Mössbauer and RBS study of thermally annealed Te-implanted GaAs

Te-ions have been implanted at room temperature into GaAs single crystals up to a fluence of 10 ¹⁵{atoms}/{cm ²}. The recovery of the damage caused by implantation and the final positions of the Te-atoms in the GaAs lattice have been studied simultaneously by Mössbauer spectroscopy and Rutherford backscattering-channeling measurements. At high annealing temperatures the rapid thermal anneal method without encapsulation of the GaAs single crystals was used. Almost complete recovery of the GaAs from the implantation damage is observed in the RBS spectra at about 500°C oven annealing. The Mössbauer measurements show an almost cubic surrounding of the Te-atoms at 400°C thermal annealing, which suddenly changes to a less cubic environment at 500°C annealing temperature and cannot be reached again at higher annealing temperatures.