Integration scheme for 3D NAND with nonreplacement word line and its cell characteristics investigation
Jiang Liu, Chang Seok Kang, Ashish Pal, El Mehdi Bazizi, Tomohiko Kitajima, Nancy Fung, Gabriela Alva, Amy Child, Bhaskar Bhuyan, Takehito Koshizawa, Sung-Kwan Kang, Gill Lee, David K. Hwang, Blessy Alexander, Buvna Ayyagari · 2021
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.