OBSERVATION OF OXIDE SI(001)-INTERFACE DURING LAYER-BY-LAYER OXIDATION BY SCANNING REFLECTION ELECTRON-MICROSCOPY/

We have found that terrace contrast of oxidized Si(001) substrate obse rved with a scanning reflection electron microscopy (SREM) is reversed by progress in thermal oxidation by one atomic layer of Si. The cause for such terrace contrast reversion is that reflection electron inten sity depends on Si-bond direction at oxide/Si interface. This fact was confirmed by calculations based on a multiple scattering theory. The motion of oxide/Si-bulk interface can be, thus, observed by SREM. The reversion and continuous change of the terrace contrast indicate that oxidation occurs monolayer by monolayer on Si(001) substrate. (C) 1997 American Institute of Physics.