Analysis of preferred orientations in PST and PZT thin films on various substrates

Abstract

Orientation distributions of Pb(Zr, Ti)O₃ and Pb₂ScTaO₆ thin films deposited on various substrates and buffer layers are described. All observed textures are basically fibre textures. Only PST films deposited on show a weak in-plane alignment, with ⟨100⟩ PST perpendicular to the film surface. PST films deposited on a Pt/(100)-Si substrate exhibit strong ⟨111⟩ fibre texute, tilted 5° to the normal. The Pt substrate has also a ⟨111⟩ fibre texture, with orientation densities as high as 60 times the random distribution (m.r.d.). On both substrates, PST films show maxima in the orientation distribution near 35 m.r.d.

PZT films (PZT/Pt/Si-(100) and PZT/Pt/Ti/SiO₂/Si-(100)) have a ⟨111⟩ fibre texture. The maximum orientation distribution observed for PZT is 200 m.r.d. A minor (100) fibre component may be present. The Pt textures resemble qualitatively those of PZT, mainly (111). The addition of a Ti buffer layer on grown SiO₂ favors the stabilization of PZT in a tetragonal crystal system, and increases strongly the Pt texture, and to a lesser degree that of PZT.

Key Words:

• Ferroelectrics
• texture
• thin films
• PST
• PZT
• orientation distribution