Damage production in semiconductor materials by a focused Ga+ ion beam

The semiconductor materials Si, SiC, GaP, InP, GaAs, and InAs were irradiated at normal incidence and room temperature with a focused Ga+ ion beam in order to investigate the damage production at high current densities on the order of some A cm−2. The samples were irradiated with ion fluences between 2×1013 and 2×1015 Ga+ cm−2 at an ion energy of 50 keV. The critical ion fluences for amorphization were determined by Rutherford backscattering spectrometry and by Raman spectroscopy. It was found that for SiC, GaP, and InP the number of displacements per atom necessary for amorphization is about the same one as that required for irradiation at low current densities, but in the cases of Si, GaAs, and InAs the high and low current density results differ remarkably. The reason for the different behavior of these materials is discussed.