Reactive ion beam etching of GaAs and related compounds in an inductively coupled plasma of Cl2–Ar mixture

Abstract

Reactive ion beam etching (RIBE) of GaAs, GaP, AlGaAs, and GaSb was performed in a Cl2–Ar mixture using an inductively coupled plasma source. The etch rates and yields were strongly affected by ion energy and substrate temperature. The RIBE was dominated by ion-assisted etching at <600 eV and by physical sputtering beyond 600 eV. The temperature dependence of the etch rates revealed three different regimes, depending on the substrate temperature: (1) sputtering-etch limited, (2) products-desorption limited, and (3) mass-transfer limited regions. GaSb showed the overall highest etch rates, while GaAs and AlGaAs were etched at the same rates. The etched features showed extremely smooth morphologies with anisotropic sidewalls.