High energy oxide traps and anomalous soft-programming in flash memories

We study the energy location of traps responsible for anomalous stress-induced leakage current (SILC) in flash cells. Experimental technique based on the analysis of the SILC under injection of drain-accelerated electrons is presented. We provide evidence for the existence of high-energy traps assisting the leakage process, sensing also the electron energy at the SILC spot and verifying that this energy correlates with the position along the channel. Finally, the behavior of SILC-affected cells under soft-programming condition is discussed with reference to the energy location of oxide traps.