| For nearly 40 years, Moore's law has continued unabated. Every two years the number of transistors that can be mass produced on a given surface area has doubled, mainly due to shrinking the lateral dimensions of the transistors. Recently, in addition to shrinking the lateral dimensions, silicon-on-insulator technology promises to shrink the vertical thickness of the substrate to as little as ten nanometers in the next few years, making surface and interface studies significantly more important. Simultaneously, strained Si layers will also likely come into widespread use. Lastly, the incorporation of Ge with all of these Si technologies will be required for bandgap engineered devices including quantum wells for quantum computers, as well as faster conventional devices.; With these trends in mind, we investigate the behavior of Ge on strained Si(100) as well as the behavior of Ge on ultra-thin SOI template layers. We develop two independent methods for extracting the macroscopic surface diffusion coefficient for Ge on a Ge wetting layer on bulk Si as well as on strained Si. One method involves measuring the denuded zone between a patterned edge and the formation of 3D islands in a growth context. The advantage of this method is its extreme simplicity. The other method involves a similar denuded zone measurement, but involves monitoring island evaporation during a coarsening process rather than a growth process. Although this coarsening method is slightly more complicated to model than the growth method, it provides an independent method for determining a value for the macroscopic diffusion coefficient for Ge on a Ge wetting layer on Si. In addition, due to the coarsening process, we are able to also estimate a value for the rate at which metastable hut-shaped islands evaporate.; In other experiments, we also find that ultra-thin (∼10 nm) Si template layers on SOI, when combined with Ge film growth can result in unique film responses at elevated temperatures above 675 degrees C. A local bowing of the thin Si template layer is found underneath hut-shaped islands, and pitting and electrical isolation of the islands from each other is found underneath dome shaped islands. |
