Variation; key issue of the advanced CMOS & LSI´s

The problem of V,ι, local variations for the state-of-art MOSFETs imposes a limit on the scaling of the technologies, and therefore, it is an urgent issue to understand causes and find solutions. The variety of the V_th local variation sources can be cited. However, the main causes of the V_th variability have not been confirmed yet. The investigations of the mechanism are crucial to improve the V_th local variation by deriving the new process/device technologies. In this paper, the status of the studies for the V_th variation has been presented. The results presented here come from the activities of "Robust Design of Transistors" program that started in 2006 in the framework of the MIRAI Project which is supported by NEDO.