Rutherford backscattering spectrometry and channeling studies on MeV Au-implanted GaAs(100) crystals

Samples of GaAs(100) single crystals have been implanted with Au++ ions of 1.43 MeV energy to a dose of similar to 1.5 x 10(15) atoms/cm(2) at a tilted geometry. Rutherford backscattering spectrometry together with ion channeling analysis with a B++ beam have been used to study the Au distribution and radiation damage after implantation and subsequent vacuum annealing in the temperature range of 500-850 degrees C. The experiments reveal the existence of extensive damage (possibly an amorphous layer) in the crystal surface region and annealing up to 850 degrees C for 30 minutes does not result in the complete recovery of the lattice order. A two component split profile of Au is observed at higher temperature annealing. Most of the Au atoms have diffused slightly towards the bulk of GaAs whereas a small fraction is diffused out towards the surface. These results suggest that the defect structure which results from ion implantation has a strong influence on the diffusion of Au. A tentative explanation for these results is presented.