Surface bonding state of germanium via cyclic dry treatments using plasma of hydrogen iodine and pure oxygen gases

The effect of HI and O-2 plasma treatments on a Ge surface is studied by X-ray photoelectron spectroscopy. Ge oxide on a Ge surface can be effectively removed at room temperature by remote HI plasma in inductively coupled plasma reactive ion etching system without substrate bias. The re-oxidation of oxide-free HI plasma-treated Ge has been performed sequentially by O-2 plasma. By utilizing HI and O-2 plasma treatment cyclically, we have proved the viability of Ge digital dry etching. Ge digital dry etching by controlling the plasma power and the processing time of HI and O-2 plasma treatments will be the building block for achieving Ge atomic layer etching.