Transient effect of DC stressed dielectric breakdown in thin SiO2 films

A post-breakdown resistance of SiO₂ has been studied as a quantitative monitor to describe the dielectric breakdown characteristics. First, the usefulness of post-breakdown SiO₂ analysis is discussed on the basis of experimental results. Clear differences between dry and wet oxides or stress polarities are shown in terms of the post-breakdown resistance of SiO₂ as well as the charge-to-breakdown. Then, the soft- and hard- breakdowns typically observed in sub-10 nm SiO₂ are discussed qualitatively but statistically. A main point discussed is to consider a time constant in MOS closed circuit including a sample itself just at the dielectric breakdown. The results imply that the intrinsic parasitic effects become more important in modeling and assessment of scaled-down CMOS device reliability.