RANGES OF 1.0-2.7 MEV H-1 AND HE-4 IONS IN GAAS

Ranges of H-1 and He-4 ions in GaAs single crystals are reported in the high energy implantation range of 1.0-2.7 MeV. Experiments were performed at random and for H-1 ions also at [100] axial channeling orientation. Ion beam irradiation of the samples resulted in exfoliation of the surface layer and craters were produced. The crater depths corresponding to the projected range were measured by a profilometer. At [100] channeling orientation the H-1 ions penetrated slightly deeper than in the random case. The random ranges are compared to transport equation and Monte Carlo calculations (PRAL and TRIM codes). In the H-1 ion case, the experimental data were well reproduced by the calculations, while the data for He-4 ions clearly exceeded the calculations.