Origin of random telegraph noise in silicon-based devices: Insights from first-principles study

The microscopic origin of random telegraph noise (RTN) in semiconductor devices remains a subject of debate. Previous studies proposed several hypotheses involving phosphorus–vacancy center and oxygen–vacancy centers, while recent experimental evidence indicates that it may be due to electrically active defects formed by the addition of carbon. In this work, first-principles calculations based on density functional theory are performed to systematically investigate the structural configurations, formation energetics, charge-state transition levels, and migration behaviors of carbon-related defects. Both carbon interstitial (Ci) and CiCs pairs exhibit multiple metastable configurations with distinct charge-state transition levels, leading to pronounced variations in their contribution to carrier recombination. Furthermore, the low migration barriers between metastable states suggest frequent structural conversions, which provide a mechanistic explanation for the two-level RTN behaviors observed in experiments. By directly correlating atomistic defect behavior and macroscopic RTN characteristics, this study provides a fundamental framework for understanding defect-induced RTN in semiconductor devices. These findings provide an essential theoretical foundation for the development of strategies to suppress RTN in advanced semiconductor technologies.