An investigation was made of the effects, upon atom lithography, of 2 barriers to thermally activated atomic diffusion. These were a thermally-activated Ehrlich–Schwoebel barrier, and contamination by residual gases in the vacuum system. Kinetic Monte Carlo simulations were performed by using a 1-dimensional surface grid. It was found that the Ehrlich–Schwoebel barrier failed to explain the experimentally observed lack of temperature dependence. The dependence of the structure width upon temperature, vacuum conditions and beam characteristics could be explained by using the contaminant adatom hypothesis. Only a variation in structure-width, as a function of deposition duration, was not fully reproduced by this model. This was attributed to the 1-dimensional nature of the simulation. The results demonstrated that barrier-limited diffusion could play an important role in atom lithography, and that contaminant adatoms were likely candidates as barriers.

Barrier-Limited Surface Diffusion in Atom Lithography. E.te Sligte, K.M.R.van der Stam, B.Smeets, P.van der Straten, R.E.Scholten, H.C.W.Beijerinck, K.A.H.van Leeuwen: Journal of Applied Physics, 2004, 95[4], 1749-55