Fabrication of open and buried quantum wires using a removable mask applicable for multiple processing steps

We have carried out detailed investigations on dry etch selectivity, ion penetration depths, and adhesion properties for a wide variety of materials to find a suitable combination for the fabrication of multiple process masks (MPM). A combination of Al2O3, TiO, and Pt yield the best results for the use in the In0.53Ga0.47As/InP system. Using this type of MPM for different fabrication processes, we have realized wires by deep dry etching (i.e., open wires) and also buried wires either by deep dry etching with an additional overgrowth or by ion implantation. All three kinds of wires show characteristic size effects in magnetotransport experiments.