The most recent advances and greatest remaining challenges in dry etch processing of the III-V mitrides are reviewed. The challenge of reasonable etch rates has been solved largely through application of high density plasma sources. However, maintenance of etched surface stoichiometry, minimization of residual damage, and selectrivity between the nitrides continue to present major challenges. A detailed discussion is given with respect of GaN etching in a high density plasma. Parameteric studies reveal that preferential sputtering is the leading cause of surface stoichiometry deviations, rendering them nitrogen deficient-a condition beneficial to ohmic contacts to n-GaN, but detrimental to all other types of contacts. This progblem can be dminimize through the addition of a strong chemical component to the etch. A more fundamental study, emplying in stu diagnostics of the Gan etch process, confirms the improtance of high ion flux to the substrate and of sufficient ion energy (>100 eV) for reasonable etch rates at room temperatue.
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