Critical role of surface steps in the alloying of Ge on Si(001)

The intermixing of Ge on Si(001) during growth was enhanced on stepped surfaces and terraces was discussed. The study was carried out by using a low-energy electron microscopy. A dynamic and unanticipated structural rearrangement was identified that facilitates intermixing. The results show that the driving force for step formation was the entropy gain associated with the enhanced intermixing of Ge.