Surface Morphology of Lead-Based Thin Films and Their Properties

Abstract

Surface morphology of lead-zirconate-titanate [PZT(52/48)] thin films prepared by sol-gel processing on Pt/Ti/ SiO2/Si substrates was studied. When the atomic ratio [Pb/(Zr+Ti)] of PZT gel films was 1, rosette structure was observed in the films after annealing at 600° C for one hour. The crystal structure of the rosette was identified as perovskite and that of the other area was nonperovskite, by electron diffraction analysis. Lead deficiency in the non-perovskite phase caused by lead diffusion into the bottom electrode was detected by energy dispersive X-ray spectroscopy and Auger electron spectroscopy. In order to prepare PZT films with a smooth surface, the following four means were efficient: addition of lead excess, rapid thermal annealing (RTA), adoption of buffer layer, and preparation of crystal nucleus on the substrate.

Crystal structure and microstructure of lead zirconate titanate (PZT) thin films with various Zr/Ti ratios grown by hybrid processing

“…This suggests that the rosettes occur in the case of low nucleation rate of the columnar grains. The same phenomenon was previously observed in the PZT films fabricated by the sol-gel method [21].…”

Ferroelectric properties of heterolayered lead zirconate titanate thin films

“…For example, the six-layered film consisting of PZ 70 T 30 is rather different from that of PZ 30 T 70 , when both were annealed at 650 • C. The PZ 70 T 30 multilayer showed an extensive rosette structure, while PZ 30 T 70 multilayer did not. This is consistent with the observation that less lead diffusion occurred in the titanium-rich PZT films [9]. The cross section of the six-heterolayered PZT film is shown in Fig.…”

“…They exhibited a rosette structure, where an increase in annealing temperature promoted formation of such rosette structure. Indeed, such structure has been reported for PZT films derived from sol-gel, due to the lead deficiency arising from the loss at elevated temperatures [9][10][11]. The lead loss can occur as a consequence of the evaporation of Pb from the surface and/or the diffusion to the bottom electrode [9], giving rise to the rosette structure, where the film surface is inhomogeneous and rough.…”

Dependence of annealing time on structural and morphological properties of Ca(Zr0.05Ti0.95)O3 thin films

“…6(a) shows a uniform and homogeneous CZT grain distribution. The rosette structure, which is typical for PZT thin films [17,18], was not observed in our analysis. The increase of annealing time leads to bigger grains evidencing that the oxygen atmosphere promotes the grains coalescence ( Fig.…”