POSITIVELY CHARGED BONDED STATES OF HYDROGEN AT THE (111)SI SIO2 INTERFACE/

Annealing of thermal (111)Si/SiO2 in hydrogen in the temperature range 450-800 degrees C is found to introduce a considerable density (up to 10(13) cm(-2)) of positively charged centres, ascribed to H bonding. However, there is no comparable density of dangling bonds initially pr esent nor generated at the Si/SiO2 interface that could account for th e observed hydrogen bonding. The hydrogen is suggested to be trapped i n the positively charged valence-alternation state-threefold-coordinat ed oxygen-resembling the well known hydronium ion (H3O)(+). The activa tion energy of dissociation of this state was found to be about 2.4 eV .