Novel dry etch chemistries for InP and related compounds

A novel dry etch mixture based on HI/H/sub 2/ is shown to be a universal etchant for In-based 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 HI percentages in the discharge, whereas rates >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. Moreover, there is no polymer deposition on the mask or within the reactor chamber with HI/H/sub 2/. Auger electron spectroscopy reveals residue-free, stoichiometric surfaces after dry etching in this mixture. Results of etching with electron cyclotron resonance discharges of HBr/Ar, HBr/CH/sub 4/, and HBr/H/sub 2/ are also discussed. It is concluded that the HI/H/sub 2//Ar chemistry provides a strong alternative to CH/sub 4//H/sub 2//Ar, particularly for the etching of deep features.<>