Advanced GaAs/AlGaAs ICP-DRIE etching for optoelectronic applications

We investigate the parameter optimization for micron-scale etching by Inductive Coupled Plasma - Deep Reactive Ion Etching (ICP-DRIE) of GaAs/AlGaAs semiconductor heterostructures. Although dry etching approaches have been reported in the literature using a broad variety of plasma etch tools, there is still need to meet the majority of microsystems dry etching requirements. The desired etch characteristics for GaAs/AlGaAs heterostructures can be achieved by controlling the various process parameters with good reliability, high selectivity, and – simultaneously – high etch rates and sidewall verticality. Etch rates from 1 to over 5.5μm/min have been obtained. The selectivity with optical photoresist varies from 2.3 to 16. The presented results can be
valuable for a wide range of applications involving fabrication of micro-electro-mechanical-systems or Micro Optoelectronic Mechanical Systems.

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