Low-voltage hot electrons and soft-programming lifetime prediction in nonvolatile memory cells

This paper reports experiments and Monte Carlo (MC) simulations of flash me mory cells at the typical bias conditions of read operations (high V-GS and low V-DS) leading to the soft-programming phenomenon. Comparing experiment s with simulations we first show that, differently from the previously repo rted ease of homogeneous injection experiments, efficient energy gain mecha nisms must be invoked to explain the order of magnitude of gate (I-G) and s ubstrate (I-B) currents at low voltage, Second, the voltage scaling behavio r of the soft-programming lifetime is analyzed and the validity of usual ex trapolation techniques to evaluate this parameter is addressed.