INVESTIGATION OF SI SIGE HETEROSTRUCTURES PATTERNED BY REACTIVE ION ETCHING/

We present a modified pattern technique for fabrication of nanometer s tructures in the Si/SiGe heterosystem. A special multilayer-resist sys tem is developed for pattern transfer by electron-beam lithography and anisotropic SF6/O-2 dry etching. Photoluminescence measurements are c arried out on homogeneously etched samples to determine the influence of the RIE process on the optical properties. Etching induced damages are reduced by a low-temperature post-annealing step. Additionally, su rface contaminations are investigated using laser desorption mass spec trometry. SiGe wires with lateral widths from 4 mu m down to 25 nm hav e been fabricated, but photoluminescence has been observed for structu res down to 600 nm lateral width, only. Further improvement has been o btained by sidewall-passivation of the nanostructures with a low tempe rature plasma enhanced-chemical-vapour-deposited oxide. Up to now, cle ar excitonic emission is detected for wires as small as 250 nm.