Study of epitaxial growth by combination of STM and LEED
The first stages of epitaxial growth determine the growth of films with respect to general growth, orientation, smoothness, homogeneity and all other types of possible deviations from an ideal epitaxial film. For those studies it is important to see details of the starting substrate and of growing islands by direct microscopy, which is best accomplished by STM. The same way it is necessary to have good average values and distribution functions of sizes, distances and defect densities, which is best done by diffraction. It will be demonstrated, how the STM images from small areas and the diffraction patterns from large areas with low energy electrons (LEED) combine static informations on single defects and single islands with kinetic informations during growth at any temperature for a best description of homo-epitaxy and heteroepitaxy. The presence of defects like dislocations, stacking faults or domain boundaries is shown as their importance for nucleation. The kinetics of film growth is derived from diffraction measurements during deposition or annealing. Some defects like lattice constant variations (strain) or orientational defects (mosaics) are also seen in diffraction. In this way only a combination of techniques will enable a detailed description of growth processes.
KeywordsScan Tunneling Microscopy Step Height Partial Dislocation Scan Tunneling Microscopy Image Reflection High Energy Electron Diffraction
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