Differences in Ferroelectric Characteristics of Similar Hafnium Zirconium Oxide Films Studied Using X - Ray Photoelectron Spectroscopy

The ferroelectric (FE) properties of hafnium zirco-nium oxide
$(\text{Hf}_{l-x}\text{Zr}_{x}\mathrm{O}_{2})$
, a material of importance for many electronic applications such as low-power computing and non-volatile memories, are heavily dependent on the Zr content
$(x)$
. Here we report that in some cases, samples with the same
$x$
display different FE character and these variations can be related to changes in the location of the Zr
$3\mathrm{t}1$
and
$O Is$
peaks in X-ray photoelectron spectroscopy (XPS) spectra. This suggests that lattice strain and Zr-O bonding variations play a significant role in the FE character of
$\text{Hf}_{l-x}\text{Zr}_{x}\mathrm{O}_{2}$
thin films.