In situ monitoring of arsenic desorption on GaAs (1 1 1)B surface in atomic layer epitaxy

The arsenic desorption from the (1 1 1)B GaAs surface is investigated under an atmospheric pressure by two in situ monitoring methods: gravimetric and optical monitoring systems in a halogen transport atomic layer epitaxy (ALE). The growth rate can be monitored in each ALE cycle by the in situ gravimetric monitoring system. It is shown that the growth rate decreases from > 1.0 to 0.5 ML/cycle with increasing Hz purge time according to the As desorption from surface, and three kinds of reconstruction surfaces exist on the (1 1 1)B GaAs surface in the atmospheric ALE. The smooth surfaces were obtained on the surfaces of(1 x 1)(LT), (1 x 1)(LT) + (root 19 x root 19) and (root 19 x root 19). The in situ optical monitoring also shows that the reconstructed surfaces are reproducibly formed according to the As desorption. (C) 1999 Published by Elsevier Science B.V. All rights reserved.