MULTILAYER REFERENCE COATINGS FOR DEPTH PROFILE STANDARDS

Depth profiles of layer systems consisting of different film materials and having different thicknesses are of great practical importance. M ultilayer reference coatings of conducting (Ti/Al) and non-conducting (SiO2/Si3N4) material are analyzed with Auger electron spectroscopy (A ES) and glow discharge optical emission spectroscopy (GDOES) depth pro filing. Deposition techniques, physical vapor deposition for Ti/Al lay ers and plasma-enhanced chemical vapor deposition for SiO2/Si3N4 layer s, as well as measurement and testing procedures for the determination of layer thickness such as optical and mechanical stylus and spectros copic ellipsometry are discussed. GDOES depth profiles in direct curre nt (d.c.) and radio frequency (r.f.) mode are related to measurements of crater profiles and compared with line scans and depth profiles per formed by AES. It is shown that such multilayer reference systems are appropriate for calibration of depth profiles, i.e. the definition and the evaluation of the depth resolution at the interface, the determin ation of sputter rates both for d.c.- and r.f.-GDOES and AES, the opti mization of the conditions of analysis, and the quantification of anal ysis itself.