BEYOND THE SOLID-ON-SOLID MODEL - AN ATOMIC DISLOCATION FORMATION MECHANISM

We investigate the growth of mismatched thin films by a kinetic Monte Carlo computer simulation. The strain is introduced through an elastic energy term based on a valence force field approximation and stress i s relaxed along ''atomic chains'' at each step of the simulation. The calculations use a set of elementary atomic processes including, besid es well-known standard processes, the collective incorporation of atom s. This leads us to introduce a new ''hanging'' position with only one bond created toward the substrate contrary to solid on solid models. This position plays a role of defects initiation, and thus an atomic d islocation nucleation mechanism is described. Finally, we present the influence of a step in the dislocations creation. (C) 1998 American In stitute of Physics. [S0021-8979(98)07222-3].