VALENCE ALTERNATION PAIR MODEL OF CHARGE STORAGE IN MNOS MEMORY DEVICES

Certain point defects in amorphous silicon nitride called valence alternation pairs (VAP) appear to be able to account not only for the charge storage and decay characteristics of MNOS memory devices but also for the fatigue phenomena that occur in these devices after undergoing a sufficiently large number of write-erase operations. The theory and properties of VAP defects in the nitride are described. A model for the MNOS memory device based on the existence of VAP defects in the nitride is proposed. Charge storage, decay, and fatigue characteristics of MNOS devices are explained in terms of the model.