Simulation of displacement damage in Si & SiO2 caused by protons

Abstract

Nowadays Si & SiO₂ have been the most widely used materials in semiconductor devices as CPU and other various integrated circuit chips, utilized in aerospace electronic systems, and at the same time protons are important components of cosmic rays that can cause displacement damage in Si & SiO₂. Therefore, it is essential to study the displacement damage of Si & SiO₂ caused by protons. The software of Geant4 is adopted in this paper, to simulate transportation process of incident protons with different energy in Si & SiO₂. The simulation results indicates that primary knock-on atom (PKA) generated by incident proton in Si & SiO₂ is predominant in lower energy range, its spatial distribution increases gradually along the direction of incident proton, and the scattering angle of the PKA is about 90°, following a Gaussian distribution approximately. And in lower energy range, ²⁸Si and ¹⁶O generated by elastic scattering are a primary source of radiation damage in Si & SiO₂. But as the proton energy increases, the contribution of nuclear inelastic scattering becomes more and more important, but the overall level of induced damage diminishes gradually. Meanwhile, the simulation results indicate that with increasing depth of the material, the non-ionizing energy loss (NIEL) increases gradually, and NIEL caused by elastic scattering is higher near the surface layer of the materials, and as for NIEL caused by nuclear inelastic scattering is also higher near the surface layer of the materials. The simulation results in this paper can provide useful data and theoretical guidance for study on Si & SiO₂ displacement damage caused by proton irradiation.