Nucleation-limited amorphization of GaAs at elevated temperatures

By a detailed correlation of damage profiles from Rutherford backscattering and channeling with cross-sectional transmission electron microscopy images, we have identified an intriguing nucleation-limited amorphization regime in GaAs irradiated with ions at elevated temperatures. When the rate of dynamic annealing during irradiation exceeds the damage production rate, amorphization can take place at depths significantly different from the maximum in the energy deposition density. This process results from the incomplete annihilation of mobile irradiation-induced defects and occurs either at the surface or at a dislocation hand, formed hy the agglomeration of interstitials. Once formed such amorphous layers grow by a layer-by-layer process.