Chlorine and HCl radical beam etching of III–V semiconductors

Abstract

This work presents etch rate versus temperature data for GaAs and InP etched by Cl2 and HCl both with and without a remote plasma. The data is described both qualitatively and quantitatively by a thermodynamic model utilizing reactant-flux-limited and product-desorption-limited regimes. This ‘‘ionless’’ etching technique demonstrates reactant-flux-limited, temperature-independent behavior for HCl etching of GaAs for over five orders of magnitude of flux. InP and GaAs show nearly equirate etching at T>150 °C with both gases. Reactive ion etching (RIE) with Cl2 of InP at elevated temperatures produces only moderate rate enhancements; RIE gave a maximum etch rate of ∼800 Å/min at 175 °C compared to ∼0.5 μm/min obtained with the remote plasma system at the same temperature.