Structural studies of Al thin layer on misoriented GaAs(100) substrate by transmission electron microscopy

A thin Al layer has been grown on a misoriented GaAs(100) substrate by molecular beam epitaxy and its structure has been studied by means of transmission electron microscopy. The metal layer is formed as grains of three orientations Al(100), Al(110) and Al(110)R. Digital analysis of dark-field micrographs made it possible to obtain their grain sizes and relative coverage areas. By comparison with an Al layer grown on an exactly oriented GaAs(100) substrate it has been found that on the vicinal surface the relative coverage area and grain size of the Al(110)R orientation increase and the Al(100) relative coverage area decreases. This is attributed to surface atomic steps, which have been visualized in high-resolution micrographs. The edge misfit dislocation system at the Al/GaAs interface has been revealed, which is insensitive to the substrate misorientation. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)