Area Dependence of Reliability characteristics for Atomic Layer Deposition HfO_2 Film under Static and Dynamic Stress

摘要

The reliability characteristics of high-k gate stacks of HfO_2 films under static and dynamic stresses have been investigated. Weibull slopes (β), area scaling factor, and lifetime projection model have been checked, in order to further understanding of the breakdown mechanism of HfO_2 gate stacks. Irrespective of the static and dynamic stress, the breakdown distributions of HfO_2 capacitors with various areas can be merged to a single Weilbull plot, suggesting that the dielectric breakdown is intrinsic for both cases. This study shows that a higher frequency and a lower duty cycle in the bipolar stress resulted in a longer lifetime enhancement. With respect to gate area effect, the amount of lifetime enhancement increases as the gate area decreases. A higher weibull slope is observed on a smaller gate area under dynamic stress.