Electrical Characteristics of (Ba,Sr)TiO3/RuO2 Thin Films

Abstract

The structural, electrical properties of (Ba, Sr)TiO3[BSTO]/RuO2 thin films were examined by the addition of amorphous BSTO layer between crystlline BSTO film and RuO2 substrate. We prepared BSTO films with double-layered structure, that is, amorphous layers deposited at 60C and crystalline films. Crystalline films were prepared at 550 on amorphous BSTO layer. The thickness of the amorphous layers was varied from 0 to 170 nm. During the deposition of crystalline films, the crystallization of the amorphous layers occurred and the structure was changed to circular while crystalline BSTO films showed columnar structure. Due to insufficient annealing effect, amorphous BSTO phase was observed when the thickness of the amorphous layers exceeded 30 nm. Amorphous BSTO layer could also prevent the formation of oxygen deficient region in RuO2 surface. Leakage current of total BSTO films decreased with increasing amorphous layer thickness due to structural modifications. Dielectric constant showed maximum value of 343 when amorphous layer thickness was 30 nm at which the improvement by grain growth and the degradation by amorphous phase were balanced.