Quasi-breakdown in ultra-thin dielectrics

In this paper, the quasi-breakdown is demonstrated to be a dominant failure mechanism in ultra-thin dielectrics with thicknesses less than 50 A and should be considered as a reliability issue to avoid overestimation of dielectric breakdown. Under high stress current density (-Vg), the charge to catastrophic breakdown decreases with decreasing the oxide thickness because of dielectric breakdown in the structural transition layer existing SiO 2 /Si interface. But the Qbd rapidly increases again with decreasing the oxide thickness below 50A under low stress current density due to the difficulty in building up electric field to cause catastrophic breakdown through the localized conduction path induced by the quasi-breakdown prior to catastrophic breakdown. The quasi-breakdown was suppressed in NO-annealed oxide.