Effect of Interfacial Oxide Thickness on Titanium Silicide Formation

TiSi2 formation on various substrates has been widely investigated in the past and one of the critical parameters has been found to be the quality of the interface before deposition. In this paper the quality of the suicide formed on a range of oxides, from lnm to 15nm, has been systematically studied using sheet resistance measurements, Scanning Electron Microscopy, Atomic Force Microscopy and Auger Electron Microscopy. The critical thickness, above which the quality of the suicide formed is affected, was found to be 2.2nm and no suicide was detected > 13.0nm. A notable difference in the suicide formation occured in a narrow band around 5.0nm. It is proposed that this is the transition region in which the oxide becomes the main source of Si for TiSi2 formation rather than the substrate.