Defect-tolerant logic hardening for crossbar-based nanosystems

Crossbar-based architectures are promising for the future nanoelectronic systems. However, due to the inherent unreliability of nanoscale devices, the implementation of any logic functions relies on aggressive defect-tolerant schemes applied at the post-manufacturing stage. Most of such defect-tolerant approaches explore mapping choices between logic variables/products and crossbar vertical/horizontal wires. In this paper, we develop a new approach, namely fine-grained logic hardening, based on the idea of adding redundancies into a logic function so as to boost the success rate of logic implementation. We propose an analytical framework to evaluate and fine-tune the amount and location of redundancy to be added for a given logic function. Furthermore, we devise a method to optimally harden the logic function so as to maximize the defect tolerance capability. Simulation results show that the proposed logic hardening scheme boosts defect tolerance capability significantly in yield improvement, compared to mapping-only schemes with the same amount of hardware cost.