SURFACE NUCLEATION OF TI SILICIDES AT ELEVATED-TEMPERATURES

The nucleation of Ti silicide at the surfaces of Si was studied. Depos ition of Ti and codeposition of TiSix at elevated temperatures on sing le crystal and amorphous Si led to the direct growth of silicides. The temperature and composition of the deposition and the crystallinity o f the substrate were found to have a strong effect on the phases(s) of the silicide layer. A remarkably low nucleation temperature, similar to 500 degrees C, for the low-resistivity C54-TiSi2 phase was observed on amorphous Si. Stoichiometric and uniform TiSi2 layers were grown w ith the depositions of pure Ti. On crystalline Si, uniform TiSi2 layer s were also grown at similar to 500 degrees C with the deposition of e ssentially Ti. The significant difference between silicide formation i n the present scheme and that under conventional silicide processing w as discussed in terms of a possible circumvention of precursor amorpho us salicide phases during surface nucleation. (C) 1996 American Instit ute of Physics.