Chemical kinetics of hydrogen and (111) Si-SiO2 interface defects

Abstract

Electron paramagnetic resonance (EPR) measurements and theoretical considerations have yielded a unified model for the hydrogen chemistry of silicon dangling bond Pb defects at the (111) Si-SiO2 interface. Previous EPR measurements indicated that passivation of Pb centers with H2 proceeds by the reaction H2+Pb→HPb+H with an activation energy of 1.66±0.06 eV. New EPR studies reported here show that HPb centers dissociate by the reaction HPb→Pb+H with an activation energy of 2.56±0.06 eV. When combined, these two reactions yield H2→H+H, which in vacuum requires an energy input of 4.52 eV. Comparison of these energies indicates that the reverse reactions H+HPb→Pb+H2 and H+Pb→HPb occur with essentially no energy barrier and are controlled by the local availability of atomic hydrogen.