Oxidation behaviors of SiGe nanowire arrays fabricated by Au-assisted wet chemical etching

This study investigates the oxidation behaviors of Si_0.95Ge _0.05 nanowire arrays fabricated by combining nanosphere lithography and Au-assisted chemical etching. After oxidation at 450°C for 8 hours, the diameter of SiGe nanowires can be reduced from 360 nm to 250 nm. Furthermore, the SiGe nanowires were transformed into the taper-like structures with a deep trench around the bottom regions after oxidation. We elucidate these phenomena in terms of the nonuniform oxidation rate caused by the nonuniform oxygen ambient and the Au-Si-Ge eutectic alloying. This work provides an effective approach to design the low-dimensional SiGe-based nanostructures for possible applications.