Analysis of cell characteristics depending on vertical channel profile and multiple dielectric WL space in 3D NAND flash memory

Abstract Convex and concave channel structures are formed due to the increase in the number of layers of 3D NAND flash, along with the limitations of the technology to etch holes in the channel. Program, interference, and retention characteristics of convex and concave structures are investigated. The program and interference characteristics are improved in the convex structure due to the concentrated E-field in the word line. The retention characteristics are improved in the concave structure due to the dispersed E-field. In addition, various space materials are considered to confirm cell characteristics according to the dielectric constant, and it is found that these characteristics are improved when air space is used.