Effect of AC stress on oxide TDDB and trapped charge in interface states

This study is driven by the need to improve the oxide reliability of a memory cell. The effects of dynamic high electric field stressing on thin oxide have been studied. Difference between time to breakdown with static stress and dynamic stress has been shown. Trapped charge in interface states under dynamic and static oxide field stress has been investigated with quasi-static capacitance voltage measurement. The duty cycle of the dynamic stress has an important effect on the oxide lifetime. This duty cycle effect is also impacted by the electric field. Interface Hydrogen Released model have been studied to understand relaxation phenomena. Real use stress conditions show an important gain on lifetime.