CORRELATION OF STRESS-INDUCED LEAKAGE CURRENT IN THIN OXIDES WITH TRAP GENERATION INSIDE THE OXIDES

It has been observed that the low-level pre-tunneling leakage currents in thin oxides increased after the oxides had been subjected to high voltage stresses. These increases in the pre-tunneling currents have b een correlated with the number of traps generated inside of the oxides by the high-voltage stresses. The densities of the stress-generated t raps inside of the oxides were calculated using the tunneling front mo del and analyzing the transient currents that flowed through the oxide s after removal of the stress voltage pulses. It was found that the st ress-generated trap distributions were relatively uniform throughout t he small portion of the oxide sampled by the transient currents. The t rap densities increased as the cube root of the fluence of electrons t hat had passed through the oxide during the stress, independent of the stress polarity. The voltage dependence of the low-level pre-tunnelin g current was dependent on the sequence in which the stress voltage po larities and the low-level current measurement polarities were applied , The portion of the low-level pre-tunneling current that was not depe ndent on the polarity sequence was best fitted by a voltage dependence consistent with Schottky emission.