A mechanism for Frenkel defect creation in amorphous SiO₂ facilitated by electron injection

Using density functional theory (DFT) calculations we demonstrate how electron injection can facilitate the creation of Frenkel defects in amorphous (a)-SiO₂. The precursor sites composed of wide O-Si-O bond angles in amorphous SiO₂ act as deep electron traps and can accommodate up to two extra electrons. Trapping of two electrons at these intrinsic sites results in weakening of a Si-O bond and creates an efficient bond breaking pathway for producing neutral O vacancies and [Formula: see text] interstitial ions characterized by low transition barriers. The low barriers for the migration of [Formula: see text] ions of about 0.2 eV facilitate the separation of created defects. This mechanism may have important implications for our understanding of dielectric breakdown and resistance switching in a-SiO₂ based electronic and memory devices.