PULSE CONTROL FOR NONVOLATILE MEMORY

摘要

This disclosure provides a nonvolatile memory device that uses pulsed control and rest periods to mitigate the formation of defect precursors. A first embodiment uses pulsed bitline control, where the coupling between a memory cell channel and a reference voltage (selected in response to the bitline) is pulsed when it is desired to change state in the associated memory cell. Each pulse may be chosen to be less than about (20) nanoseconds, while a "rest period" between pulses typically is chosen to be on the order of about a hundred nanoseconds or greater (e.g., one microsecond). Because bitline control is used, very short rise times can be enabled, enabling generation of pulse durations of (50) nanoseconds or less. In other embodiments, these methods may also be more generally applied to other conductors (e.g., wordline or substrate well, for program or erase operations); if desired, segmented wordlines or bitlines may also be used, to minimize RC loading and enable sufficiently short rise times to make pulses robust.