EXPERIMENTAL-DETERMINATION OF THE FREQUENCY FACTOR OF THERMAL ANNEALING PROCESSES IN METAL-OXIDE-SEMICONDUCTOR GATE-OXIDE STRUCTURES

Radiation-induced trapped charge annealing processes in the gate and f ield oxides of metal-oxide-semiconductor field-effect transistors are thermally activated. The activation energy and the frequency factor ar e related to the relaxation time constant by an Arrhenius law. A simpl e measurement of the relaxation time constant defines the activation e nergy, frequency factor (E, nu) pair. Choosing arbitrarily a ''realist ic'' frequency factor corresponds to determining a characteristic ener gy, on which depends any subsequent annealing prediction. A controvers y exists about the appropriate value of nu for silicon dioxide, with p ublished values ranging from 1x10(7) to 1x10(14) s(-1). In this paper, a new method is presented that yields values for both frequency facto r and activation energy. This method leads to an unexpectedly low (but consistent) value of nu (about 1x10(7) s(-1)) when applied to three d ifferent devices, obtained from three different manufacturers. The exp erimental procedure and the results for all three cases are presented and discussed. (C) 1997 American Institute of Physics.