Statistical evaluation of random telegraph signal amplitudes in sub-mu m MOSFETs

The amplitudes of random telegraph signals (RTSs) caused by individual traps at the Si-SiO2 interface of sub-pm MOSFETs depend on the channel non-uniformities and, in particular, on the current distribution in the immediate vicinity of the trap. We find that to a good approximation an RTS amplitude is proportional to the square of the local current density. RTS amplitudes may thus be used as atomic current probes. By the evaluation of 187 RTS amplitudes in different MOSFETs of the same type we deduce for the first time a histogram showing the probability distribution of the spatial current density in such devices.