The effects of 2 barriers to thermally activated atomic diffusion on atom lithography were investigated: a thermally activated Ehrlich–Schwoebel barrier, and pollution from residual gas in the vacuum system. Kinetic Monte Carlo simulations were performed using a 1-dimensional surface grid. It was found that the Ehrlich–Schwoebel barrier failed to explain the lack of temperature dependence observed experimentally. The dependences of the structure width upon temperature, vacuum conditions and beam characteristics could be explained by using the pollutant adatom hypothesis. Only the variation of structure width with deposition duration was not entirely reproduced by this model. This was attributed to the 1-dimensional nature of the simulations. These results demonstrated that barrier-limited diffusion could play an important role in atom lithography, and that pollutant adatoms were a likely candidate barrier.

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