Impact of the free electron distribution on the random telegraph signal capture kinetics in submicron n-metal–oxide–semiconductor field-effect transistors

In this letter, the role of the free electron distribution on the capture kinetics of repulsive random telegraph signals in deep submicron n-channel metal–oxide–semiconductor field-effect transistors is studied. The inversion layer density and profile is varied by changing simultaneously the substrate and the gate bias of the transistor which is in linear operation at a constant drain current I. Detailed results are obtained for a class of repulsive trap centers when charged by an electron, which show a I−m variation of the capture time constant, with m>1. Such a nonstandard behavior can be understood in the framework of the Coulomb blockade model, whereby the image charge of the trapped carrier is stored on the gate electrode and in the inversion and depletion layer in the silicon substrate. As is shown here the capture time constant is a unique function of the ratio of the inversion layer surface density and the squared thickness of the inversion layer.