Growth of nanoscale Ge magic islands on Si( [formula omitted])-7 × 7 substrate

Abstract

We reported a formation of uniform nanoscale Ge islands, which shows rounded shape having a diameter of 3.8 nm, on a Si(1 1 1)-7 × 7 substrate as a template. The rearrangement process of stacking-fault layer in the 7 × 7 reconstructed structure is a rate determinant process, when the growing layer covers the substrate. The lateral growth of Ge island is hindered by the stacking-fault layer and the hindrance restricts the size distribution of Ge islands, so called “magic islands”. We observed the nanoscale Ge magic islands formed at the temperature of 300–360 °C. The some characteristic peaks in the size distribution suggest that the step energy for the Ge islands is smaller than that of Si island. From the temperature dependence of the size distribution, we estimate that the amount of the activation energy of the rearrangement is 2.1 eV. The value is slightly smaller than that for the homo-epitaxial case.