High Tunable BaTi_xZr_1-xO₃ Films on Dielectric Substrate for Microwave Applications

In this study, the structural and microwave properties of BaTiZrO₃ films deposited on alumina substrate were investigated. The films were deposited by RF magnetron sputtering in Ar/O₂ ambient atmosphere. The research of the island films at the initial stages of the growth showed that the pyramidal type of growth prevails. It was demonstrated that as-deposited film is a BaZrTiO₃ solid solution with a deficiency of titanium compared to the target. The air annealing at temperatures of 1100-1200 °C leads to the formation of a well-formed crystalline solid solution of BaZr_0.3Ti_0.7O₃ with a predominant orientation (h00). The investigation of microwave parameters of the films fabricated at different conditions showed that the best performance with the tunability of 4.6 (78%), and the Q-factor of 18 to 40 at 2 GHz was achieved at annealing temperature of 1150 °C.