Calcium-doping for enhanced temperature stability of (Ba 0.6Sr 0.4) 1− xCa xTiO 3 thin film dielectric properties

Abstract

Ternary (Ba 0.6Sr 0.4) 1− x Ca x TiO 3 (BSCT) ( x = 0, 0.1, 0.2, 0.3 and 0.4) thin films with thickness of around 500 nm were prepared on Pt(111)/TiO 2/SiO 2/Si substrates by sol–gel methods. BSCT forms the complete solid solutions in a single cubic perovskite structure. The lattice constant, dielectric constant, tan δ and tunability of BSCT decrease, whereas the temperature stability of dielectric properties increases with increasing the Ca concentration. From 25 to 100 °C, the decrease of tunability is about 11% for BSCT with 40 at.% of Ca. BSCT thin films exhibit the comparable tunability, low loss and enhanced temperature stability.