Cl2‐Based Dry Etching of GaAs, AlGaaAs, and GaP

Abstract

‐based plasmas for etching GaAs, AlGaAs, and GaP have been examined as a function of gas additive (Ar, or ), radio frequency (RF) and microwave power, plasma composition, mask material, and process pressure. In a load‐locked reactor, smooth etched surface morphologies were obtained over basically all conditions investigated, with typical root‐mean‐square roughness of ⩽ 1.5 nm measured by atomic force microscopy. The etch rates for all three materials increase with RF power (ion energy), microwave power (ion current), percentage, and pressure, with controlled rates of ∼0.4 μm/min at a condition of , 850 W microwave power, 1.5 mTorr, and 100 to 150 W of RF power. Operating under electron cyclotron resonance conditions where the ion density is (measured by microwave reflection interferometry) produces rapid degradation of photoresist, and more robust mask materials such as , or W are necessary.