DEFECT-DEFECT HOLE TRANSFER AND THE IDENTITY OF BORDER TRAPS IN SIO2-FILMS

We have found evidence for hole-transfer events between oxygen-vacancy -related defects in thermal SiO2 films selectively injected with holes using electron paramagnetic resonance (EPR) and capacitance-voltage m easurements. We find that hole injection into SiO2 films reveals two t ypes of EPR centers: oxygen-vacancy-related E(delta)'and E(gamma)' cen ters; both centers are positively charged. Upon annealing the Si/SiO2 structures at room temperature, the E(delta)' defect transfers its hol e to a neutral oxygen-vacancy (O-3 drop Si-Si drop O-3) site forming t he classic E(gamma)' center. Electrically, we observe a concomitant gr owth in the border-trap density, suggesting that some of the transfer- created E(gamma)' centers may be the microscopic entities responsible for the border traps. These results constitute spectroscopic evidence that hole transfer between defect sites can occur over extremely long time scales (hours) in SiO2 films.