The reaction processes of selective titanium silicide low-pressure chemical vapor deposition using a TiCl4/SiH4 gas system at 720 to 740-degrees-C are studied, in conjunction with film properties, using quadrupole mass spectrometry measurements and other analyses. In the initial stage of deposition, TiCl4 and the silicon substrate react to produce Ti5Si4, C54-TiSi2, an undetermined silicide, and SiCl(n) (n = 1, 2, 3, 4). This reaction explains the high sensitivity to the native oxide. After that, the SiH4 gas joins into the reaction to produce C54-TiSi2, HCl, H-2, relatively small amounts of SiCl(n) (n = 1, 2,3,4), and SiHCl. This reaction moderates silicon consumption and changes the film properties. The features of this reaction at higher temperatures of 780 to 820-degrees-C are similar to those exhibited at 720 to 740-degrees-C. Nucleation is discussed in terms of stress generation by a gradient in the Ti/Si composition, caused by independent changes in the source-gas decomposition rates.