THE ROLE OF SI ATOMS IN IN SI(111) SURFACE PHASE-FORMATION/

The deposition of In onto the Si(111)-(root 3 x root 3)-In surface app ears to result, depending on the temperature, in the formation of thre e different reconstructions, Si(111)-(2 x 2)-In (20-100 degrees C), Si (111)-(4 x 1)-In (similar to 200 degrees C) and Si(111)-(root 31 x roo t 31)-In (similar to 450 degrees C). The formation of each surface pha se has been determined to be controlled by the mobility of the top Si atoms. Al the (root 3 x root 3) to (2 x 2) transition, the bulk-like t ermination of the Si(111) substrate is preserved. At the formation of the Si(111)-(4 x 1)-In phase, Si atoms reorder via a bond-switching pr ocess. The formation of the Si(111)-(root 31 x root 31)-In phase invol ves surface Si mass transport. The applicability of the results obtain ed to other submonolayer adsorbate/Si systems is discussed, and the cr iterion for revealing the surface phases with a reconstructed substrat e is formulated. (C) 1998 Published by Elsevier Science B.V.