Selforganization phenomena in heteroepitaxial growth

Three dimensional finite element (3D FE) calculations are performed to explain the physical origin of selforganized growth of island structures (that are of equal shape, of equal lateral dimensions and interdistances) in a strained film growing heteroepitaxially on a misfitted substrate. The selforganized island growth is a result of the inhomogeneous strain distribution in the 3D laterally limited islands that leads to a strain dependent locally varying adatom incorporation rate R(r). Based upon the same argument of locally varying: strain distribution we may also explain further selforganization phenomena, that are experimentally observed in, for example, (Si-Ge)(n)/Si(001) multilayer structures, such as: (i) the flattening of a Si capping layer on top of an islanded Ge/Si structure and (ii) the vertical alignment of islands in (Si-Ge)(n) layers.