THE RELAXATION PHENOMENA OF POSITIVE CHARGES IN THIN GATE OXIDE DURING FOWLER-NORDHEIM TUNNELING STRESS

In this study, new relaxation phenomena of positive charges in gate ox ide with Fowler-Nordheim (FN) constant current injections have been in vestigated and characterized. It was found that the magnitudes of appl ied gate voltage shifts (Delta V-FN) during FN injections, after posit ive charges relaxed or discharged, have a logarithmic dependence with the relaxation time for both injection polarities, The results can der ive the relationship of transient discharging currents, that flow thro ugh the oxides after removal of the stress voltage, with the relaxatio n time. We have shown that the current has a lit dependence for both i njection polarities which can be also derived from the tunneling front model. The effects of oxide fields (lower than the necessary voltage for FN tunneling) and wafer temperatures (373 and 423 K) for the relax ation of positive charges are also studied.