Reflection high energy electron diffraction studies of epitaxial growth on semiconductor surfaces

Abstract

Reflection high-energy electron diffraction (RHEED) is so well suited to studies of epitaxial growth that it has become the standard in situ technique for monitoring the growth of III–V semiconductors during molecular beam epitaxy. The characteristic diffraction pattern for a smooth surface is a family of parallel streaks. The intensity along the length of these streaks is shown to be due primarily to the distribution of atomic steps over the surface. These steps are readily observable because RHEED is able to resolve order over long distances. During epitaxial growth synchronous oscillations in the intensity and width of the diffracted beams are observed. These are due to the competition between cluster nucleation and step propagation. The period of the oscillations is the time required to deposit a monolayer.