Dielectric Properties of (Na, K)NbO₃ Thin Films for Tunable Microwave Device Application

Abstract

The (Na _x K_{1− x} )NbO₃ (NKN) thin films were fabricated by using the alkoxide-based sol-gel method. The NKN stock solution was spin-coated onto a Pt/Ti/SiO₂/Si substrate. The coating and drying procedures were repeated several times to obtain the film thickness of about 200 nm, and then the films were annealed at 550–700°C for 1 h. Structural properties of the NKN thin films were investigated by thermogravimetric analysis/differential scanning calorimetry, field emission scanning electron microscope and X-ray diffraction spectroscopy. The dielectric constant and the dielectric loss for the films sintered at 650°C were found to be 338 and 0.018, respectively. The results show that the NKN thin films are promising candidate for use in tunable devices application.

Keywords:

• NKN
• sol-gel
• tunability: dielectric properties

Acknowledgments

This work was supported by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD)′ (KRF-2005-041-D00462).