Scanning tunneling microscopy study of surface morphology of Si(111) aftersynchrotron radiation stimulated desorption of SiO2

The surface morphology of Si(111) was investigated using scanning tunneling microscopy after desorption of surface SiO2 by synchrotron radiation illum ination. The surface shows large regions of an atomically flat Si(111)-7 x 7 structure, and is characterized by the formation of single bilayer steps nicely registered to the crystal structure. This is in sharp contrast to Si (111) surfaces after thermal desorption of SiO2 at temperatures of 880 degr ees C and above, where the surface steps are much more irregular. X-ray pho toemission spectroscopy is also used to investigate the process of synchrot ron radiation stimulated desorption. (C) 2000 American Vacuum Society. [S0734-2101(00)04304-9].