KTN Dielectric Properties at Microwave Frequencies: Substrate Influence

Abstract

To determine the dielectric properties of ferroelectric thin-films over a wide range of frequencies we developed a simple and efficient method based on the measurement of coplanar waveguide realized on ferroelectric/dielectric heterostructures by using a Spectral Domain Approach. We applied this method to KTa _1−x Nb _x O ₃ (KTN) thin-films deposited on different substrates. The strong differences observed in the dielectric behavior of KTNs according to the growth substrate suggest that it is affected not only via the resulting microstructure, but also by the induced strains. Accuracy of the method was estimated to 15 and 10% on permittivity and loss tangent, respectively.

Keywords:

• Thin films
• ferroelectrics
• dielectric characterization
• microwaves

Acknowledgments

The authors are grateful to Raymond Jézéquel, member of the Laboratoire d'Electronique et des Systèmes de Télécommunications, for his helpful contribution to the measurements of the devices under study.