Statistical Analysis and Modeling of Random Telegraph Noise Based on Gate Delay Measurement

We propose a characterization methodology for random telegraph noise (RTN) based on gate delay measurement. To convert delay change to MOSFET threshold voltage fluctuation, Delta V-T, a topology-reconfigurable ring oscillator is utilized. We discuss the issue of detecting RTN-induced discrete fluctuations in the delay and develop a kernel density-based method to detect the fluctuations. Characterization results of several RTN properties from a test chip fabricated in a 65 nm bulk process are presented. Particular focus is given on the suitable distribution to present RTN-induced overall Delta V-T distribution and its gate area dependency. The results show that lognormal distribution is better at representing the total Delta V-T distribution. RTN-induced delay fluctuation of 40% has been observed for a single gate under weak inversion operation. Local process variation and RTN amplitude are found to be uncorrelated. The proposed methodology is thus suitable for characterizing RTN of devices operating under switching condition.