Low loss, high tunable BaZr_(0.2)Ti_(0.8)O_3/BaSn_(0.85)Ti_(0.15)O_3 heterostructure thin films

摘要

Ferroelectric BaZr_(0.2)Ti_(0.8)O_3/BaSn_(0.85)Ti_(0.15)O_3 (BZT/BTS) heterostructure thin films (～200-nm-thick) have been prepared on Pt/TiO_x/SiO_2/Si substrates by pulsed laser deposition. The heterostructure thin films are crack free, compact, and crystallized in a perovskite structure. Dielectric measurements indicate that the BZT/BTS heterostructure thin films exhibit a low dielectric loss of below 0.007, a medium dielectric constant of ～441, and the superior tunable dielectric properties at room temperature. Calculations of tunability and figure of merit (FOM) display a maximum value of 68.5% at 500kV/cm and ～101, respectively. The FOM value is higher than that of the single-layer BTS and BZT thin films. A brief discussion is given on the lower loss compared to the single-layer thin films. The results indicate that BZT/BTS heterostructure thin films are excellent candidates for electrically steerable applications.