Abstract: A method of forming a stacked silicon-germanium nanowire structure on a support substrate is disclosed. The method includes forming a stacked structure on the support substrate, the stacked structure comprising at least one channel layer and at least one interchannel layer deposited on the channel layer; forming a fin structure from the stacked structure, the fin structure comprising at least two supporting portions and a fin portion arranged there between; oxidizing the fin portion of the fin structure thereby forming the silicon-germanium nanowire being surrounded by a layer of oxide; and removing the layer of oxide to form the silicon-germanium nanowire. A method of forming a gate-all-around transistor comprising forming a stacked silicon-germanium nanowire structure that has been formed on a support substrate is also disclosed. A stacked silicon-germanium nanowire structure and a gate-all-around transistor comprising the stacked silicon-germanium nanowire structure are also disclosed.