“…Amongst such architectures are ultra-thin fully depleted siliconon-insulator (SOI) FETs [1,2], double-gate FETs [3], O-FETs [4], silicon-on-nothing (SON) FETs [5,6], multi-bridge-channel (MBC) FETs [7,8], etc. The latter two approaches rely on the epitaxy of SiGe/Si multilayers, on the formation of trenches and most importantly on the high degree of selectivity (versus Si) that can be achieved when dry etching laterally the SiGe layers (with Ge contents above 15%) [9].…”