Defect-tolerant N²-transistor structure for reliable nanoelectronic designs

Nanodevices-based circuit design will be based on the acceptance that a high percentage of devices in the design will be defective. This study investigates a defect-tolerant technique that adds redundancy at the transistor level and provides built-in immunity to permanent defects (stuck-open, stuck-short and bridges). The proposed technique is based on replacing each transistor by N²-transistor structure (N≥2) that guarantees defect tolerance of all N-1 defects as validated by theoretical analysis and simulation. As demonstrated by extensive simulation results using ISCAS 85 and 89 benchmark circuits, the investigated technique achieves significantly higher defect tolerance than recently reported nanoelectronics defect-tolerant techniques (even with up to 4-5 times more transistor defect probability) and at reduced area overhead. For example, the quadded-transistor structure technique requires nearly half the area of the quadded-logic technique.