In situ UHV-TEM observation of the direct formation of Pd Si 2 islands on Si 111/ surfaces at high temperature

Pd was deposited on clean Si surfaces at about 680 K in an ultrahigh-vacuum transmission electron microscope. The direct formation process of Pd2Si islands on Si 111.surfaces was observed in situ by high-resolution transmission electron microscopy in a cross-sectional view. At a low deposition amount, Si 111.7=7 surfaces were transformed to a new layer due to the coverage by Pd. With further deposition, Pd2Si islands appeared on Si surfaces. Some Pd2Si islands were single crystals and grew epitaxially on Si 111.surfaces in the Stranski–Krastanow mode. After stopping Pd deposition, the surface of the Pd2Si islands exhibited a reconstruction structure with threefold periodicity, which consists of two atomic layers. q2000 Elsevier Science B.V. All rights reserved.