(20/80) / PST(80/20) heterolayered thin films structures were created by a consequent deposition of the PST (20180) and PST (80120) thin films on the Pt/Ti/SiO2/Si substrate using alkoxide-based sol-gel method. Both structural and dielectric properties of heterolayered PST thin films were investigated for the tunable microwave device applications. As the number of coating increases, the lattice distortion decreased. It can be assumed that the lower PST layer affects a nucleation site or a seeding layer for the formation of the upper PST layer. The dielectric constant, dielectric loss and tunability of the PST-6 heterolayered structure measured at 100 kHz were 399, 0.022 and 57.9%, respectively. All these parameters showed an increase with increasing number of coatings due to the decrease in lattice distortion.