Au adsorption on Si(5512) surfaces and facet formation studied by high resolution in situ REM

Adsorption processes of An on a high index Si(5 5 12) surface were studied in situ by high resolution reflection electron microscopy with subunit cell resolution. Growth of new phases is quite anisotropic and rapid along the [1 1 0] direction reflecting quite anisotropic substrate surface structure. At around 715 degreesC, successive changes from (5 5 12) to two-fold (3 3 7), (5 5 11) and (2 2 5) facet were noted as an increase of An deposit. (7 7 17) surface units are locally formed before formation of the two-fold (3 3 7) surfaces. At higher temperature 780 degreesC (above roughening tempera ture 750 degreesC of (5 5 1 )-Au surface), a disordered surface is formed a fter formation of the two-fold (3 3 7) facet. The disordered surface is a h igher temperature phase of the (5 5 11) surface. Above changes are discusse d in terms of characteristics of these high index surface structures. (C) 2 001 Elsevier Science B.V. All rights reserved.