3D Memory Cell Strings With Direct Channel-to-Tier Coupling

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Solution Overview

Problem

Existing memory array technologies face challenges in efficiently forming memory cells with optimal contact areas and electrical coupling between channel material and conductor material, particularly in narrower trenches and thinner conductive tiers, which can affect the performance and reliability of memory arrays.

Innovation Solution

The method involves forming channel-material-string constructions through alternating insulative and conductive tiers, comprising charge-blocking, storage, and charge-passage materials, with the channel material directly electrically coupled to the conductor tier, ensuring optimal contact and electrical coupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional memory cell formation methods are used, then manufacturing process is simpler, but contact area and electrical coupling between channel material and conductor material are insufficient

Engineering Contradiction:

Improveelectrical couplingVSAvoidformation process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The method performs preliminary actions by forming the channel material string construction with conductor material tiers and insulative material tiers in a specific sequence before finalizing the memory cell structure. The conductor material is deposited in first and second tiers with insulative material between them, preparing the electrical coupling pathway in advance to ensure optimal contact area and electrical coupling between channel material and conductor material.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If narrower trenches and thinner conductive tiers are used, then memory array density is improved, but contact area and electrical coupling are reduced

Engineering Contradiction:

Improvememory array densityVSAvoidelectrical coupling

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The method transitions from a single-layer conductor structure to a multi-tier vertical structure. By stacking conductor material tiers and insulative material tiers vertically, the invention increases the contact area and electrical coupling in the vertical dimension while maintaining narrow trench widths, thus achieving both high density and reliable electrical coupling.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The invention uses composite material structures by combining conductor material and insulative material in alternating tiers. This composite approach allows for optimized electrical coupling through the conductor-insulator-conductor stacking, where the insulative material provides electrical isolation while the conductor material tiers provide multiple contact interfaces with the channel material, enhancing overall reliability without increasing trench width.

Inventive Principle:

Principle #40Composite materials

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

This approach enhances the contact area and electrical coupling between channel and conductor materials, improving the performance and reliability of memory arrays, particularly in narrower trenches and thinner conductive tiers.

Implementation Method 1

a charge-blocking-material string (85), a storage-material string (87) laterally-inward of the charge-blocking-material string

Methodology Applied

Scientific EffectCharge blocking:

Implementation Method 2

a charge-passage-material string (89) laterally-inward of the storage-material string (87)

Methodology Applied

Scientific EffectCharge passage:

Implementation Method 3

Conductive material is formed in the lowest first tier that directly electrically couples together the channel material of individual of the channel-material strings and the conductor material of the conductor tier

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS12396172B2Memory arrays comprising strings of memory cells and methods used in forming a memory array comprising strings of memory cells

Publication Date: 2025.08.19 MICRON TECHNOLOGY INC

AI summary

A memory array comprising strings of memory cells comprises laterally-spaced memory-blocks individually comprising a vertical stack comprising alternating insulative tiers and conductive tiers directly above conductor material of a conductor tier. Channel-material-string constructions extend through the insulative and conductive tiers to a lowest of the conductive tiers. The channel-material-string constructions individually comprise a charge-blocking-material string, a storage-material string laterally-inward of the charge-blocking-material string, a charge-passage-material string laterally-inward of the storage-material string, and a channel-material string laterally-inward of the charge-passage-material string. A lowest surface of the charge-blocking-material string that is above a lowest surface of the lowest conductive tier is below a lowest surface of a lowest of the insulative tiers that is immediately-above the lowest conductive tier. Conductive material in the lowest conductive tier directly electrically couples together the channel material of individual of the channel-material strings and the conductor material of the conductor tier. Structure independent of method is disclosed.