OPTIMIZATION OF ELECTRON-CYCLOTRON-RESONANCE REACTIVE ION-BEAM ETCHING REACTORS FOR DRY-ETCHING OF GAAS WITH CL-2

Dry etching of GaAs in plasma reactors is an important technology for the fabrication of optoelectronic devices. Currently, process optimiza tion is done by trial and error, which is expensive in both time and m oney. Optimization techniques must therefore be developed based on a f undamental understanding of the related processes, and include a macro scopic understanding of the plasma chemistry. In this work, we examine d the effect of gas flow rate on the peak intensity of the optical emi ssion spectra of the chemical species in an etching chamber and on the etch rate of the GaAs substrate. From our results we developed a simp lified model of the dry etching process of GaAs with Cl-2 in electron cyclotron resonance reactive ion beam etching that accounts for the de gree of gas homogeneity in the reactor, especially the Cl-2 concentrat ion. The effect of the reactor geometry and operating conditions on th e performance of the dry etching process is well explained with this m odel, which can be used to optimize dry etching processes.