On the relationship between stress induced leakage currents and catastrophic breakdown in ultra-thin SiO2 based dielectrics

Abstract Stress induced leakage currents have been measured on capacitor structures with gate dielectrics approximately 19 A thick, grown in N 2 O. Both n + /p and p + /n (poly-silicon gate/ silicon substrate) structures were fabricated to allow electron injection using both positive and negative bias. We have measured the statistical distribution (64 devices for each condition) of the SILC as a function of the stress bias condition. Both charge to breakdown (Q DB ) and time to breakdown (T DB ) are found to be strong functions of the applied bias. The change in the stress induced leakage (ΔJ/J o ) at breakdown is found to be relatively independent of the magnitude and polarity of the bias during stress. We suggest that (ΔJ/J o ) at breakdown is a measure of a critical defect density required to cause catastrophic breakdown in ultra-thin dielectrics and this critical density is not dependent upon the electron energy during stress.