The oxidation of surface layers during reactive ion etching of GaAs in CF2Cl2+O-2 and O-2 plasmas

The RF plasma was created in a plasmatron system with accelerating potentia l of 20-700 V, discharge power of 0.5-5.0 W/cm(2) and at pressure of 10(-4) -10(-2) Torr. The thickness and composition of formed oxide layer is consid ered experimentally at various etching parameters: ion current density, pla sma composition, substrate temperature. The experimental curves were modele d by proposed phenomenological model. The model includes the main processes taking place during reactive ion etching: sputtering, adsorption, heteroge neous chemical reactions, desorption of volatile compounds and radiation en hanced diffusion. The model gives the kinetics of elemental composition on the surface and the composition of the altered layer. (C) 1999 Elsevier Sci ence B.V. All rights reserved.