TBD prediction from low-voltage near-interfacetrap-assisted tunneling current measurements

In this paper, we present a new method to predict oxide breakdown directly from measurements at low voltage and room temperature, therefore without the need for any voltage/field extrapolation. Previously, it has been shown that in ultrathin oxide (t_ox<2 nm) MOS devices with high substrate doping (N_A >10¹⁸ cm^-13) a current component of cathode electrons tunneling into anode near-interface traps (TNIT) is present when the applied voltage is between zero and the flat-band voltage. Here, we show that there is a correlation between this TNIT component and oxide breakdown. Then, we introduce a new method exploiting this correlation to predict oxide lifetime from stress measurements at the real operation conditions without any questionable voltage/field extrapolation. The results are consistent with other extrapolation techniques. However, the present methodology is particularly suitable for T_BD characterization of future technologies since, as the scaling process continues, TNIT will be more and more important and visible, while the traditional techniques to assess oxide defects (like capacitance-voltage (C-V) or stress-induced leakage current (SILC) measurements) or to directly detect breakdown will become less feasible