IMPROVED DEPTH RESOLUTION IN AUGER DEPTH PROFILES OF TIN THIN-FILMS BY OPTIMIZED SPUTTERING PARAMETERS

The depth resolution in Auger in‐depth profiles of TiN thin films on smooth Si substrates is determined by the evolution of a sputter‐induced surface roughness. It is shown that this effect depends critically on the ion angle of incidence. Therefore, the depth resolution can be improved most efficiently by optimizing the bombardment angle. The ideal sputter angle for Ar+ ions is found to be ∼76° and for Xe+ ions >80° to the surface normal, although slightly less grazing angles of incidence are preferred for more practical sputter rates. For any angle, the depth resolution can be improved further by reducing the ion energy and using Xe+ instead of Ar+ ions for etching. Thus, for TiN thicknesses of 83 nm and 650 nm, the sputter‐induced interface broadening can be as low as 3.5 nm and 8 nm, respectively. Copyright © 1990 John Wiley & Sons Ltd.