Etching of GaAs/AlGaAs by bisdimethylaminochlorarsine

We report on the etching characteristics of GaAs and AlGaAs by gas source molecular beam epitaxy (GSMBE) using a new precursor bisdimethylaminochloroarsine (BDMAAsCl). The etching rate of GaAs is linearly dependent on the BDMAAsCl flow rate. The activation energy of GaAs etching was 0.25 eV. However, $Al0.28Ga0.72As$ etching shows the negative activation energy of $−0.29 eV$ at the substrate temperature below 500 °C. The etchings of GaAs and AlGaAs are probably attributed to the formation of GaCl and $AlCl2$ or $AlCl3,$ respectively. Furthermore, we demonstrated that the BDMAAsCl etching remarkably reduced the interfacial impurity (carbon, oxygen, silicon) density of GSMBE-grown GaAs epilayers/epiready substrates by one order of magnitude compared with trisdimethylaminoarsine cleaning only.