Table 3: Relative permittivity and loss tangent of typical large-area BaxSr1−x TiO3 thin films grown by PLD or sputtering on the indicated substrates (size 5 0 × 5 0  mm2 or 2-inch diameter), measured at 35 GHz and 300 K with an open Fabry-Perot resonator by R. Heidinger at Karlsruhe Research Center. The BSTO films grow with polycrystalline structure on the ceramic substrates and with oriented epitaxial structure on the single-crystalline substrates.

Growth methodSubstrateBaxSr1−x TiO3-filmThickn. 𝜖 r t a n 𝛿

PLD (U Leipzig)CoorsTec*Ba0.45Sr0.55TiO3 (poly)500 nm1140–1640 ( 0 . 3 b i s 0 . 8 ) × 1 0 2
PLD (U Leipzig)CoorsTec*Ba0.6Sr0.4TiO3 (poly)500 nm720 5 × 1 0 2
PLD (U Leipzig)LTCC*Ba0.7Sr0.3TiO3 (poly)390 nm500 3 0 × 1 0 2
PLD (U Leipzig)r-sapphireBa0.7Sr0.3TiO3 (110)130 nm900–1150 3 5 × 1 0 2
PLD (U Leipzig)LaAlO3Ba0.7Sr0.3TiO3 (100)180 nm1300–1600 5 0 × 1 0 2
sputtering (FZK)LaAlO3Ba0.7Sr0.3TiO3 (100)200 nm500–550 ( 7 t o 9 ) × 1 0 2

 *Al2O3-based polycrystalline microwave ceramics. The surface roughness Ra of the LTCC-substrates was 95 to 145 nm, and Ra of the CoorsTec substrates 21–27 nm (A-face HIREL quality).