Energy Release, Chemical Selectivity, and Stereochemistry of Interhalogen Reactions with Low Work Function Surfaces

University Of California-San Diego, La Jolla CA

Investigators

Abstract

This research project addresses the fundamental mechanisms of non-adiabatic gas-surface interactions. With the support of the Analytical and Surface Chemistry Program, Professor Andrew Kummel and his coworkers at UC-San Diego are carrying out detailed experimental studies of the dissociative adsorption of halogen and interhalogen molecules interacting with low work function surfaces such as Al(111). Velocity dependent molecular beams of dihalogens and interhalogens are used to probe the mechanisms of remote dissociative and abstractive chemisorption. Velocity distributions of scattered halogen atoms, coupled with scanning probe microscopic examination of the reacted surface provide the details of energy partitioning and mechanism in these studies. The interaction of oriented interhalogen molecules is also examined. In addition to the fundamental insights obtained concerning non-adiabatic processes at surfaces, information relevant to the dry etching of electronic materials results from this work. The mechanisms of halogen etching reactions taking place on low work function surfaces is the focus of this research project carried out by Professor Kummel and coworkers at UCSD. Using a combination of molecular beam methods, laser spectroscopic characterization of scattered species, and scanning probe microscopy to characterize the reacted surface, detailed information about halogen based plasma enhanced etching processes is obtained. This fundamental research has broad impact on the development of electronic materials etching processes, as well as providing fundamental insight into the mechanisms of an important class of surface reactions.