Impact of endurance degradation on the programming efficiency and the energy consumption of NOR flash memories

摘要

In this paper the impact of the endurance degradation on the programming window and the energy consumption of flash floating gate memories is investigated. Using a new measurement technique we characterized the evolution of the dynamic drain current during the channel hot electron programming through the cycling. This experimental method has been developed for 90 nm technology node flash floating gate memories, but it is fully compatible with the highly scaled devices. We define the programming efficiency as a new figure of merit to evaluate the performances of flash memories and we demonstrate why this decreases during the cell aging. Moreover we confirm that the efficiency optimization point varies with the cell degradation. Finally, with a complete set of measurements, we show that our experimental protocol enables the understanding of the role of defects generation on the programming efficiency of NOR flash memories for embedded low energy applications.