Thermally Activated Electron Capture By Mobile Protons In Sio2 Thin Films

The annihilation of mobile protons in thin SiO2 films by capture of ultraviolet-excited electrons has been analyzed for temperatures between 77 and 500 K. We observe a strong increase in proton annihilation with 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 excited vibrational states of the ground electronic (valence band) state to a nearby excited electronic (SiO2 gap) state. It is argued that the latter excitation can result in H-0 formation at elevated temperatures. (C) 1998 American Institute of Physics.