Bulk oxide charge and slow states in Si-SiO2 structures generated by RIE-mode plasma

The damage induced in the thin SiO2-Si system after an exposure to O-2 and N-2 plasma working in reactive ion etching (RIE) mode has been studied. A g eneration of high density (up to similar to 5 x 10(12) cm(-2) in the first 15 s plasma exposure) of positive oxide charge in bulk traps as well as in slow states has been established. The RIE damage effects become highly proc ess dependent as the plasma time increases, the fixed oxide charge first in creases and then slows down or even turns around depending on discharge con ditions. II is suggested that the relative contribution of the two main pla sma components (ion bombardment and vacuum UV photons) at different dischar ge regimes is the reason for the appearance or the absence of the "turn-aro und" effect. It is established that the combination O-2 plasma and low pres sure is critical for the degradation of the plasma treated samples. The res ults reveal a strong linear correlation between the leakage current detecte d and plasma created positive charge. (C) 2000 Elsevier Science Ltd. All ri ghts reserved.