SELF-ASSEMBLED GE DOTS - GROWTH, CHARACTERIZATION, ORDERING, AND APPLICATIONS

The Stranski-Krastanow growth mode, which leads; to the self-assembled formation of dots, allows one to exceed the critical thickness withou t introducing dislocations. We report the coverage limits for the disl ocation-free dot regime in dependence of the Ge content, and also the composition dependent thickness of the two-dimensional wetting layer. To reduce the size inhomogeneity of the self-assembled dots, we invest igated ordering effects in Si/Ge-dot multilayers. The experiments do n ot only reveal a strong vertical ordering of the dots, but also a late ral correlation and a significantly increased size homogeneity is obse rved. Results on first device structures, a npn-infrared detector and a silicon based tunneling structure, both with embedded layers of self -assembled Ge dots, are presented. (C) 1998 American Vacuum Society.