QuickTrace: An Efficient Contour Tracing Algorithm for Defect Robustness Simulation of Silicon Dangling Bond Logic

As traditional transistor scaling reaches its physical and economic limits, Silicon Dangling Bond (SiDB) logic is emerging as a promising post-CMOS technology for atomic-scale computation. However, despite mitigation efforts, atomic defects persist on the hydrogen-passivated silicon surface and remain challenging to eliminate. Since SiDB logic is highly sensitive to these charged atomic defects, efficient defect robustness simulation is essential for reliable SiDB logic design and successful operation. Existing simulation methods, however, are inefficient, limiting their practical applicability. To address this shortcoming, we present QuickTrace, an efficient algorithm to simulate the defect robustness of SiDB logic. QuickTrace uses contour tracing to identify the boundary in the simulation area between operational and non-operational states caused by defect positions, allowing defect robustness to be simulated with significantly fewer simulator calls. Experimental evaluations show that QuickTrace precisely and accurately computes defect robustness while avoiding the need to consider 88% of potential defect positions in simulations—and thus reducing runtime by the same percentage—compared to the state-of-the-art approach. This enables efficient and scalable defect robustness simulation of SiDB logic for the first time, contributing to the advancement of SiDB technology as a promising post-CMOS technology.