High-quality Si(111)-(7 x 7) surface reconstructions were observed on (111)-oriented Si/SiO2/Si substrates; prepared via separation by implantation of oxygen, with top-layer thicknesses as small as 220Å. Scanning tunnelling microscopy and spectroscopy data indicated that the electrically and physically isolated top layer was electrically conducting, in contrast to that of (100) separation by implantation of oxygen material, which accumulated charge under typical imaging conditions. It was speculated that the 7 x 7 reconstruction on (111) separation by implantation of oxygen material was an efficient conduction channel; permitting atomic resolution imaging of the isolated Si top layer.

Isolation of a Metallic Si(111)7 x 7 Surface Reconstruction via Separation by Implanted Oxygen. M.Noh, G.E.Jellison, F.Namavar, H.H.Weitering: Applied Physics Letters, 2000, 76[6], 733