Self-organization of two-dimensional SiGe nanodot arrays using selective etching of pure-edge dislocation network

A self-organization technique of two-dimensional SiGe nanodot arrays was developed using selective etching of SiGe/Si substrates that have a pure-edge dislocation network at the interface. The pure-edge dislocation network was selectively etched by a water solution of CrO3 and HF. This produced SiGe nanodot arrays with nanometer-scale periodicities. The periodicities and the compositions of the SiGe nanodot arrays correspond with that of the interfacial pure-edge dislocation network and that at the interface, respectively, in the SiGe/Si substrates prior to etching. We found that the etchant temperature strongly affects the etching rate and selectivity. We demonstrated self-organized formation of an array with a periodicity of 17 nm of dome-shaped Si0.82Ge0.18 nanodots with an aspect ratio of 0.12.