The Origins of Random Telegraph Noise in Highly Scaled SiON nMOSFETs

Random telegraph noise (RTN) has recently become an important issue in advanced circuit performance. It has also recently been used as a tool for gate dielectric defect profiling. In this work, we show that the widely accepted model thought to govern RTN behavior cannot be used to describe our experimental observations. The basis of this model (charge exchange between inversion layer and bulk oxide defects via tunneling) is inconsistent with our RTN observations on advanced SiON nMOSFETs with 1.4 nm physical gate oxide thickness. Alternatively, we show that RTN is qualitatively consistent with the capture and emission of inversion charge by interface states. Our results suggest that a large body of the low-frequency noise literature very likely needs to be re-interpreted.