DEPASSIVATION OF DAMP-OXIDE PB CENTERS BY THERMAL AND ELECTRIC-FIELD STRESS

The kinetics of thermal and electric field-induced depassivation of P(b) centers in damp oxide Si/SiO2 systems have been examined. Negative field-induced depassivation is maximized at intermediate oxide water content, while the activation energy E(a) for thermal depassivation is minimized. The thermal E(a) in damp-oxides is about 0.6 eV, and for dry and wet oxides, 2.5 eV and 2 eV, respectively. This unusual reaction fingerprint is compared to well-characterized charge-transfer processes in other systems. The activation minimum and correlated P(b) maximum suggest the so-called Marcus inversion regime or the "volcano" effect. It is then argued that the depassivation is explainable by a single rate-limiting reaction of the form SiH + A + hole+ --> Si. + AH+, where A is a hydrogenous species. Some aspects of the observed depassivation are in accord with the negative bias temperature instability (NBTI) in metal oxide silicon structures; however, there are important differences. The extended electrochemical and physical arguments developed for the depassivation have significant implications for other Si/SiO2 physicochemical phenomena, such as radiation damage and oxidation mechanisms.