Dielectric enhancement in polycrystalline BaTiO₃/Ba_0.6Sr_0.4TiO₃ multilayered thin films on Pt/Ti/SiO₂/Si substrates

Polycrystalline BaTiO₃/Ba_0.6Sr_0.4TiO₃ multilayered thin films were deposited layer by layer onto Pt/Ti/SiO₂/Si substrates by using pulsed laser deposition. The dielectric constant of the films was enhanced more than four times with decreasing the periodicity down to 60 nm, while the dielectric loss was kept at the low level compared with that of the solid solution Ba_0.8Sr_0.2TiO₃ thin films. A large dielectric constant 1336 at 10 kHz was observed at room temperature with a stacking periodicity of 60 nm and the dielectric loss is smaller than 0.05. The results show high application potential of such multilayered thin films for high-density DRAM capacitors.