The TDDB Characteristics of Ultra-Thin Gate Oxide MOS Capacitors under Constant Voltage Stress and Substrate Hot-Carrier Injection

Abstract EN

The breakdown characteristics of ultra-thin gate oxide MOS capacitors fabricated in 65 nm CMOS technology under constant voltage stress and substrate hot-carrier injection are investigated.

Compared to normal thick gate oxide, the degradation mechanism of time-dependent dielectric breakdown (TDDB) of ultra-thin gate oxide is found to be different.

It is found that the gate current ( I g ) of ultra-thin gate oxide MOS capacitor is more likely to be induced not only by Fowler-Nordheim (F-N) tunneling electrons, but also by electrons surmounting barrier and penetrating electrons in the condition of constant voltage stress.

Moreover it is shown that the time to breakdown ( t b d ) under substrate hot-carrier injection is far less than that under constant voltage stress when the failure criterion is defined as a hard breakdown according to the experimental results.

The TDDB mechanism of ultra-thin gate oxide will be detailed.

The differences in TDDB characteristics of MOS capacitors induced by constant voltage stress and substrate hot-carrier injection will be also discussed.