Ambient Gas Effects on the Reaction of Titanium with Silicon

Because of its low resistivity and excellent thermal stability, TiSi2 is finding widespread application as an interconnect material in novel schemes such as the salicide structure. The Ti-Si reaction is complex and has been studied previously in certain regimes. This investigation shows that the ambience in which the reaction is conducted influences the reaction considerably. We show that after the commencement of the interfacial reaction, i.e., after reduction of interfacial oxides, the initial stage of the reaction proceeds rapidly. The extent to which it proceeds depends on the nature of the Ti ambient gas interaction. A final stage of the reaction begins when the silicide phase and the ambient species phase interfere; the reaction then proceeds relatively slowly at a rate depending on the nature of the ambient species. Some important implications of these observations for device processing applications are pointed out. © 1985, The Electrochemical Society, Inc. All rights reserved.