Some conventional embedded flash memory devices utilize a split gate floating gate device with source side junction Fowler-Nordheim (FN) tunnel erase to provide page erase functionality. These memory cells have limited scalability. For example, a conventional 0.18 um embedded flash memory cell cannot be scaled due to the source erase option. In general, the source junction needs to be graded enough to improve the post cycling induced read current degradation. Since the graded source junction takes a large portion of the channel region area to prevent punch-through of the device, the cell cannot be scaled accordingly. Moreover, the cell size is not small enough to be competitive in many flash memory devices, and the application is limited.
USPTO Backgrounds
USPTO Backgrounds