Barium strontium titanate (BSTO) thin films were deposited on Pt(111) by high throughput evaporative physical vapor deposition and then annealed at 650 °C for 30 min under ${\mathrm{N}}_2$ atmosphere. Using advanced transmission electron microscopy, energy-dispersive x-ray spectroscopy and electron energy-loss spectroscopy, we directly show that not only does N substitute for O in the BSTO lattice but that it also compensates for $\mathrm{T}{\mathrm{i}}^{3+}$ ions, suppressing conductivity, thereby reducing dielectric loss and enhancing dielectric tunability. However, this effect is negated near the film edge where we speculate that exposed Pt acts as a reservoir of adsorbed/absorbed O and alters the local ${\mathrm{N}}_2$ concentration during annealing.

• Received 12 May 2020
• Revised 28 July 2020
• Accepted 2 September 2020

DOI:https://doi.org/10.1103/PhysRevMaterials.4.094410