Effect of Barium Titanate buffer layer on dielectric properties of Sodium Bismuth Titanate thin films grown using Pulsed Laser Deposition

Lead free bilayer capacitor structure has been fabricated as a combination of Sodium Bismuth Titanate, (Na_0.5Bi_0.5)TiO₃ (NBT) thin films with Barium Titanate, (BaTiO₃) (BT) buffer layer in situ using Pulsed Laser Deposition (PLD). PLD control parameters have been optimized using Taguchi approach to obtain good quality NBT and BT thin films. In order to understand the effect of buffer layer on the structural and dielectric properties of NBT thin films, 50 nm thickness of BT buffer layer has been grown on Pt coated Si substrate. It has been found that dielectric constant and dielectric loss of NBT thin films is 735 and 0.07 at 1 kHz respectively. It is observed that dielectric properties of NBT thin films enhanced by inserting BT buffer layer. This improvement in the dielectric properties of NBT thin films have been discussed in relation to the effect of the buffer layer on the structure, microstructure and interface of the NBT/BT bilayer capacitor.