  We study the formation and evolution of coherent islands on lattice
mismatched epitaxially strained films. Faceted islands form in films with
aniostropic surface tension. Under annealing, these islands ripen until a
stable array is formed, with an island density which increases with film
thickness. Under deposition, an island shape transition occurs, which leads to
a bimodal island size distribution. In films with isotropic surface tension we
observe continual ripening of islands above a certain film thickness. A stable
wavy morphology is found in thinner films.
