Gate-oxide breakdown accelerated by large drain current inn-channel MOSFET's

A study of the time-dependent dielectric breakdown (TDDB) of thin gate oxides in small n-channel MOSFETs operated beyond punchthrough is discussed. Catastrophic gate-oxide breakdown is accelerated when holes generated by the large drain current are injected into the gate oxide. More specifically, the gate-oxide breakdown in a MOSFET (gate length=1.0 μm, gate width-15 μm) occurs in ~100 s at an applied gate oxide field of ~5.2 MV/cm during the high drain current stress, while it occurs in ~100 s at an applied gate oxide field of ~10.7 MV/cm during a conventional time-dependent dielectric breakdown (TDDB) test. The results indicate that the gate oxide lifetime is much shorter in MOSFETs when there is hot-hole injection than that expected using the conventional TDDB method