The effect of channel hot-carrier stressing on gate-oxide integrity in MOSFETs

The correlation between channel hot-carrier stressing and gate-oxide integrity is studied. It is found that channel hot carriers have no detectable effect on gate-oxide integrity even when other parameters (e.g., Delta V/sub T/ and Delta I/sub D/) have become intolerably degraded. In the extreme cases of stressing at V/sub G/ approximately=V/sub T/ with measurable hole injection current, however, the oxide charge to breakdown decreases linearly with the amount of hole fluence injected during the channel hot-hole stressing. This may limit the endurance of a nonvolatile memory using hot holes for erasing. This can also explain the gate-to-drain breakdown of a device biased in the snap-back region, since snap-back at low gate voltage is favorable for hole injection. Snap-back-induced oxide breakdown could be an ESD (electrostatic discharge) failure mechanism.>