In-situ etching of GaAs/Al_xGa_1-xAs by CBr₄

Published in:
J. Cryst. Growth, vol. 310, no. 23, pp. 4754-4756 (2008).
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Abstract:
In-situ etching of GaAs and Al_xGa_1-xAs in LP-MOVPE has been studied using carbon tetrabromide (CBr₄). This source is routinely used by us as a source for carbon doping in GaAs and AlGaAs. The etching rate decreases with increasing AsH₃ partial pressure. While the etch rate is nearly constant for GaAs between 600 and 700°C it strongly drops towards higher temperatures with higher Al content in the layers. A model based on blocking of the surface by non-volatile Al-Br compounds is proposed. The observed effects allow for selective in-situ etching of GaAs against AlGaAs.

Keywords:
A1.Etching A3. Metalorganic vapour phase epitaxy B1. Halides B2. Semiconducting aluminium compounds B2. Semiconducting gallium compounds

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