Analysis, measurement, and simulation of dynamic write inhibit in an nvSRAM cell

Dynamic write inhibit (DWI) is a method of selectively inhibiting the programming (writing) of nonvolatile semiconductor memory cells. Its primary use is in silicon nitride oxide semiconductor (SNOS) and metal nitride oxide semiconductor (MNOS) memories, although it may be generalized to other nonvolatile technologies. This technique is based on a mechanism generally known as deep-depletion channel shielding (DDCS). A characterization of this phenomenon from the vantage points of analytic, experimental, and numerical simulations is presented. In addition, a brief review of the literature and the introduction of a novel memory cell used in a 64K nonvolatile static random access memory (nvSRAM) demonstrate the need for this better physical understanding