Growth Instability of Strained Film: An Elastic Green's Function Force Monopole Approach

摘要

We analyze the growth stability of an epitaxial strained film on a flat substrate by the elastic Green's function force monopole approach. We calculate and compare the strain energies and growth instability of three different forms of surface undulations: sinusoidal waviness, surface faceting and island formation. In general, the instability occurs beyond a critical length scale, in agreement with the conventional analysis of ATG instability based on the stress function approach. For isotropic surface energies, the critical length scale for the island formation is the smallest, because it offers the most effective mode of strain relaxation.