Intermixing in Stranski-Krastanov germanium overlayer on Si(100)

The growth behaviors of Ge overlayers and the intermixing between Ge and Si on Si(100)-(2×1) substrate were studied using scanning tunneling microscopy (STM) and medium energy ion scattering spectroscopy (MEIS). At the growth temperature of 350 °C, as Ge coverage increase, the Si surface peak in MEIS channeling decreases due to the shadowing of Ge atoms and can be fitted by a simple growth model with approximately 15% intermixing, an upper bound value, at a Ge coverage less than 4 ML. At Ge coverages between 4 and 8 ML, Si surface peak shows a broad enhancement, which can be explained with the growth of three-dimensional hut clusters at the expense of Ge wetting layers.