Influence of Intercell Trapped Charge on Vertical NAND Flash Memory

The influence of intercell trapped charge (ITC)—the charge trapped at the inter-cell nitride regions by fringe electric fields during program and erase operations—on vertical NAND (VNAND) flash memory is investigated. In addition to conventional degradation mechanisms such as tunnel oxide damage, ITC deteriorates the transconductance and read current of VNAND flash memory cells. The influence of ITC-induced degradation on VNAND flash memory is discussed, using both simulation and experimental results. A solution for ITC suppression is also proposed: the use of low-k intercell regions.