Kinetic energy distributions of ions ejected during laser ablation of lead zirconate titanate and their correlation to deposition of ferroelectric thin films
ABSTRACTLead zirconate-titanate (PZT) thin films were prepared by the laser ablation technique. The PZT (Zr/Ti=53/47) target was irradiated using a focused q-switched Nd:YAG laser (15 ns, 100 mJ at 1.064 μ;m). The as-deposited films were amorphous as indicated by X-ray powder patterns, but crystallized readily with brief annealing above 650°C. The dielectric constant and the resistivity of the crystallized films were studied using a parallel-plate type capacitor structure.
Ferroelectric thin films have recently proven viable for nonvolatile memory applications in semiconductor technology. Current research is focused on the development of processing technologies and deposition on metallized semiconductor substrates. In this study, niobium-doped lead zirconate titanate thin films were prepared by a dc magnetron-sputtering technique using a multielement metal target. Films were deposited on indium tin oxide coated glass and on metallizations on silicon substrates. The crystallographic structure and surface morphology of the films was examined by scanning electron microscopy and X-ray diffraction as a function of processing variables such as sputtering pressure, film thickness, and niobium content. Electrical characterization of the films is discussed in terms of ferroelectric hysteresis and polarization properties. Improved ferroelectric properties are achieved through a densified structure resulting from niobium-doping.
