Hydrogen Iodide‐Based Dry Etching of GaAs , InP , and Related Compounds

Abstract

HI/H/sub 2//Ar discharges are shown to be universal etchants for III-V semiconductors, giving rise to highly anisotropic features with smooth surface morphologies. At low DC self bias (-100 V) and low pressure (1 mTorr), etch rates for all III-V materials of >2000 AA.min/sup -1/ are possible for high III percentages in the discharges, whereas rates greater than 1 mu m.min/sup -1/ are obtained at higher pressures and DC biases. These etch rates are approximately an order of magnitude faster than for CH/sub 4//H/sub 2//Ar mixtures under the same conditions and there is no polymer deposition on the mask or within the reactor chamber with HI/H/sub 2//Ar. Auger electron spectroscopy reveals residue-free, stoichiometric surfaces after dry etching in this mixture. As a result, photoluminescent intensities from dry etched samples remain high with little apparent damage introduction. Changes in the near-surface carrier concentration due to hydrogen passivation effects are also negligible with HI-based mixtures in comparison to CH/sub 4/-based dry etching.