Dielectric response of K(Ta,Nb)O3 thin films

Abstract

The dielectric response of K(Nb,Ta)O3 films grown on (001) MgAl2O4 (100) by pulsed laser deposition from a mosaic target of KTa0.63Nb0.37O3 and KNO3 has been examined. In particular, the effects of growth temperature (650–800 °C), growth pressure (1–100 mTorr O2), and annealing conditions on the tunability, dielectric constant, and dielectric losses in interdigitated capacitor device structures fabricated with these films are described. Annealing treatments lead to a reduction in the loss tangents for most of the films considered. Figure of merit calculations indicate that the best dielectric response (tunability = 37%, tan δ=0.022) is achieved for films grown at 750 °C in an oxygen pressure of 100 mTorr and then annealing at 1000 °C for 2 h in air.