AbstractThe copper catalyzed fluorination of silicon is first-order in [F2] and in [Cu]s until the coverage reaches ∼4 monolayers. Above ∼4 monolayers the reaction rate is zero order in copper, suggesting a limited number of catalytically active Cu/Si sites. Surface diffusion of copper leads to decrease in the etch rate as a function of time as well as feature size-dependent etch depths. The copper compounds CuF2, CuO, and copper silicides, Cu5 Si and Cu3 Si all catalyzed the F2-Si reaction which suggests that they are all converted to the same active species. The results can be explained by mechanisms involving copper fluorides or copper silicides as active intermediates.
