Low-Overhead Defect Tolerance in Crossbar Nanoarchitectures
It is anticipated that the number of defects in nanoscale devices fabricated using bottom-up self-assembly process is significantly higher than that for CMOS devices fabricated by conventional top-down lithography patterning. This is mainly because of inherent lack of control in self-assembly fabrication as well as atomic scale of devices. The goal of defect tolerance, as an integral part of nano computing, is to obtain error-free computation from such fabrics containing defective elements. In this article, an application-independent defect tolerant scheme for reconfigurable crossbar array nanoarchitectures is presented. The main feature of this approach is that the existence and location of defective resources within the nano-fabric are hidden from the entire design flow, resulting in minimum post-fabrication customization per chip and minimum changes to the entire design and synthesis flow. It is also shown how to drastically minimize the area overhead associated with this flow. The proposed technique requires extraction of regular yet incomplete defect-free subsets, in contrast to previously proposed complete defect-free subsets. This can greatly reduce the area overhead required for defect tolerance while not sacrificing logic mapping or signal routing capabilities. Extensive simulation results confirm considerable reduction in the area overhead without any negative impact on the usability of modified defect-free subsets.
defect tolerance nanotechnology reconfigurable architectures