It was found that hole injection into film samples revealed the presence of 2 types of electron paramagnetic resonance center: O vacancy-related E and E. Both centers were positively charged. Upon annealing Si/SiO2 structures at room temperature, the E defect transferred its hole to a neutral O-vacancy (O3Si-SiO3) site to form a classic E center. Electrical data indicated a concomitant growth of the border-trap density. This suggested that some of the transfer-created E centers might be the microscopic entities which were responsible for the border traps. The results indicated that hole transfer between defect sites could occur over extremely long time-scales (hours) in SiO2 films.

W.L.Warren, D.M.Fleetwood, M.R.Shaneyfelt, P.S.Winokur, R.A.B.Devine: Physical Review B, 1994, 50[19], 14710-3