This work investigates the effect of channel engineering on the short channel performance of considered sub-20-nm 3D NAND flash memory. Here, the threshold voltage roll-off (ΔVth), subthreshold swing and drain induced barrier lowering metrics is studied to evaluate the short channel effects (SCEs) for the examined device. The effect of variation in doping density on SCEs of proposed channel engineered NAND flash memory is also studied. Based on the observation, a thin layer of high doping concentration in the centre of the channel, covering 25% of channel area, has been found to improve the SCE of NAND flash memory compared with the device with uniform channel doping while maintaining sufficient drive current.