First-principles exploration of possible trap terminators in SiO2

Oxygen vacancies (O vacancies) are considered to be charge trap centers in SiO2. This letter explores possible terminators of Si-dangling bonds associated with the O vacancies by performing first-principles total energy calculations. The present exploration is focused on the terminators which retain their chemical bonds after hole trapping. We have found that Cl atoms, NH and OH molecules firmly terminate the Si-dangling bond while H atoms are dissociated from a Si-H bond after hole trapping. The H dissociation is accompanied by the generation of gap states which can contribute to the leakage currents in the SiO2 films. (C) 1998 American Institute of Physics. [S0003-6951(98)04534-3]