EN
Amorphization of P and As implanted GaAs at liquid nitrogen temperature has been investigated. The post-implantation damage was measured by means of Rutherford Backscattering (RBS) He^{+} channeling technique. The critical dose and critical energy densities for amorphization were determined. From the results obtained it is concluded that for both ions the amorphization process can be satisfactorily described by the heterogeneous model.