V. Mahadev et al., EFFECT OF DOPANTS ON ARSENIC PRECIPITATION IN GAAS DEPOSITED AT LOW-TEMPERATURES, Journal of electronic materials, 23(10), 1994, pp. 1015-1020
High resolution x-ray diffraction using synchrotron radiation was use
to characterize GaAs grown by MBE at low temperatures (LT-GaAs). LT-Ga
As grown at 225-degrees-C is nonstoichiometric and exhibits a 0.15% la
ttice expansion along the growth direction. Annealing LT-GaAs results
in arsenic clusters with a well-defined orientation relationship with
the GaAs matrix and a relaxation of the LT-GaAs lattice. The arsenic p
recipitation corresponds to a classical case of diffusion controlled n
ucleation and growth followed by coarsening. While the rates of growth
and coarsening in the n-doped and the p-doped samples are observed to
be identical, the effects of the superlattice seem to accelerate the
precipitation kinetics in the p-n superlattice sample. The enhanced co
arsening in the p-n superlattice sample is consistent with a previousl
y proposed model involving interaction between charged precipitate and
arsenic defects.