Abstract

Ti-Zr alloy thin films of 20-60 nm in thickness were evaporated on Pt-coated silicon wafers. The films exhibited a layered Ti-Zr depth distribution. The films were then treated hydrothermally in 0.25 M Ba(OH) 2 at 150 and 200 °C for 4-8 h. Films treated at 150 °C did not exhibit reflections from the Ba(Ti xZr 1-x)O 3 perovskite structure by x-ray diffraction, although a slight barium content was detected by x-ray photoelectron spectrometry. On the other hand, the films treated hydrothermally at 200 °C revealed reflections corresponding to perovskite Ba(Ti xZr 1-x)O 3. These films exhibited a homogeneous titanium and zirconium depth distribution, as shown by x-ray photoelectron spectroscopy and Auger depth profiles, proving that either titanium or zirconium ions diffuse during the hydrothermal treatment. The initial Ti-Zr film was completely consumed during the hydrothermal process, leading to a film of homogeneous composition (Ba, Ti, and Zr) up to the interface with the platinum layer.