Kinetics of the Slow‐Trapping Instability at the Si / SiO2 Interface

The slow‐trapping instability can be a potentially major threat to reliability of p‐channel enhancement‐mode IGFET's. We have determined the kinetics of slow trapping for Al‐gate MOS structures on (111) n‐Si and evaluated the role of surface states, , for n‐ and p‐type Si of (111) and (100) orientation. Slow trapping, as revealed by negative bias‐temperature aging, generates a characteristic distribution of with a peak near the midgap. This effect is responsible for the fact that for n‐Si, the threshold shift, , the flatband shift, and for p‐Si, . In the regime where is less than the saturation value, our data on slow‐trapping kinetics can be represented by the factorial relationship where is the applied negative bias (10–40V), is the time (10–10 3 min), is the temperature (373°–573°K), is the Boltzmann constant, , , and is the thermal activation energy (∼0.64 eV). This equation emphasizes the strong field dependence of at lower temperatures.