DIFFUSING ARSENIC VACANCIES AND THEIR INTERACTION WITH THE NATIVE DEFECT EL2 IN GAAS

We model the indiffusion of arsenic vacancies and their interaction wi th the midgap electron trap EL2 in GaAs samples that occurs during unp rotected and proximity high-temperature anneals. From fits to existing data we find the diffusive capture of V-As by EL2 to be inhibited by a large (>1 eV) repulsive barrier of unknown origin. In conjunction wi th other results from the literature we estimate the diffusivity of V- As to be 4x10(-3) exp(-1.8 eV/kT) cm(2)/s, a value uncertain by at lea st an order of magnitude. (C) 1996 American Institute of Physics.