IN-SITU SPECTROSCOPIC ELLIPSOMETRY FOR MONITORING THE TI-SI MULTILAYERS DURING GROWTH AND ANNEALING

The TiSix formation and properties depend strongly on the deposition a nd annealing process. We employ spectroscopic ellipsometry (SE) to mon itor both processes as well as transmission electron microscopy (XTEM) to verify the above results. The Ti and Si layers were deposited by m agnetron sputtering on (100)Si. The multilayer thickness is about 930 Angstrom and the Si/Ti ratio approximate to 2.2, while the thickness o f each Ti-Si bilayer approximate to 120 Angstrom. After deposition of each Ti or Si layer and during annealing of Ti-Si multilayers up to 68 0 degrees C we obtain the SE spectra in the energy region 1.5-5.5 eV. Their analysis and XTEM observations show that during deposition an in termixing of 20 Angstrom width at each Ti-Si interface occurred. By us ing SE we found that during annealing below 150 degrees C there is no drastic intermixing or reaction between Ti and Si. A fast interdiffusi on of Ti and a-Si and their reaction is observed between 200 and 580 d egrees C. A phase transition occurs at 580 degrees C from the amorphou s Ti5Si3 compound to the C49 TiSi2 structure and above this temperatur e XTEM depicts that only structural modification within the interdiffu sed layers of Ti-Si is observed.