TITANIUM DISILICIDE ON SILICON BY INTERDIFFUSION OF TITANIUM AND AMORPHOUS-SILICON MULTILAYERS - TRANSMISSION ELECTRON-MICROSCOPY, SPECTROSCOPIC ELLIPSOMETRY AND RESISTIVITY MEASUREMENTS

Titanium disilicide is formed by interdiffusion of multilayer structures, obtained by alternate amorphous silicon and titanium thin films, deposited by electron gun evaporation. The results presented here are complementary to previously published results on the influencer of the bilayer Si-Ti thickness ratio on the thin film properties. Transmission electron microscopy, spectroscopic ellipsometry and electrical measurements in the temperature range 80-450 K are used. It is found that all samples with an excess of silicon in the deposited layers show lower sheet resistivity, compared with samples with a deficiency in the deposited silicon. This is in agreement with the grain sizes measured by transmission electron microscopy. The surface and interface of TiSi2 obtained from multilayers are very sharp compared with TiSi2 films obtained from a single deposited titanium layer on top of the silicon substrate.