The Ga diffusion from focused ion beam milled grooves was studied using X-ray photo-emission electron microscopy and mirror electron microscopy. The surface chemistry of the focused ion beam structures was analyzed by measuring the presence of Ga in the top layers of the milled grooves, and morphological defects inside the grooves. The Ga was initially strictly confined to the grooves. However, annealing at temperatures as low as 150C leads to rapid and significant Ga surface diffusion from the focused ion beam structures. The out-diffused Ga forms a thin layer extending up to several microns laterally in a non-regular pattern. The diffusion was significantly enhanced at small crystallites at the edges of the grooves. The general behavior was explained using an atomic scale model in which interstitial Ga in the milled areas diffused out and replaced silanol groups on the surface.

Low Temperature Ga Surface Diffusion from Focused Ion Beam Milled Grooves. A.Mikkelsen, E.Hilner, J.N.Andersen, S.Ghatnekar-Nilsson, L.Montelius, A.A.Zakharov: Nanotechnology, 2009, 20[32], 325304