Restructuring process of the Si(111) surface upon Ca deposition

Using scanning tunneling microscopy and high-resolution spot profile analys is low-energy electron diffraction (SPA-LEED), the process of Si(111)3 x 1- Ca phase formation induced by Ca adsorption on Si(111)7 x 7 samples has bee n studied. Our observation revealed that what has been considered to be 3 x 1 reconstruction is actually a mixture of 3 x 2 and c(6 x 2) reconstructio ns. The redistribution of Si atoms in a top Si(111) layer has been found to play a critical role in the Si(111)3 x 2-Ca growth. From the quantitative consideration of Si mass transport balance, top Si atom density of Si(111)3 x 2-Ca phase has been determined to be a 4/3 monolayer. (C) 2000 Elsevier Science B.V. All rights reserved.