Ohmic resistance of thin yttria stabilized zirconia film and electrode-electrolyte contact area

This paper describes the factors influencing the measured value of ohmic resistance together with the structural and optical characterization of two thin yttria stabilized zirconia films. The investigated films were deposited on n-doped Si (1 1 1) substrates using e-beam evaporation of (YO1.5)(0.18)(ZrO2)(0.82) pellets at 150 degreesC. The crystallographic structures of both films were found as amorphous (thickness of 240 nm) and polycrystalline (thickness of 330 nm) with the grain size similar to 36 nm. The imperfection of the electrical contact, in the case of thin films the thicknesses of which an similar to 100 nm, can dramatically influence the magnitude of measured ohmic resistance. Moreover, the ratio of R-eff/R-true cannot be determined from measurements of films with various thicknesses, but only estimated from micrographs or from measurements of films of the material with the known electrical conductivity. The different behaviour of the refractive index and the extinction coefficient of the two investigated films can be attributed to different crystallographic structures of the films. (C) 2001 Elsevier Science B.V. All rights reserved.