학술논문

Azimuthal Charge Redistribution of Hemi-Cylindrical Vertical NAND Flash Memory
Document Type
Periodical
Source
IEEE Electron Device Letters IEEE Electron Device Lett. Electron Device Letters, IEEE. 44(6):931-934 Jun, 2023
Subject
Engineered Materials, Dielectrics and Plasmas
Components, Circuits, Devices and Systems
Flash memories
Electron traps
Tunneling
Three-dimensional displays
Data models
SONOS devices
Analytical models
Hemi-cylindrical vertical NAND (HC VNAND)
channel hole remaining ratio (CHRR)
azimuthal redistribution (AR)
data retention
Language
ISSN
0741-3106
1558-0563
Abstract
The reliability issues of the hemi-cylindrical (HC) vertical NAND (VNAND) flash memory are investigated with various channel hole remaining ratios (CHRRs). Unlike conventional VNAND cells, carriers are nonuniformly injected to the charge-trapping layer in the case of HC VNAND during program/erase operations. Hence, in addition to conventional lateral migration, a novel charge redistribution mechanism—-azimuthal redistribution (AR)—-is proposed. The simulation and experimental results indicate that AR is a major component of the data retention as a function of the CHRR of HC VNAND cells.