IN-SITU X-RAY-DIFFRACTION MEASUREMENTS OF SILICIDE FORMATION IN THE CO-SI SYSTEM

The applicability of in situ X-ray diffraction for studying reactions characterizing thin silicide film formation was explored. The Co-Si sy stem was chosen as a test case for the validity of the technique, beca use the importance of this system in very-large-scale integration micr oelectronic applications. It is shown that the technique is useful for kinetics and phase relations studies. CoSi is the only phase detected by in situ X-ray diffraction in specimens annealed in the range 400-4 50 degrees C. Clear coexistence of CoSi and CoSi2 is indicated in the samples annealed at 500-550 degrees C. Above 600 degrees C in situ X-r ay diffraction revealed that only CoSi2 exists. An activation energy o f 1.2 eV was derived from the in situ diffraction data for the diffusi on-controlled growth of CoSi2. It is assumed that this value is associ ated with grain boundary diffusion.