The influence of stress on the growth of titanium silicide thin films on (001) silicon substrates

The influence of stress on the enhanced formation of C54-TiSi₂ phase has been investigated. Tensile stress induced by backside CoSi₂ film on the silicon substrate has been found to enhance the growth of C54-TiSi₂ on (001)Si. The thickness of amorphous interlayers (a-interlayers) between Ti films and silicon substrates was found to be thicker and thinner in the tensilly and compressively stressed samples, respectively. From auto-correlation function analysis, the thicker a-interlayer was found to consist of a higher density of crystallites. The crystallites provide nucleation sites for C49-TiSi₂ and facilitate the formation of C49-TiSi₂ of small size. The larger total area of C49-TiSi₂ grain boundaries supplies more nucleation sites for the phase transformation of C49- to C54-TiSi₂. Therefore, the tensile stress present in the silicon substrate promotes the formation of a-interlayer and decreases the grain size of C49-TiSi₂, which increases the nucleation density of the C54-TiSi₂ phase. As a result, the transformation of C49- to C54-TiSi₂ phase is enhanced.