Electrical and optical characterizations by prism-coupling method of PZT deposited in-situ by sputtering

摘要

Thin films of lead titano-zirconate (PZT) were prepared in-situ using radio-frequency sputter-deposition. Then in-situ perovskite formation is very sensitive to the substrate temperature (T-s) and the sputtered lead flux; the incident lead flux is controlled by the lead content in the target (X). Perovskite phase can be obtained under a relatively wide range of (X, T-s) combinations. The lower growth temperature is 510degreesC associated to X = 1.10 and the optimized growth temperature, in terms of optical and electric properties, is T-s = 550degrees (X = 1.50). At this temperature, the relative dielectric constant is equal to 860 and the dielectric losses are in the order of 0.019. The remnant polarization and the coercive field are, respectively, 19 muC/cm(2) and 42 kV/cm. The piezoelectric coefficient e(31) is maximum without poling treatment; it is in the order of -5.2 C/m(2). The prism coupling method is used to characterize the optical properties of the films. Both ordinary (n(0)) and extraordinary (n(e)) refractive indices were determined from transverse electric and transverse magnetic mode excitations; n(0) = 2.558 and n(e) = 2.507 at 632.8 nm. Furthermore, the refractive index profile analysis reveals a step-like behavior of PZT films, synonymous of a good optical homogeneity along the layer thickness. (C) 2002 Elsevier Science Ltd. All rights reserved. [References: 18]