Application of CCl 2F 2- and CCl 4-based plasmas for RIE of GaSb and related materials

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We report on the RIE etching of GaSb, AlGaAsSb and InGaAsSb materials in CCl 2F 2 and CCl 4 plasmas diluted with either H 2 or N 2. The highest etch rate (∼2 μm/min for GaSb) was achieved with CCl 4/N 2 chemistry, however, with an important degree of selectivity in etching of GaSb and quaternary alloys. By contrast, CCl 4/H 2 plasma enables anisotropic etching of heterostructure materials at an etch rate of ∼0.2 μm/min. CCl 2F 2-based plasma exhibited very slow etch rates (≤100 nm/min) and high selectivity in etching of GaSb over AlGaAsSb. The obtained results were applied in patterning of micrometer-size circular and stripe mesas in photonic GaSb/InGaAsSb/AlGaAsSb device structures, as well as in the fabrication of submicron circular gratings in GaSb.