We investigate plasma etching of IV-VI nanostructures using a CH 4 /H 2 gas mixture. For various IV-VI compounds we find that the etch rate decreases with the energy band gap. For Pb 1−x Eu x Te, in contrast, the etch rate decreases drastically with increasing Eu content. This property can be utilized for selective etching. Furthermore, we demonstrate IV-VI quantum wires with vertical side walls by a combination of laser holography and CH 4 /H 2 /Ar plasma etching.