Microstructure and Dielectric Properties of $BaTi_4O_9$ Thin Film for Microwave Devices

고주파 소자용 $BaTi_4O_9$ 박막의 미세구조와 유전특성 연구

[ $BaTi_4O_9$ ] thin film were grown on $Pt/Ti/SiO_2/Si$ substrate using rf magnetron sputter, and the microstructure and dielectric properties of the thin films were investigated. For the film grown at $350^{\circ}C$ and rapidly thermal annealed at $900^{\circ}C$, the $BaTi_5O_{11}$ Phase was formed. However, the $BaTi_4O_9$ phase was formed when the growing temperature exceeded $450^{\circ}C$ The dielectric constant of the $BaTi_4O_9$ thin film grown at $550^{\circ}C$ and rapidly thermal annealed at $900^{\circ}C$ was about 40 at low frequency range($100kHz{\sim}1MHz$) and 36 at microwave range($1{\sim}10GHz$) which is very close to that of the bulk $BaTi_4O_9$ phase. The dissipation factor was very low, about 0.005 at low frequency as well as microwave range.