PMN-PT thin films grown by sputtering on silicon substrate: influence of the annealing temperature on the physico-chemical and electrical properties of the films

Studies of piezoelectric and electrostrictive properties of (1?x)PMN-xPT thin films were carried out. We have chosen the compositions 90/10 and 70/30, which exhibit, respectively, mostly electrostrictive and piezoelectric behaviour in bulk material. Annealing temperature effects on PMN-PT structural, dielectric, ferroelectric and electromechanical properties have been investigated. We demonstrate that with conventional annealing the pure perovskite phase can be obtained at very low temperature (400°C) without any pyrochlore phase for the two compositions. We show that electromechanical response is a mix between electrostrictive and piezoelectric response for the two compositions. However, as can be easily understood, piezoelectric contribution is larger for 70/30. It is shown that electrical responses of the films obtained at 400°C are largely satisfied for many applications; for higher annealing temperature we observe an enhance of the electrical properties due to an improvement of the material quality in terms of crystalline structure.