Memory Device Intermediate Select Gate Lines Read Disturbance

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Solution Overview

Problem

Current NAND type flash memory devices face challenges in improving operation characteristics, such as reducing reading disturbance and capacitance components, which affect power consumption and operation speed, due to the complexity of controlling select gate lines and array layers in three-dimensional memory cell arrays.

Innovation Solution

The implementation of intermediate select gate lines and transistors between memory cells allows for electrical separation of array layers during read operations, reducing parasitic capacitance and enhancing control over electrical connections, thereby improving operation efficiency and memory density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If intermediate select gate lines and transistors are added to enable electrical separation of array layers, then reading disturbance and parasitic capacitance are reduced, but device structure and wiring complexity increase

Engineering Contradiction:
Improvereading disturbance reductionVSAvoidselect gate line structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The memory device divides the select gate lines into multiple independent segments: first select gate lines connected to first select transistors, second select gate lines connected to second select transistors, and intermediate select gate lines connected to intermediate select transistors. This segmentation allows independent control of each array layer, enabling electrical separation during read operations to reduce reading disturbance and parasitic capacitance between layers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Intermediate select gate lines and intermediate select transistors are introduced as intermediary elements between the first and second array layers. These intermediaries provide independent control over the electrical connections between array layers, allowing selective isolation of layers during read operations to reduce parasitic capacitance and reading disturbance without requiring complete redesign of the memory structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If multiple select gate lines and array layers are used to increase memory density, then capacitance components and power consumption increase, but the number of required wirings and structural complexity increase

Engineering Contradiction:
Improvememory densityVSAvoidpower consumption
Core Design Contradiction:
Quantity of substanceVSUse of energy by stationary object

Solution Approach 1:

The memory device segments the array layers into first and second array layers with independent select gate line control. This allows selective activation of only the necessary array layers during read operations, reducing the number of simultaneously active transistors and thereby reducing total power consumption while maintaining high memory density through vertical stacking.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The memory device dynamically controls the electrical connections between array layers by selectively activating first select transistors, second select transistors, and intermediate select transistors based on read operation requirements. This dynamic control optimizes power consumption by minimizing the number of active electrical paths while maintaining high memory density through multi-layer architecture.

Inventive Principle:
Principle #15Dynamics

3Speed

If array layers are electrically separated during read operations, then operation speed and efficiency are improved, but control complexity over electrical connections increases

Engineering Contradiction:
Improveoperation speedVSAvoidelectrical connection control
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The memory device segments control of electrical connections into independent groups: first select gate lines for first select transistors, second select gate lines for second select transistors, and intermediate select gate lines for intermediate select transistors. This segmentation simplifies control logic by allowing independent activation of specific array layers during read operations, improving operation speed through reduced interference while maintaining manageable control complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Intermediate select gate lines serve as intermediary control elements that simplify the management of electrical connections between array layers. By introducing these intermediaries, the device achieves electrical separation for improved read speed while maintaining straightforward control logic, as each intermediate select gate line directly controls the connection state between specific layers without requiring complex multi-variable control.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS11990190B2Memory device to execute read operation using read target voltage
Publication Date: 2024.05.21 KIOXIA CORP
  • US11990190B2 patent drawing
  • US11990190B2 patent drawing
  • US11990190B2 patent drawing

AI summary

A memory device includes first and second memory strings, first and second word lines and a controller. The first memory string includes first and second memory cells, a first select transistor, a second select transistor, and a third select transistor between the first and second memory cells. The second memory string includes third and fourth memory cells, a fourth select transistor above the third memory cell, a fifth select transistor below the fourth memory cell, and a sixth select transistor between the third and fourth memory cells. The first word line is electrically connected to gates of the first and third memory cells. The second word line is electrically connected to gates of the second and fourth memory cells. The controller is configured to execute a read operation on one of the memory cells, the read operation including a first phase and a second phase after the first phase.