BaTiO_3 Doped Na_(0.5)K_(0.5)NbO_3 Thin Films Deposited by Using Eclipse Shutter Enhanced Pulsed Laser Deposition Method

摘要

We have investigated structural, electrical, and electro-mechanical properties of lead-free piezoelectric BaTiO_3 doped Na_(0.5)K_(0.5)NbO_3 (BTO-NKN) thin films deposited by pulsed laser deposition (PLD) methods. BTO-NKN thin films have been deposited on La_(0.5)Sr_(0.5)CoO_3 (LSCO) bottom electrodes with LaAlO_3 (LAO) substrates. X-ray diffraction data have shown that all the BTO-NKN and bottom electrodes are highly oriented with their c-axes normal to the substrates. In order to improve the morphology of BTO-NKN thin films, we have located an eclipse shutter between a target and a substrate. Root-mean-square roughness was changed from 91 nm to 21 nm with eclipse shutter enhanced PLD (E-PLD) method. Furthermore, the enhanced surface morphology leads to the improvement in electrical or electro-mechanical properties mainly due to increased density. Typical capacitance and d_(33) values of a BTO-NKN film deposited by E-PLD method are 1000 pF and 30 pm/V, respectively.