RANDOM TELEGRAPH SIGNAL - AN ATOMIC PROBE OF THE LOCAL CURRENT IN FIELD-EFFECT TRANSISTORS

The switching amplitude of random telegraph signals (RTSs) caused by t rapping a single electron at an individual interface defect is studied in sub-mu m-sized metal oxide field-effect transistors (MOSFETs). The amplitudes of RTSs depend on the channel nonuniformity and, in partic ular, on the current distribution in the immediate vicinity of the tra p. We find that to a good approximation the RTS amplitude is proportio nal to the square of the local current density. This mathematical rela tion is tested and verified with the help of a computer simulation. RT S amplitudes may thus be used as atomic probes of the local current de nsity. By the evaluation of 187 RTS amplitudes in different MOSFETs of the same type, we deduce for the first time a histogram showing the m agnitude distribution of the local current density in such devices. (C ) 1998 American Institute of Physics. [S0021-8979(98)09403-1].