Inductively coupled plasma etching in ICl- and IBr-based chemistries. PartI: GaAs, GaSb, and AlGaAs

High-density plasma etching of GaAs, GaSb, and AlGaAs was performed in ICl/ Ar and IBr/AI chemistries using an Inductively Coupled Plasma (ICP) source. GaSb and AlGaAs showed maxima in their etch rates for both plama chemistri es as a function of interhalogen percentage, while GaAs showed increased et ch rates with plasma composition in both chemistries. Etch rates of all mat erials increased substantially with increasing rf chuck power, but rapidly decreased with chamber pressure. Selectivities > 10 for GaAs and GaSb over AlGaAs were obtained in both chemistries. The etched surfaces of GaAs showe d smooth morphology which were somewhat better with ICl/Ar than with IBr/Ar discharge. Auger Electron Spectroscopy analysis revealed equirate of remov al of group III and V components or the corresponding etch products, mainta ining the stoichiometry of the etched surface.