CHEMICAL BEAM EPITAXIAL-GROWTH OF STRAINED CARBON-DOPED GAAS

We report an investigation of the growth characteristics of GaAs by chemical beam epitaxy using trimethyl-Ga and arsine. The growth rate behaviors as a function of temperature, As overpressure, and alkyl arrival rate are qualitatively similar to those using triethyl-Ga with differences that can be explained by differences in the alkyl-Ga bond strength. A unified description of the growth kinetics assuming a unimolecular reaction mechanism is possible. Lattice parameter is found to decrease with increasing carbon concentration. A high quality GaAs/GaAs:C doping superlattice has been prepared. Although the composition modulation is too small for x-ray diffraction measurement, the structural deformation gives rise to satellite peaks with order n up to ±7 observed for the first time. X-ray analysis of the superlattice after annealing has been employed to study the carbon diffusion in GaAs.