Influence of the growth parameters on self-assembled Ge islands on Si(100)

The effect of deposition temperature on the growth dynamic, the shape. the size and the composition of Chemical Vapor Deposition (CVD) grown Ge/Si(100) islands have been investigated in the range bemeen 500 and 850 degreesC. We found that the growth dynamic of the islands changes strongly between 500 and 600 degreesC, going from a kinetically limited growth regime to nearly equilibrium conditions. At higher temperatures the island growth is instead mainly affected by Ge/Si alloying. We found that the increase of the growth temperature above 600 degreesC results in an increased Si/Ge alloying, the mean Ge concentration in the islands changing from x=0.75 at 600 degreesC to 0.28 at 850 degreesC, The determined SiGe intermixing and the consequent reduction of the effective mismatch completely accounts for observed island enlargement in the same temperature range. (C) 2002 Published by Elsevier Science B.V