Processing math: 100%
Channel Thickness and Grain Size Engineering for Improvement of Variability and Performance in 3-D NAND Flash Memory | IEEE Journals & Magazine | IEEE Xplore

Channel Thickness and Grain Size Engineering for Improvement of Variability and Performance in 3-D NAND Flash Memory


Abstract:

In this study, to improve the threshold voltage ( {V}_{\text {th}} ) variability and cell performance in three-dimensional (3-D) NAND flash memory, we analyzed the elec...Show More

Abstract:

In this study, to improve the threshold voltage ( {V}_{\text {th}} ) variability and cell performance in three-dimensional (3-D) NAND flash memory, we analyzed the electrical characteristics with respect to various channel thickness ( {T}_{\textsf {ch}} ) and average grain size (GS) values. The 3-D random Voronoi grain patterns were applied to a polycrystalline silicon (poly-Si) channel to determine the actual grain shape using technology computer-aided design (TCAD). For statistical analysis, key electrical characteristics such as the threshold voltage ( {V}_{\textsf {th}} ), subthreshold swing (SS), maximum transconductance ( {g}_{m} ), and on-current ( I_{\mathrm{\scriptscriptstyle ON}} ) were extracted from samples with different patterns of grain boundaries (GBs) at specific {T}_{\text {ch}} and GS values. The standard deviation of {V}_{\text {th}} ( \sigma {V}_{\text {th}} ) increased with an increase in GS at {T}_{\text {ch}} >22 nm, and no increase trend was observed for \sigma {V}_{\text {th}} at {T}_{\text {ch}} < 22 nm. The mean SS, {g}_{m} , and I_{\mathrm{\scriptscriptstyle ON}} related to the performance improved overall with an increase in GS at the same {T}_{\textsf {ch}} value. Based on a comprehensive analysis of various 3-D grain patterns, optimal structures were proposed in terms of variability and/or performance. Furthermore, based on the results, we suggest suitable {T}_{\textsf {ch}} and GS parameters for the given target of 3-D NAND flash devices.
Published in: IEEE Transactions on Electron Devices ( Volume: 69, Issue: 7, July 2022)
Page(s): 3681 - 3687
Date of Publication: 25 May 2022

ISSN Information:

Funding Agency:


Contact IEEE to Subscribe

References

References is not available for this document.