TRENCH FORMATION IN SURFACTANT MEDIATED EPITAXIAL FILM GROWTH OF GE ON SI(100)

We have used STM to study the surface morphology of thin epitaxial Ge films grown on Si(001) in the presence of the "surfactant" As. The sur factant forces layer-by-layer growth up to 12 ML Ge coverage which cou ld partly be explained by the geometrical surface arrangement of the g rowing film. Beyond 12 ML coverage we observed a network of trenches w hich decorate the earlier described V -shaped defects inside the film. Overgrowth of such defects is studied and a mechanism discussed.