In situ transmission electron microscopy observations of the formation of self-assembled Ge islands on Si.

The in situ transmission electron microscope allows us to visualise processes occurring at surfaces and interfaces in real time and is therefore capable of providing detailed, quantitative information about reaction mechanisms. We have used a UHV TEM equipped with in situ growth capabilities to study the process of chemical vapour deposition of Ge on Si(100), with particular emphasis on the formation of self-assembled, nanosize Ge islands. Video-rate image acquisition enables us to track the development of individual islands from nucleation onwards and to observe the introduction of dislocations as the strained islands relax.