Ferroelectric properties of (Sr0.5Ba0.5)Nb2O6 thin films synthesized by pulsed laser deposition

Strontium barium niobate (Sr0.5Ba0.5)Nb2O6 (SBN) thin films have been prepared by pulsed laser deposition technique. The substrate temperature higher than 680°C was necessary to form crystalline SBN films on either Si or Pt-coated Si substrates. The oxygen pressure (PO2), on the other hand, modified the texture property of SBN films. SBN films with (001)-preferred orientation were fabricated under 680°C (1 × 10−2 mbar PO2) conditions. A butterfly-shaped capacitance-voltage (C-V) curve was obtained for SBN/Pt/Si film with metal-insulator-metal (MIM) structure. An asymmetric C-V curve was obtained for SBNSi film with metal-insulator-semiconductor (MIS) structure. The zero-biased dielectric constant for MIM films and the forwardly biased dielectric constant for MIS films were around KMIM = 220 and KMIS = 80, respectively. Lower dielectric constant of MIS films can be attributed to the formation of an interfacial layer between SBN and Si. Both SBN/Pt/Si and SBNSi films, however, possess good ferroelectric properties and are promising for DRAM and FRAM applications.