CHLORINE-ENHANCED F-ATOM ETCHING OF SILICON

Reactive ion etching processes, currently in use in microstructure fab rication, often use more than one feed gas and more than one reactive etching specie. An example is die use of gases containing both chlorin e and fluorine. These processes have been developed empirically with l ittle understanding of the detailed surface science. Directed beam mea surements have been carried out using mixed chlorine-fluorine chemistr ies and an unexpected enhancement of the F-atom etching of Si by molec ular chlorine has been observed.