An enabling material design to promote highly tunable, low loss, performance consistent BST thin films for tunable device applications

In this work we demonstrate that a compositionally stratified Ba1¿xSrxTiO3 (BST) thin film design (BST60/40-BST75/25-BST90/10) combined with optimized metal-organic solution deposition (MOSD) film fabrication and post-deposition annealing process protocols results in low loss, highly tunable and temperature stable thin film heterostructures. The experimental data demonstrates that the compositionally stratified BST thin film heterostructure has a small-signal dielectric permittivity of 360 with a dissipation factor of 0.012 and a dielectric tunability of 65% at 444 kV/cm. These material properties exhibited minimal dispersion as a function of temperature ranging from 90 to ¿10 °C. Thus, our results suggest that this compositionally stratified material design is an excellent candidate for tunable devices which require both enhanced dielectric response and performance consistency in harsh operational temperature regimes.