Growth of piezoelectric thin films with fine grain microstructure by high energy pulsed laser deposition

Thin piezoelectric films of lead zirconate-titanate (PZT). were deposited by pulsed laser ablation from prepared PZT targets and compared with films obtained from commercial samples. The special targets were obtained from nanosized powders synthesised by spray-drying of precursor solution and sintered at 700°C. The depositions were performed on Si (100). substrates carefully cleaned and heated in a vacuum chamber at 400°C. The same experimental set-up (Nd-YAG laser, 0.3 Jrpulse, 1064 nm, 10 ns, 10 Hz.) and parameters (reactive O2 atmosphere of pressure 150 mTorr, substrate temperature 370°C)were used for all the films. After deposition samples were investigated by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy (EDS). Similar analysis were performed on targets before and after deposition. It has been observed that the evolution of the two types of targets during deposition was very different and this aspect was reflected in differences of film morphologies. Films deposited from special targets presented an uniform fine grained microstructure with only few particulates on surface, while films deposited from commercial targets had a much rougher surface. EDS analysis showed important chemical differences between these particulates and the surrounding film