Variability of random telegraph noise in analog MOS transistors

Random telegraph signals (RTS) are investigated on MOSFETs where a systematic procedure is developed to extract the RTS parameters from a large volume of multi-level switching events with a Poisson distribution. RTS measurements can be utilized to identify and characterize gate oxide defects with better resolution than frequency domain power spectral density, deep level transient spectroscopy, or charge pumping techniques. We demonstrate here multi-level RTS method to investigate gate dielectric trap characteristics including type (acceptor or donor), position of the traps from the of Si/SiO₂ interface in the oxide, and along the channel, using the effect of gate bias on the mean carrier capture and emission times, and the number of active traps.