The adsorption processes in physical vapor deposition (PVD) and alternating vapor deposition polymerization (AVDP) of organic compounds are analyzed to estimate the parameters associated with the adsorption characteristics. Observation by a simple technique using a precisely tuned quartz crystal microbalance (QCM) reveals that the first stage in the thin film formation comprises two types of adsorption, namely physisorption and chemisorption. A modified model for physisorption involving free and metastable states is proposed for the analysis of the physisorption behavior in order to estimate the average lifetime and the adsorption energy of molecules on the substrate. (C) 2002 Elsevier Science B.V. All rights reserved.