Electrical & Computer Engineering, Department of
Document Type
Article
Date of this Version
4-15-1997
Abstract
Correct determination of layer thicknesses on a subnanometer scale is crucial for studies of giant magnetoresistance, magneto-optical (MO) Kerr rotation, magnetic interlayer coupling, and other magnetic properties of metallic multilayers. Some structures such as [Co/Ni] and [Co/Pt] with fewer than 20 repeats are difficult to be analyzed by x-ray diffraction (XRD) due to too little material. In this work, in-situ spectroscopic ellipsometry (in-situ SE) is used to precisely determine the optical constants undisturbed by oxidation, and the growth rates of different metal films deposited in a sputtering chamber. In-situ SE determines both the constant and continuously changing growth rates during deposition of individual layers. SE data were also taken during multilayer thin-film growth, from which we determine the individual layer thicknesses in the superlattice to a fraction of an angstrom. The in-situ SE data and ellipsometric analysis of [Co/Au] and [Co/Ni] multilayers on thick gold-coated silicon, and [Co/Pt] multilayers with a Pt underlayer are presented. Less than a few percent difference was found by comparing the XRD thickness results to thein-situ SE thickness results. In-situ SE permits studies of oxidation kinetics, important because oxidation strongly influences both the magnetic and MO results. Specifically, spectroscopic MO Kerr rotation, ellipticity, and figure of merit of [Co/Ni] and [Co/Pt] multilayers with different repeat structures, with and without capping layers are reported covering the spectral range from ultraviolet to near infrared.
Comments
Published in J. Appl. Phys. 81 (8), 15 April 1997. © 1997 American Institute of Physics 3845. Used by permission.