Strain dependent growth of silicon on Ge/Si-C heterostructures

We report on structural investigations of strain dependent growth of Si on Ge/Si-C heterostructures. Very small islands of Ge were obtained by using a little C precoverage before the Ge deposition. These islands are visualize d by scanning tunneling microscopy (STM) and the subsequent Si epitaxy is p ursued. STM pictures taken upon some monolayers of Si epitaxy reveal an inh omogeneous growth mode, which leads to ditch like rings formed around the i slands. Pictures of the following Si deposition suggest a strain dependent surface diffusion of Si until sufficient material has been deposited which then flattens the surface resulting in perfect epitaxial structures. (C) 19 99 Elsevier Science B.V. All rights reserved.