RAMAN-SCATTERING STUDY OF DRY ETCHING OF GAAS - A COMPARISON OF CHEMICALLY ASSISTED ION-BEAM ETCHING AND REACTIVE ION ETCHING

Chemically assisted ion beam etching (CAIBE) and reactive ion etching (RIE) are two popular dry etching techniques routinely used in the fabrication of submicron features. We have used both in situ and ex situ Raman spectroscopy to study the effects of dry etching on the depletion layer in heavily doped GaAs. We find that both CAIBE and RIE produce large numbers of traps that produce an insulating layer on the surface. CAIBE using ion energies greater than 2 keV also produces a damaged layer. For both techniques the use of chlorine based species reduces both traps and damage. Sputtering with chlorine alone, is shown to be able to eliminate both damage and traps. Finally, Raman spectroscopy is shown as a powerful in situ tool for studying etch damage.