APPLICATION OF AES MICRO-ANALYSIS TO INTERFACE CHARACTERIZATION IN TI-SI DIFFUSION COUPLES .1. PHASE-ANALYSIS

A detailed analysis of the silicides which are formed by diffusion at a titanium-silicon interface was performed by quantitative AES analysis. The diffusion couples were annealed in vacuum at temperatures ranging from 450 to 700°C. Semi-quantitative AES spectrum/peak-to-peak height analytical mode was found to be not accurate enough to identify the titanium silicides particularly at low temperatures and short durations annealing. A quantitative method based on E &middot N(E) spectra and peak-to-background ratios, was used which led to more reliable results. Furthermore, the shape of the titanium Auger electron peaks were used to confirm the phase nature. After a diffusion treatment of moderate intensity, the interaction zone is mainly formed of two silicides, Ti5Si3 and TiSi2. On the contrary, under severe diffusion conditions, the disilicide phase is predominant. Finally, the growth of TiSi2 rejects oxygen (present in trace amounts in the titanium film) in the Ti-rich side of the couple.