Regensburg 2007 – scientific programme

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DS: Fachverband Dünne Schichten

DS 26: Oxides

DS 26.7: Talk

Thursday, March 29, 2007, 16:30–16:45, H34

GaPO₄ epitaxial thin films: Growth and thermal stability — •Johannes Pedarnig, Stefan Roither, Martin Peruzzi, and Dieter Bäuerle — Institut für Angewandte Physik, Johannes Kepler Universität Linz, A-4040 Linz

Gallium orthophosphate (GaPO₄) is an outstanding novel piezoelectric material that remains piezoelectric up to a temperature of 970^∘C. Crystalline GaPO₄ films have not been reported so far due to the complex materials chemistry.

We are reporting on solid phase epitaxial growth of GaPO₄ thin films on alpha - quartz (SiO₂) substrates. Amorphous stoichiometric precursor layers are fabricated by pulsed-laser deposition on (001) SiO₂ substrates and are subsequently transformed to crystalline GaPO₄ by post-annealing in air at elevated temperature. Epitaxial films with thicknesses up to 300 nm exhibit strong in-plane and out-of-plane textures (angular widths < 0.6^∘). Long-term annealing in air at temperatures above the alpha - to beta - phase transition of the quartz substrate (573^∘C) does not degrade these films.

This work is supported by the Austrian Federal Ministry of Economics and Labour (Micro@Nanofabrication Austria network) and the European Science Foundation (Thin Films for Novel Oxide Devices project).