Molecular Adsorption and Desorption Behavior on Silicon Surface in a Complex Ambient Atmosphere Containing Vapors of Diethylphthalate, Acetic Acid and Water

Using a complex ambient atmosphere containing vapors of an organic compound, acid and water, the molecular adsorption and desorption behavior on a silicon surface was studied using the in-situ measurement of a quartz crystal micro-balance linked to the rate theory. Because the behavior of diethylphthalate (DEP) could be reproduced assuming a single-component system, acetic acid (ACA) and DEP are concluded to separately exist in the water film and at the water film surface, respectively. This conclusion was obtained from both the adsorption and desorption behaviors. The process developed in this study is useful for determining the layer in which chemical compounds are present.