A scanning transmission electron microscope study of silicon–germanium alloying using annular dark field or Z-contrast imaging and electron energy loss spectroscopy was presented. Results and techniques were considered. The growth of 11 equivalent monolayers of Ge onto Si at 650C resulted in dome-shaped islands or quantum dots that contained up to 40%Si. The interface between the as-grown island and substrate exhibited a highly disordered or amorphous zone some 1.5nm-wide directly under the island. Annealing (1h, 650C) gives larger pyramidal islands with diffuse crystalline interfaces and an equilibrium distribution of up to 70%Si in the islands.

Silicon–Germanium Interdiffusion and Interfaces in Self-Assembled Quantum Dots. R.R.Vanfleet, D.P.Basile, T.I.Kamins, J.Silcox, R.S.Williams: Applied Physics A, 2007, 86[1], 1-9