Study of YBa2Cu3O7-δ/SrTiO3 heterostructures on 2" LaAlO3 substrates for microwave applications

Agile microwave components require tunable material homogeneous on large area, SrTiO3 (STO) material, associated with the superconductor YBa2Cu3O7-delta (YBCO), was chosen for its electric properties at low temperature. Two different sputtering systems were used for STO deposition: plane target in face to face configuration (film A) and inverted cylindrical target in off-axis configuration (film B). Then superconductor film was grown ex situ on film A and in situ on film B. The crystallographic properties were studied by X-rays diffraction and the cationic composition by EDX and RBS. The electric properties epsilon, tan delta and agility were studied by patterning resonators composed of two interdigited combs. In STO films, we observed a balance between the deposition rate and the homogeneity of the thickness and of the cationic composition. High-quality YBCO (400 nm)/STO (400 nm) heterostructures with R, 0.4 mOmega were obtained on 2" LaAlO3 substrates. (C) 2002 Elsevier Science B.V. All rights reserved.