Influence of substrate bias on the structural and dielectrical properties of magnetron-sputtered BaxSr1-xTiO3 thin films

TL;DR

This study investigates how applying substrate bias during magnetron sputtering influences the structural, morphological, and dielectric properties of BaxSr1-xTiO3 thin films, revealing significant modifications in phase transition, permittivity, and film strain.

Contribution

It demonstrates the effects of substrate bias on the properties of BaxSr1-xTiO3 films, highlighting the correlation between bias, strain, composition, and dielectric behavior.

Findings

Substrate bias shifts ferroelectric to paraelectric transition to higher temperatures.

Dielectric permittivity and tunability increase with substrate bias.

Dielectric loss deteriorates as substrate bias increases.

Abstract

The application of a substrate bias during rf magnetron sputtering alters the crystalline structure, grain morphology, lattice strain and composition of BaxSr1-xTiO3 thin films. As a result, the dielectric properties of Pt/BaxSr1-xTiO3/Pt parallel-plate capacitors change significantly. With increasing substrate bias we observe a clear shift of the ferroelectric to paraelectric phase transition towards higher temperature, an increase of the dielectric permittivity and tunability at room temperature, and a deterioration of the dielectric loss. To a large extent these changes correlate to a gradual increase of the tensile in-plane film strain with substrate bias and an abrupt change in film composition.