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 field oxides of metal-oxide-semiconductor field-effect transistors are thermally activated. The activation energy and the frequency factor are related to the relaxation time constant by an Arrhenius law. A simple measurement of the relaxation time constant defines the activation energy, frequency factor (E, nu) pair. Choosing arbitrarily a ''realistic'' frequency factor corresponds to determining a characteristic energy, on which depends any subsequent annealing prediction. A controversy exists about the appropriate value of nu for silicon dioxide, with published values ranging from 1x10(7) to 1x10(14) s(-1). In this paper, a new method is presented that yields values for both frequency factor and activation energy. This method leads to an unexpectedly low (but consistent) value of nu (about 1x10(7) s(-1)) when applied to three different devices, obtained from three different manufacturers. The experimental procedure and the results for all three cases are presented and discussed. (C) 1997 American Institute of Physics.