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.