This work investigates the impact of geometric distortion on random telegraph noise (RTN)–induced threshold-voltage shift (ΔVt) in 3D NAND flash memory using TCAD simulations. Elliptical-shaped cells with varying circularity are analyzed under multiple program and erase conditions, revealing stronger and nonmonotonic RTN behavior in geometrically asymmetric cells. A modified program verify (PV) distribution is proposed to mitigate RTN effects, demonstrating reduced ΔVt variation and improved reliability, particularly in bottom word-line cells.