Theoretical studies on intrinsic electron traps in strained amorphous silica

Charge trapping in amorphous silica (a-Si O 2 ) dielectric layer can degrade electrical performances of semiconductor devices. Earlier studies demonstrate that a SiO 4 tetrahedra unit with a wide O-Si-O angle ( ≥ 132 . 0 ∘ ) can act as an electron trapping site in unstrained a-Si O 2 cells. With first-principle calculations, in conjunction with molecular dynamic calculations, this work investigates the impacts of uniaxial tensile strain on one-electron trapping behaviors of a-Si O 2 , including atomic configurations and electronic properties. Stable states of strained a-Si O 2 cells with an extra electron indicate that a SiO 4 with a wide O-Si-O angle ( ≥ 132 . 0 ∘ ) and a long Si-O bond ( ≥ 1 . 660 Å ) making up the angle can act as a novel intrinsic electron tap. An electron trapping on this trap can generate a stable defect complex with two components: a negatively charged non-bridging oxygen hole center and a neutral oxygen vacancy with an unpaired electron.