Model for the incorporation of excess arsenic into interstitial positions during the low-temperature growth of GaAs(001) layers

Using the GAUSSIAN 94 program package on a Ga16As17H36 cluster, the interaction of an As-2 molecule approaching an As-terminated nonreconstructed GaAs(001) surface along the symmetry axis C-2 of the cluster is studied. To describe the interaction between As-2 molecule and cluster, the total energy of the system was calculated for various cluster As-2 distances. The results show that the system (cluster plus molecule) has a stable conformation where one As atom resides at a tetrahedral interstitial site below the surface, i.e., inside the crystal. This result indicates the possibility of As incorporation by the particular process presented here. (C) 2001 American Institute of Physics.