Performance improvements of KTN ferroelectric thin films for microwave tunable devices

The investigations reported in this paper constitute three solutions for enhancement of KTa_1-xNb_xO₃ (KTN) ferroelectric material performances displayed by microwave tunable devices. Quasi-epitaxial KTN films with strongly improved microwave performances (especially tunability) were grown on R-sapphire substrates through the use of KNbO₃ seed layers. Doping of the KTN layer with two different compounds through either Ti substitution or MgO addition led to a significant reduction of the KTN dielectric losses. This study deals also with the influence of the microwave characteristics upon the KTN-based tunable devices through comparison of Chemical Solution- and Pulsed Laser-Depositions.