  A strained epitaxial film deposited on a deformable substrate undergoes a
morphological instability relaxing the elastic energy by surface diffusion. The
nonlinear and nonlocal dynamical equations of such films with wetting
interactions are derived and solved numerically in two and three dimensions.
Above some critical thickness, the surface evolves towards an array of islands
separated by a wetting layer. The island chemical potential decreases with its
volume, so that the system experiences a non-interrupted coarsening described
by power laws with a marked dimension dependence.
