Orientationally ordered ridge structures of aluminum films on hydrogen terminated silicon

Films of aluminum deposited onto Si(100) substrates show a surface structure of parallel ridges. On films deposited on oxidized silicon substrates the direction of the ridges is arbitrary, but on films deposited on hydrogen-terminated Si(100) the ridges are oriented parallel to the < 110 > directions on the silicon substrate. The ridge structure appears when the film thickness is above 500 nm, and increasing the film thickness makes the structure more distinct. Anodic oxidation enhances the structure even further. X-ray diffraction indicates that grains in the film have mostly (110) facets parallel to the surface, and that the crystallographic texture consists of two components. It is discussed, that the orientational ordering of the grains and ridge structure may be induced by the anisotropic elastic properties of the Si(100) surface or by epitaxial effects. (c) 2006 Elsevier B.V. All rights reserved.