Surface reconstructions of the Si(100)-Ge system

The surface reconstruction of epitaxial Ge layer on Si(100) was studied wit h ultrahigh vacuum scanning tunneling microscopy. The surface with 0.8 ML G e grown in the presence of a hydrogen surfactant reveals the same structure s as found in chemical-vapor-deposited Ge on Si(100): (i) defective (2 x 1) structure at 290 degrees C, (ii) irregular (2 x N) in Ge layer and defecti ve (2 x 1) in bare Si regions at 420 degrees C, and (iii) (2 x N) in Ge-cov ered regions and c(4 x 4) in bare Si regions at 570 degrees C. The morpholo gy of step edges does not change with temperature, implying that the c(4 x 4) reconstruction is anisotropic in nature. (C) 1999 Published by Elsevier Science B.V. All rights reserved.