Nanoscale density variations induced by high energy heavy ions in amorphous silicon nitride and silicon dioxide

摘要: The cylindrical nanoscale density variations resulting from the interaction of 185 MeV and 2.2 GeV Au ions with 1.0 μm thick amorphous SiN x :H SiO layers are determined using small angle x-ray scattering measurements. profiles resembles an under-dense core surrounded by over-dense shell a smooth transition between two regions, consistent molecular-dynamics simulations. For :H, show radius 4.2 nm relative change three times larger than value for 5.5 nm. Complementary infrared spectroscopy measurements exhibit damage cross-section comparable to dimensions. morphology results freezing in local viscous flow arising non-uniform temperature profile radial direction ion path. concomitant drop viscosity mediated thermal conductivity appears be main driving force rather presence anomaly.