The material was implanted with 125keV Na and 660keV Xe ions at 15K. Defect analysis was performed in situ by using Rutherford back-scattering spectrometry in the channelling configuration, without temperature change. An ion-beam induced interfacial amorphization of AlAs was observed at the interface with the GaAs cap layer, and was related to the energy deposited into collision processes; yielding an amorphization rate of 0.44nm/dpa. For a wide range of ion fluences, only point defects and point-defect

complexes existed in the implanted layer; thus indicating a balance between defect formation and recombination during irradiation. In this depth region, amorphization occurred if the volume introduced by the implanted ions exceeded some critical value. It was assumed that this caused the breaking of bonds in the AlAs lattice, and the nucleation of amorphous nuclei which grew rapidly during further irradiation.

Anomalous Damaging Behaviour of AlAs during Ion Implantation at 15K. E.Wendler, B.Breeger, W.Wesch: Nuclear Instruments and Methods in Physics Research B, 2001, 175-177, 78-82