Preparation of Pb(Zr, Ti)O₃ Thin Films by Multi-Target Sputtering

Abstract

Lead zirconate titanate (PZT) thin films have been prepared with a multi-target sputtering system onto Pt-coated Si substrates. Structure, composition and dielectric properties have been investigated on films ranging in thickness from 60 nm to 1400 nm. The dominant phase of PZT thin films varied from pyrochlore to perovskite with increasing film thickness. An interface PZT layer with about 100 nm thickness, which was confirmed to mainly consist of pyrochlore phase grains, was observed at the PZT/Pt interface in a cross-sectional transmission electron microscopy (TEM) image of an 850 nm thick film. That is, the pyrochlore grains preferentially grow at the early stage of deposition and do not change their structure during subsequent deposition. Dielectric constant and remnant polarization were degraded with decreasing thickness. This can be explained in view of the existence of the interface layer with a low dielectric constant.

Mechanisms of imprint effect on ferroelectric thin films

“…[45][46][47] Such degradation of ferroelectric properties 19 has been suggested to occur for reasons such as: ͑a͒ interdiffusion between a ferroelectric thin film and electrode, 48 ͑b͒ insufficient flatness of bottom electrode and film, and ͑c͒ vacancies of Pb and/or oxygen. 49 It is justifiable to model the surface layer as a graded one in which the permittivity and remanent polarization decrease gradually from the bulk values ͑Fig.…”

Fast Deposition of Lead-Zirconate-Titanate Thick Films by Arc Discharged Reactive Ion-Plating Method

“…Such tendencies have also been reported in films fabricated by sputtering. 8) Therefore, it is considered that the similar growth mechanism reported in PZT films prepared by sputtering 9) is effective in the growth by the ADRIP method. In the early stage of the film growth, insufficient Pb content in the PZT layer caused by Pb diffusion to the bottom electrode is due to the growth of a pyrochlore phase.…”

Multi-target reactive sputtering—A promising technology for large-area Pb(Zr,Ti)O3 thin film deposition

“…By this way, a non-ferroelectric interface layer with a thickness of up to 100 nm is formed. 21 By using a thin TiO 2 seed layer, we have significantly reduced Pb loss at the initial deposition stage. In this way, we exploit the decreased PbO vapor pressure in the Pb(Zr,Ti)O 3 + TiO 2 system compared to Pb(Zr,Ti)O 3 + PbO by about one order of magnitude.…”