Low-power pulsed-laser annealing of implanted GaAs

Low-power annealing by a pulsed laser is used to recover the structure of low-dose implanted (100) GaAs crystals. Reflection high-energy electron diffraction with variable glancing incidence is employed to detect the structural changes at different depths in the specimens. The depth dependence of the damage is studied in more detail by Rutherford backscattering analysis. The annealing results depend on the irradiation conditions. A laser energy window below the melting threshold is found within which the structure can be restored to about as high degree of crystallinity as the virgin one, without any visible surface damage. A simple theoretical estimate shows that the temperature rise of the material is far below the melting threshold. This rise is too short in time to cause substantial dopant diffusion; however, it can enhance well the point-defect mobility.