Roughness and ordering of growing films

In many deposition processes particles are highly mobile in an active layer at the surface, but an relatively inert once incorporated in the bulk. Inh omogeneities in the deposition process then lead to formation of rough surf aces, whose height fluctuations can be probed directly by scanning microsco py, or indirectly by scattering. I shall first briefly review analytical or numerical treatments of simple homoepitaxial growth models which suggest t hat the height fluctuations have a self-similar character. Well described b y a dynamic scaling form. I then study models of hereroepitaxial growth in which different atoms are allowed to interact, equilibrate, and order (e.g. phase separate) on the surface, but are frozen in the bulk. Order paramete r correlations in the resulting bulk material are highly anisotropic, refle cting its growth history. In a flat (layer by layer) growth mode, correlati ons perpendicular to the growth direction are similar to a two-dimensional system in equilibrium, while parallel correlations reflect the dynamics of such a system. When the growing film is rough, various couplings between he ight and order parameter fluctuations are possible. Such couplings modify t he dynamic scaling properties of surface roughness, and may also change the critical behavior of the order parameter. Even the deterministic growth of the surface profile can result in interesting textures for the order param eter. (C) 2000 Elsevier Science B.V. All rights reserved.