广东工业大学 信息工程学院,广东,广州,510006
林训涛(2000–),男,硕士研究生,主要研究方向为3D NAND闪存器件建模与NAND特性分析,E-mail:1986254495@qq.com
韩国军(1974–),男,教授,博士,主要研究方向为信息论与差错控制编译码技术、储存器件与系统、智能通信与车联网等,E-mail:gjhan@gdut.edu.cn
纸质出版:2026
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林训涛, 韩国军. 融合沟道倾斜角的3D NAND存储单元建模及编程策略优化[J]. 广东工业大学学报, 2026, 43(2): 91-100.
林训涛, 韩国军. 融合沟道倾斜角的3D NAND存储单元建模及编程策略优化[J]. 广东工业大学学报, 2026, 43(2): 91-100. DOI: 10.12052/gdutxb.250167.
随着3D NAND闪存堆叠层数的不断增加,深孔刻蚀工艺造成的深宽比也相应增加,由此形成的沟道倾斜角导致存储单元阈值电压分布展宽,影响了器件存储可靠性。当前针对该问题的解决方案主要包括刻蚀优化、沟道补偿等工艺方法,以及纠错编码、读重试等策略,然而这些方法普遍面临实现复杂、硬件开销大等问题。为克服上述局限性并有效地降低倾斜角的影响,本文首先基于 Sentaurus TCAD 平台构建了含倾斜角的存储串仿真模型,验证分析了深孔倾角对阈值电压分布梯度的影响,在此基础上,提出了一种相邻单元导通电压幅度动态调整的策略,该策略根据目标存储单元在存储串中的垂直位置,差异化调整其相邻字线的导通电压值,以精准补偿因沟道倾斜引起的纵向电压梯度。仿真结果表明,本文所提出的编程策略与传统编程策略相比,在线性调节模式下,最大电压差与分布标准差分别降低了62.4%与61.4%;在非线性调节模式下,二者分别降低了 63.7%与 64.3%,同时将相邻单元的阈值电压扰动控制在 3 mV以内,且在不同编程时间下写入速率保持稳定。
With the continuous increase in the number of stacking layers in 3D NAND flash memory
the aspect ratio caused by deep hole etching processes also increases accordingly. The resulting taper angle leads to a broadening of the threshold voltage distribution of memory cells
adversely affecting device storage reliability. Current solutions to this problem primarily include process-based methods such as etching optimization and channel compensation
or strategies like error correction coding and read-retry. However
these approaches generally face challenges such as implementation complexity and high hardware overhead. To overcome these limitations and effectively mitigate the impact of the taper angle
a simulation model of a memory string incorporating taper angles is first constructed based on the Sentaurus TCAD platform
validating and analyzing the influence of deep hole taper on the threshold voltage distribution gradient. On this basis
a strategy for dynamic optimization of the pass voltage amplitude in adjacent cells is proposed. This strategy differentially optimizes the pass voltage of word lines adjacent to the target memory cell according to its vertical position in the memory string
thereby accurately compensating for the longitudinal voltage gradient induced by channel taper. Simulation results demonstrate that compared to conventional programming strategy
the proposed strategy optimizes the maximum voltage difference and the standard deviation of distribution
achieving reductions of 62.4% and 61.4%
respectively
in linear mode
and 63.7% and 64.3% in nonlinear mode
while constraining the threshold voltage disturbance of adjacent cells within 3 mV and maintaining stable programming speed.
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