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, measuring the Ga presence 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 as low as 150C led to rapid and significant Ga surface diffusion from the focused ion beam structures. The out-diffused Ga formed a thin layer which extended 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 behaviour 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