Extremely high selective Si1−xGex-film wet etchant generating highly dissolved oxygen via peracetic acid oxidant for lateral gate-all-around FETs with a logic node of less than 3-nm

•Design of a novel high selective Si1−xGex-film etchant using the oxidant PAA.•High Si0.5Ge0.5-film etch rate (82 nm⋅min-1) and Si0.5Ge0.5- and Si-film etch rate selectivity of 265:1.•Higher dissolved oxygen concentration led to a higher formation degree of GeO2 on the Si1−xGex-film surface.•Completely etched the LGAA line pattern with 30-nm-width Si0.5Ge0.5-layers.