Self-Organization of Ripples and Islands with SiGe-MBE

We explored two methods to obtain laterally ordered Ge/Si quantum dot arrays. For the first we exploit the two independent growth instabilities of the SiGe/Si(001) hetero-system, namely kinetic step bunching and Stranski-Krastanov (SK) island growth, to implement a two-stage growth scheme for the fabrication of long-range ordered SiGe islands. The second approach is to deposit Ge/SiGe onto prepatterned Si substrates, which are prepared via lithography and subsequent reactive ion etching (RIE). It results in perfectly ordered, 2D dot arrays that can be extended into 3D by strain-ordering of a Ge-dot superlattice.