High resolution REM studies of Si(5512) surfaces and their roughening phase transition

High resolution reflection electron microscopy has been applied to studies of a high index Si(5 5 12) surface at a subunit cell resolution. Lattice fr inges with different widths were found to be directly corresponding to the subunits of the (5 5 12) surface. Defects on the surface were resolved as n ano-facets with close orientation to (5 5 12). (13 13 31) and (7 7 17) face ts were identified based on the subunit arrangement. An incommensurate stru cture (q = a(bk)(*)/2.43) was revealed at a temperature just below the roug hening transition. Formation of an incommensurate structure as well as defe cts was discussed in terms of surface steps. (C) 2001 Elsevier Science B.V. All rights reserved.