Reliability of Mo as Word Line Metal in 3D NAND

We evaluate the reliability of Mo as word line metal for 3-D NAND Flash devices, by mimicking the stacked architecture using planar capacitors with SiO ₂ /Al ₂ O ₃ and SiO ₂ /HfO ₂ dielectric stacks. By combining TDDB and TVS measurements with simulations, we show that Mo does not drift in the two examined stacks. Moreover, our study highlights the importance of controlling the defectivity at the SiO ₂ /high-k interface and within the high-k to avoid the risk of early dielectric breakdown.