Effect of Stacking Layers on the Microwave Dielectric Properties of (Li0.5Sm0.5)TiO3/CaTiO3 Thin Films

概要

論文の詳細を見る
Effect of stacking layers on the microwave dielectric properties of the (Li0.5Sm0.5)TiO3/CaTiO3 (LSTO/CTO) thin films prepared by the metalorganic solution deposition technique (MOSD) was investigated. The dielectric constant ($K$), dielectric loss ($\tan\delta$) and temperature coefficient of dielectric constant (TCK) of CaTiO3 films measured at 6 GHz were 160, 0.003 and $-1340$ ppm/°C, respectively. In contrast, the (Li0.5Sm0.5)TiO3 films showed $K$ of 35, $\tan\delta$ of 0.001 and TCK of $+320$ ppm/°C. As the thickness of CTO layer in the LSTO/CTO films increased, $K$ increased and TCK changed from positive values to negative values by dielectric mixing rule. Especially, LSTO(200 nm)/CTO(200 nm) films exhibited TCK of $+10$ ppm/°C, indicating temperature stability. The $\tan\delta$ of LSTO/CTO films increased with increasing the thickness of CTO layer. This result was attributed to the fact that the stresses were induced by the higher thermal-expansion coefficient of CTO than that of LSTO. Also, as compared with LSTO(200 nm)/CTO(200 nm) film, the $K$ and TCK of LSTO(100 nm)/CTO(200 nm)/LSTO(100 nm) film were not changed, but the dielectric loss increased. This result indicated that the dielectric loss was affected by the number of interfaces between CTO and LSTO layers.
2005-03-15