Patterning of tunable planar ferroelectric capacitors based on the YBCO/BSTO film structure

Superconductor/ferroelectric (SF) and normal conducting metal/ferroelectric (NF) film structures were grown using DC and RF magnetron sputtering of ceramic and targets. Low-energy ion beam etching was used for patterning an SF planar capacitor with an electrode gap of about . Ferroelectric films displayed a rather smooth temperature dependence of with a maximal value of about 850 at K . Planar ferroelectric capacitors were intended for application in microwave tunable devices, so structures without hysteresis in voltage-capacitance characteristics were demanded. The SF and NF structures demonstrated a high enough coefficient of capacitance tuning (more than 1.5) and lower hysteresis for structures with YBCO electrodes.