RANGE OF ENERGETIC Xe¹²⁵ IONS IN MONOCRYSTALLINE SILICON

An electrochemical "peeling" technique for dissolving thin (40–600 Å) uniform layers from the surface of a silicon crystal has been developed and calibrated. Using this technique, range distributions of 5–80 kev Xe 125 ions in monocrystal-line silicon have been measured as a function of the crystallographic direction. The ranges were found to depend strongly on the initial direction of ion motion, with the observed order being:[Formula: see text]These results for a diamond-type lattice are in qualitative agreement with the recent computer studies of Robinson and Oen (1963). Even for the least penetrating directions, the observed range is about three times the value expected in the absence of crystal lattice effects. At ion bombardments exceeding 10 12 Xe + /cm 2 , the observed penetration decreased significantly; this sensitivity to rather low levels of ion bombardment suggests that bombardment induces a change in crystal structure.