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

The effect of HI and O2 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 O2 plasma. By utilizing HI and O2 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 O2 plasma treatments will be the building block for achieving Ge atomic layer etching.