Vertical Memory Cell String Dielectric Body Segmentation
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Solution Overview
Problem
Three-dimensional (3D) memory devices, such as 3D NAND memory devices, face the risk of failure during voltage boosting operations due to select-gate snapback under high electric fields, leading to excessive hole generation and accumulation, which can cause boosting failure.
Innovation Solution
The introduction of a dielectric structure in the memory cell string that suppresses hole accumulation by partially blocking the channel, reducing the risk of boosting failure during voltage boosting operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a high electric field is imposed on the select gate during voltage boosting operation, then voltage boosting capability is improved, but select-gate snapback occurs leading to excessive hole generation and accumulation
Solution Approach 1:
A dielectric layer is introduced as an intermediary between the select gate and the channel body. This dielectric layer mediates the electric field distribution, preventing direct high field exposure of the channel while maintaining gate control, thereby suppressing hole generation and accumulation during voltage boosting operations
Solution Approach 2:
The patent modifies the electrical parameters by introducing a dielectric material with specific permittivity properties. This changes the electric field distribution and potential profile in the channel, enabling voltage boosting while controlling the electric field strength to prevent snapback and hole accumulation
2Device complexity
If the channel is left floating to maintain simple structure, then device complexity is reduced, but boosting failure risk increases due to hole accumulation
Solution Approach 1:
The dielectric layer serves as a mediator that allows the channel to remain structurally simple and floating while preventing the harmful effects of complete floating. It provides controlled electrical interaction without requiring complex doping or connection structures
Solution Approach 2:
The channel body is segmented into different regions with respect to dielectric coverage. The dielectric is positioned to cover specific portions of the channel body adjacent to the select gate, providing localized protection against hole accumulation while maintaining channel continuity and simplicity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution effectively reduces the accumulation of holes, thereby minimizing the risk of boosting collapse and enhancing the reliability of 3D memory devices during voltage boosting operations.
Implementation Method 1
a dielectric in a portion of the body
Data Source
AI summary
Some embodiments include a memory cell string having a body having a channel extending therein and in contact with a source/drain, a select gate adjacent to the body, a plurality of access lines adjacent to the body, and a dielectric in a portion of the body between the source/drain and a level corresponding to an end of the plurality of access lines most adjacent to the select gate. The dielectric in the portion of the body does not extend along an entire length of the body. Other embodiments are described and claimed.