Effect of stacking layers on the microwave dielectric properties of MgTiO 3/CaTiO 3 multilayered thin films

Abstract

Effect of stacking layers on the microwave dielectric properties of the MgTiO 3/CaTiO 3 (MTO/CTO) multilayered thin films prepared by the metalorganic solution deposition technique (MOSD) was investigated. As the thickness of CTO film in the MTO/ CTO multilayered films increased, the dielectric constant (K) increased and temperature coefficient of dielectric constant (TCK) changed from positive to negative values by dielectric series mixing rule. Especially, MTO(100 nm)/CTO(200 nm) multilayered films exhibited a TCK of +10 ppm/°C, indicating temperature stability. The dielectric losses (tan δ) of MTO/CTO multilayered films increased with an increase of CTO layers. This result was attributed to the fact that the stresses induced by the higher thermal-expansion coefficient of CTO than that of MTO. Also, as compared with MTO(100 nm)/CTO(200 nm) film, the K and TCK of MTO(50 nm)/CTO(200 nm)/MTO(50 nm) film were not changed, but the dielectric losses increased. This result indicated that the dielectric loss was affected by the number of interfaces between CTO and MTO layers.