TDDB characteristics of PETEOS SiO/sub 2/ under pulse stress

Assuming that time dependent dielectric breakdown (TDDB) depends on the density of trapped charges in the dielectrics, we propose a model which explains the difference of TDDB characteristics between pulsed stress and constant stress. Trapped charges increase under electrical stress because of the trap generation while decrease after the stress is removed due to detrapping. With the pulse stress TDDB lifetime test system designed by ourselves, TDDB characteristics of PETEOS SiO/sub 2/ films under both pulse stress and constant stress are compared. The results indicate that TDDB characteristics of PETEOS SiO/sub 2/ develop as the pulse frequency increase.