Modeling of altered layer formation during reactive ion etching of GaAs

The binary collision based SDTrimSP model has been used to simulate the reactive ion beam etching (RIBE) of GaAs in the presence of energetic Ar ions and thermal O atoms. It includes the collisional effects, diffusive processes and chemical reactions taking place in the system. The model parameters are fitted using the experimental observations of Grigonis and co-workers [1] and validated with the experimental results obtained during the GaAs ion etching presented in this paper. A detailed analysis is presented to understand the effect of the diffusive processes and the role of O during RIBE of GaAs. It is shown how the presence of damage caused by the energetic Ar coupled with the presence of thermal O opens up chemical reaction channels which eventually leads to the preferential sputtering of Ga observed at the ion etching facility at University of Greifswald.

► Experimental result showing the preferential sputtering of GaAs (150 keV Ar+ and thermal O on GaAs) during reactive ion beam etching (RIBE) has been reported. ► A model based on binary collisions (SDTrimSP) is presented to simulate RIBE. ► The model is used to explain the reported experimental data and also the results by Grigonis and co-workers [1].