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

摘要

The arsenic desorption form the (1 1 1)B GaAs surface is investigated under an atomospheric pressure by two in situ monitoring methods: gravimetric and optical monitoring systems in a halogen transport atomic layer epitaxy (ALE). The grwoth rate can be monitored in each ALE cycle by the in situ gravimetric montioring syste. It is shwon that the growth rate decrases from >1.0 to 0.5 ML/cycle with increasing H_2 purge time according to the As desorption form surface, and three kinds of reconstruction surfaces exist on the (1 1 1)B GaAs surface in the atomspheric ALE. The smooth surfaces were obtained on the surfaces of (1×1)_LT, (1×1)_LT ＋19×19 and (19×19). The in situ otical monitoring also shwos that the reconstructed surfaces are repreoducibly formed according to the As desorption.