OBSERVATION OF A DISTRIBUTED EPITAXIAL OXIDE IN THERMALLY GROWN SIO2 ON SI(001)

We present direct evidence of an ordered oxide which is epitaxially re lated to the underlying Si(001) substrate and is distributed throughou t thermally grown oxide films with thicknesses between 80 and 1000 Ang strom. This evidence consists of diffraction peaks at the [1,1,0.45] p ositions. For films with thickness in the range 80-160 Angstrom the in tegrated intensity of these diffraction peaks increases roughly linear ly and the ordered oxide grain size parallel to the surface is constan t at 130 Angstrom.