Concentration microprofiles in iron silicides induced by low energy Ar+ ion bombardment

Auger electron spectroscopy (AES) in conjunction with sputter removal by Ar+ ions of only 120 eV has been used to determine the concentration microprofiles generated in polycrystalline Fe3Si, FeSi and FeSi2 samples by a preceding bombardment with Ar+ ions of 1-5 keV. The conversion of the surface sensitive AES ptp-signals measured in dependence of the profiling ion fluence into concentration-versus-depth profiles was facilitated by the fact that the bombardment-induced stoichiometry changes had no noticeable influence on the relative AES detection factors between Si and Fe. The concentration microprofiles extended up to about 16 nm into the solid, and displayed a rather uniform behaviour with a pronounced minimum of the Si concentration at 1-2 nm. Their characteristic features are related to the mean projected ranges of the keV-projectiles in the different iron silicides, and are assumed to provide direct experimental information on the corresponding deposited energy functions. (C) 2000 Elsevier Science B.V. All rights reserved.