Positive charge and interface state creation at the Si-SiO2 interface during low-fluence and high-field electron injections

Abstract

Positive charge and interface state creation at the Si‐SiO₂ interface has been studied when low‐fluence electron injections (lower than 10⁻³ C/cm²) are performed at high‐field (higher than 7 MV/cm) across the oxide. Temperature dependencies for the formation of both types of interface defects are examined in the range 90–300 K. It is found that positive charge formation is temperature independent, while interface state creation is thermally activated. The former result (no temperature dependence) is consistent with impact ionization in SiO₂, while the latter (temperature dependence) is explained by a trap creation due to hydrogen‐related species diffusion. These results show that both mechanisms can occur together, and that they trigger two different kinds of damage at the Si‐SiO₂ interface.