Phase transformation and paired-plate precipitate formation in Pb0.91La0.09Zr0.65Ti0.35O3 films grown on sapphire substrates

Abstract

We report on the phase transformation behavior of Pb0.91La0.09Zr0.65Ti0.35O3 (9/65/35) PLZT films grown on r-sapphire substrates via rf-magnetron sputtering. A complex microstructure results in these films depending on deposition and annealing conditions. A random equiaxed polycrystalline grain morphology was observed after rapid thermal annealing or furnace annealing when the as-deposited films were predominantly pyrochlore. Precipitate formation (100-150 nm) was observed in PLZT films that were deposited at temperatures in excess of 490degreesC with a perovskite structure, after furnace annealing at 700degreesC. We believe that this is related to internal stresses in the films due to both the lattice mismatch and the thermal expansion mismatch between the PLZT film and the sapphire substrate. (C) 2002 Elsevier Science Ltd. All rights reserved.