Threshold displacement energy of amorphous SiO2: A molecular dynamics study

Amorphous SiO2 is a vital insulation or isolation material in modern silicon-based devices and chips, which is exposed to irradiations of energetic particles when working in space environment. In order to evaluate the radiation resistance of a-SiO2, the threshold displacement energy (TDE) with molecular dynamic simulations is calculated. We found a linear dependence of the TDE of O atoms on the Si-O-Si bond angles, which corresponds to a reduction in the stresses exerted on the central O atom as the bond angle increases. The further exploration about the oxide manufacturing process showed that the higher annealing temperature increases the probability of Si-O-Si bond angles in the range of 135 degrees -155 degrees. This work will shed light on the promotion of anti-radiation ability of silicon-based devices.