High-Energy Heavy Ion Tracks in Nanocrystalline Silicon Nitride

At present, silicon nitride is the only nitride ceramic in which latent ion tracks resulting from swift heavy ion irradiation have been observed. Data related to the effects of SHIs on the nanocrystalline form of Si3N4 are sparse. The size of grains is known to play a role in the formation of latent ion tracks and other defects that result from SHI irradiation. In this investigation, the effects of irradiation with high-energy heavy ions on nanocrystalline silicon nitride is studied, using transmission electron microscopy techniques. The results suggest that threshold electronic stopping power, Set, lies within the range 12.3 ± 0.8 keV/nm to 15.2 ± 1.0 keV/nm, based on measurements of track radii. We compared the results to findings for polycrystalline Si3N4 irradiated under similar conditions. Our findings suggest that the radiation stability of silicon nitride is independent of grain size.