SI(100)4X3 IN SURFACE PHASE - IDENTIFICATION OF SILICON SUBSTRATE ATOM RECONSTRUCTION

The arrangement of Si substrate atoms in Si(100)4 x 3-In surface phase was studied using removal of In atoms al exposure of the surfaces to atomic hydrogen and monitoring the surface transformations by low ener gy electron diffraction and Auger electron spectroscopy. The Si(100)4 x 3-In surface was found to transform at H exposure to Si(100)4 x 1-H( In) surface showing definitely that Si substrate atoms are reconstruct ed. The persistence of 4 x 1 structure at high hydrogen exposures (whe n no Si dimerization can be preserved) unambiguously reduces the choic e of possible structural models of Si substrate reconstruction to only three; candidates. In turn, STM data [A.A. Baski et al., Phys. Rev. B 43 (1991) 9316] of similar to 0.5 ML Si atom density in Si(100)4 x 3- In phase leaves a single realistic structure, namely Si(100) surface h aving every second Si atom double row missing. (C) 1997 Elsevier Scien ce B.V.