Influence of the deposition temperature and PB species flux on the characteristics of PbTiO₃thin films deposited by sputtering on optical fibers

Abstract

Integrated optical devices can be fabricated by the deposition of an electrode/piezoelectric/electrode multilayer thin film structure onto optical fibers. The particular structure used in this work is Au/PbTi03/Pt/Ti, where the PbTiO3 is deposited by DC reactive magnetron sputtering at high temperature to obtain in situ crystallised perovskite structure. Preliminary studies showed that the deposition temperature and the relative fluences of the Pb and Ti species are determining parameters for the growth of phase pure perovskite PbTiO,. This study shows the effect of both parameters on the resulting film. The occurrence of a self-stabilising region for the growth of pure perovskite phase PbTi03 has been observed. The maximal achievable dielectric constant depends on the relative Pb flux used. It increases with increasing PbO to TiO, fluxes ratio. X-ray, microstructure, conductivity results and optical response of the devices are also briefly presented. An optical phase shift of 0.4 mradN has been measured for low frequency electrical excitation.

Excess lead in the perovskite lattice of pzt thin films made by in-situ reactive sputtering

“…Optical fibers were coated in a self-built tool having three rectangular magnetrons directed towards the center of the cylindrical chamber where the fibers were rotating around their long axes. Details about the processes have been published earlier [8,13,14]. In both cases, platinum bottom electrodes were used.…”

“…Lead self-stabilization was found to take place above 600°C in case of co-evaporation of PbO and TiO 2 [7]. Later work in PZT coatings, especially the one on optical fibers [8,9] learned us that there can be a considerable amount of lead excess in the perovskite films, even in the ones showing no sign of a second phase. The problem of lead excess in a perovskite was previously also encountered in reactively, in-situ sputter deposited thin films of PbSc 1/2 Ta 1/2 O 3 by Whatmore, Huang and Todd [10].…”