Conductive AFM Reveals Oxide Breakdown Mechanism

摘要

With all the studies that have been done to examine thin gate dielectric breakdown (BD) and how it occurs, there is nonetheless an ongoing need to better characterize this breakdown phenomena due to the increasing influence on device reliability as transistors continue to scale. In a recent study, researchers from the Universitat Au-tonoma de Barcelona (Bellaterra, Spain) have electrically imaged, for the first time, breakdown spots in standard MOS devices (silicon dioxide insulator with polysilicon gates) with two conductive atomic force microscopy (C-AFM) tools. The study provides insight into the local nature of oxide degradation, where initial breakdown affects an area that is a function of breakdown hardness and the applied current. With a simple modification to an AFM tool, the C-AFM provides a practical method for observing oxide breakdown. The researchers reported on their findings at the IEEE's 40th annual International Reliability Physics Symposium held in Dallas in May.