Kinetics of Formation and Decay of Nanoscale Structures on Si(001)

J. Erlebacher, M. J. Aziz, M. B. Sinclair, J. A. Floro, E. Chason
Harvard University

We have experimentally studied the creation and subsequent relaxation of nano-ripples on crystalline surfaces. Nano-ripples are produced as a results of a pattern forming instability observed on heated surfaces bombarded by an ion beam at glancing angles. These ripples can be made on almost any kind of material including insulating ceramics. We show that the activation energy associated with ripple formation is the migration energy associated with surface diffusion. Subsequent annealing of the nano-ripples yields an activation energy that is the sum of this migration energy with the formation energy of the diffusing species. The combination of a rippling and annealing experiment is thus a straightforward method for measuring these important surface energetic quantities. We demonstrate the technique for the Si(001) surface.