Exponential dependence of percolation resistance on gate voltage and its impacts on progressive breakdown [MOSFETs]

The evolution of the percolation resistance (R/sub perc/) in ultrathin gate dielectrics during progressive breakdown (PBD) is studied. For a given PBD hardness, R/sub perc/ is found to be exponentially dependent on gate voltage. Our study on the voltage-dependence of R/sub perc/ further reveals that the parasitic resistances (R/sub para/) play a vital role in determining the subsequent stages of PBD. Specifically, R/sub perc/ is found to decrease with increasing PBD hardness. In the initial stage of PBD, a rapid degradation in R/sub perc/ can be observed. As PBD continues to evolve and R/sub para/ is no longer negligible, the degradation in R/sub perc/ gradually slows down. When R/sub perc/ becomes comparable to R/sub para/ a significant localized heating in the vicinity of the BD spot, responsible for the occurrence of catastrophic failure, is triggered. Moreover, the voltage-dependence of R/sub perc/ associated with the evolution of /spl alpha/ and K provides new insight into the study of PBD.