AFM FABRICATION AND CHARACTERIZATION OF INAS ALGASB NANOSTRUCTURES/

We describe two distinct fabrication processes based on atomic force m icroscope (AFM) oxidation for nanoscale device fabrication which are p articularly useful for GaSb/AlGaSb/InAs heterostructures. One utilizes water immersion which selectively removes the oxidized GaSb region. T he other makes use of the enhanced etching rate for oxidized GaSb and AlGaSb layers for a developer solution resulting in;the formation of d eep grooves down to the InAs channel layer. The latter is used togethe r with a selective InAs etching for the formation of a narrow constric ted structure:. A 0.3-mu m-period corrugation on the GaSb surface is f abricated by the former process in order to make a two-dimensional ele ctron gas (2DEG) with its electron concentration laterally modified. T he magnetotransport measure; ments of the structure show Weiss oscilla tions corresponding to the corrugation period verifying the successful formation of the laterally modified 2DEG. A single electronic device structure fabricated by the latter shows non-linear I-V characteristic behavior indicating the capability of these AFM oxidation processes f or the fabrication of various types of nanostructure devices. (C) 1998 Elsevier Science Ltd. All rights reserved.