EXAMPLES FOR THE IMPROVEMENTS IN AES DEPTH PROFILING OF MULTILAYER THIN-FILM SYSTEMS BY APPLICATION OF FACTOR-ANALYSIS DATA EVALUATION

Factor analysis has proved to be a powerful tool for the full exploita tion of the chemical information included in the peak shapes and peak positions of spectra measured by AES depth profiling. Due to its abili ty to extract the number of independent chemical components, their spe ctra and their depth distributions, its information content exceeds th e one of the usual peak-to-peak height evaluation of AES depth profile data. Using modern software with a graphically interactive user inter face the analysi is put into a position, where he can work with Factor Analysis on a physically intuitive level despite of all the matrix al gebra mathematics which it is based upon. The progress brought about b y Factor Analysis to AES depth profiles of thin films is demonstrated by the analysis of two thin film systems. The first one is a Pt/Ti met allisation used as bottom electrode for ferroelectric thin films, the second one is a multilayer system where a Ti silicide formation of bur ied Ti/Si bilayers has been induced. Both examples show that Factor An alysis evaluation of AES depth profile data is capable to give access to stoichiometry information and to reveal interfacial layer phases, i nformation which is hardly obtained from the conventional peak-to-peak height data evaluation.