Preparation of Pb(Zrx,Ti1-x)O3 thin films by source gas pulse-introduced metalorganic chemical vapor deposition

We prepared Pb(Zr,. Ti1-x)O-3 [PZT] thin films on (1 1 1)Pt/Ti/SiO2/Si substrates at 620 degreesC by metalorganic chemical vapor deposition (MOCVD). PZT [Zr/(Zr+Ti) = 0.68] thin films of different thicknesses prepared by the conventional continuous source gas introduction MOCVD (continuous-MOCVD) and by pulsed gas introduction MOCVD (pulse-MOCVD) were compared to investigate the growth mechanism of these films. Stoichiometric PZT films were obtained for a wider range of Ph source input gas flow rates under fixed Zr and Ti sources for pulse-MOCVD compared with that for continuous-MOCVD. Highly (1 1 1)-oriented films were obtained for pulse-MOCVD regardless of their thickness. while the (1 1 1)-orientation decreased with film thickness for continuous-MOCVD. This suggests that the orientation homogeneity along the film thickness is higher for pulse-MOCVD films than for continuous-MOCVD films. The surface roughness of the pulse-MOCVD films was smaller than that of the continuous-MOCVD films and this result corresponds to the decrease of the leakage current density of the film. Well-saturated hysteresis loops with good square shapes were obtained. and the remanent polarization (P-r) and the coercive field (E-c) values of 100-nm-thick films prepared by pulse-MOCVD were 37 muC/cm(2) and 82 kV/cm. respectively.