(a) Transfer curves of the ONFGM device in the initial and a series of post-P/E operations at various of V_P/V_E voltages in a time of 5 s. The inset shows the shifts in transfer curves during P operations at V_GS ranging from −5 V to −30 V. (b) Corresponding variations of charge stored in the poly-Si floating gate in logarithmic coordinates and the inset in linear coordinates during P operation and (c) E operation. (d) Memory windows for various V_P and V_E voltages.