Atomic layer etching of germanium

Atomic layer etching of Ge has been investigated experimentally based on the surface chemistry that Cl can adsorb on the clean Ge surface at room temperature and desorb thermally as GeCl2 at high temperatures. The ideal etching rate of one monolayer per cycle has been achieved. The critical Cl2 dosage for the saturated etching rate was about 7.2×106 L. Increase of the surface roughness after etching of 100 cycles was about 3.5 monolayers.