A mechanism for Frenkel defect creation in amorphous SiO 2 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 O-2-interstitial ions characterized by low transition barriers. The low barriers for the migration of O-2-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.