Evaluation of Molecular Interaction between Organic Molecules Physisorbed on Silicon Native Oxide Surface in Dry and Humid Atmosphere

Abstract

An experimental method for evaluating the intensity of molecular interactions between organic molecules and surfaces was studied. The organic compounds’ physisorption and desorption rates to and from the silicon native oxide surface were in situ measured using a quartz crystal microbalance and analyzed following the multicomponent organic species adsorption-induced contamination model. Three organic compounds, isopropanol, octanol and diethylphthalate, in each single-component system and in a multicomponent system were used in dry and humid atmosphere. The physisorption and desorption rate constants of these compounds in the dry atmosphere were higher than those in the humid atmosphere. However, the molecular radii in both atmospheres were similar. Thus, the interaction between the organic molecules and the surface was influenced by the existence of a thin water layer, while the interaction between the organic molecules had less influence by the atmosphere.