LEEM investigations of the domain growth of the (7×7) reconstruction on Si(111)

Abstract

Low-energy electron microscopy (LEEM) has been used to record images of large step-free regions of Si(111) which are quenched below the (7×7)-to-(1×1) transition temperature. Almost immediately after the quench the surfaces are composed of a large number of domains of average dimension less than 1000 Å separated by narrow domain boundaries. The average size of the domains subsequently increases to on the order of a micron on a time scale of minutes. The shapes of the domains remain relatively compact, as one expects for a phase with the highly degenerate ground state of the (7×7) reconstruction. In marked contrast to boundaries of (7×7) domains growing into unreconstructed regions, there is no observable preference for any particular domain boundary orientation between (7×7) domains. By comparing the time dependence of the structure of the domain boundaries to the theory of von Neumann, we find that the domain gr oth is not driven solely by changes in domain-boundary curvature. Finite-size effects are important in these measurements; the requirements for quantitative comparison with theory are discussed.