학술논문
Origin of Post-Irradiation Vₜₕ-Shift Variability in 3-D NAND Memory Array
Document Type
Periodical
Author
Source
IEEE Transactions on Nuclear Science IEEE Trans. Nucl. Sci. Nuclear Science, IEEE Transactions on. 71(4):405-411 Apr, 2024
Subject
Language
ISSN
0018-9499
1558-1578
1558-1578
Abstract
In this article, we report total-ionizing-dose (TID)-induced threshold-voltage ( ${V}_{\text {th}}$ ) shift characteristics of commercial-off-the-shelf (COTS) 64-layer 3-D NAND flash memory chips. Our measurements of cell ${V}_{\text {th}}$ distributions after irradiation up to 50 krad(Si) indicate that significant ${V}_{\text {th}}$ -shift variability exists among the memory cells of the chip. We find that a certain fraction of cells is very responsive to ionizing irradiation while a significant amount of the cells stays surprisingly resilient. We model the TID-tolerance behavior of these cells using pre-existing trap states in the tunnel oxide and provide three independent supporting evidence.