The structures and mechanical strength existing in three different hydrophobic silane compounds, Henicosyl-1,1,2,2-tetrahydrododecyltrichlorosilane (FDDTS), Tridecafloro-1,1,2,2-tetrahydrooctyltrichlorosilane (FOTS) and [Tris(trimethylsiloxy)silyethyl]dimethylchlorosilane (Alkyl) under same deposition conditions were studied and presented in this paper. The effect of the chemical composition on the mechanical strength and the structural evolutions as related to chlorosilane was inquired. The structures were investigated by using field emission scanning electron microscope (FESEM), atomic force microscope (AFM) and surface profiler while the nature of the mechanical strength was determined from nanoindentation and nano scratch. From the data obtained, the FDDTS showed to be denser in structures than both Alkyl and FOTS. The root-mean-square (RMS) roughness exhibited by FDDTS was larger when compared to the other two silanes. The mechanical ability shows that the FDDTS has the largest maximum penetration load as well as highest scratch resistance. Overall, the FDDTS would perform excellently in the applications where combine hard and wear resistance organic coating is required.