In this letter, evidence is given for a new class of random telegraph signals (RTSs) in submicron n-metal-oxide-semiconductor field-effect transistors (n-MOSFETs). These two-level fluctuations not only occur when the MOSFET is biased in linear operation but also when it is operated in the source or drain-substrate diode mode. A detailed investigation of the RTS parameters. i.e., the amplitude, the emission, and the capture time constants, reveal a close correlation with the current through the forward biased drain- (or source-) substrate diode. At the same time, from the substrate bias dependence of the trap characteristics, it is inferred that it behaves like a near-interface oxide trap. From this, it is concluded that the most likely position is along the channel width perimeter, at the isolation edges of the transistors and close to the source or drain junction. (C) 1997 Academic Institute of Physics.