SCANNING-TUNNELING-MICROSCOPY OF SI SIO2 INTERFACE ROUGHNESS AND ITS DEPENDENCE ON GROWTH-CONDITIONS/

The interface between silicon (100) and thermal silicon dioxide grown by wet, dry, and trichloroethylene oxidation has been investigated by scanning tunneling microscopy and scanning tunneling spectroscopy. The scanning tunneling microscopy images of the silicon surface, after re moval of oxide, reveal the presence of silicon bumps (protrusions) in samples prepared by wet and dry oxidation while no protrusions are see n at the interface of trichloroethylene oxidized samples. The spectros copic measurements predict that these are silicon protrusions and are produced by oxide growth conditions. X-ray photon spectroscopy on samp les containing protrusions also supports the above prediction. Thus, o ur study suggests that roughness of the silicon-silicon dioxide interf ace depends on oxide growth conditions and a relatively smooth interfa ce is obtained by trichloroethylene oxidation. (C) 1996 American Insti tute of Physics.