Quantitative analysis of SILCs (stress-induced leakage currents) based on the inelastic trap-assisted tunneling model

Abstract

We have successfully developed a new quantitative analytical ITAT-based SILC model which can explain both of the two field dependencies, i.e. Fowler-Nordheim (FN)-field and the direct tunneling (DT)-field dependent of A-mode and B-mode SILCs. While DT-field dependence of A-mode comes from the single trap assisted tunneling, FN-field dependence of B- mode originates at the tunneling via the multi-trap leakage path. We have also developed an analytical model for the anomalous SILC of the flash memory cell and investigate the properties of retention lifetime of failure bits. The anomalous SILC shows the DT-field dependence because of the tunneling via the incomplete multi-trap path. A remarkable behavior of retention characteristics predicted by our models is a nearly logarithmic time dependence. The Fowler- Nordheim tunneling model leads to an overestimation of lifetime at low Vth region. To take into account a position of each trap and clarify the detail characteristics of SILC, we have proposed a new Monte Carlo like approach for hopping conduction and successfully explained the anomalous SILC using only physical based parameters.