Abstract

Deposition and etching reactions induced by a laser beam incident on a surface are uniquely influenced by the nature of the excitation source. For example, considerable effort has been made to clarify the relative importance of reactions from the ground and electronically excited states in decomposition and desorption. In order to use results of such studies to understand real systems, however, the fact that the level of optical excitation may vary in time must be explicitly considered. Indeed, as a surface reaction proceeds substantial changes in the chemical nature of the system, and hence its optical and thermal properties, may take place. These changes directly affect the amount of excitation coupled into the system, feeding back into the chemistry. This circular interdependence of excitation and reaction can lead to considerable complexity in apparently simple processes. For this reason caution must be exercised in deriving mechanistic information from macroscopic rate measurements during etching and deposition reactions.

© 1987 Optical Society of America