Effect of strain on surface diffusion in semiconductor heteroepitaxy.pdfVIP

Effect of strain on surface diffusion in semiconductor heteroepitaxy Evgeni Penev, Peter Kratzer, and Matthias Scheffler Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin-Dahlem, Germany (Submitted 25 January 2001) 1 We present a first-principles analysis of the strain renormalization of the cation diffusivity on the 0 GaAs(001) surface. For the example of In/GaAs(001)-c(4 × 4) it is shown that the binding of In is 0 increased when the substrate lattice is expanded. The diffusion barrier ∆E (ε) has a non-monotonic 2 strain dependence with a maximum at compressive strain values (ε 0), while being a decreasing y function for any tensile strain (ε 0) studied. We discuss the consequences of spatial variations of a both the binding energy and the diffusion barrier of an adatom caused by the strain field around a M heteroepitaxial island. For a simplified geometry, we evaluate the speed of growth of two coherently strained islands on the GaAs(001) surface and identify a growth regime where island sizes tend to 1 equalize during growth due to the strain dependence of surface diffusion. 2 ] i c s- I. INTRODUCTION eroepitaxial islands, the islands themselves are under l compressive strain, whereas the substrate beneath the r t In recent years, the heteroepitaxial growth of lattice- island is expanded. As a consequence of this expansion, m mismatched semiconductor systems has at