Integration scheme for 3D NAND with nonreplacement word line and its cell characteristics investigation

We demonstrate an integration scheme for a 3D NAND memory cell with non-replacement word line (WL) by investigating the cell characteristics, including program, erase, retention, and interference based on our in-house process and device flow of 3D NAND memory arrays. The non-replacement WL is called WL-First in which P+ polysilicon is implemented as the gate material. We investigate the figures of merits of the WL-First scheme compared with the WL-Last scheme, which uses metal as the gate material.