Investigation of progressive breakdown and non-Weibull failure distribution of high-k and SiO2 dielectric by ramp voltage stress

In this work, the progressive breakdown (PBD) phase and non-Weibull final failure distributions of multi layer high-k and SiO₂ gate dielectric were investigated by voltage ramp stress (VRS) technique. A new hybrid two-stage constant voltage stress/voltage ramp stress methodology was developed to exclusively evaluate the PBD phase. Then the VRS technique was applied to investigate the non-Weibull failure distribution at a specified current (I_FAIL) with large sample-size (~1000) experiments. An excellent agreement was achieved in both cases in comparison with the conventional CVS technique, thus demonstrates that VRS is an effective technique to replace the CVS technique for investigation of post-BD and non-Weibull statistics in both SiO₂ and high-k dielectrics.