Tunable performance of BaZr0.2Ti0.8O3 thin films prepared by pulsed laser deposition

BaZr0.2Ti0.8O3 (BZT) thin films were deposited at various oxygen pressures (0-60 Pa) on Pt/TiOx/SiO2/Si substrates by using pulsed laser deposition. The crystallinity of the thin films initially improves but subsequently deteriorates with increasing oxygen pressure. The tunable performance of BZT thin films is associated with crystal structure and oxygen vacancies. The theoretical mechanisms for the relative permittivity and dielectric loss as a function of electric field are proposed. The frequency response of dielectric properties is also investigated and the variation mechanisms are supposed. Eventually, BZT thin films fabricated under 15 Pa have the highest tunability (70.3% at 400 kV/cm) with the largest relative permittivity of 486, the lowest loss tangent of 0.021 and the maximum commutation quality factor of 7744.8. The results imply that BZT thin films are potential candidates for tunable device applications.