High selectivity Inductively Coupled Plasma etching of GaAs over InGaP

The dry etch selectivity of GaAs over InGaP in BCl3rSF6discharges with additives of He, Ar, or Xe under Inductively Coupled Plasma conditions was examined. Selectivities over 200 were achieved in BCl3rSF6or BCl3rSF6rHe at low ion energies and moderate ion fluxes. The mechanism for achieving selective etching was studied with Electron Spectroscopy for Chemical Analysis, and is due to formation of non-volatile InCl and InF reaction products. The key to achieving high X X selectivity is to minimize sputter-induced desorption of these reaction products. Ion-induced damage in the InGaP was also minimized at low ion energies and moderate ion fluxes. q2000 Elsevier Science B.V. All rights reserved.