THERMALLY ACTIVATED ELECTRON-CAPTURE BY MOBILE PROTONS IN SIO2 THIN-FILMS

The annihilation of mobile protons in thin SiO2 films by capture of ul traviolet-excited electrons has been analyzed for temperatures between 77 and 500 K. We observe a strong increase in proton annihilation wit h increasing temperature, and derive an activation energy for electron capture of about 0.2 eV. Based on quantum chemical [(OH)(3)Si](2)-O-H + cluster calculations, we suggest photoexcitation of electrons from e xcited vibrational states of the ground electronic (valence band) stat e to a nearby excited electronic (SiO2 gap) state. It is argued that t he latter excitation can result in H-0 formation at elevated temperatu res. (C) 1998 American Institute of Physics.