Optimization of large-area YBa2Cu3O7-& delta; thin films by pulsed laser deposition for planar microwave devices

This paper presents high quality YBa2Cu3O7-& delta; (YBCO) thin films on LaAlO3 substrate for microwave devices prepared by pulsed laser deposition (PLD). The double-sided YBCO films cover a large area and have been optimized for key parameters relevant to microwave device applications, such as surface morphology and surface resistance (R (s)). This was achieved by improving the target quality and increasing the oxygen pressure during deposition, respectively. To evaluate the suitability of the YBCO films for microwave devices, a pair of microwave filters based on microstrip fabricated on films from this work and a commercial company were compared. The results show that the YBCO films in this work could completely meet the requirements for microwave devices.