STRUCTURAL STUDY OF THE SI B(ROOT-3X-ROOT-3)R30-DEGREES GEXSI1-X(111)INTERFACE BY SPATIALLY SELECTIVE DIFFRACTION ANOMALOUS FINE-STRUCTURE(DAFS)/

We have applied a new x-ray structural technique, Diffraction Anomalou s Fine Structure (DAFS), to a buried reconstructed interface, Si/B(squ are-root 3 x square-root 3)R30-degrees/GexSi1-x(111) (abbreviated Si/B square-root 3/GexSi1-x(111)). While Ge K-edge XAFS alone gives inform ation about the average local structure surrounding all of the Ge in t he sample, by combining the complementary abilities of XAFS and x-ray diffraction, DAFS is able to examine the local structure surrounding j ust the Ge at the interface, thus exhibiting spatial selectivity. We h ave made simultaneous XAFS and DAFS measurements of this interface and observed clear differences in the derived chi(k) and resulting Fourie r transforms.