In order to further understand organosilane oscillatory adsorption, we have adsorbed octyltrichlorosilane (C8H17SiCl3 or OS) on model hydroxyl terminated surfaces consisting of a thiol-alcohol self-assembled on gold. The adsorption kinetics was followed with the time-of-flight secondary ion mass spectrometry (TOF-SIMS) technique. The OS adsorption is readily detected by means of a variety of silicon containing ions, some non-specific (e.g. SiH-, SiO2-) and others specific of the OS (C8H17SiO2- or dimers C16H35Si2O4-). Interestingly, a complex non-monotonic adsorption pattern is observed. Moreover, carefully selected ions exhibit different intensity variations with the adsorption time, providing some insight not only on adsorption kinetics, but also on film cross-linking, adsorption sites occupation and even on HCl production due to the trichlorosilane hydrolysis. Small, non-specific fragments (SiH-) are believed to indicate the OS surface coverage whereas large specific fragments are strongly dependent on the interface cross-linking, which reduces their probability of sputtering. (C) 2002 Elsevier Science B.V. All rights reserved.