High performance devices often require good quality layers, homogeneous com
position and crystallinity, then the homogeneity in depth of the layers is
of major interest. Our study investigates the possibility of evaluating the
inhomogeneity of the refractive index of transplant films deposited on abs
orbing substrate by multiple-angle ellipsometry. We propose a method which
is based upon the determination of the best experimental conditions leading
to thr minimal uncertainty one can expect on the physical parameters to be
determined. A theoretical study of an inhomogeneous Al2O3 layer deposited
on an InP substrate is presented as an example. (C) 1998 Elsevier Science S
.A. All rights reserved.